[karo-tx-linux.git] / drivers / usb / host / xhci.c

/*
 * xHCI host controller driver
 *
 * Copyright (C) 2008 Intel Corp.
 *
 * Author: Sarah Sharp
 * Some code borrowed from the Linux EHCI driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/pci.h>
#include <linux/irq.h>
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/dmi.h>
#include <linux/dma-mapping.h>

#include "xhci.h"
#include "xhci-trace.h"
#include "xhci-mtk.h"

#define DRIVER_AUTHOR "Sarah Sharp"
#define DRIVER_DESC "'eXtensible' Host Controller (xHC) Driver"

#define PORT_WAKE_BITS  (PORT_WKOC_E | PORT_WKDISC_E | PORT_WKCONN_E)

/* Some 0.95 hardware can't handle the chain bit on a Link TRB being cleared */
static int link_quirk;
module_param(link_quirk, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(link_quirk, "Don't clear the chain bit on a link TRB");

static unsigned int quirks;
module_param(quirks, uint, S_IRUGO);
MODULE_PARM_DESC(quirks, "Bit flags for quirks to be enabled as default");

/* TODO: copied from ehci-hcd.c - can this be refactored? */
/*
 * xhci_handshake - spin reading hc until handshake completes or fails
 * @ptr: address of hc register to be read
 * @mask: bits to look at in result of read
 * @done: value of those bits when handshake succeeds
 * @usec: timeout in microseconds
 *
 * Returns negative errno, or zero on success
 *
 * Success happens when the "mask" bits have the specified value (hardware
 * handshake done).  There are two failure modes:  "usec" have passed (major
 * hardware flakeout), or the register reads as all-ones (hardware removed).
 */
int xhci_handshake(void __iomem *ptr, u32 mask, u32 done, int usec)
{
        u32     result;

        do {
                result = readl(ptr);
                if (result == ~(u32)0)          /* card removed */
                        return -ENODEV;
                result &= mask;
                if (result == done)
                        return 0;
                udelay(1);
                usec--;
        } while (usec > 0);
        return -ETIMEDOUT;
}

/*
 * Disable interrupts and begin the xHCI halting process.
 */
void xhci_quiesce(struct xhci_hcd *xhci)
{
        u32 halted;
        u32 cmd;
        u32 mask;

        mask = ~(XHCI_IRQS);
        halted = readl(&xhci->op_regs->status) & STS_HALT;
        if (!halted)
                mask &= ~CMD_RUN;

        cmd = readl(&xhci->op_regs->command);
        cmd &= mask;
        writel(cmd, &xhci->op_regs->command);
}

/*
 * Force HC into halt state.
 *
 * Disable any IRQs and clear the run/stop bit.
 * HC will complete any current and actively pipelined transactions, and
 * should halt within 16 ms of the run/stop bit being cleared.
 * Read HC Halted bit in the status register to see when the HC is finished.
 */
int xhci_halt(struct xhci_hcd *xhci)
{
        int ret;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Halt the HC");
        xhci_quiesce(xhci);

        ret = xhci_handshake(&xhci->op_regs->status,
                        STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
        if (ret) {
                xhci_warn(xhci, "Host halt failed, %d\n", ret);
                return ret;
        }
        xhci->xhc_state |= XHCI_STATE_HALTED;
        xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
        return ret;
}

/*
 * Set the run bit and wait for the host to be running.
 */
int xhci_start(struct xhci_hcd *xhci)
{
        u32 temp;
        int ret;

        temp = readl(&xhci->op_regs->command);
        temp |= (CMD_RUN);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Turn on HC, cmd = 0x%x.",
                        temp);
        writel(temp, &xhci->op_regs->command);

        /*
         * Wait for the HCHalted Status bit to be 0 to indicate the host is
         * running.
         */
        ret = xhci_handshake(&xhci->op_regs->status,
                        STS_HALT, 0, XHCI_MAX_HALT_USEC);
        if (ret == -ETIMEDOUT)
                xhci_err(xhci, "Host took too long to start, "
                                "waited %u microseconds.\n",
                                XHCI_MAX_HALT_USEC);
        if (!ret)
                /* clear state flags. Including dying, halted or removing */
                xhci->xhc_state = 0;

        return ret;
}

/*
 * Reset a halted HC.
 *
 * This resets pipelines, timers, counters, state machines, etc.
 * Transactions will be terminated immediately, and operational registers
 * will be set to their defaults.
 */
int xhci_reset(struct xhci_hcd *xhci)
{
        u32 command;
        u32 state;
        int ret, i;

        state = readl(&xhci->op_regs->status);

        if (state == ~(u32)0) {
                xhci_warn(xhci, "Host not accessible, reset failed.\n");
                return -ENODEV;
        }

        if ((state & STS_HALT) == 0) {
                xhci_warn(xhci, "Host controller not halted, aborting reset.\n");
                return 0;
        }

        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "// Reset the HC");
        command = readl(&xhci->op_regs->command);
        command |= CMD_RESET;
        writel(command, &xhci->op_regs->command);

        /* Existing Intel xHCI controllers require a delay of 1 mS,
         * after setting the CMD_RESET bit, and before accessing any
         * HC registers. This allows the HC to complete the
         * reset operation and be ready for HC register access.
         * Without this delay, the subsequent HC register access,
         * may result in a system hang very rarely.
         */
        if (xhci->quirks & XHCI_INTEL_HOST)
                udelay(1000);

        ret = xhci_handshake(&xhci->op_regs->command,
                        CMD_RESET, 0, 10 * 1000 * 1000);
        if (ret)
                return ret;

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                         "Wait for controller to be ready for doorbell rings");
        /*
         * xHCI cannot write to any doorbells or operational registers other
         * than status until the "Controller Not Ready" flag is cleared.
         */
        ret = xhci_handshake(&xhci->op_regs->status,
                        STS_CNR, 0, 10 * 1000 * 1000);

        for (i = 0; i < 2; i++) {
                xhci->bus_state[i].port_c_suspend = 0;
                xhci->bus_state[i].suspended_ports = 0;
                xhci->bus_state[i].resuming_ports = 0;
        }

        return ret;
}


#ifdef CONFIG_USB_PCI
/*
 * Set up MSI
 */
static int xhci_setup_msi(struct xhci_hcd *xhci)
{
        int ret;
        /*
         * TODO:Check with MSI Soc for sysdev
         */
        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);

        ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_MSI);
        if (ret < 0) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "failed to allocate MSI entry");
                return ret;
        }

        ret = request_irq(pdev->irq, xhci_msi_irq,
                                0, "xhci_hcd", xhci_to_hcd(xhci));
        if (ret) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "disable MSI interrupt");
                pci_free_irq_vectors(pdev);
        }

        return ret;
}

/*
 * Set up MSI-X
 */
static int xhci_setup_msix(struct xhci_hcd *xhci)
{
        int i, ret = 0;
        struct usb_hcd *hcd = xhci_to_hcd(xhci);
        struct pci_dev *pdev = to_pci_dev(hcd->self.controller);

        /*
         * calculate number of msi-x vectors supported.
         * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
         *   with max number of interrupters based on the xhci HCSPARAMS1.
         * - num_online_cpus: maximum msi-x vectors per CPUs core.
         *   Add additional 1 vector to ensure always available interrupt.
         */
        xhci->msix_count = min(num_online_cpus() + 1,
                                HCS_MAX_INTRS(xhci->hcs_params1));

        ret = pci_alloc_irq_vectors(pdev, xhci->msix_count, xhci->msix_count,
                        PCI_IRQ_MSIX);
        if (ret < 0) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "Failed to enable MSI-X");
                return ret;
        }

        for (i = 0; i < xhci->msix_count; i++) {
                ret = request_irq(pci_irq_vector(pdev, i), xhci_msi_irq, 0,
                                "xhci_hcd", xhci_to_hcd(xhci));
                if (ret)
                        goto disable_msix;
        }

        hcd->msix_enabled = 1;
        return ret;

disable_msix:
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "disable MSI-X interrupt");
        while (--i >= 0)
                free_irq(pci_irq_vector(pdev, i), xhci_to_hcd(xhci));
        pci_free_irq_vectors(pdev);
        return ret;
}

/* Free any IRQs and disable MSI-X */
static void xhci_cleanup_msix(struct xhci_hcd *xhci)
{
        struct usb_hcd *hcd = xhci_to_hcd(xhci);
        struct pci_dev *pdev = to_pci_dev(hcd->self.controller);

        if (xhci->quirks & XHCI_PLAT)
                return;

        /* return if using legacy interrupt */
        if (hcd->irq > 0)
                return;

        if (hcd->msix_enabled) {
                int i;

                for (i = 0; i < xhci->msix_count; i++)
                        free_irq(pci_irq_vector(pdev, i), xhci_to_hcd(xhci));
        } else {
                free_irq(pci_irq_vector(pdev, 0), xhci_to_hcd(xhci));
        }

        pci_free_irq_vectors(pdev);
        hcd->msix_enabled = 0;
}

static void __maybe_unused xhci_msix_sync_irqs(struct xhci_hcd *xhci)
{
        struct usb_hcd *hcd = xhci_to_hcd(xhci);

        if (hcd->msix_enabled) {
                struct pci_dev *pdev = to_pci_dev(hcd->self.controller);
                int i;

                for (i = 0; i < xhci->msix_count; i++)
                        synchronize_irq(pci_irq_vector(pdev, i));
        }
}

static int xhci_try_enable_msi(struct usb_hcd *hcd)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct pci_dev  *pdev;
        int ret;

        /* The xhci platform device has set up IRQs through usb_add_hcd. */
        if (xhci->quirks & XHCI_PLAT)
                return 0;

        pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
        /*
         * Some Fresco Logic host controllers advertise MSI, but fail to
         * generate interrupts.  Don't even try to enable MSI.
         */
        if (xhci->quirks & XHCI_BROKEN_MSI)
                goto legacy_irq;

        /* unregister the legacy interrupt */
        if (hcd->irq)
                free_irq(hcd->irq, hcd);
        hcd->irq = 0;

        ret = xhci_setup_msix(xhci);
        if (ret)
                /* fall back to msi*/
                ret = xhci_setup_msi(xhci);

        if (!ret) {
                hcd->msi_enabled = 1;
                return 0;
        }

        if (!pdev->irq) {
                xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
                return -EINVAL;
        }

 legacy_irq:
        if (!strlen(hcd->irq_descr))
                snprintf(hcd->irq_descr, sizeof(hcd->irq_descr), "%s:usb%d",
                         hcd->driver->description, hcd->self.busnum);

        /* fall back to legacy interrupt*/
        ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
                        hcd->irq_descr, hcd);
        if (ret) {
                xhci_err(xhci, "request interrupt %d failed\n",
                                pdev->irq);
                return ret;
        }
        hcd->irq = pdev->irq;
        return 0;
}

#else

static inline int xhci_try_enable_msi(struct usb_hcd *hcd)
{
        return 0;
}

static inline void xhci_cleanup_msix(struct xhci_hcd *xhci)
{
}

static inline void xhci_msix_sync_irqs(struct xhci_hcd *xhci)
{
}

#endif

static void compliance_mode_recovery(unsigned long arg)
{
        struct xhci_hcd *xhci;
        struct usb_hcd *hcd;
        u32 temp;
        int i;

        xhci = (struct xhci_hcd *)arg;

        for (i = 0; i < xhci->num_usb3_ports; i++) {
                temp = readl(xhci->usb3_ports[i]);
                if ((temp & PORT_PLS_MASK) == USB_SS_PORT_LS_COMP_MOD) {
                        /*
                         * Compliance Mode Detected. Letting USB Core
                         * handle the Warm Reset
                         */
                        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                        "Compliance mode detected->port %d",
                                        i + 1);
                        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                        "Attempting compliance mode recovery");
                        hcd = xhci->shared_hcd;

                        if (hcd->state == HC_STATE_SUSPENDED)
                                usb_hcd_resume_root_hub(hcd);

                        usb_hcd_poll_rh_status(hcd);
                }
        }

        if (xhci->port_status_u0 != ((1 << xhci->num_usb3_ports)-1))
                mod_timer(&xhci->comp_mode_recovery_timer,
                        jiffies + msecs_to_jiffies(COMP_MODE_RCVRY_MSECS));
}

/*
 * Quirk to work around issue generated by the SN65LVPE502CP USB3.0 re-driver
 * that causes ports behind that hardware to enter compliance mode sometimes.
 * The quirk creates a timer that polls every 2 seconds the link state of
 * each host controller's port and recovers it by issuing a Warm reset
 * if Compliance mode is detected, otherwise the port will become "dead" (no
 * device connections or disconnections will be detected anymore). Becasue no
 * status event is generated when entering compliance mode (per xhci spec),
 * this quirk is needed on systems that have the failing hardware installed.
 */
static void compliance_mode_recovery_timer_init(struct xhci_hcd *xhci)
{
        xhci->port_status_u0 = 0;
        setup_timer(&xhci->comp_mode_recovery_timer,
                    compliance_mode_recovery, (unsigned long)xhci);
        xhci->comp_mode_recovery_timer.expires = jiffies +
                        msecs_to_jiffies(COMP_MODE_RCVRY_MSECS);

        add_timer(&xhci->comp_mode_recovery_timer);
        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                        "Compliance mode recovery timer initialized");
}

/*
 * This function identifies the systems that have installed the SN65LVPE502CP
 * USB3.0 re-driver and that need the Compliance Mode Quirk.
 * Systems:
 * Vendor: Hewlett-Packard -> System Models: Z420, Z620 and Z820
 */
static bool xhci_compliance_mode_recovery_timer_quirk_check(void)
{
        const char *dmi_product_name, *dmi_sys_vendor;

        dmi_product_name = dmi_get_system_info(DMI_PRODUCT_NAME);
        dmi_sys_vendor = dmi_get_system_info(DMI_SYS_VENDOR);
        if (!dmi_product_name || !dmi_sys_vendor)
                return false;

        if (!(strstr(dmi_sys_vendor, "Hewlett-Packard")))
                return false;

        if (strstr(dmi_product_name, "Z420") ||
                        strstr(dmi_product_name, "Z620") ||
                        strstr(dmi_product_name, "Z820") ||
                        strstr(dmi_product_name, "Z1 Workstation"))
                return true;

        return false;
}

static int xhci_all_ports_seen_u0(struct xhci_hcd *xhci)
{
        return (xhci->port_status_u0 == ((1 << xhci->num_usb3_ports)-1));
}


/*
 * Initialize memory for HCD and xHC (one-time init).
 *
 * Program the PAGESIZE register, initialize the device context array, create
 * device contexts (?), set up a command ring segment (or two?), create event
 * ring (one for now).
 */
static int xhci_init(struct usb_hcd *hcd)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        int retval = 0;

        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "xhci_init");
        spin_lock_init(&xhci->lock);
        if (xhci->hci_version == 0x95 && link_quirk) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "QUIRK: Not clearing Link TRB chain bits.");
                xhci->quirks |= XHCI_LINK_TRB_QUIRK;
        } else {
                xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                                "xHCI doesn't need link TRB QUIRK");
        }
        retval = xhci_mem_init(xhci, GFP_KERNEL);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Finished xhci_init");

        /* Initializing Compliance Mode Recovery Data If Needed */
        if (xhci_compliance_mode_recovery_timer_quirk_check()) {
                xhci->quirks |= XHCI_COMP_MODE_QUIRK;
                compliance_mode_recovery_timer_init(xhci);
        }

        return retval;
}

/*-------------------------------------------------------------------------*/


static int xhci_run_finished(struct xhci_hcd *xhci)
{
        if (xhci_start(xhci)) {
                xhci_halt(xhci);
                return -ENODEV;
        }
        xhci->shared_hcd->state = HC_STATE_RUNNING;
        xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;

        if (xhci->quirks & XHCI_NEC_HOST)
                xhci_ring_cmd_db(xhci);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Finished xhci_run for USB3 roothub");
        return 0;
}

/*
 * Start the HC after it was halted.
 *
 * This function is called by the USB core when the HC driver is added.
 * Its opposite is xhci_stop().
 *
 * xhci_init() must be called once before this function can be called.
 * Reset the HC, enable device slot contexts, program DCBAAP, and
 * set command ring pointer and event ring pointer.
 *
 * Setup MSI-X vectors and enable interrupts.
 */
int xhci_run(struct usb_hcd *hcd)
{
        u32 temp;
        u64 temp_64;
        int ret;
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);

        /* Start the xHCI host controller running only after the USB 2.0 roothub
         * is setup.
         */

        hcd->uses_new_polling = 1;
        if (!usb_hcd_is_primary_hcd(hcd))
                return xhci_run_finished(xhci);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "xhci_run");

        ret = xhci_try_enable_msi(hcd);
        if (ret)
                return ret;

        xhci_dbg_cmd_ptrs(xhci);

        xhci_dbg(xhci, "ERST memory map follows:\n");
        xhci_dbg_erst(xhci, &xhci->erst);
        temp_64 = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
        temp_64 &= ~ERST_PTR_MASK;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "ERST deq = 64'h%0lx", (long unsigned int) temp_64);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Set the interrupt modulation register");
        temp = readl(&xhci->ir_set->irq_control);
        temp &= ~ER_IRQ_INTERVAL_MASK;
        /*
         * the increment interval is 8 times as much as that defined
         * in xHCI spec on MTK's controller
         */
        temp |= (u32) ((xhci->quirks & XHCI_MTK_HOST) ? 20 : 160);
        writel(temp, &xhci->ir_set->irq_control);

        /* Set the HCD state before we enable the irqs */
        temp = readl(&xhci->op_regs->command);
        temp |= (CMD_EIE);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Enable interrupts, cmd = 0x%x.", temp);
        writel(temp, &xhci->op_regs->command);

        temp = readl(&xhci->ir_set->irq_pending);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Enabling event ring interrupter %p by writing 0x%x to irq_pending",
                        xhci->ir_set, (unsigned int) ER_IRQ_ENABLE(temp));
        writel(ER_IRQ_ENABLE(temp), &xhci->ir_set->irq_pending);
        xhci_print_ir_set(xhci, 0);

        if (xhci->quirks & XHCI_NEC_HOST) {
                struct xhci_command *command;

                command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
                if (!command)
                        return -ENOMEM;

                xhci_queue_vendor_command(xhci, command, 0, 0, 0,
                                TRB_TYPE(TRB_NEC_GET_FW));
        }
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "Finished xhci_run for USB2 roothub");
        return 0;
}
EXPORT_SYMBOL_GPL(xhci_run);

/*
 * Stop xHCI driver.
 *
 * This function is called by the USB core when the HC driver is removed.
 * Its opposite is xhci_run().
 *
 * Disable device contexts, disable IRQs, and quiesce the HC.
 * Reset the HC, finish any completed transactions, and cleanup memory.
 */
static void xhci_stop(struct usb_hcd *hcd)
{
        u32 temp;
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);

        mutex_lock(&xhci->mutex);

        /* Only halt host and free memory after both hcds are removed */
        if (!usb_hcd_is_primary_hcd(hcd)) {
                /* usb core will free this hcd shortly, unset pointer */
                xhci->shared_hcd = NULL;
                mutex_unlock(&xhci->mutex);
                return;
        }

        spin_lock_irq(&xhci->lock);
        xhci->xhc_state |= XHCI_STATE_HALTED;
        xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
        xhci_halt(xhci);
        xhci_reset(xhci);
        spin_unlock_irq(&xhci->lock);

        xhci_cleanup_msix(xhci);

        /* Deleting Compliance Mode Recovery Timer */
        if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) &&
                        (!(xhci_all_ports_seen_u0(xhci)))) {
                del_timer_sync(&xhci->comp_mode_recovery_timer);
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "%s: compliance mode recovery timer deleted",
                                __func__);
        }

        if (xhci->quirks & XHCI_AMD_PLL_FIX)
                usb_amd_dev_put();

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Disabling event ring interrupts");
        temp = readl(&xhci->op_regs->status);
        writel((temp & ~0x1fff) | STS_EINT, &xhci->op_regs->status);
        temp = readl(&xhci->ir_set->irq_pending);
        writel(ER_IRQ_DISABLE(temp), &xhci->ir_set->irq_pending);
        xhci_print_ir_set(xhci, 0);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init, "cleaning up memory");
        xhci_mem_cleanup(xhci);
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "xhci_stop completed - status = %x",
                        readl(&xhci->op_regs->status));
        mutex_unlock(&xhci->mutex);
}

/*
 * Shutdown HC (not bus-specific)
 *
 * This is called when the machine is rebooting or halting.  We assume that the
 * machine will be powered off, and the HC's internal state will be reset.
 * Don't bother to free memory.
 *
 * This will only ever be called with the main usb_hcd (the USB3 roothub).
 */
static void xhci_shutdown(struct usb_hcd *hcd)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);

        if (xhci->quirks & XHCI_SPURIOUS_REBOOT)
                usb_disable_xhci_ports(to_pci_dev(hcd->self.sysdev));

        spin_lock_irq(&xhci->lock);
        xhci_halt(xhci);
        /* Workaround for spurious wakeups at shutdown with HSW */
        if (xhci->quirks & XHCI_SPURIOUS_WAKEUP)
                xhci_reset(xhci);
        spin_unlock_irq(&xhci->lock);

        xhci_cleanup_msix(xhci);

        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "xhci_shutdown completed - status = %x",
                        readl(&xhci->op_regs->status));

        /* Yet another workaround for spurious wakeups at shutdown with HSW */
        if (xhci->quirks & XHCI_SPURIOUS_WAKEUP)
                pci_set_power_state(to_pci_dev(hcd->self.sysdev), PCI_D3hot);
}

#ifdef CONFIG_PM
static void xhci_save_registers(struct xhci_hcd *xhci)
{
        xhci->s3.command = readl(&xhci->op_regs->command);
        xhci->s3.dev_nt = readl(&xhci->op_regs->dev_notification);
        xhci->s3.dcbaa_ptr = xhci_read_64(xhci, &xhci->op_regs->dcbaa_ptr);
        xhci->s3.config_reg = readl(&xhci->op_regs->config_reg);
        xhci->s3.erst_size = readl(&xhci->ir_set->erst_size);
        xhci->s3.erst_base = xhci_read_64(xhci, &xhci->ir_set->erst_base);
        xhci->s3.erst_dequeue = xhci_read_64(xhci, &xhci->ir_set->erst_dequeue);
        xhci->s3.irq_pending = readl(&xhci->ir_set->irq_pending);
        xhci->s3.irq_control = readl(&xhci->ir_set->irq_control);
}

static void xhci_restore_registers(struct xhci_hcd *xhci)
{
        writel(xhci->s3.command, &xhci->op_regs->command);
        writel(xhci->s3.dev_nt, &xhci->op_regs->dev_notification);
        xhci_write_64(xhci, xhci->s3.dcbaa_ptr, &xhci->op_regs->dcbaa_ptr);
        writel(xhci->s3.config_reg, &xhci->op_regs->config_reg);
        writel(xhci->s3.erst_size, &xhci->ir_set->erst_size);
        xhci_write_64(xhci, xhci->s3.erst_base, &xhci->ir_set->erst_base);
        xhci_write_64(xhci, xhci->s3.erst_dequeue, &xhci->ir_set->erst_dequeue);
        writel(xhci->s3.irq_pending, &xhci->ir_set->irq_pending);
        writel(xhci->s3.irq_control, &xhci->ir_set->irq_control);
}

static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)
{
        u64     val_64;

        /* step 2: initialize command ring buffer */
        val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
        val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
                (xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
                                      xhci->cmd_ring->dequeue) &
                 (u64) ~CMD_RING_RSVD_BITS) |
                xhci->cmd_ring->cycle_state;
        xhci_dbg_trace(xhci, trace_xhci_dbg_init,
                        "// Setting command ring address to 0x%llx",
                        (long unsigned long) val_64);
        xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
}

/*
 * The whole command ring must be cleared to zero when we suspend the host.
 *
 * The host doesn't save the command ring pointer in the suspend well, so we
 * need to re-program it on resume.  Unfortunately, the pointer must be 64-byte
 * aligned, because of the reserved bits in the command ring dequeue pointer
 * register.  Therefore, we can't just set the dequeue pointer back in the
 * middle of the ring (TRBs are 16-byte aligned).
 */
static void xhci_clear_command_ring(struct xhci_hcd *xhci)
{
        struct xhci_ring *ring;
        struct xhci_segment *seg;

        ring = xhci->cmd_ring;
        seg = ring->deq_seg;
        do {
                memset(seg->trbs, 0,
                        sizeof(union xhci_trb) * (TRBS_PER_SEGMENT - 1));
                seg->trbs[TRBS_PER_SEGMENT - 1].link.control &=
                        cpu_to_le32(~TRB_CYCLE);
                seg = seg->next;
        } while (seg != ring->deq_seg);

        /* Reset the software enqueue and dequeue pointers */
        ring->deq_seg = ring->first_seg;
        ring->dequeue = ring->first_seg->trbs;
        ring->enq_seg = ring->deq_seg;
        ring->enqueue = ring->dequeue;

        ring->num_trbs_free = ring->num_segs * (TRBS_PER_SEGMENT - 1) - 1;
        /*
         * Ring is now zeroed, so the HW should look for change of ownership
         * when the cycle bit is set to 1.
         */
        ring->cycle_state = 1;

        /*
         * Reset the hardware dequeue pointer.
         * Yes, this will need to be re-written after resume, but we're paranoid
         * and want to make sure the hardware doesn't access bogus memory
         * because, say, the BIOS or an SMI started the host without changing
         * the command ring pointers.
         */
        xhci_set_cmd_ring_deq(xhci);
}

static void xhci_disable_port_wake_on_bits(struct xhci_hcd *xhci)
{
        int port_index;
        __le32 __iomem **port_array;
        unsigned long flags;
        u32 t1, t2;

        spin_lock_irqsave(&xhci->lock, flags);

        /* disable usb3 ports Wake bits */
        port_index = xhci->num_usb3_ports;
        port_array = xhci->usb3_ports;
        while (port_index--) {
                t1 = readl(port_array[port_index]);
                t1 = xhci_port_state_to_neutral(t1);
                t2 = t1 & ~PORT_WAKE_BITS;
                if (t1 != t2)
                        writel(t2, port_array[port_index]);
        }

        /* disable usb2 ports Wake bits */
        port_index = xhci->num_usb2_ports;
        port_array = xhci->usb2_ports;
        while (port_index--) {
                t1 = readl(port_array[port_index]);
                t1 = xhci_port_state_to_neutral(t1);
                t2 = t1 & ~PORT_WAKE_BITS;
                if (t1 != t2)
                        writel(t2, port_array[port_index]);
        }

        spin_unlock_irqrestore(&xhci->lock, flags);
}

/*
 * Stop HC (not bus-specific)
 *
 * This is called when the machine transition into S3/S4 mode.
 *
 */
int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup)
{
        int                     rc = 0;
        unsigned int            delay = XHCI_MAX_HALT_USEC;
        struct usb_hcd          *hcd = xhci_to_hcd(xhci);
        u32                     command;

        if (!hcd->state)
                return 0;

        if (hcd->state != HC_STATE_SUSPENDED ||
                        xhci->shared_hcd->state != HC_STATE_SUSPENDED)
                return -EINVAL;

        /* Clear root port wake on bits if wakeup not allowed. */
        if (!do_wakeup)
                xhci_disable_port_wake_on_bits(xhci);

        /* Don't poll the roothubs on bus suspend. */
        xhci_dbg(xhci, "%s: stopping port polling.\n", __func__);
        clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
        del_timer_sync(&hcd->rh_timer);
        clear_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
        del_timer_sync(&xhci->shared_hcd->rh_timer);

        spin_lock_irq(&xhci->lock);
        clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
        clear_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);
        /* step 1: stop endpoint */
        /* skipped assuming that port suspend has done */

        /* step 2: clear Run/Stop bit */
        command = readl(&xhci->op_regs->command);
        command &= ~CMD_RUN;
        writel(command, &xhci->op_regs->command);

        /* Some chips from Fresco Logic need an extraordinary delay */
        delay *= (xhci->quirks & XHCI_SLOW_SUSPEND) ? 10 : 1;

        if (xhci_handshake(&xhci->op_regs->status,
                      STS_HALT, STS_HALT, delay)) {
                xhci_warn(xhci, "WARN: xHC CMD_RUN timeout\n");
                spin_unlock_irq(&xhci->lock);
                return -ETIMEDOUT;
        }
        xhci_clear_command_ring(xhci);

        /* step 3: save registers */
        xhci_save_registers(xhci);

        /* step 4: set CSS flag */
        command = readl(&xhci->op_regs->command);
        command |= CMD_CSS;
        writel(command, &xhci->op_regs->command);
        if (xhci_handshake(&xhci->op_regs->status,
                                STS_SAVE, 0, 10 * 1000)) {
                xhci_warn(xhci, "WARN: xHC save state timeout\n");
                spin_unlock_irq(&xhci->lock);
                return -ETIMEDOUT;
        }
        spin_unlock_irq(&xhci->lock);

        /*
         * Deleting Compliance Mode Recovery Timer because the xHCI Host
         * is about to be suspended.
         */
        if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) &&
                        (!(xhci_all_ports_seen_u0(xhci)))) {
                del_timer_sync(&xhci->comp_mode_recovery_timer);
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "%s: compliance mode recovery timer deleted",
                                __func__);
        }

        /* step 5: remove core well power */
        /* synchronize irq when using MSI-X */
        xhci_msix_sync_irqs(xhci);

        return rc;
}
EXPORT_SYMBOL_GPL(xhci_suspend);

/*
 * start xHC (not bus-specific)
 *
 * This is called when the machine transition from S3/S4 mode.
 *
 */
int xhci_resume(struct xhci_hcd *xhci, bool hibernated)
{
        u32                     command, temp = 0, status;
        struct usb_hcd          *hcd = xhci_to_hcd(xhci);
        struct usb_hcd          *secondary_hcd;
        int                     retval = 0;
        bool                    comp_timer_running = false;

        if (!hcd->state)
                return 0;

        /* Wait a bit if either of the roothubs need to settle from the
         * transition into bus suspend.
         */
        if (time_before(jiffies, xhci->bus_state[0].next_statechange) ||
                        time_before(jiffies,
                                xhci->bus_state[1].next_statechange))
                msleep(100);

        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &xhci->shared_hcd->flags);

        spin_lock_irq(&xhci->lock);
        if (xhci->quirks & XHCI_RESET_ON_RESUME)
                hibernated = true;

        if (!hibernated) {
                /* step 1: restore register */
                xhci_restore_registers(xhci);
                /* step 2: initialize command ring buffer */
                xhci_set_cmd_ring_deq(xhci);
                /* step 3: restore state and start state*/
                /* step 3: set CRS flag */
                command = readl(&xhci->op_regs->command);
                command |= CMD_CRS;
                writel(command, &xhci->op_regs->command);
                if (xhci_handshake(&xhci->op_regs->status,
                              STS_RESTORE, 0, 10 * 1000)) {
                        xhci_warn(xhci, "WARN: xHC restore state timeout\n");
                        spin_unlock_irq(&xhci->lock);
                        return -ETIMEDOUT;
                }
                temp = readl(&xhci->op_regs->status);
        }

        /* If restore operation fails, re-initialize the HC during resume */
        if ((temp & STS_SRE) || hibernated) {

                if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) &&
                                !(xhci_all_ports_seen_u0(xhci))) {
                        del_timer_sync(&xhci->comp_mode_recovery_timer);
                        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Compliance Mode Recovery Timer deleted!");
                }

                /* Let the USB core know _both_ roothubs lost power. */
                usb_root_hub_lost_power(xhci->main_hcd->self.root_hub);
                usb_root_hub_lost_power(xhci->shared_hcd->self.root_hub);

                xhci_dbg(xhci, "Stop HCD\n");
                xhci_halt(xhci);
                xhci_reset(xhci);
                spin_unlock_irq(&xhci->lock);
                xhci_cleanup_msix(xhci);

                xhci_dbg(xhci, "// Disabling event ring interrupts\n");
                temp = readl(&xhci->op_regs->status);
                writel((temp & ~0x1fff) | STS_EINT, &xhci->op_regs->status);
                temp = readl(&xhci->ir_set->irq_pending);
                writel(ER_IRQ_DISABLE(temp), &xhci->ir_set->irq_pending);
                xhci_print_ir_set(xhci, 0);

                xhci_dbg(xhci, "cleaning up memory\n");
                xhci_mem_cleanup(xhci);
                xhci_dbg(xhci, "xhci_stop completed - status = %x\n",
                            readl(&xhci->op_regs->status));

                /* USB core calls the PCI reinit and start functions twice:
                 * first with the primary HCD, and then with the secondary HCD.
                 * If we don't do the same, the host will never be started.
                 */
                if (!usb_hcd_is_primary_hcd(hcd))
                        secondary_hcd = hcd;
                else
                        secondary_hcd = xhci->shared_hcd;

                xhci_dbg(xhci, "Initialize the xhci_hcd\n");
                retval = xhci_init(hcd->primary_hcd);
                if (retval)
                        return retval;
                comp_timer_running = true;

                xhci_dbg(xhci, "Start the primary HCD\n");
                retval = xhci_run(hcd->primary_hcd);
                if (!retval) {
                        xhci_dbg(xhci, "Start the secondary HCD\n");
                        retval = xhci_run(secondary_hcd);
                }
                hcd->state = HC_STATE_SUSPENDED;
                xhci->shared_hcd->state = HC_STATE_SUSPENDED;
                goto done;
        }

        /* step 4: set Run/Stop bit */
        command = readl(&xhci->op_regs->command);
        command |= CMD_RUN;
        writel(command, &xhci->op_regs->command);
        xhci_handshake(&xhci->op_regs->status, STS_HALT,
                  0, 250 * 1000);

        /* step 5: walk topology and initialize portsc,
         * portpmsc and portli
         */
        /* this is done in bus_resume */

        /* step 6: restart each of the previously
         * Running endpoints by ringing their doorbells
         */

        spin_unlock_irq(&xhci->lock);

 done:
        if (retval == 0) {
                /* Resume root hubs only when have pending events. */
                status = readl(&xhci->op_regs->status);
                if (status & STS_EINT) {
                        usb_hcd_resume_root_hub(xhci->shared_hcd);
                        usb_hcd_resume_root_hub(hcd);
                }
        }

        /*
         * If system is subject to the Quirk, Compliance Mode Timer needs to
         * be re-initialized Always after a system resume. Ports are subject
         * to suffer the Compliance Mode issue again. It doesn't matter if
         * ports have entered previously to U0 before system's suspension.
         */
        if ((xhci->quirks & XHCI_COMP_MODE_QUIRK) && !comp_timer_running)
                compliance_mode_recovery_timer_init(xhci);

        /* Re-enable port polling. */
        xhci_dbg(xhci, "%s: starting port polling.\n", __func__);
        set_bit(HCD_FLAG_POLL_RH, &xhci->shared_hcd->flags);
        usb_hcd_poll_rh_status(xhci->shared_hcd);
        set_bit(HCD_FLAG_POLL_RH, &hcd->flags);
        usb_hcd_poll_rh_status(hcd);

        return retval;
}
EXPORT_SYMBOL_GPL(xhci_resume);
#endif  /* CONFIG_PM */

/*-------------------------------------------------------------------------*/

/**
 * xhci_get_endpoint_index - Used for passing endpoint bitmasks between the core and
 * HCDs.  Find the index for an endpoint given its descriptor.  Use the return
 * value to right shift 1 for the bitmask.
 *
 * Index  = (epnum * 2) + direction - 1,
 * where direction = 0 for OUT, 1 for IN.
 * For control endpoints, the IN index is used (OUT index is unused), so
 * index = (epnum * 2) + direction - 1 = (epnum * 2) + 1 - 1 = (epnum * 2)
 */
unsigned int xhci_get_endpoint_index(struct usb_endpoint_descriptor *desc)
{
        unsigned int index;
        if (usb_endpoint_xfer_control(desc))
                index = (unsigned int) (usb_endpoint_num(desc)*2);
        else
                index = (unsigned int) (usb_endpoint_num(desc)*2) +
                        (usb_endpoint_dir_in(desc) ? 1 : 0) - 1;
        return index;
}

/* The reverse operation to xhci_get_endpoint_index. Calculate the USB endpoint
 * address from the XHCI endpoint index.
 */
unsigned int xhci_get_endpoint_address(unsigned int ep_index)
{
        unsigned int number = DIV_ROUND_UP(ep_index, 2);
        unsigned int direction = ep_index % 2 ? USB_DIR_OUT : USB_DIR_IN;
        return direction | number;
}

/* Find the flag for this endpoint (for use in the control context).  Use the
 * endpoint index to create a bitmask.  The slot context is bit 0, endpoint 0 is
 * bit 1, etc.
 */
static unsigned int xhci_get_endpoint_flag(struct usb_endpoint_descriptor *desc)
{
        return 1 << (xhci_get_endpoint_index(desc) + 1);
}

/* Find the flag for this endpoint (for use in the control context).  Use the
 * endpoint index to create a bitmask.  The slot context is bit 0, endpoint 0 is
 * bit 1, etc.
 */
static unsigned int xhci_get_endpoint_flag_from_index(unsigned int ep_index)
{
        return 1 << (ep_index + 1);
}

/* Compute the last valid endpoint context index.  Basically, this is the
 * endpoint index plus one.  For slot contexts with more than valid endpoint,
 * we find the most significant bit set in the added contexts flags.
 * e.g. ep 1 IN (with epnum 0x81) => added_ctxs = 0b1000
 * fls(0b1000) = 4, but the endpoint context index is 3, so subtract one.
 */
unsigned int xhci_last_valid_endpoint(u32 added_ctxs)
{
        return fls(added_ctxs) - 1;
}

/* Returns 1 if the arguments are OK;
 * returns 0 this is a root hub; returns -EINVAL for NULL pointers.
 */
static int xhci_check_args(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint *ep, int check_ep, bool check_virt_dev,
                const char *func) {
        struct xhci_hcd *xhci;
        struct xhci_virt_device *virt_dev;

        if (!hcd || (check_ep && !ep) || !udev) {
                pr_debug("xHCI %s called with invalid args\n", func);
                return -EINVAL;
        }
        if (!udev->parent) {
                pr_debug("xHCI %s called for root hub\n", func);
                return 0;
        }

        xhci = hcd_to_xhci(hcd);
        if (check_virt_dev) {
                if (!udev->slot_id || !xhci->devs[udev->slot_id]) {
                        xhci_dbg(xhci, "xHCI %s called with unaddressed device\n",
                                        func);
                        return -EINVAL;
                }

                virt_dev = xhci->devs[udev->slot_id];
                if (virt_dev->udev != udev) {
                        xhci_dbg(xhci, "xHCI %s called with udev and "
                                          "virt_dev does not match\n", func);
                        return -EINVAL;
                }
        }

        if (xhci->xhc_state & XHCI_STATE_HALTED)
                return -ENODEV;

        return 1;
}

static int xhci_configure_endpoint(struct xhci_hcd *xhci,
                struct usb_device *udev, struct xhci_command *command,
                bool ctx_change, bool must_succeed);

/*
 * Full speed devices may have a max packet size greater than 8 bytes, but the
 * USB core doesn't know that until it reads the first 8 bytes of the
 * descriptor.  If the usb_device's max packet size changes after that point,
 * we need to issue an evaluate context command and wait on it.
 */
static int xhci_check_maxpacket(struct xhci_hcd *xhci, unsigned int slot_id,
                unsigned int ep_index, struct urb *urb)
{
        struct xhci_container_ctx *out_ctx;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_command *command;
        int max_packet_size;
        int hw_max_packet_size;
        int ret = 0;

        out_ctx = xhci->devs[slot_id]->out_ctx;
        ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
        hw_max_packet_size = MAX_PACKET_DECODED(le32_to_cpu(ep_ctx->ep_info2));
        max_packet_size = usb_endpoint_maxp(&urb->dev->ep0.desc);
        if (hw_max_packet_size != max_packet_size) {
                xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                                "Max Packet Size for ep 0 changed.");
                xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                                "Max packet size in usb_device = %d",
                                max_packet_size);
                xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                                "Max packet size in xHCI HW = %d",
                                hw_max_packet_size);
                xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                                "Issuing evaluate context command.");

                /* Set up the input context flags for the command */
                /* FIXME: This won't work if a non-default control endpoint
                 * changes max packet sizes.
                 */

                command = xhci_alloc_command(xhci, false, true, GFP_KERNEL);
                if (!command)
                        return -ENOMEM;

                command->in_ctx = xhci->devs[slot_id]->in_ctx;
                ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
                if (!ctrl_ctx) {
                        xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                        __func__);
                        ret = -ENOMEM;
                        goto command_cleanup;
                }
                /* Set up the modified control endpoint 0 */
                xhci_endpoint_copy(xhci, xhci->devs[slot_id]->in_ctx,
                                xhci->devs[slot_id]->out_ctx, ep_index);

                ep_ctx = xhci_get_ep_ctx(xhci, command->in_ctx, ep_index);
                ep_ctx->ep_info2 &= cpu_to_le32(~MAX_PACKET_MASK);
                ep_ctx->ep_info2 |= cpu_to_le32(MAX_PACKET(max_packet_size));

                ctrl_ctx->add_flags = cpu_to_le32(EP0_FLAG);
                ctrl_ctx->drop_flags = 0;

                ret = xhci_configure_endpoint(xhci, urb->dev, command,
                                true, false);

                /* Clean up the input context for later use by bandwidth
                 * functions.
                 */
                ctrl_ctx->add_flags = cpu_to_le32(SLOT_FLAG);
command_cleanup:
                kfree(command->completion);
                kfree(command);
        }
        return ret;
}

/*
 * non-error returns are a promise to giveback() the urb later
 * we drop ownership so next owner (or urb unlink) can get it
 */
static int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        unsigned long flags;
        int ret = 0;
        unsigned int slot_id, ep_index, ep_state;
        struct urb_priv *urb_priv;
        int num_tds;

        if (!urb || xhci_check_args(hcd, urb->dev, urb->ep,
                                        true, true, __func__) <= 0)
                return -EINVAL;

        slot_id = urb->dev->slot_id;
        ep_index = xhci_get_endpoint_index(&urb->ep->desc);

        if (!HCD_HW_ACCESSIBLE(hcd)) {
                if (!in_interrupt())
                        xhci_dbg(xhci, "urb submitted during PCI suspend\n");
                return -ESHUTDOWN;
        }

        if (usb_endpoint_xfer_isoc(&urb->ep->desc))
                num_tds = urb->number_of_packets;
        else if (usb_endpoint_is_bulk_out(&urb->ep->desc) &&
            urb->transfer_buffer_length > 0 &&
            urb->transfer_flags & URB_ZERO_PACKET &&
            !(urb->transfer_buffer_length % usb_endpoint_maxp(&urb->ep->desc)))
                num_tds = 2;
        else
                num_tds = 1;

        urb_priv = kzalloc(sizeof(struct urb_priv) +
                           num_tds * sizeof(struct xhci_td), mem_flags);
        if (!urb_priv)
                return -ENOMEM;

        urb_priv->num_tds = num_tds;
        urb_priv->num_tds_done = 0;
        urb->hcpriv = urb_priv;

        trace_xhci_urb_enqueue(urb);

        if (usb_endpoint_xfer_control(&urb->ep->desc)) {
                /* Check to see if the max packet size for the default control
                 * endpoint changed during FS device enumeration
                 */
                if (urb->dev->speed == USB_SPEED_FULL) {
                        ret = xhci_check_maxpacket(xhci, slot_id,
                                        ep_index, urb);
                        if (ret < 0) {
                                xhci_urb_free_priv(urb_priv);
                                urb->hcpriv = NULL;
                                return ret;
                        }
                }
        }

        spin_lock_irqsave(&xhci->lock, flags);

        if (xhci->xhc_state & XHCI_STATE_DYING) {
                xhci_dbg(xhci, "Ep 0x%x: URB %p submitted for non-responsive xHCI host.\n",
                         urb->ep->desc.bEndpointAddress, urb);
                ret = -ESHUTDOWN;
                goto free_priv;
        }

        switch (usb_endpoint_type(&urb->ep->desc)) {

        case USB_ENDPOINT_XFER_CONTROL:
                ret = xhci_queue_ctrl_tx(xhci, GFP_ATOMIC, urb,
                                         slot_id, ep_index);
                break;
        case USB_ENDPOINT_XFER_BULK:
                ep_state = xhci->devs[slot_id]->eps[ep_index].ep_state;
                if (ep_state & (EP_GETTING_STREAMS | EP_GETTING_NO_STREAMS)) {
                        xhci_warn(xhci, "WARN: Can't enqueue URB, ep in streams transition state %x\n",
                                  ep_state);
                        ret = -EINVAL;
                        break;
                }
                ret = xhci_queue_bulk_tx(xhci, GFP_ATOMIC, urb,
                                         slot_id, ep_index);
                break;


        case USB_ENDPOINT_XFER_INT:
                ret = xhci_queue_intr_tx(xhci, GFP_ATOMIC, urb,
                                slot_id, ep_index);
                break;

        case USB_ENDPOINT_XFER_ISOC:
                ret = xhci_queue_isoc_tx_prepare(xhci, GFP_ATOMIC, urb,
                                slot_id, ep_index);
        }

        if (ret) {
free_priv:
                xhci_urb_free_priv(urb_priv);
                urb->hcpriv = NULL;
        }
        spin_unlock_irqrestore(&xhci->lock, flags);
        return ret;
}

/*
 * Remove the URB's TD from the endpoint ring.  This may cause the HC to stop
 * USB transfers, potentially stopping in the middle of a TRB buffer.  The HC
 * should pick up where it left off in the TD, unless a Set Transfer Ring
 * Dequeue Pointer is issued.
 *
 * The TRBs that make up the buffers for the canceled URB will be "removed" from
 * the ring.  Since the ring is a contiguous structure, they can't be physically
 * removed.  Instead, there are two options:
 *
 *  1) If the HC is in the middle of processing the URB to be canceled, we
 *     simply move the ring's dequeue pointer past those TRBs using the Set
 *     Transfer Ring Dequeue Pointer command.  This will be the common case,
 *     when drivers timeout on the last submitted URB and attempt to cancel.
 *
 *  2) If the HC is in the middle of a different TD, we turn the TRBs into a
 *     series of 1-TRB transfer no-op TDs.  (No-ops shouldn't be chained.)  The
 *     HC will need to invalidate the any TRBs it has cached after the stop
 *     endpoint command, as noted in the xHCI 0.95 errata.
 *
 *  3) The TD may have completed by the time the Stop Endpoint Command
 *     completes, so software needs to handle that case too.
 *
 * This function should protect against the TD enqueueing code ringing the
 * doorbell while this code is waiting for a Stop Endpoint command to complete.
 * It also needs to account for multiple cancellations on happening at the same
 * time for the same endpoint.
 *
 * Note that this function can be called in any context, or so says
 * usb_hcd_unlink_urb()
 */
static int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
{
        unsigned long flags;
        int ret, i;
        u32 temp;
        struct xhci_hcd *xhci;
        struct urb_priv *urb_priv;
        struct xhci_td *td;
        unsigned int ep_index;
        struct xhci_ring *ep_ring;
        struct xhci_virt_ep *ep;
        struct xhci_command *command;
        struct xhci_virt_device *vdev;

        xhci = hcd_to_xhci(hcd);
        spin_lock_irqsave(&xhci->lock, flags);

        trace_xhci_urb_dequeue(urb);

        /* Make sure the URB hasn't completed or been unlinked already */
        ret = usb_hcd_check_unlink_urb(hcd, urb, status);
        if (ret)
                goto done;

        /* give back URB now if we can't queue it for cancel */
        vdev = xhci->devs[urb->dev->slot_id];
        urb_priv = urb->hcpriv;
        if (!vdev || !urb_priv)
                goto err_giveback;

        ep_index = xhci_get_endpoint_index(&urb->ep->desc);
        ep = &vdev->eps[ep_index];
        ep_ring = xhci_urb_to_transfer_ring(xhci, urb);
        if (!ep || !ep_ring)
                goto err_giveback;

        /* If xHC is dead take it down and return ALL URBs in xhci_hc_died() */
        temp = readl(&xhci->op_regs->status);
        if (temp == ~(u32)0 || xhci->xhc_state & XHCI_STATE_DYING) {
                xhci_hc_died(xhci);
                goto done;
        }

        if (xhci->xhc_state & XHCI_STATE_HALTED) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                "HC halted, freeing TD manually.");
                for (i = urb_priv->num_tds_done;
                     i < urb_priv->num_tds;
                     i++) {
                        td = &urb_priv->td[i];
                        if (!list_empty(&td->td_list))
                                list_del_init(&td->td_list);
                        if (!list_empty(&td->cancelled_td_list))
                                list_del_init(&td->cancelled_td_list);
                }
                goto err_giveback;
        }

        i = urb_priv->num_tds_done;
        if (i < urb_priv->num_tds)
                xhci_dbg_trace(xhci, trace_xhci_dbg_cancel_urb,
                                "Cancel URB %p, dev %s, ep 0x%x, "
                                "starting at offset 0x%llx",
                                urb, urb->dev->devpath,
                                urb->ep->desc.bEndpointAddress,
                                (unsigned long long) xhci_trb_virt_to_dma(
                                        urb_priv->td[i].start_seg,
                                        urb_priv->td[i].first_trb));

        for (; i < urb_priv->num_tds; i++) {
                td = &urb_priv->td[i];
                list_add_tail(&td->cancelled_td_list, &ep->cancelled_td_list);
        }

        /* Queue a stop endpoint command, but only if this is
         * the first cancellation to be handled.
         */
        if (!(ep->ep_state & EP_STOP_CMD_PENDING)) {
                command = xhci_alloc_command(xhci, false, false, GFP_ATOMIC);
                if (!command) {
                        ret = -ENOMEM;
                        goto done;
                }
                ep->ep_state |= EP_STOP_CMD_PENDING;
                ep->stop_cmd_timer.expires = jiffies +
                        XHCI_STOP_EP_CMD_TIMEOUT * HZ;
                add_timer(&ep->stop_cmd_timer);
                xhci_queue_stop_endpoint(xhci, command, urb->dev->slot_id,
                                         ep_index, 0);
                xhci_ring_cmd_db(xhci);
        }
done:
        spin_unlock_irqrestore(&xhci->lock, flags);
        return ret;

err_giveback:
        if (urb_priv)
                xhci_urb_free_priv(urb_priv);
        usb_hcd_unlink_urb_from_ep(hcd, urb);
        spin_unlock_irqrestore(&xhci->lock, flags);
        usb_hcd_giveback_urb(hcd, urb, -ESHUTDOWN);
        return ret;
}

/* Drop an endpoint from a new bandwidth configuration for this device.
 * Only one call to this function is allowed per endpoint before
 * check_bandwidth() or reset_bandwidth() must be called.
 * A call to xhci_drop_endpoint() followed by a call to xhci_add_endpoint() will
 * add the endpoint to the schedule with possibly new parameters denoted by a
 * different endpoint descriptor in usb_host_endpoint.
 * A call to xhci_add_endpoint() followed by a call to xhci_drop_endpoint() is
 * not allowed.
 *
 * The USB core will not allow URBs to be queued to an endpoint that is being
 * disabled, so there's no need for mutual exclusion to protect
 * the xhci->devs[slot_id] structure.
 */
static int xhci_drop_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct xhci_hcd *xhci;
        struct xhci_container_ctx *in_ctx, *out_ctx;
        struct xhci_input_control_ctx *ctrl_ctx;
        unsigned int ep_index;
        struct xhci_ep_ctx *ep_ctx;
        u32 drop_flag;
        u32 new_add_flags, new_drop_flags;
        int ret;

        ret = xhci_check_args(hcd, udev, ep, 1, true, __func__);
        if (ret <= 0)
                return ret;
        xhci = hcd_to_xhci(hcd);
        if (xhci->xhc_state & XHCI_STATE_DYING)
                return -ENODEV;

        xhci_dbg(xhci, "%s called for udev %p\n", __func__, udev);
        drop_flag = xhci_get_endpoint_flag(&ep->desc);
        if (drop_flag == SLOT_FLAG || drop_flag == EP0_FLAG) {
                xhci_dbg(xhci, "xHCI %s - can't drop slot or ep 0 %#x\n",
                                __func__, drop_flag);
                return 0;
        }

        in_ctx = xhci->devs[udev->slot_id]->in_ctx;
        out_ctx = xhci->devs[udev->slot_id]->out_ctx;
        ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return 0;
        }

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
        /* If the HC already knows the endpoint is disabled,
         * or the HCD has noted it is disabled, ignore this request
         */
        if ((GET_EP_CTX_STATE(ep_ctx) == EP_STATE_DISABLED) ||
            le32_to_cpu(ctrl_ctx->drop_flags) &
            xhci_get_endpoint_flag(&ep->desc)) {
                /* Do not warn when called after a usb_device_reset */
                if (xhci->devs[udev->slot_id]->eps[ep_index].ring != NULL)
                        xhci_warn(xhci, "xHCI %s called with disabled ep %p\n",
                                  __func__, ep);
                return 0;
        }

        ctrl_ctx->drop_flags |= cpu_to_le32(drop_flag);
        new_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags);

        ctrl_ctx->add_flags &= cpu_to_le32(~drop_flag);
        new_add_flags = le32_to_cpu(ctrl_ctx->add_flags);

        xhci_endpoint_zero(xhci, xhci->devs[udev->slot_id], ep);

        if (xhci->quirks & XHCI_MTK_HOST)
                xhci_mtk_drop_ep_quirk(hcd, udev, ep);

        xhci_dbg(xhci, "drop ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n",
                        (unsigned int) ep->desc.bEndpointAddress,
                        udev->slot_id,
                        (unsigned int) new_drop_flags,
                        (unsigned int) new_add_flags);
        return 0;
}

/* Add an endpoint to a new possible bandwidth configuration for this device.
 * Only one call to this function is allowed per endpoint before
 * check_bandwidth() or reset_bandwidth() must be called.
 * A call to xhci_drop_endpoint() followed by a call to xhci_add_endpoint() will
 * add the endpoint to the schedule with possibly new parameters denoted by a
 * different endpoint descriptor in usb_host_endpoint.
 * A call to xhci_add_endpoint() followed by a call to xhci_drop_endpoint() is
 * not allowed.
 *
 * The USB core will not allow URBs to be queued to an endpoint until the
 * configuration or alt setting is installed in the device, so there's no need
 * for mutual exclusion to protect the xhci->devs[slot_id] structure.
 */
static int xhci_add_endpoint(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        struct xhci_hcd *xhci;
        struct xhci_container_ctx *in_ctx;
        unsigned int ep_index;
        struct xhci_input_control_ctx *ctrl_ctx;
        u32 added_ctxs;
        u32 new_add_flags, new_drop_flags;
        struct xhci_virt_device *virt_dev;
        int ret = 0;

        ret = xhci_check_args(hcd, udev, ep, 1, true, __func__);
        if (ret <= 0) {
                /* So we won't queue a reset ep command for a root hub */
                ep->hcpriv = NULL;
                return ret;
        }
        xhci = hcd_to_xhci(hcd);
        if (xhci->xhc_state & XHCI_STATE_DYING)
                return -ENODEV;

        added_ctxs = xhci_get_endpoint_flag(&ep->desc);
        if (added_ctxs == SLOT_FLAG || added_ctxs == EP0_FLAG) {
                /* FIXME when we have to issue an evaluate endpoint command to
                 * deal with ep0 max packet size changing once we get the
                 * descriptors
                 */
                xhci_dbg(xhci, "xHCI %s - can't add slot or ep 0 %#x\n",
                                __func__, added_ctxs);
                return 0;
        }

        virt_dev = xhci->devs[udev->slot_id];
        in_ctx = virt_dev->in_ctx;
        ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return 0;
        }

        ep_index = xhci_get_endpoint_index(&ep->desc);
        /* If this endpoint is already in use, and the upper layers are trying
         * to add it again without dropping it, reject the addition.
         */
        if (virt_dev->eps[ep_index].ring &&
                        !(le32_to_cpu(ctrl_ctx->drop_flags) & added_ctxs)) {
                xhci_warn(xhci, "Trying to add endpoint 0x%x "
                                "without dropping it.\n",
                                (unsigned int) ep->desc.bEndpointAddress);
                return -EINVAL;
        }

        /* If the HCD has already noted the endpoint is enabled,
         * ignore this request.
         */
        if (le32_to_cpu(ctrl_ctx->add_flags) & added_ctxs) {
                xhci_warn(xhci, "xHCI %s called with enabled ep %p\n",
                                __func__, ep);
                return 0;
        }

        /*
         * Configuration and alternate setting changes must be done in
         * process context, not interrupt context (or so documenation
         * for usb_set_interface() and usb_set_configuration() claim).
         */
        if (xhci_endpoint_init(xhci, virt_dev, udev, ep, GFP_NOIO) < 0) {
                dev_dbg(&udev->dev, "%s - could not initialize ep %#x\n",
                                __func__, ep->desc.bEndpointAddress);
                return -ENOMEM;
        }

        if (xhci->quirks & XHCI_MTK_HOST) {
                ret = xhci_mtk_add_ep_quirk(hcd, udev, ep);
                if (ret < 0) {
                        xhci_free_or_cache_endpoint_ring(xhci,
                                virt_dev, ep_index);
                        return ret;
                }
        }

        ctrl_ctx->add_flags |= cpu_to_le32(added_ctxs);
        new_add_flags = le32_to_cpu(ctrl_ctx->add_flags);

        /* If xhci_endpoint_disable() was called for this endpoint, but the
         * xHC hasn't been notified yet through the check_bandwidth() call,
         * this re-adds a new state for the endpoint from the new endpoint
         * descriptors.  We must drop and re-add this endpoint, so we leave the
         * drop flags alone.
         */
        new_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags);

        /* Store the usb_device pointer for later use */
        ep->hcpriv = udev;

        xhci_dbg(xhci, "add ep 0x%x, slot id %d, new drop flags = %#x, new add flags = %#x\n",
                        (unsigned int) ep->desc.bEndpointAddress,
                        udev->slot_id,
                        (unsigned int) new_drop_flags,
                        (unsigned int) new_add_flags);
        return 0;
}

static void xhci_zero_in_ctx(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev)
{
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_slot_ctx *slot_ctx;
        int i;

        ctrl_ctx = xhci_get_input_control_ctx(virt_dev->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return;
        }

        /* When a device's add flag and drop flag are zero, any subsequent
         * configure endpoint command will leave that endpoint's state
         * untouched.  Make sure we don't leave any old state in the input
         * endpoint contexts.
         */
        ctrl_ctx->drop_flags = 0;
        ctrl_ctx->add_flags = 0;
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
        slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
        /* Endpoint 0 is always valid */
        slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(1));
        for (i = 1; i < 31; i++) {
                ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, i);
                ep_ctx->ep_info = 0;
                ep_ctx->ep_info2 = 0;
                ep_ctx->deq = 0;
                ep_ctx->tx_info = 0;
        }
}

static int xhci_configure_endpoint_result(struct xhci_hcd *xhci,
                struct usb_device *udev, u32 *cmd_status)
{
        int ret;

        switch (*cmd_status) {
        case COMP_COMMAND_ABORTED:
        case COMP_STOPPED:
                xhci_warn(xhci, "Timeout while waiting for configure endpoint command\n");
                ret = -ETIME;
                break;
        case COMP_RESOURCE_ERROR:
                dev_warn(&udev->dev,
                         "Not enough host controller resources for new device state.\n");
                ret = -ENOMEM;
                /* FIXME: can we allocate more resources for the HC? */
                break;
        case COMP_BANDWIDTH_ERROR:
        case COMP_SECONDARY_BANDWIDTH_ERROR:
                dev_warn(&udev->dev,
                         "Not enough bandwidth for new device state.\n");
                ret = -ENOSPC;
                /* FIXME: can we go back to the old state? */
                break;
        case COMP_TRB_ERROR:
                /* the HCD set up something wrong */
                dev_warn(&udev->dev, "ERROR: Endpoint drop flag = 0, "
                                "add flag = 1, "
                                "and endpoint is not disabled.\n");
                ret = -EINVAL;
                break;
        case COMP_INCOMPATIBLE_DEVICE_ERROR:
                dev_warn(&udev->dev,
                         "ERROR: Incompatible device for endpoint configure command.\n");
                ret = -ENODEV;
                break;
        case COMP_SUCCESS:
                xhci_dbg_trace(xhci, trace_xhci_dbg_context_change,
                                "Successful Endpoint Configure command");
                ret = 0;
                break;
        default:
                xhci_err(xhci, "ERROR: unexpected command completion code 0x%x.\n",
                                *cmd_status);
                ret = -EINVAL;
                break;
        }
        return ret;
}

static int xhci_evaluate_context_result(struct xhci_hcd *xhci,
                struct usb_device *udev, u32 *cmd_status)
{
        int ret;

        switch (*cmd_status) {
        case COMP_COMMAND_ABORTED:
        case COMP_STOPPED:
                xhci_warn(xhci, "Timeout while waiting for evaluate context command\n");
                ret = -ETIME;
                break;
        case COMP_PARAMETER_ERROR:
                dev_warn(&udev->dev,
                         "WARN: xHCI driver setup invalid evaluate context command.\n");
                ret = -EINVAL;
                break;
        case COMP_SLOT_NOT_ENABLED_ERROR:
                dev_warn(&udev->dev,
                        "WARN: slot not enabled for evaluate context command.\n");
                ret = -EINVAL;
                break;
        case COMP_CONTEXT_STATE_ERROR:
                dev_warn(&udev->dev,
                        "WARN: invalid context state for evaluate context command.\n");
                ret = -EINVAL;
                break;
        case COMP_INCOMPATIBLE_DEVICE_ERROR:
                dev_warn(&udev->dev,
                        "ERROR: Incompatible device for evaluate context command.\n");
                ret = -ENODEV;
                break;
        case COMP_MAX_EXIT_LATENCY_TOO_LARGE_ERROR:
                /* Max Exit Latency too large error */
                dev_warn(&udev->dev, "WARN: Max Exit Latency too large\n");
                ret = -EINVAL;
                break;
        case COMP_SUCCESS:
                xhci_dbg_trace(xhci, trace_xhci_dbg_context_change,
                                "Successful evaluate context command");
                ret = 0;
                break;
        default:
                xhci_err(xhci, "ERROR: unexpected command completion code 0x%x.\n",
                        *cmd_status);
                ret = -EINVAL;
                break;
        }
        return ret;
}

static u32 xhci_count_num_new_endpoints(struct xhci_hcd *xhci,
                struct xhci_input_control_ctx *ctrl_ctx)
{
        u32 valid_add_flags;
        u32 valid_drop_flags;

        /* Ignore the slot flag (bit 0), and the default control endpoint flag
         * (bit 1).  The default control endpoint is added during the Address
         * Device command and is never removed until the slot is disabled.
         */
        valid_add_flags = le32_to_cpu(ctrl_ctx->add_flags) >> 2;
        valid_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags) >> 2;

        /* Use hweight32 to count the number of ones in the add flags, or
         * number of endpoints added.  Don't count endpoints that are changed
         * (both added and dropped).
         */
        return hweight32(valid_add_flags) -
                hweight32(valid_add_flags & valid_drop_flags);
}

static unsigned int xhci_count_num_dropped_endpoints(struct xhci_hcd *xhci,
                struct xhci_input_control_ctx *ctrl_ctx)
{
        u32 valid_add_flags;
        u32 valid_drop_flags;

        valid_add_flags = le32_to_cpu(ctrl_ctx->add_flags) >> 2;
        valid_drop_flags = le32_to_cpu(ctrl_ctx->drop_flags) >> 2;

        return hweight32(valid_drop_flags) -
                hweight32(valid_add_flags & valid_drop_flags);
}

/*
 * We need to reserve the new number of endpoints before the configure endpoint
 * command completes.  We can't subtract the dropped endpoints from the number
 * of active endpoints until the command completes because we can oversubscribe
 * the host in this case:
 *
 *  - the first configure endpoint command drops more endpoints than it adds
 *  - a second configure endpoint command that adds more endpoints is queued
 *  - the first configure endpoint command fails, so the config is unchanged
 *  - the second command may succeed, even though there isn't enough resources
 *
 * Must be called with xhci->lock held.
 */
static int xhci_reserve_host_resources(struct xhci_hcd *xhci,
                struct xhci_input_control_ctx *ctrl_ctx)
{
        u32 added_eps;

        added_eps = xhci_count_num_new_endpoints(xhci, ctrl_ctx);
        if (xhci->num_active_eps + added_eps > xhci->limit_active_eps) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Not enough ep ctxs: "
                                "%u active, need to add %u, limit is %u.",
                                xhci->num_active_eps, added_eps,
                                xhci->limit_active_eps);
                return -ENOMEM;
        }
        xhci->num_active_eps += added_eps;
        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                        "Adding %u ep ctxs, %u now active.", added_eps,
                        xhci->num_active_eps);
        return 0;
}

/*
 * The configure endpoint was failed by the xHC for some other reason, so we
 * need to revert the resources that failed configuration would have used.
 *
 * Must be called with xhci->lock held.
 */
static void xhci_free_host_resources(struct xhci_hcd *xhci,
                struct xhci_input_control_ctx *ctrl_ctx)
{
        u32 num_failed_eps;

        num_failed_eps = xhci_count_num_new_endpoints(xhci, ctrl_ctx);
        xhci->num_active_eps -= num_failed_eps;
        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                        "Removing %u failed ep ctxs, %u now active.",
                        num_failed_eps,
                        xhci->num_active_eps);
}

/*
 * Now that the command has completed, clean up the active endpoint count by
 * subtracting out the endpoints that were dropped (but not changed).
 *
 * Must be called with xhci->lock held.
 */
static void xhci_finish_resource_reservation(struct xhci_hcd *xhci,
                struct xhci_input_control_ctx *ctrl_ctx)
{
        u32 num_dropped_eps;

        num_dropped_eps = xhci_count_num_dropped_endpoints(xhci, ctrl_ctx);
        xhci->num_active_eps -= num_dropped_eps;
        if (num_dropped_eps)
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Removing %u dropped ep ctxs, %u now active.",
                                num_dropped_eps,
                                xhci->num_active_eps);
}

static unsigned int xhci_get_block_size(struct usb_device *udev)
{
        switch (udev->speed) {
        case USB_SPEED_LOW:
        case USB_SPEED_FULL:
                return FS_BLOCK;
        case USB_SPEED_HIGH:
                return HS_BLOCK;
        case USB_SPEED_SUPER:
        case USB_SPEED_SUPER_PLUS:
                return SS_BLOCK;
        case USB_SPEED_UNKNOWN:
        case USB_SPEED_WIRELESS:
        default:
                /* Should never happen */
                return 1;
        }
}

static unsigned int
xhci_get_largest_overhead(struct xhci_interval_bw *interval_bw)
{
        if (interval_bw->overhead[LS_OVERHEAD_TYPE])
                return LS_OVERHEAD;
        if (interval_bw->overhead[FS_OVERHEAD_TYPE])
                return FS_OVERHEAD;
        return HS_OVERHEAD;
}

/* If we are changing a LS/FS device under a HS hub,
 * make sure (if we are activating a new TT) that the HS bus has enough
 * bandwidth for this new TT.
 */
static int xhci_check_tt_bw_table(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                int old_active_eps)
{
        struct xhci_interval_bw_table *bw_table;
        struct xhci_tt_bw_info *tt_info;

        /* Find the bandwidth table for the root port this TT is attached to. */
        bw_table = &xhci->rh_bw[virt_dev->real_port - 1].bw_table;
        tt_info = virt_dev->tt_info;
        /* If this TT already had active endpoints, the bandwidth for this TT
         * has already been added.  Removing all periodic endpoints (and thus
         * making the TT enactive) will only decrease the bandwidth used.
         */
        if (old_active_eps)
                return 0;
        if (old_active_eps == 0 && tt_info->active_eps != 0) {
                if (bw_table->bw_used + TT_HS_OVERHEAD > HS_BW_LIMIT)
                        return -ENOMEM;
                return 0;
        }
        /* Not sure why we would have no new active endpoints...
         *
         * Maybe because of an Evaluate Context change for a hub update or a
         * control endpoint 0 max packet size change?
         * FIXME: skip the bandwidth calculation in that case.
         */
        return 0;
}

static int xhci_check_ss_bw(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev)
{
        unsigned int bw_reserved;

        bw_reserved = DIV_ROUND_UP(SS_BW_RESERVED*SS_BW_LIMIT_IN, 100);
        if (virt_dev->bw_table->ss_bw_in > (SS_BW_LIMIT_IN - bw_reserved))
                return -ENOMEM;

        bw_reserved = DIV_ROUND_UP(SS_BW_RESERVED*SS_BW_LIMIT_OUT, 100);
        if (virt_dev->bw_table->ss_bw_out > (SS_BW_LIMIT_OUT - bw_reserved))
                return -ENOMEM;

        return 0;
}

/*
 * This algorithm is a very conservative estimate of the worst-case scheduling
 * scenario for any one interval.  The hardware dynamically schedules the
 * packets, so we can't tell which microframe could be the limiting factor in
 * the bandwidth scheduling.  This only takes into account periodic endpoints.
 *
 * Obviously, we can't solve an NP complete problem to find the minimum worst
 * case scenario.  Instead, we come up with an estimate that is no less than
 * the worst case bandwidth used for any one microframe, but may be an
 * over-estimate.
 *
 * We walk the requirements for each endpoint by interval, starting with the
 * smallest interval, and place packets in the schedule where there is only one
 * possible way to schedule packets for that interval.  In order to simplify
 * this algorithm, we record the largest max packet size for each interval, and
 * assume all packets will be that size.
 *
 * For interval 0, we obviously must schedule all packets for each interval.
 * The bandwidth for interval 0 is just the amount of data to be transmitted
 * (the sum of all max ESIT payload sizes, plus any overhead per packet times
 * the number of packets).
 *
 * For interval 1, we have two possible microframes to schedule those packets
 * in.  For this algorithm, if we can schedule the same number of packets for
 * each possible scheduling opportunity (each microframe), we will do so.  The
 * remaining number of packets will be saved to be transmitted in the gaps in
 * the next interval's scheduling sequence.
 *
 * As we move those remaining packets to be scheduled with interval 2 packets,
 * we have to double the number of remaining packets to transmit.  This is
 * because the intervals are actually powers of 2, and we would be transmitting
 * the previous interval's packets twice in this interval.  We also have to be
 * sure that when we look at the largest max packet size for this interval, we
 * also look at the largest max packet size for the remaining packets and take
 * the greater of the two.
 *
 * The algorithm continues to evenly distribute packets in each scheduling
 * opportunity, and push the remaining packets out, until we get to the last
 * interval.  Then those packets and their associated overhead are just added
 * to the bandwidth used.
 */
static int xhci_check_bw_table(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                int old_active_eps)
{
        unsigned int bw_reserved;
        unsigned int max_bandwidth;
        unsigned int bw_used;
        unsigned int block_size;
        struct xhci_interval_bw_table *bw_table;
        unsigned int packet_size = 0;
        unsigned int overhead = 0;
        unsigned int packets_transmitted = 0;
        unsigned int packets_remaining = 0;
        unsigned int i;

        if (virt_dev->udev->speed >= USB_SPEED_SUPER)
                return xhci_check_ss_bw(xhci, virt_dev);

        if (virt_dev->udev->speed == USB_SPEED_HIGH) {
                max_bandwidth = HS_BW_LIMIT;
                /* Convert percent of bus BW reserved to blocks reserved */
                bw_reserved = DIV_ROUND_UP(HS_BW_RESERVED * max_bandwidth, 100);
        } else {
                max_bandwidth = FS_BW_LIMIT;
                bw_reserved = DIV_ROUND_UP(FS_BW_RESERVED * max_bandwidth, 100);
        }

        bw_table = virt_dev->bw_table;
        /* We need to translate the max packet size and max ESIT payloads into
         * the units the hardware uses.
         */
        block_size = xhci_get_block_size(virt_dev->udev);

        /* If we are manipulating a LS/FS device under a HS hub, double check
         * that the HS bus has enough bandwidth if we are activing a new TT.
         */
        if (virt_dev->tt_info) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Recalculating BW for rootport %u",
                                virt_dev->real_port);
                if (xhci_check_tt_bw_table(xhci, virt_dev, old_active_eps)) {
                        xhci_warn(xhci, "Not enough bandwidth on HS bus for "
                                        "newly activated TT.\n");
                        return -ENOMEM;
                }
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Recalculating BW for TT slot %u port %u",
                                virt_dev->tt_info->slot_id,
                                virt_dev->tt_info->ttport);
        } else {
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Recalculating BW for rootport %u",
                                virt_dev->real_port);
        }

        /* Add in how much bandwidth will be used for interval zero, or the
         * rounded max ESIT payload + number of packets * largest overhead.
         */
        bw_used = DIV_ROUND_UP(bw_table->interval0_esit_payload, block_size) +
                bw_table->interval_bw[0].num_packets *
                xhci_get_largest_overhead(&bw_table->interval_bw[0]);

        for (i = 1; i < XHCI_MAX_INTERVAL; i++) {
                unsigned int bw_added;
                unsigned int largest_mps;
                unsigned int interval_overhead;

                /*
                 * How many packets could we transmit in this interval?
                 * If packets didn't fit in the previous interval, we will need
                 * to transmit that many packets twice within this interval.
                 */
                packets_remaining = 2 * packets_remaining +
                        bw_table->interval_bw[i].num_packets;

                /* Find the largest max packet size of this or the previous
                 * interval.
                 */
                if (list_empty(&bw_table->interval_bw[i].endpoints))
                        largest_mps = 0;
                else {
                        struct xhci_virt_ep *virt_ep;
                        struct list_head *ep_entry;

                        ep_entry = bw_table->interval_bw[i].endpoints.next;
                        virt_ep = list_entry(ep_entry,
                                        struct xhci_virt_ep, bw_endpoint_list);
                        /* Convert to blocks, rounding up */
                        largest_mps = DIV_ROUND_UP(
                                        virt_ep->bw_info.max_packet_size,
                                        block_size);
                }
                if (largest_mps > packet_size)
                        packet_size = largest_mps;

                /* Use the larger overhead of this or the previous interval. */
                interval_overhead = xhci_get_largest_overhead(
                                &bw_table->interval_bw[i]);
                if (interval_overhead > overhead)
                        overhead = interval_overhead;

                /* How many packets can we evenly distribute across
                 * (1 << (i + 1)) possible scheduling opportunities?
                 */
                packets_transmitted = packets_remaining >> (i + 1);

                /* Add in the bandwidth used for those scheduled packets */
                bw_added = packets_transmitted * (overhead + packet_size);

                /* How many packets do we have remaining to transmit? */
                packets_remaining = packets_remaining % (1 << (i + 1));

                /* What largest max packet size should those packets have? */
                /* If we've transmitted all packets, don't carry over the
                 * largest packet size.
                 */
                if (packets_remaining == 0) {
                        packet_size = 0;
                        overhead = 0;
                } else if (packets_transmitted > 0) {
                        /* Otherwise if we do have remaining packets, and we've
                         * scheduled some packets in this interval, take the
                         * largest max packet size from endpoints with this
                         * interval.
                         */
                        packet_size = largest_mps;
                        overhead = interval_overhead;
                }
                /* Otherwise carry over packet_size and overhead from the last
                 * time we had a remainder.
                 */
                bw_used += bw_added;
                if (bw_used > max_bandwidth) {
                        xhci_warn(xhci, "Not enough bandwidth. "
                                        "Proposed: %u, Max: %u\n",
                                bw_used, max_bandwidth);
                        return -ENOMEM;
                }
        }
        /*
         * Ok, we know we have some packets left over after even-handedly
         * scheduling interval 15.  We don't know which microframes they will
         * fit into, so we over-schedule and say they will be scheduled every
         * microframe.
         */
        if (packets_remaining > 0)
                bw_used += overhead + packet_size;

        if (!virt_dev->tt_info && virt_dev->udev->speed == USB_SPEED_HIGH) {
                unsigned int port_index = virt_dev->real_port - 1;

                /* OK, we're manipulating a HS device attached to a
                 * root port bandwidth domain.  Include the number of active TTs
                 * in the bandwidth used.
                 */
                bw_used += TT_HS_OVERHEAD *
                        xhci->rh_bw[port_index].num_active_tts;
        }

        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                "Final bandwidth: %u, Limit: %u, Reserved: %u, "
                "Available: %u " "percent",
                bw_used, max_bandwidth, bw_reserved,
                (max_bandwidth - bw_used - bw_reserved) * 100 /
                max_bandwidth);

        bw_used += bw_reserved;
        if (bw_used > max_bandwidth) {
                xhci_warn(xhci, "Not enough bandwidth. Proposed: %u, Max: %u\n",
                                bw_used, max_bandwidth);
                return -ENOMEM;
        }

        bw_table->bw_used = bw_used;
        return 0;
}

static bool xhci_is_async_ep(unsigned int ep_type)
{
        return (ep_type != ISOC_OUT_EP && ep_type != INT_OUT_EP &&
                                        ep_type != ISOC_IN_EP &&
                                        ep_type != INT_IN_EP);
}

static bool xhci_is_sync_in_ep(unsigned int ep_type)
{
        return (ep_type == ISOC_IN_EP || ep_type == INT_IN_EP);
}

static unsigned int xhci_get_ss_bw_consumed(struct xhci_bw_info *ep_bw)
{
        unsigned int mps = DIV_ROUND_UP(ep_bw->max_packet_size, SS_BLOCK);

        if (ep_bw->ep_interval == 0)
                return SS_OVERHEAD_BURST +
                        (ep_bw->mult * ep_bw->num_packets *
                                        (SS_OVERHEAD + mps));
        return DIV_ROUND_UP(ep_bw->mult * ep_bw->num_packets *
                                (SS_OVERHEAD + mps + SS_OVERHEAD_BURST),
                                1 << ep_bw->ep_interval);

}

static void xhci_drop_ep_from_interval_table(struct xhci_hcd *xhci,
                struct xhci_bw_info *ep_bw,
                struct xhci_interval_bw_table *bw_table,
                struct usb_device *udev,
                struct xhci_virt_ep *virt_ep,
                struct xhci_tt_bw_info *tt_info)
{
        struct xhci_interval_bw *interval_bw;
        int normalized_interval;

        if (xhci_is_async_ep(ep_bw->type))
                return;

        if (udev->speed >= USB_SPEED_SUPER) {
                if (xhci_is_sync_in_ep(ep_bw->type))
                        xhci->devs[udev->slot_id]->bw_table->ss_bw_in -=
                                xhci_get_ss_bw_consumed(ep_bw);
                else
                        xhci->devs[udev->slot_id]->bw_table->ss_bw_out -=
                                xhci_get_ss_bw_consumed(ep_bw);
                return;
        }

        /* SuperSpeed endpoints never get added to intervals in the table, so
         * this check is only valid for HS/FS/LS devices.
         */
        if (list_empty(&virt_ep->bw_endpoint_list))
                return;
        /* For LS/FS devices, we need to translate the interval expressed in
         * microframes to frames.
         */
        if (udev->speed == USB_SPEED_HIGH)
                normalized_interval = ep_bw->ep_interval;
        else
                normalized_interval = ep_bw->ep_interval - 3;

        if (normalized_interval == 0)
                bw_table->interval0_esit_payload -= ep_bw->max_esit_payload;
        interval_bw = &bw_table->interval_bw[normalized_interval];
        interval_bw->num_packets -= ep_bw->num_packets;
        switch (udev->speed) {
        case USB_SPEED_LOW:
                interval_bw->overhead[LS_OVERHEAD_TYPE] -= 1;
                break;
        case USB_SPEED_FULL:
                interval_bw->overhead[FS_OVERHEAD_TYPE] -= 1;
                break;
        case USB_SPEED_HIGH:
                interval_bw->overhead[HS_OVERHEAD_TYPE] -= 1;
                break;
        case USB_SPEED_SUPER:
        case USB_SPEED_SUPER_PLUS:
        case USB_SPEED_UNKNOWN:
        case USB_SPEED_WIRELESS:
                /* Should never happen because only LS/FS/HS endpoints will get
                 * added to the endpoint list.
                 */
                return;
        }
        if (tt_info)
                tt_info->active_eps -= 1;
        list_del_init(&virt_ep->bw_endpoint_list);
}

static void xhci_add_ep_to_interval_table(struct xhci_hcd *xhci,
                struct xhci_bw_info *ep_bw,
                struct xhci_interval_bw_table *bw_table,
                struct usb_device *udev,
                struct xhci_virt_ep *virt_ep,
                struct xhci_tt_bw_info *tt_info)
{
        struct xhci_interval_bw *interval_bw;
        struct xhci_virt_ep *smaller_ep;
        int normalized_interval;

        if (xhci_is_async_ep(ep_bw->type))
                return;

        if (udev->speed == USB_SPEED_SUPER) {
                if (xhci_is_sync_in_ep(ep_bw->type))
                        xhci->devs[udev->slot_id]->bw_table->ss_bw_in +=
                                xhci_get_ss_bw_consumed(ep_bw);
                else
                        xhci->devs[udev->slot_id]->bw_table->ss_bw_out +=
                                xhci_get_ss_bw_consumed(ep_bw);
                return;
        }

        /* For LS/FS devices, we need to translate the interval expressed in
         * microframes to frames.
         */
        if (udev->speed == USB_SPEED_HIGH)
                normalized_interval = ep_bw->ep_interval;
        else
                normalized_interval = ep_bw->ep_interval - 3;

        if (normalized_interval == 0)
                bw_table->interval0_esit_payload += ep_bw->max_esit_payload;
        interval_bw = &bw_table->interval_bw[normalized_interval];
        interval_bw->num_packets += ep_bw->num_packets;
        switch (udev->speed) {
        case USB_SPEED_LOW:
                interval_bw->overhead[LS_OVERHEAD_TYPE] += 1;
                break;
        case USB_SPEED_FULL:
                interval_bw->overhead[FS_OVERHEAD_TYPE] += 1;
                break;
        case USB_SPEED_HIGH:
                interval_bw->overhead[HS_OVERHEAD_TYPE] += 1;
                break;
        case USB_SPEED_SUPER:
        case USB_SPEED_SUPER_PLUS:
        case USB_SPEED_UNKNOWN:
        case USB_SPEED_WIRELESS:
                /* Should never happen because only LS/FS/HS endpoints will get
                 * added to the endpoint list.
                 */
                return;
        }

        if (tt_info)
                tt_info->active_eps += 1;
        /* Insert the endpoint into the list, largest max packet size first. */
        list_for_each_entry(smaller_ep, &interval_bw->endpoints,
                        bw_endpoint_list) {
                if (ep_bw->max_packet_size >=
                                smaller_ep->bw_info.max_packet_size) {
                        /* Add the new ep before the smaller endpoint */
                        list_add_tail(&virt_ep->bw_endpoint_list,
                                        &smaller_ep->bw_endpoint_list);
                        return;
                }
        }
        /* Add the new endpoint at the end of the list. */
        list_add_tail(&virt_ep->bw_endpoint_list,
                        &interval_bw->endpoints);
}

void xhci_update_tt_active_eps(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                int old_active_eps)
{
        struct xhci_root_port_bw_info *rh_bw_info;
        if (!virt_dev->tt_info)
                return;

        rh_bw_info = &xhci->rh_bw[virt_dev->real_port - 1];
        if (old_active_eps == 0 &&
                                virt_dev->tt_info->active_eps != 0) {
                rh_bw_info->num_active_tts += 1;
                rh_bw_info->bw_table.bw_used += TT_HS_OVERHEAD;
        } else if (old_active_eps != 0 &&
                                virt_dev->tt_info->active_eps == 0) {
                rh_bw_info->num_active_tts -= 1;
                rh_bw_info->bw_table.bw_used -= TT_HS_OVERHEAD;
        }
}

static int xhci_reserve_bandwidth(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct xhci_container_ctx *in_ctx)
{
        struct xhci_bw_info ep_bw_info[31];
        int i;
        struct xhci_input_control_ctx *ctrl_ctx;
        int old_active_eps = 0;

        if (virt_dev->tt_info)
                old_active_eps = virt_dev->tt_info->active_eps;

        ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return -ENOMEM;
        }

        for (i = 0; i < 31; i++) {
                if (!EP_IS_ADDED(ctrl_ctx, i) && !EP_IS_DROPPED(ctrl_ctx, i))
                        continue;

                /* Make a copy of the BW info in case we need to revert this */
                memcpy(&ep_bw_info[i], &virt_dev->eps[i].bw_info,
                                sizeof(ep_bw_info[i]));
                /* Drop the endpoint from the interval table if the endpoint is
                 * being dropped or changed.
                 */
                if (EP_IS_DROPPED(ctrl_ctx, i))
                        xhci_drop_ep_from_interval_table(xhci,
                                        &virt_dev->eps[i].bw_info,
                                        virt_dev->bw_table,
                                        virt_dev->udev,
                                        &virt_dev->eps[i],
                                        virt_dev->tt_info);
        }
        /* Overwrite the information stored in the endpoints' bw_info */
        xhci_update_bw_info(xhci, virt_dev->in_ctx, ctrl_ctx, virt_dev);
        for (i = 0; i < 31; i++) {
                /* Add any changed or added endpoints to the interval table */
                if (EP_IS_ADDED(ctrl_ctx, i))
                        xhci_add_ep_to_interval_table(xhci,
                                        &virt_dev->eps[i].bw_info,
                                        virt_dev->bw_table,
                                        virt_dev->udev,
                                        &virt_dev->eps[i],
                                        virt_dev->tt_info);
        }

        if (!xhci_check_bw_table(xhci, virt_dev, old_active_eps)) {
                /* Ok, this fits in the bandwidth we have.
                 * Update the number of active TTs.
                 */
                xhci_update_tt_active_eps(xhci, virt_dev, old_active_eps);
                return 0;
        }

        /* We don't have enough bandwidth for this, revert the stored info. */
        for (i = 0; i < 31; i++) {
                if (!EP_IS_ADDED(ctrl_ctx, i) && !EP_IS_DROPPED(ctrl_ctx, i))
                        continue;

                /* Drop the new copies of any added or changed endpoints from
                 * the interval table.
                 */
                if (EP_IS_ADDED(ctrl_ctx, i)) {
                        xhci_drop_ep_from_interval_table(xhci,
                                        &virt_dev->eps[i].bw_info,
                                        virt_dev->bw_table,
                                        virt_dev->udev,
                                        &virt_dev->eps[i],
                                        virt_dev->tt_info);
                }
                /* Revert the endpoint back to its old information */
                memcpy(&virt_dev->eps[i].bw_info, &ep_bw_info[i],
                                sizeof(ep_bw_info[i]));
                /* Add any changed or dropped endpoints back into the table */
                if (EP_IS_DROPPED(ctrl_ctx, i))
                        xhci_add_ep_to_interval_table(xhci,
                                        &virt_dev->eps[i].bw_info,
                                        virt_dev->bw_table,
                                        virt_dev->udev,
                                        &virt_dev->eps[i],
                                        virt_dev->tt_info);
        }
        return -ENOMEM;
}


/* Issue a configure endpoint command or evaluate context command
 * and wait for it to finish.
 */
static int xhci_configure_endpoint(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct xhci_command *command,
                bool ctx_change, bool must_succeed)
{
        int ret;
        unsigned long flags;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_virt_device *virt_dev;

        if (!command)
                return -EINVAL;

        spin_lock_irqsave(&xhci->lock, flags);

        if (xhci->xhc_state & XHCI_STATE_DYING) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                return -ESHUTDOWN;
        }

        virt_dev = xhci->devs[udev->slot_id];

        ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
        if (!ctrl_ctx) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return -ENOMEM;
        }

        if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK) &&
                        xhci_reserve_host_resources(xhci, ctrl_ctx)) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_warn(xhci, "Not enough host resources, "
                                "active endpoint contexts = %u\n",
                                xhci->num_active_eps);
                return -ENOMEM;
        }
        if ((xhci->quirks & XHCI_SW_BW_CHECKING) &&
            xhci_reserve_bandwidth(xhci, virt_dev, command->in_ctx)) {
                if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK))
                        xhci_free_host_resources(xhci, ctrl_ctx);
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_warn(xhci, "Not enough bandwidth\n");
                return -ENOMEM;
        }

        if (!ctx_change)
                ret = xhci_queue_configure_endpoint(xhci, command,
                                command->in_ctx->dma,
                                udev->slot_id, must_succeed);
        else
                ret = xhci_queue_evaluate_context(xhci, command,
                                command->in_ctx->dma,
                                udev->slot_id, must_succeed);
        if (ret < 0) {
                if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK))
                        xhci_free_host_resources(xhci, ctrl_ctx);
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_dbg_trace(xhci,  trace_xhci_dbg_context_change,
                                "FIXME allocate a new ring segment");
                return -ENOMEM;
        }
        xhci_ring_cmd_db(xhci);
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* Wait for the configure endpoint command to complete */
        wait_for_completion(command->completion);

        if (!ctx_change)
                ret = xhci_configure_endpoint_result(xhci, udev,
                                                     &command->status);
        else
                ret = xhci_evaluate_context_result(xhci, udev,
                                                   &command->status);

        if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK)) {
                spin_lock_irqsave(&xhci->lock, flags);
                /* If the command failed, remove the reserved resources.
                 * Otherwise, clean up the estimate to include dropped eps.
                 */
                if (ret)
                        xhci_free_host_resources(xhci, ctrl_ctx);
                else
                        xhci_finish_resource_reservation(xhci, ctrl_ctx);
                spin_unlock_irqrestore(&xhci->lock, flags);
        }
        return ret;
}

static void xhci_check_bw_drop_ep_streams(struct xhci_hcd *xhci,
        struct xhci_virt_device *vdev, int i)
{
        struct xhci_virt_ep *ep = &vdev->eps[i];

        if (ep->ep_state & EP_HAS_STREAMS) {
                xhci_warn(xhci, "WARN: endpoint 0x%02x has streams on set_interface, freeing streams.\n",
                                xhci_get_endpoint_address(i));
                xhci_free_stream_info(xhci, ep->stream_info);
                ep->stream_info = NULL;
                ep->ep_state &= ~EP_HAS_STREAMS;
        }
}

/* Called after one or more calls to xhci_add_endpoint() or
 * xhci_drop_endpoint().  If this call fails, the USB core is expected
 * to call xhci_reset_bandwidth().
 *
 * Since we are in the middle of changing either configuration or
 * installing a new alt setting, the USB core won't allow URBs to be
 * enqueued for any endpoint on the old config or interface.  Nothing
 * else should be touching the xhci->devs[slot_id] structure, so we
 * don't need to take the xhci->lock for manipulating that.
 */
static int xhci_check_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
{
        int i;
        int ret = 0;
        struct xhci_hcd *xhci;
        struct xhci_virt_device *virt_dev;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_slot_ctx *slot_ctx;
        struct xhci_command *command;

        ret = xhci_check_args(hcd, udev, NULL, 0, true, __func__);
        if (ret <= 0)
                return ret;
        xhci = hcd_to_xhci(hcd);
        if ((xhci->xhc_state & XHCI_STATE_DYING) ||
                (xhci->xhc_state & XHCI_STATE_REMOVING))
                return -ENODEV;

        xhci_dbg(xhci, "%s called for udev %p\n", __func__, udev);
        virt_dev = xhci->devs[udev->slot_id];

        command = xhci_alloc_command(xhci, false, true, GFP_KERNEL);
        if (!command)
                return -ENOMEM;

        command->in_ctx = virt_dev->in_ctx;

        /* See section 4.6.6 - A0 = 1; A1 = D0 = D1 = 0 */
        ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                ret = -ENOMEM;
                goto command_cleanup;
        }
        ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
        ctrl_ctx->add_flags &= cpu_to_le32(~EP0_FLAG);
        ctrl_ctx->drop_flags &= cpu_to_le32(~(SLOT_FLAG | EP0_FLAG));

        /* Don't issue the command if there's no endpoints to update. */
        if (ctrl_ctx->add_flags == cpu_to_le32(SLOT_FLAG) &&
            ctrl_ctx->drop_flags == 0) {
                ret = 0;
                goto command_cleanup;
        }
        /* Fix up Context Entries field. Minimum value is EP0 == BIT(1). */
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
        for (i = 31; i >= 1; i--) {
                __le32 le32 = cpu_to_le32(BIT(i));

                if ((virt_dev->eps[i-1].ring && !(ctrl_ctx->drop_flags & le32))
                    || (ctrl_ctx->add_flags & le32) || i == 1) {
                        slot_ctx->dev_info &= cpu_to_le32(~LAST_CTX_MASK);
                        slot_ctx->dev_info |= cpu_to_le32(LAST_CTX(i));
                        break;
                }
        }

        ret = xhci_configure_endpoint(xhci, udev, command,
                        false, false);
        if (ret)
                /* Callee should call reset_bandwidth() */
                goto command_cleanup;

        /* Free any rings that were dropped, but not changed. */
        for (i = 1; i < 31; i++) {
                if ((le32_to_cpu(ctrl_ctx->drop_flags) & (1 << (i + 1))) &&
                    !(le32_to_cpu(ctrl_ctx->add_flags) & (1 << (i + 1)))) {
                        xhci_free_or_cache_endpoint_ring(xhci, virt_dev, i);
                        xhci_check_bw_drop_ep_streams(xhci, virt_dev, i);
                }
        }
        xhci_zero_in_ctx(xhci, virt_dev);
        /*
         * Install any rings for completely new endpoints or changed endpoints,
         * and free or cache any old rings from changed endpoints.
         */
        for (i = 1; i < 31; i++) {
                if (!virt_dev->eps[i].new_ring)
                        continue;
                /* Only cache or free the old ring if it exists.
                 * It may not if this is the first add of an endpoint.
                 */
                if (virt_dev->eps[i].ring) {
                        xhci_free_or_cache_endpoint_ring(xhci, virt_dev, i);
                }
                xhci_check_bw_drop_ep_streams(xhci, virt_dev, i);
                virt_dev->eps[i].ring = virt_dev->eps[i].new_ring;
                virt_dev->eps[i].new_ring = NULL;
        }
command_cleanup:
        kfree(command->completion);
        kfree(command);

        return ret;
}

static void xhci_reset_bandwidth(struct usb_hcd *hcd, struct usb_device *udev)
{
        struct xhci_hcd *xhci;
        struct xhci_virt_device *virt_dev;
        int i, ret;

        ret = xhci_check_args(hcd, udev, NULL, 0, true, __func__);
        if (ret <= 0)
                return;
        xhci = hcd_to_xhci(hcd);

        xhci_dbg(xhci, "%s called for udev %p\n", __func__, udev);
        virt_dev = xhci->devs[udev->slot_id];
        /* Free any rings allocated for added endpoints */
        for (i = 0; i < 31; i++) {
                if (virt_dev->eps[i].new_ring) {
                        xhci_ring_free(xhci, virt_dev->eps[i].new_ring);
                        virt_dev->eps[i].new_ring = NULL;
                }
        }
        xhci_zero_in_ctx(xhci, virt_dev);
}

static void xhci_setup_input_ctx_for_config_ep(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_container_ctx *out_ctx,
                struct xhci_input_control_ctx *ctrl_ctx,
                u32 add_flags, u32 drop_flags)
{
        ctrl_ctx->add_flags = cpu_to_le32(add_flags);
        ctrl_ctx->drop_flags = cpu_to_le32(drop_flags);
        xhci_slot_copy(xhci, in_ctx, out_ctx);
        ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
}

static void xhci_setup_input_ctx_for_quirk(struct xhci_hcd *xhci,
                unsigned int slot_id, unsigned int ep_index,
                struct xhci_dequeue_state *deq_state)
{
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_container_ctx *in_ctx;
        struct xhci_ep_ctx *ep_ctx;
        u32 added_ctxs;
        dma_addr_t addr;

        in_ctx = xhci->devs[slot_id]->in_ctx;
        ctrl_ctx = xhci_get_input_control_ctx(in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return;
        }

        xhci_endpoint_copy(xhci, xhci->devs[slot_id]->in_ctx,
                        xhci->devs[slot_id]->out_ctx, ep_index);
        ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, ep_index);
        addr = xhci_trb_virt_to_dma(deq_state->new_deq_seg,
                        deq_state->new_deq_ptr);
        if (addr == 0) {
                xhci_warn(xhci, "WARN Cannot submit config ep after "
                                "reset ep command\n");
                xhci_warn(xhci, "WARN deq seg = %p, deq ptr = %p\n",
                                deq_state->new_deq_seg,
                                deq_state->new_deq_ptr);
                return;
        }
        ep_ctx->deq = cpu_to_le64(addr | deq_state->new_cycle_state);

        added_ctxs = xhci_get_endpoint_flag_from_index(ep_index);
        xhci_setup_input_ctx_for_config_ep(xhci, xhci->devs[slot_id]->in_ctx,
                        xhci->devs[slot_id]->out_ctx, ctrl_ctx,
                        added_ctxs, added_ctxs);
}

void xhci_cleanup_stalled_ring(struct xhci_hcd *xhci,
                        unsigned int ep_index, struct xhci_td *td)
{
        struct xhci_dequeue_state deq_state;
        struct xhci_virt_ep *ep;
        struct usb_device *udev = td->urb->dev;

        xhci_dbg_trace(xhci, trace_xhci_dbg_reset_ep,
                        "Cleaning up stalled endpoint ring");
        ep = &xhci->devs[udev->slot_id]->eps[ep_index];
        /* We need to move the HW's dequeue pointer past this TD,
         * or it will attempt to resend it on the next doorbell ring.
         */
        xhci_find_new_dequeue_state(xhci, udev->slot_id,
                        ep_index, ep->stopped_stream, td, &deq_state);

        if (!deq_state.new_deq_ptr || !deq_state.new_deq_seg)
                return;

        /* HW with the reset endpoint quirk will use the saved dequeue state to
         * issue a configure endpoint command later.
         */
        if (!(xhci->quirks & XHCI_RESET_EP_QUIRK)) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_reset_ep,
                                "Queueing new dequeue state");
                xhci_queue_new_dequeue_state(xhci, udev->slot_id,
                                ep_index, ep->stopped_stream, &deq_state);
        } else {
                /* Better hope no one uses the input context between now and the
                 * reset endpoint completion!
                 * XXX: No idea how this hardware will react when stream rings
                 * are enabled.
                 */
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Setting up input context for "
                                "configure endpoint command");
                xhci_setup_input_ctx_for_quirk(xhci, udev->slot_id,
                                ep_index, &deq_state);
        }
}

/* Called when clearing halted device. The core should have sent the control
 * message to clear the device halt condition. The host side of the halt should
 * already be cleared with a reset endpoint command issued when the STALL tx
 * event was received.
 *
 * Context: in_interrupt
 */

static void xhci_endpoint_reset(struct usb_hcd *hcd,
                struct usb_host_endpoint *ep)
{
        struct xhci_hcd *xhci;

        xhci = hcd_to_xhci(hcd);

        /*
         * We might need to implement the config ep cmd in xhci 4.8.1 note:
         * The Reset Endpoint Command may only be issued to endpoints in the
         * Halted state. If software wishes reset the Data Toggle or Sequence
         * Number of an endpoint that isn't in the Halted state, then software
         * may issue a Configure Endpoint Command with the Drop and Add bits set
         * for the target endpoint. that is in the Stopped state.
         */

        /* For now just print debug to follow the situation */
        xhci_dbg(xhci, "Endpoint 0x%x ep reset callback called\n",
                 ep->desc.bEndpointAddress);
}

static int xhci_check_streams_endpoint(struct xhci_hcd *xhci,
                struct usb_device *udev, struct usb_host_endpoint *ep,
                unsigned int slot_id)
{
        int ret;
        unsigned int ep_index;
        unsigned int ep_state;

        if (!ep)
                return -EINVAL;
        ret = xhci_check_args(xhci_to_hcd(xhci), udev, ep, 1, true, __func__);
        if (ret <= 0)
                return -EINVAL;
        if (usb_ss_max_streams(&ep->ss_ep_comp) == 0) {
                xhci_warn(xhci, "WARN: SuperSpeed Endpoint Companion"
                                " descriptor for ep 0x%x does not support streams\n",
                                ep->desc.bEndpointAddress);
                return -EINVAL;
        }

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_state = xhci->devs[slot_id]->eps[ep_index].ep_state;
        if (ep_state & EP_HAS_STREAMS ||
                        ep_state & EP_GETTING_STREAMS) {
                xhci_warn(xhci, "WARN: SuperSpeed bulk endpoint 0x%x "
                                "already has streams set up.\n",
                                ep->desc.bEndpointAddress);
                xhci_warn(xhci, "Send email to xHCI maintainer and ask for "
                                "dynamic stream context array reallocation.\n");
                return -EINVAL;
        }
        if (!list_empty(&xhci->devs[slot_id]->eps[ep_index].ring->td_list)) {
                xhci_warn(xhci, "Cannot setup streams for SuperSpeed bulk "
                                "endpoint 0x%x; URBs are pending.\n",
                                ep->desc.bEndpointAddress);
                return -EINVAL;
        }
        return 0;
}

static void xhci_calculate_streams_entries(struct xhci_hcd *xhci,
                unsigned int *num_streams, unsigned int *num_stream_ctxs)
{
        unsigned int max_streams;

        /* The stream context array size must be a power of two */
        *num_stream_ctxs = roundup_pow_of_two(*num_streams);
        /*
         * Find out how many primary stream array entries the host controller
         * supports.  Later we may use secondary stream arrays (similar to 2nd
         * level page entries), but that's an optional feature for xHCI host
         * controllers. xHCs must support at least 4 stream IDs.
         */
        max_streams = HCC_MAX_PSA(xhci->hcc_params);
        if (*num_stream_ctxs > max_streams) {
                xhci_dbg(xhci, "xHCI HW only supports %u stream ctx entries.\n",
                                max_streams);
                *num_stream_ctxs = max_streams;
                *num_streams = max_streams;
        }
}

/* Returns an error code if one of the endpoint already has streams.
 * This does not change any data structures, it only checks and gathers
 * information.
 */
static int xhci_calculate_streams_and_bitmask(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_host_endpoint **eps, unsigned int num_eps,
                unsigned int *num_streams, u32 *changed_ep_bitmask)
{
        unsigned int max_streams;
        unsigned int endpoint_flag;
        int i;
        int ret;

        for (i = 0; i < num_eps; i++) {
                ret = xhci_check_streams_endpoint(xhci, udev,
                                eps[i], udev->slot_id);
                if (ret < 0)
                        return ret;

                max_streams = usb_ss_max_streams(&eps[i]->ss_ep_comp);
                if (max_streams < (*num_streams - 1)) {
                        xhci_dbg(xhci, "Ep 0x%x only supports %u stream IDs.\n",
                                        eps[i]->desc.bEndpointAddress,
                                        max_streams);
                        *num_streams = max_streams+1;
                }

                endpoint_flag = xhci_get_endpoint_flag(&eps[i]->desc);
                if (*changed_ep_bitmask & endpoint_flag)
                        return -EINVAL;
                *changed_ep_bitmask |= endpoint_flag;
        }
        return 0;
}

static u32 xhci_calculate_no_streams_bitmask(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_host_endpoint **eps, unsigned int num_eps)
{
        u32 changed_ep_bitmask = 0;
        unsigned int slot_id;
        unsigned int ep_index;
        unsigned int ep_state;
        int i;

        slot_id = udev->slot_id;
        if (!xhci->devs[slot_id])
                return 0;

        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                ep_state = xhci->devs[slot_id]->eps[ep_index].ep_state;
                /* Are streams already being freed for the endpoint? */
                if (ep_state & EP_GETTING_NO_STREAMS) {
                        xhci_warn(xhci, "WARN Can't disable streams for "
                                        "endpoint 0x%x, "
                                        "streams are being disabled already\n",
                                        eps[i]->desc.bEndpointAddress);
                        return 0;
                }
                /* Are there actually any streams to free? */
                if (!(ep_state & EP_HAS_STREAMS) &&
                                !(ep_state & EP_GETTING_STREAMS)) {
                        xhci_warn(xhci, "WARN Can't disable streams for "
                                        "endpoint 0x%x, "
                                        "streams are already disabled!\n",
                                        eps[i]->desc.bEndpointAddress);
                        xhci_warn(xhci, "WARN xhci_free_streams() called "
                                        "with non-streams endpoint\n");
                        return 0;
                }
                changed_ep_bitmask |= xhci_get_endpoint_flag(&eps[i]->desc);
        }
        return changed_ep_bitmask;
}

/*
 * The USB device drivers use this function (through the HCD interface in USB
 * core) to prepare a set of bulk endpoints to use streams.  Streams are used to
 * coordinate mass storage command queueing across multiple endpoints (basically
 * a stream ID == a task ID).
 *
 * Setting up streams involves allocating the same size stream context array
 * for each endpoint and issuing a configure endpoint command for all endpoints.
 *
 * Don't allow the call to succeed if one endpoint only supports one stream
 * (which means it doesn't support streams at all).
 *
 * Drivers may get less stream IDs than they asked for, if the host controller
 * hardware or endpoints claim they can't support the number of requested
 * stream IDs.
 */
static int xhci_alloc_streams(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint **eps, unsigned int num_eps,
                unsigned int num_streams, gfp_t mem_flags)
{
        int i, ret;
        struct xhci_hcd *xhci;
        struct xhci_virt_device *vdev;
        struct xhci_command *config_cmd;
        struct xhci_input_control_ctx *ctrl_ctx;
        unsigned int ep_index;
        unsigned int num_stream_ctxs;
        unsigned int max_packet;
        unsigned long flags;
        u32 changed_ep_bitmask = 0;

        if (!eps)
                return -EINVAL;

        /* Add one to the number of streams requested to account for
         * stream 0 that is reserved for xHCI usage.
         */
        num_streams += 1;
        xhci = hcd_to_xhci(hcd);
        xhci_dbg(xhci, "Driver wants %u stream IDs (including stream 0).\n",
                        num_streams);

        /* MaxPSASize value 0 (2 streams) means streams are not supported */
        if ((xhci->quirks & XHCI_BROKEN_STREAMS) ||
                        HCC_MAX_PSA(xhci->hcc_params) < 4) {
                xhci_dbg(xhci, "xHCI controller does not support streams.\n");
                return -ENOSYS;
        }

        config_cmd = xhci_alloc_command(xhci, true, true, mem_flags);
        if (!config_cmd)
                return -ENOMEM;

        ctrl_ctx = xhci_get_input_control_ctx(config_cmd->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                xhci_free_command(xhci, config_cmd);
                return -ENOMEM;
        }

        /* Check to make sure all endpoints are not already configured for
         * streams.  While we're at it, find the maximum number of streams that
         * all the endpoints will support and check for duplicate endpoints.
         */
        spin_lock_irqsave(&xhci->lock, flags);
        ret = xhci_calculate_streams_and_bitmask(xhci, udev, eps,
                        num_eps, &num_streams, &changed_ep_bitmask);
        if (ret < 0) {
                xhci_free_command(xhci, config_cmd);
                spin_unlock_irqrestore(&xhci->lock, flags);
                return ret;
        }
        if (num_streams <= 1) {
                xhci_warn(xhci, "WARN: endpoints can't handle "
                                "more than one stream.\n");
                xhci_free_command(xhci, config_cmd);
                spin_unlock_irqrestore(&xhci->lock, flags);
                return -EINVAL;
        }
        vdev = xhci->devs[udev->slot_id];
        /* Mark each endpoint as being in transition, so
         * xhci_urb_enqueue() will reject all URBs.
         */
        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                vdev->eps[ep_index].ep_state |= EP_GETTING_STREAMS;
        }
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* Setup internal data structures and allocate HW data structures for
         * streams (but don't install the HW structures in the input context
         * until we're sure all memory allocation succeeded).
         */
        xhci_calculate_streams_entries(xhci, &num_streams, &num_stream_ctxs);
        xhci_dbg(xhci, "Need %u stream ctx entries for %u stream IDs.\n",
                        num_stream_ctxs, num_streams);

        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                max_packet = usb_endpoint_maxp(&eps[i]->desc);
                vdev->eps[ep_index].stream_info = xhci_alloc_stream_info(xhci,
                                num_stream_ctxs,
                                num_streams,
                                max_packet, mem_flags);
                if (!vdev->eps[ep_index].stream_info)
                        goto cleanup;
                /* Set maxPstreams in endpoint context and update deq ptr to
                 * point to stream context array. FIXME
                 */
        }

        /* Set up the input context for a configure endpoint command. */
        for (i = 0; i < num_eps; i++) {
                struct xhci_ep_ctx *ep_ctx;

                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                ep_ctx = xhci_get_ep_ctx(xhci, config_cmd->in_ctx, ep_index);

                xhci_endpoint_copy(xhci, config_cmd->in_ctx,
                                vdev->out_ctx, ep_index);
                xhci_setup_streams_ep_input_ctx(xhci, ep_ctx,
                                vdev->eps[ep_index].stream_info);
        }
        /* Tell the HW to drop its old copy of the endpoint context info
         * and add the updated copy from the input context.
         */
        xhci_setup_input_ctx_for_config_ep(xhci, config_cmd->in_ctx,
                        vdev->out_ctx, ctrl_ctx,
                        changed_ep_bitmask, changed_ep_bitmask);

        /* Issue and wait for the configure endpoint command */
        ret = xhci_configure_endpoint(xhci, udev, config_cmd,
                        false, false);

        /* xHC rejected the configure endpoint command for some reason, so we
         * leave the old ring intact and free our internal streams data
         * structure.
         */
        if (ret < 0)
                goto cleanup;

        spin_lock_irqsave(&xhci->lock, flags);
        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                vdev->eps[ep_index].ep_state &= ~EP_GETTING_STREAMS;
                xhci_dbg(xhci, "Slot %u ep ctx %u now has streams.\n",
                         udev->slot_id, ep_index);
                vdev->eps[ep_index].ep_state |= EP_HAS_STREAMS;
        }
        xhci_free_command(xhci, config_cmd);
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* Subtract 1 for stream 0, which drivers can't use */
        return num_streams - 1;

cleanup:
        /* If it didn't work, free the streams! */
        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                xhci_free_stream_info(xhci, vdev->eps[ep_index].stream_info);
                vdev->eps[ep_index].stream_info = NULL;
                /* FIXME Unset maxPstreams in endpoint context and
                 * update deq ptr to point to normal string ring.
                 */
                vdev->eps[ep_index].ep_state &= ~EP_GETTING_STREAMS;
                vdev->eps[ep_index].ep_state &= ~EP_HAS_STREAMS;
                xhci_endpoint_zero(xhci, vdev, eps[i]);
        }
        xhci_free_command(xhci, config_cmd);
        return -ENOMEM;
}

/* Transition the endpoint from using streams to being a "normal" endpoint
 * without streams.
 *
 * Modify the endpoint context state, submit a configure endpoint command,
 * and free all endpoint rings for streams if that completes successfully.
 */
static int xhci_free_streams(struct usb_hcd *hcd, struct usb_device *udev,
                struct usb_host_endpoint **eps, unsigned int num_eps,
                gfp_t mem_flags)
{
        int i, ret;
        struct xhci_hcd *xhci;
        struct xhci_virt_device *vdev;
        struct xhci_command *command;
        struct xhci_input_control_ctx *ctrl_ctx;
        unsigned int ep_index;
        unsigned long flags;
        u32 changed_ep_bitmask;

        xhci = hcd_to_xhci(hcd);
        vdev = xhci->devs[udev->slot_id];

        /* Set up a configure endpoint command to remove the streams rings */
        spin_lock_irqsave(&xhci->lock, flags);
        changed_ep_bitmask = xhci_calculate_no_streams_bitmask(xhci,
                        udev, eps, num_eps);
        if (changed_ep_bitmask == 0) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                return -EINVAL;
        }

        /* Use the xhci_command structure from the first endpoint.  We may have
         * allocated too many, but the driver may call xhci_free_streams() for
         * each endpoint it grouped into one call to xhci_alloc_streams().
         */
        ep_index = xhci_get_endpoint_index(&eps[0]->desc);
        command = vdev->eps[ep_index].stream_info->free_streams_command;
        ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
        if (!ctrl_ctx) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return -EINVAL;
        }

        for (i = 0; i < num_eps; i++) {
                struct xhci_ep_ctx *ep_ctx;

                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                ep_ctx = xhci_get_ep_ctx(xhci, command->in_ctx, ep_index);
                xhci->devs[udev->slot_id]->eps[ep_index].ep_state |=
                        EP_GETTING_NO_STREAMS;

                xhci_endpoint_copy(xhci, command->in_ctx,
                                vdev->out_ctx, ep_index);
                xhci_setup_no_streams_ep_input_ctx(ep_ctx,
                                &vdev->eps[ep_index]);
        }
        xhci_setup_input_ctx_for_config_ep(xhci, command->in_ctx,
                        vdev->out_ctx, ctrl_ctx,
                        changed_ep_bitmask, changed_ep_bitmask);
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* Issue and wait for the configure endpoint command,
         * which must succeed.
         */
        ret = xhci_configure_endpoint(xhci, udev, command,
                        false, true);

        /* xHC rejected the configure endpoint command for some reason, so we
         * leave the streams rings intact.
         */
        if (ret < 0)
                return ret;

        spin_lock_irqsave(&xhci->lock, flags);
        for (i = 0; i < num_eps; i++) {
                ep_index = xhci_get_endpoint_index(&eps[i]->desc);
                xhci_free_stream_info(xhci, vdev->eps[ep_index].stream_info);
                vdev->eps[ep_index].stream_info = NULL;
                /* FIXME Unset maxPstreams in endpoint context and
                 * update deq ptr to point to normal string ring.
                 */
                vdev->eps[ep_index].ep_state &= ~EP_GETTING_NO_STREAMS;
                vdev->eps[ep_index].ep_state &= ~EP_HAS_STREAMS;
        }
        spin_unlock_irqrestore(&xhci->lock, flags);

        return 0;
}

/*
 * Deletes endpoint resources for endpoints that were active before a Reset
 * Device command, or a Disable Slot command.  The Reset Device command leaves
 * the control endpoint intact, whereas the Disable Slot command deletes it.
 *
 * Must be called with xhci->lock held.
 */
void xhci_free_device_endpoint_resources(struct xhci_hcd *xhci,
        struct xhci_virt_device *virt_dev, bool drop_control_ep)
{
        int i;
        unsigned int num_dropped_eps = 0;
        unsigned int drop_flags = 0;

        for (i = (drop_control_ep ? 0 : 1); i < 31; i++) {
                if (virt_dev->eps[i].ring) {
                        drop_flags |= 1 << i;
                        num_dropped_eps++;
                }
        }
        xhci->num_active_eps -= num_dropped_eps;
        if (num_dropped_eps)
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Dropped %u ep ctxs, flags = 0x%x, "
                                "%u now active.",
                                num_dropped_eps, drop_flags,
                                xhci->num_active_eps);
}

/*
 * This submits a Reset Device Command, which will set the device state to 0,
 * set the device address to 0, and disable all the endpoints except the default
 * control endpoint.  The USB core should come back and call
 * xhci_address_device(), and then re-set up the configuration.  If this is
 * called because of a usb_reset_and_verify_device(), then the old alternate
 * settings will be re-installed through the normal bandwidth allocation
 * functions.
 *
 * Wait for the Reset Device command to finish.  Remove all structures
 * associated with the endpoints that were disabled.  Clear the input device
 * structure?  Cache the rings?  Reset the control endpoint 0 max packet size?
 *
 * If the virt_dev to be reset does not exist or does not match the udev,
 * it means the device is lost, possibly due to the xHC restore error and
 * re-initialization during S3/S4. In this case, call xhci_alloc_dev() to
 * re-allocate the device.
 */
static int xhci_discover_or_reset_device(struct usb_hcd *hcd,
                struct usb_device *udev)
{
        int ret, i;
        unsigned long flags;
        struct xhci_hcd *xhci;
        unsigned int slot_id;
        struct xhci_virt_device *virt_dev;
        struct xhci_command *reset_device_cmd;
        int last_freed_endpoint;
        struct xhci_slot_ctx *slot_ctx;
        int old_active_eps = 0;

        ret = xhci_check_args(hcd, udev, NULL, 0, false, __func__);
        if (ret <= 0)
                return ret;
        xhci = hcd_to_xhci(hcd);
        slot_id = udev->slot_id;
        virt_dev = xhci->devs[slot_id];
        if (!virt_dev) {
                xhci_dbg(xhci, "The device to be reset with slot ID %u does "
                                "not exist. Re-allocate the device\n", slot_id);
                ret = xhci_alloc_dev(hcd, udev);
                if (ret == 1)
                        return 0;
                else
                        return -EINVAL;
        }

        if (virt_dev->tt_info)
                old_active_eps = virt_dev->tt_info->active_eps;

        if (virt_dev->udev != udev) {
                /* If the virt_dev and the udev does not match, this virt_dev
                 * may belong to another udev.
                 * Re-allocate the device.
                 */
                xhci_dbg(xhci, "The device to be reset with slot ID %u does "
                                "not match the udev. Re-allocate the device\n",
                                slot_id);
                ret = xhci_alloc_dev(hcd, udev);
                if (ret == 1)
                        return 0;
                else
                        return -EINVAL;
        }

        /* If device is not setup, there is no point in resetting it */
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
        if (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state)) ==
                                                SLOT_STATE_DISABLED)
                return 0;

        trace_xhci_discover_or_reset_device(slot_ctx);

        xhci_dbg(xhci, "Resetting device with slot ID %u\n", slot_id);
        /* Allocate the command structure that holds the struct completion.
         * Assume we're in process context, since the normal device reset
         * process has to wait for the device anyway.  Storage devices are
         * reset as part of error handling, so use GFP_NOIO instead of
         * GFP_KERNEL.
         */
        reset_device_cmd = xhci_alloc_command(xhci, false, true, GFP_NOIO);
        if (!reset_device_cmd) {
                xhci_dbg(xhci, "Couldn't allocate command structure.\n");
                return -ENOMEM;
        }

        /* Attempt to submit the Reset Device command to the command ring */
        spin_lock_irqsave(&xhci->lock, flags);

        ret = xhci_queue_reset_device(xhci, reset_device_cmd, slot_id);
        if (ret) {
                xhci_dbg(xhci, "FIXME: allocate a command ring segment\n");
                spin_unlock_irqrestore(&xhci->lock, flags);
                goto command_cleanup;
        }
        xhci_ring_cmd_db(xhci);
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* Wait for the Reset Device command to finish */
        wait_for_completion(reset_device_cmd->completion);

        /* The Reset Device command can't fail, according to the 0.95/0.96 spec,
         * unless we tried to reset a slot ID that wasn't enabled,
         * or the device wasn't in the addressed or configured state.
         */
        ret = reset_device_cmd->status;
        switch (ret) {
        case COMP_COMMAND_ABORTED:
        case COMP_STOPPED:
                xhci_warn(xhci, "Timeout waiting for reset device command\n");
                ret = -ETIME;
                goto command_cleanup;
        case COMP_SLOT_NOT_ENABLED_ERROR: /* 0.95 completion for bad slot ID */
        case COMP_CONTEXT_STATE_ERROR: /* 0.96 completion code for same thing */
                xhci_dbg(xhci, "Can't reset device (slot ID %u) in %s state\n",
                                slot_id,
                                xhci_get_slot_state(xhci, virt_dev->out_ctx));
                xhci_dbg(xhci, "Not freeing device rings.\n");
                /* Don't treat this as an error.  May change my mind later. */
                ret = 0;
                goto command_cleanup;
        case COMP_SUCCESS:
                xhci_dbg(xhci, "Successful reset device command.\n");
                break;
        default:
                if (xhci_is_vendor_info_code(xhci, ret))
                        break;
                xhci_warn(xhci, "Unknown completion code %u for "
                                "reset device command.\n", ret);
                ret = -EINVAL;
                goto command_cleanup;
        }

        /* Free up host controller endpoint resources */
        if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK)) {
                spin_lock_irqsave(&xhci->lock, flags);
                /* Don't delete the default control endpoint resources */
                xhci_free_device_endpoint_resources(xhci, virt_dev, false);
                spin_unlock_irqrestore(&xhci->lock, flags);
        }

        /* Everything but endpoint 0 is disabled, so free or cache the rings. */
        last_freed_endpoint = 1;
        for (i = 1; i < 31; i++) {
                struct xhci_virt_ep *ep = &virt_dev->eps[i];

                if (ep->ep_state & EP_HAS_STREAMS) {
                        xhci_warn(xhci, "WARN: endpoint 0x%02x has streams on device reset, freeing streams.\n",
                                        xhci_get_endpoint_address(i));
                        xhci_free_stream_info(xhci, ep->stream_info);
                        ep->stream_info = NULL;
                        ep->ep_state &= ~EP_HAS_STREAMS;
                }

                if (ep->ring) {
                        xhci_free_or_cache_endpoint_ring(xhci, virt_dev, i);
                        last_freed_endpoint = i;
                }
                if (!list_empty(&virt_dev->eps[i].bw_endpoint_list))
                        xhci_drop_ep_from_interval_table(xhci,
                                        &virt_dev->eps[i].bw_info,
                                        virt_dev->bw_table,
                                        udev,
                                        &virt_dev->eps[i],
                                        virt_dev->tt_info);
                xhci_clear_endpoint_bw_info(&virt_dev->eps[i].bw_info);
        }
        /* If necessary, update the number of active TTs on this root port */
        xhci_update_tt_active_eps(xhci, virt_dev, old_active_eps);
        ret = 0;

command_cleanup:
        xhci_free_command(xhci, reset_device_cmd);
        return ret;
}

/*
 * At this point, the struct usb_device is about to go away, the device has
 * disconnected, and all traffic has been stopped and the endpoints have been
 * disabled.  Free any HC data structures associated with that device.
 */
static void xhci_free_dev(struct usb_hcd *hcd, struct usb_device *udev)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct xhci_virt_device *virt_dev;
        struct xhci_slot_ctx *slot_ctx;
        int i, ret;
        struct xhci_command *command;

        command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
        if (!command)
                return;

#ifndef CONFIG_USB_DEFAULT_PERSIST
        /*
         * We called pm_runtime_get_noresume when the device was attached.
         * Decrement the counter here to allow controller to runtime suspend
         * if no devices remain.
         */
        if (xhci->quirks & XHCI_RESET_ON_RESUME)
                pm_runtime_put_noidle(hcd->self.controller);
#endif

        ret = xhci_check_args(hcd, udev, NULL, 0, true, __func__);
        /* If the host is halted due to driver unload, we still need to free the
         * device.
         */
        if (ret <= 0 && ret != -ENODEV) {
                kfree(command);
                return;
        }

        virt_dev = xhci->devs[udev->slot_id];
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
        trace_xhci_free_dev(slot_ctx);

        /* Stop any wayward timer functions (which may grab the lock) */
        for (i = 0; i < 31; i++) {
                virt_dev->eps[i].ep_state &= ~EP_STOP_CMD_PENDING;
                del_timer_sync(&virt_dev->eps[i].stop_cmd_timer);
        }

        xhci_disable_slot(xhci, command, udev->slot_id);
        /*
         * Event command completion handler will free any data structures
         * associated with the slot.  XXX Can free sleep?
         */
}

int xhci_disable_slot(struct xhci_hcd *xhci, struct xhci_command *command,
                        u32 slot_id)
{
        unsigned long flags;
        u32 state;
        int ret = 0;
        struct xhci_virt_device *virt_dev;

        virt_dev = xhci->devs[slot_id];
        if (!virt_dev)
                return -EINVAL;
        if (!command)
                command = xhci_alloc_command(xhci, false, false, GFP_KERNEL);
        if (!command)
                return -ENOMEM;

        spin_lock_irqsave(&xhci->lock, flags);
        /* Don't disable the slot if the host controller is dead. */
        state = readl(&xhci->op_regs->status);
        if (state == 0xffffffff || (xhci->xhc_state & XHCI_STATE_DYING) ||
                        (xhci->xhc_state & XHCI_STATE_HALTED)) {
                xhci_free_virt_device(xhci, slot_id);
                spin_unlock_irqrestore(&xhci->lock, flags);
                kfree(command);
                return ret;
        }

        ret = xhci_queue_slot_control(xhci, command, TRB_DISABLE_SLOT,
                                slot_id);
        if (ret) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_dbg(xhci, "FIXME: allocate a command ring segment\n");
                return ret;
        }
        xhci_ring_cmd_db(xhci);
        spin_unlock_irqrestore(&xhci->lock, flags);
        return ret;
}

/*
 * Checks if we have enough host controller resources for the default control
 * endpoint.
 *
 * Must be called with xhci->lock held.
 */
static int xhci_reserve_host_control_ep_resources(struct xhci_hcd *xhci)
{
        if (xhci->num_active_eps + 1 > xhci->limit_active_eps) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                                "Not enough ep ctxs: "
                                "%u active, need to add 1, limit is %u.",
                                xhci->num_active_eps, xhci->limit_active_eps);
                return -ENOMEM;
        }
        xhci->num_active_eps += 1;
        xhci_dbg_trace(xhci, trace_xhci_dbg_quirks,
                        "Adding 1 ep ctx, %u now active.",
                        xhci->num_active_eps);
        return 0;
}


/*
 * Returns 0 if the xHC ran out of device slots, the Enable Slot command
 * timed out, or allocating memory failed.  Returns 1 on success.
 */
int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct xhci_virt_device *vdev;
        struct xhci_slot_ctx *slot_ctx;
        unsigned long flags;
        int ret, slot_id;
        struct xhci_command *command;

        command = xhci_alloc_command(xhci, false, true, GFP_KERNEL);
        if (!command)
                return 0;

        /* xhci->slot_id and xhci->addr_dev are not thread-safe */
        mutex_lock(&xhci->mutex);
        spin_lock_irqsave(&xhci->lock, flags);
        ret = xhci_queue_slot_control(xhci, command, TRB_ENABLE_SLOT, 0);
        if (ret) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                mutex_unlock(&xhci->mutex);
                xhci_dbg(xhci, "FIXME: allocate a command ring segment\n");
                xhci_free_command(xhci, command);
                return 0;
        }
        xhci_ring_cmd_db(xhci);
        spin_unlock_irqrestore(&xhci->lock, flags);

        wait_for_completion(command->completion);
        slot_id = command->slot_id;
        mutex_unlock(&xhci->mutex);

        if (!slot_id || command->status != COMP_SUCCESS) {
                xhci_err(xhci, "Error while assigning device slot ID\n");
                xhci_err(xhci, "Max number of devices this xHCI host supports is %u.\n",
                                HCS_MAX_SLOTS(
                                        readl(&xhci->cap_regs->hcs_params1)));
                xhci_free_command(xhci, command);
                return 0;
        }

        if ((xhci->quirks & XHCI_EP_LIMIT_QUIRK)) {
                spin_lock_irqsave(&xhci->lock, flags);
                ret = xhci_reserve_host_control_ep_resources(xhci);
                if (ret) {
                        spin_unlock_irqrestore(&xhci->lock, flags);
                        xhci_warn(xhci, "Not enough host resources, "
                                        "active endpoint contexts = %u\n",
                                        xhci->num_active_eps);
                        goto disable_slot;
                }
                spin_unlock_irqrestore(&xhci->lock, flags);
        }
        /* Use GFP_NOIO, since this function can be called from
         * xhci_discover_or_reset_device(), which may be called as part of
         * mass storage driver error handling.
         */
        if (!xhci_alloc_virt_device(xhci, slot_id, udev, GFP_NOIO)) {
                xhci_warn(xhci, "Could not allocate xHCI USB device data structures\n");
                goto disable_slot;
        }
        vdev = xhci->devs[slot_id];
        slot_ctx = xhci_get_slot_ctx(xhci, vdev->out_ctx);
        trace_xhci_alloc_dev(slot_ctx);

        udev->slot_id = slot_id;

#ifndef CONFIG_USB_DEFAULT_PERSIST
        /*
         * If resetting upon resume, we can't put the controller into runtime
         * suspend if there is a device attached.
         */
        if (xhci->quirks & XHCI_RESET_ON_RESUME)
                pm_runtime_get_noresume(hcd->self.controller);
#endif


        xhci_free_command(xhci, command);
        /* Is this a LS or FS device under a HS hub? */
        /* Hub or peripherial? */
        return 1;

disable_slot:
        /* Disable slot, if we can do it without mem alloc */
        kfree(command->completion);
        command->completion = NULL;
        command->status = 0;
        return xhci_disable_slot(xhci, command, udev->slot_id);
}

/*
 * Issue an Address Device command and optionally send a corresponding
 * SetAddress request to the device.
 */
static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev,
                             enum xhci_setup_dev setup)
{
        const char *act = setup == SETUP_CONTEXT_ONLY ? "context" : "address";
        unsigned long flags;
        struct xhci_virt_device *virt_dev;
        int ret = 0;
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct xhci_slot_ctx *slot_ctx;
        struct xhci_input_control_ctx *ctrl_ctx;
        u64 temp_64;
        struct xhci_command *command = NULL;

        mutex_lock(&xhci->mutex);

        if (xhci->xhc_state) {  /* dying, removing or halted */
                ret = -ESHUTDOWN;
                goto out;
        }

        if (!udev->slot_id) {
                xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                                "Bad Slot ID %d", udev->slot_id);
                ret = -EINVAL;
                goto out;
        }

        virt_dev = xhci->devs[udev->slot_id];

        if (WARN_ON(!virt_dev)) {
                /*
                 * In plug/unplug torture test with an NEC controller,
                 * a zero-dereference was observed once due to virt_dev = 0.
                 * Print useful debug rather than crash if it is observed again!
                 */
                xhci_warn(xhci, "Virt dev invalid for slot_id 0x%x!\n",
                        udev->slot_id);
                ret = -EINVAL;
                goto out;
        }
        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
        trace_xhci_setup_device_slot(slot_ctx);

        if (setup == SETUP_CONTEXT_ONLY) {
                if (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state)) ==
                    SLOT_STATE_DEFAULT) {
                        xhci_dbg(xhci, "Slot already in default state\n");
                        goto out;
                }
        }

        command = xhci_alloc_command(xhci, false, true, GFP_KERNEL);
        if (!command) {
                ret = -ENOMEM;
                goto out;
        }

        command->in_ctx = virt_dev->in_ctx;

        slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);
        ctrl_ctx = xhci_get_input_control_ctx(virt_dev->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                ret = -EINVAL;
                goto out;
        }
        /*
         * If this is the first Set Address since device plug-in or
         * virt_device realloaction after a resume with an xHCI power loss,
         * then set up the slot context.
         */
        if (!slot_ctx->dev_info)
                xhci_setup_addressable_virt_dev(xhci, udev);
        /* Otherwise, update the control endpoint ring enqueue pointer. */
        else
                xhci_copy_ep0_dequeue_into_input_ctx(xhci, udev);
        ctrl_ctx->add_flags = cpu_to_le32(SLOT_FLAG | EP0_FLAG);
        ctrl_ctx->drop_flags = 0;

        trace_xhci_address_ctx(xhci, virt_dev->in_ctx,
                                le32_to_cpu(slot_ctx->dev_info) >> 27);

        spin_lock_irqsave(&xhci->lock, flags);
        trace_xhci_setup_device(virt_dev);
        ret = xhci_queue_address_device(xhci, command, virt_dev->in_ctx->dma,
                                        udev->slot_id, setup);
        if (ret) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                                "FIXME: allocate a command ring segment");
                goto out;
        }
        xhci_ring_cmd_db(xhci);
        spin_unlock_irqrestore(&xhci->lock, flags);

        /* ctrl tx can take up to 5 sec; XXX: need more time for xHC? */
        wait_for_completion(command->completion);

        /* FIXME: From section 4.3.4: "Software shall be responsible for timing
         * the SetAddress() "recovery interval" required by USB and aborting the
         * command on a timeout.
         */
        switch (command->status) {
        case COMP_COMMAND_ABORTED:
        case COMP_STOPPED:
                xhci_warn(xhci, "Timeout while waiting for setup device command\n");
                ret = -ETIME;
                break;
        case COMP_CONTEXT_STATE_ERROR:
        case COMP_SLOT_NOT_ENABLED_ERROR:
                xhci_err(xhci, "Setup ERROR: setup %s command for slot %d.\n",
                         act, udev->slot_id);
                ret = -EINVAL;
                break;
        case COMP_USB_TRANSACTION_ERROR:
                dev_warn(&udev->dev, "Device not responding to setup %s.\n", act);
                ret = -EPROTO;
                break;
        case COMP_INCOMPATIBLE_DEVICE_ERROR:
                dev_warn(&udev->dev,
                         "ERROR: Incompatible device for setup %s command\n", act);
                ret = -ENODEV;
                break;
        case COMP_SUCCESS:
                xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                               "Successful setup %s command", act);
                break;
        default:
                xhci_err(xhci,
                         "ERROR: unexpected setup %s command completion code 0x%x.\n",
                         act, command->status);
                trace_xhci_address_ctx(xhci, virt_dev->out_ctx, 1);
                ret = -EINVAL;
                break;
        }
        if (ret)
                goto out;
        temp_64 = xhci_read_64(xhci, &xhci->op_regs->dcbaa_ptr);
        xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                        "Op regs DCBAA ptr = %#016llx", temp_64);
        xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                "Slot ID %d dcbaa entry @%p = %#016llx",
                udev->slot_id,
                &xhci->dcbaa->dev_context_ptrs[udev->slot_id],
                (unsigned long long)
                le64_to_cpu(xhci->dcbaa->dev_context_ptrs[udev->slot_id]));
        xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                        "Output Context DMA address = %#08llx",
                        (unsigned long long)virt_dev->out_ctx->dma);
        trace_xhci_address_ctx(xhci, virt_dev->in_ctx,
                                le32_to_cpu(slot_ctx->dev_info) >> 27);
        /*
         * USB core uses address 1 for the roothubs, so we add one to the
         * address given back to us by the HC.
         */
        trace_xhci_address_ctx(xhci, virt_dev->out_ctx,
                                le32_to_cpu(slot_ctx->dev_info) >> 27);
        /* Zero the input context control for later use */
        ctrl_ctx->add_flags = 0;
        ctrl_ctx->drop_flags = 0;

        xhci_dbg_trace(xhci, trace_xhci_dbg_address,
                       "Internal device address = %d",
                       le32_to_cpu(slot_ctx->dev_state) & DEV_ADDR_MASK);
out:
        mutex_unlock(&xhci->mutex);
        if (command) {
                kfree(command->completion);
                kfree(command);
        }
        return ret;
}

static int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev)
{
        return xhci_setup_device(hcd, udev, SETUP_CONTEXT_ADDRESS);
}

static int xhci_enable_device(struct usb_hcd *hcd, struct usb_device *udev)
{
        return xhci_setup_device(hcd, udev, SETUP_CONTEXT_ONLY);
}

/*
 * Transfer the port index into real index in the HW port status
 * registers. Caculate offset between the port's PORTSC register
 * and port status base. Divide the number of per port register
 * to get the real index. The raw port number bases 1.
 */
int xhci_find_raw_port_number(struct usb_hcd *hcd, int port1)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        __le32 __iomem *base_addr = &xhci->op_regs->port_status_base;
        __le32 __iomem *addr;
        int raw_port;

        if (hcd->speed < HCD_USB3)
                addr = xhci->usb2_ports[port1 - 1];
        else
                addr = xhci->usb3_ports[port1 - 1];

        raw_port = (addr - base_addr)/NUM_PORT_REGS + 1;
        return raw_port;
}

/*
 * Issue an Evaluate Context command to change the Maximum Exit Latency in the
 * slot context.  If that succeeds, store the new MEL in the xhci_virt_device.
 */
static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci,
                        struct usb_device *udev, u16 max_exit_latency)
{
        struct xhci_virt_device *virt_dev;
        struct xhci_command *command;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_slot_ctx *slot_ctx;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&xhci->lock, flags);

        virt_dev = xhci->devs[udev->slot_id];

        /*
         * virt_dev might not exists yet if xHC resumed from hibernate (S4) and
         * xHC was re-initialized. Exit latency will be set later after
         * hub_port_finish_reset() is done and xhci->devs[] are re-allocated
         */

        if (!virt_dev || max_exit_latency == virt_dev->current_mel) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                return 0;
        }

        /* Attempt to issue an Evaluate Context command to change the MEL. */
        command = xhci->lpm_command;
        ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);
        if (!ctrl_ctx) {
                spin_unlock_irqrestore(&xhci->lock, flags);
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                return -ENOMEM;
        }

        xhci_slot_copy(xhci, command->in_ctx, virt_dev->out_ctx);
        spin_unlock_irqrestore(&xhci->lock, flags);

        ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
        slot_ctx = xhci_get_slot_ctx(xhci, command->in_ctx);
        slot_ctx->dev_info2 &= cpu_to_le32(~((u32) MAX_EXIT));
        slot_ctx->dev_info2 |= cpu_to_le32(max_exit_latency);
        slot_ctx->dev_state = 0;

        xhci_dbg_trace(xhci, trace_xhci_dbg_context_change,
                        "Set up evaluate context for LPM MEL change.");

        /* Issue and wait for the evaluate context command. */
        ret = xhci_configure_endpoint(xhci, udev, command,
                        true, true);

        if (!ret) {
                spin_lock_irqsave(&xhci->lock, flags);
                virt_dev->current_mel = max_exit_latency;
                spin_unlock_irqrestore(&xhci->lock, flags);
        }
        return ret;
}

#ifdef CONFIG_PM

/* BESL to HIRD Encoding array for USB2 LPM */
static int xhci_besl_encoding[16] = {125, 150, 200, 300, 400, 500, 1000, 2000,
        3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000};

/* Calculate HIRD/BESL for USB2 PORTPMSC*/
static int xhci_calculate_hird_besl(struct xhci_hcd *xhci,
                                        struct usb_device *udev)
{
        int u2del, besl, besl_host;
        int besl_device = 0;
        u32 field;

        u2del = HCS_U2_LATENCY(xhci->hcs_params3);
        field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);

        if (field & USB_BESL_SUPPORT) {
                for (besl_host = 0; besl_host < 16; besl_host++) {
                        if (xhci_besl_encoding[besl_host] >= u2del)
                                break;
                }
                /* Use baseline BESL value as default */
                if (field & USB_BESL_BASELINE_VALID)
                        besl_device = USB_GET_BESL_BASELINE(field);
                else if (field & USB_BESL_DEEP_VALID)
                        besl_device = USB_GET_BESL_DEEP(field);
        } else {
                if (u2del <= 50)
                        besl_host = 0;
                else
                        besl_host = (u2del - 51) / 75 + 1;
        }

        besl = besl_host + besl_device;
        if (besl > 15)
                besl = 15;

        return besl;
}

/* Calculate BESLD, L1 timeout and HIRDM for USB2 PORTHLPMC */
static int xhci_calculate_usb2_hw_lpm_params(struct usb_device *udev)
{
        u32 field;
        int l1;
        int besld = 0;
        int hirdm = 0;

        field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);

        /* xHCI l1 is set in steps of 256us, xHCI 1.0 section 5.4.11.2 */
        l1 = udev->l1_params.timeout / 256;

        /* device has preferred BESLD */
        if (field & USB_BESL_DEEP_VALID) {
                besld = USB_GET_BESL_DEEP(field);
                hirdm = 1;
        }

        return PORT_BESLD(besld) | PORT_L1_TIMEOUT(l1) | PORT_HIRDM(hirdm);
}

static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
                        struct usb_device *udev, int enable)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        __le32 __iomem  **port_array;
        __le32 __iomem  *pm_addr, *hlpm_addr;
        u32             pm_val, hlpm_val, field;
        unsigned int    port_num;
        unsigned long   flags;
        int             hird, exit_latency;
        int             ret;

        if (hcd->speed >= HCD_USB3 || !xhci->hw_lpm_support ||
                        !udev->lpm_capable)
                return -EPERM;

        if (!udev->parent || udev->parent->parent ||
                        udev->descriptor.bDeviceClass == USB_CLASS_HUB)
                return -EPERM;

        if (udev->usb2_hw_lpm_capable != 1)
                return -EPERM;

        spin_lock_irqsave(&xhci->lock, flags);

        port_array = xhci->usb2_ports;
        port_num = udev->portnum - 1;
        pm_addr = port_array[port_num] + PORTPMSC;
        pm_val = readl(pm_addr);
        hlpm_addr = port_array[port_num] + PORTHLPMC;
        field = le32_to_cpu(udev->bos->ext_cap->bmAttributes);

        xhci_dbg(xhci, "%s port %d USB2 hardware LPM\n",
                        enable ? "enable" : "disable", port_num + 1);

        if (enable) {
                /* Host supports BESL timeout instead of HIRD */
                if (udev->usb2_hw_lpm_besl_capable) {
                        /* if device doesn't have a preferred BESL value use a
                         * default one which works with mixed HIRD and BESL
                         * systems. See XHCI_DEFAULT_BESL definition in xhci.h
                         */
                        if ((field & USB_BESL_SUPPORT) &&
                            (field & USB_BESL_BASELINE_VALID))
                                hird = USB_GET_BESL_BASELINE(field);
                        else
                                hird = udev->l1_params.besl;

                        exit_latency = xhci_besl_encoding[hird];
                        spin_unlock_irqrestore(&xhci->lock, flags);

                        /* USB 3.0 code dedicate one xhci->lpm_command->in_ctx
                         * input context for link powermanagement evaluate
                         * context commands. It is protected by hcd->bandwidth
                         * mutex and is shared by all devices. We need to set
                         * the max ext latency in USB 2 BESL LPM as well, so
                         * use the same mutex and xhci_change_max_exit_latency()
                         */
                        mutex_lock(hcd->bandwidth_mutex);
                        ret = xhci_change_max_exit_latency(xhci, udev,
                                                           exit_latency);
                        mutex_unlock(hcd->bandwidth_mutex);

                        if (ret < 0)
                                return ret;
                        spin_lock_irqsave(&xhci->lock, flags);

                        hlpm_val = xhci_calculate_usb2_hw_lpm_params(udev);
                        writel(hlpm_val, hlpm_addr);
                        /* flush write */
                        readl(hlpm_addr);
                } else {
                        hird = xhci_calculate_hird_besl(xhci, udev);
                }

                pm_val &= ~PORT_HIRD_MASK;
                pm_val |= PORT_HIRD(hird) | PORT_RWE | PORT_L1DS(udev->slot_id);
                writel(pm_val, pm_addr);
                pm_val = readl(pm_addr);
                pm_val |= PORT_HLE;
                writel(pm_val, pm_addr);
                /* flush write */
                readl(pm_addr);
        } else {
                pm_val &= ~(PORT_HLE | PORT_RWE | PORT_HIRD_MASK | PORT_L1DS_MASK);
                writel(pm_val, pm_addr);
                /* flush write */
                readl(pm_addr);
                if (udev->usb2_hw_lpm_besl_capable) {
                        spin_unlock_irqrestore(&xhci->lock, flags);
                        mutex_lock(hcd->bandwidth_mutex);
                        xhci_change_max_exit_latency(xhci, udev, 0);
                        mutex_unlock(hcd->bandwidth_mutex);
                        return 0;
                }
        }

        spin_unlock_irqrestore(&xhci->lock, flags);
        return 0;
}

/* check if a usb2 port supports a given extened capability protocol
 * only USB2 ports extended protocol capability values are cached.
 * Return 1 if capability is supported
 */
static int xhci_check_usb2_port_capability(struct xhci_hcd *xhci, int port,
                                           unsigned capability)
{
        u32 port_offset, port_count;
        int i;

        for (i = 0; i < xhci->num_ext_caps; i++) {
                if (xhci->ext_caps[i] & capability) {
                        /* port offsets starts at 1 */
                        port_offset = XHCI_EXT_PORT_OFF(xhci->ext_caps[i]) - 1;
                        port_count = XHCI_EXT_PORT_COUNT(xhci->ext_caps[i]);
                        if (port >= port_offset &&
                            port < port_offset + port_count)
                                return 1;
                }
        }
        return 0;
}

static int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        int             portnum = udev->portnum - 1;

        if (hcd->speed >= HCD_USB3 || !xhci->sw_lpm_support ||
                        !udev->lpm_capable)
                return 0;

        /* we only support lpm for non-hub device connected to root hub yet */
        if (!udev->parent || udev->parent->parent ||
                        udev->descriptor.bDeviceClass == USB_CLASS_HUB)
                return 0;

        if (xhci->hw_lpm_support == 1 &&
                        xhci_check_usb2_port_capability(
                                xhci, portnum, XHCI_HLC)) {
                udev->usb2_hw_lpm_capable = 1;
                udev->l1_params.timeout = XHCI_L1_TIMEOUT;
                udev->l1_params.besl = XHCI_DEFAULT_BESL;
                if (xhci_check_usb2_port_capability(xhci, portnum,
                                        XHCI_BLC))
                        udev->usb2_hw_lpm_besl_capable = 1;
        }

        return 0;
}

/*---------------------- USB 3.0 Link PM functions ------------------------*/

/* Service interval in nanoseconds = 2^(bInterval - 1) * 125us * 1000ns / 1us */
static unsigned long long xhci_service_interval_to_ns(
                struct usb_endpoint_descriptor *desc)
{
        return (1ULL << (desc->bInterval - 1)) * 125 * 1000;
}

static u16 xhci_get_timeout_no_hub_lpm(struct usb_device *udev,
                enum usb3_link_state state)
{
        unsigned long long sel;
        unsigned long long pel;
        unsigned int max_sel_pel;
        char *state_name;

        switch (state) {
        case USB3_LPM_U1:
                /* Convert SEL and PEL stored in nanoseconds to microseconds */
                sel = DIV_ROUND_UP(udev->u1_params.sel, 1000);
                pel = DIV_ROUND_UP(udev->u1_params.pel, 1000);
                max_sel_pel = USB3_LPM_MAX_U1_SEL_PEL;
                state_name = "U1";
                break;
        case USB3_LPM_U2:
                sel = DIV_ROUND_UP(udev->u2_params.sel, 1000);
                pel = DIV_ROUND_UP(udev->u2_params.pel, 1000);
                max_sel_pel = USB3_LPM_MAX_U2_SEL_PEL;
                state_name = "U2";
                break;
        default:
                dev_warn(&udev->dev, "%s: Can't get timeout for non-U1 or U2 state.\n",
                                __func__);
                return USB3_LPM_DISABLED;
        }

        if (sel <= max_sel_pel && pel <= max_sel_pel)
                return USB3_LPM_DEVICE_INITIATED;

        if (sel > max_sel_pel)
                dev_dbg(&udev->dev, "Device-initiated %s disabled "
                                "due to long SEL %llu ms\n",
                                state_name, sel);
        else
                dev_dbg(&udev->dev, "Device-initiated %s disabled "
                                "due to long PEL %llu ms\n",
                                state_name, pel);
        return USB3_LPM_DISABLED;
}

/* The U1 timeout should be the maximum of the following values:
 *  - For control endpoints, U1 system exit latency (SEL) * 3
 *  - For bulk endpoints, U1 SEL * 5
 *  - For interrupt endpoints:
 *    - Notification EPs, U1 SEL * 3
 *    - Periodic EPs, max(105% of bInterval, U1 SEL * 2)
 *  - For isochronous endpoints, max(105% of bInterval, U1 SEL * 2)
 */
static unsigned long long xhci_calculate_intel_u1_timeout(
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc)
{
        unsigned long long timeout_ns;
        int ep_type;
        int intr_type;

        ep_type = usb_endpoint_type(desc);
        switch (ep_type) {
        case USB_ENDPOINT_XFER_CONTROL:
                timeout_ns = udev->u1_params.sel * 3;
                break;
        case USB_ENDPOINT_XFER_BULK:
                timeout_ns = udev->u1_params.sel * 5;
                break;
        case USB_ENDPOINT_XFER_INT:
                intr_type = usb_endpoint_interrupt_type(desc);
                if (intr_type == USB_ENDPOINT_INTR_NOTIFICATION) {
                        timeout_ns = udev->u1_params.sel * 3;
                        break;
                }
                /* Otherwise the calculation is the same as isoc eps */
        case USB_ENDPOINT_XFER_ISOC:
                timeout_ns = xhci_service_interval_to_ns(desc);
                timeout_ns = DIV_ROUND_UP_ULL(timeout_ns * 105, 100);
                if (timeout_ns < udev->u1_params.sel * 2)
                        timeout_ns = udev->u1_params.sel * 2;
                break;
        default:
                return 0;
        }

        return timeout_ns;
}

/* Returns the hub-encoded U1 timeout value. */
static u16 xhci_calculate_u1_timeout(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc)
{
        unsigned long long timeout_ns;

        if (xhci->quirks & XHCI_INTEL_HOST)
                timeout_ns = xhci_calculate_intel_u1_timeout(udev, desc);
        else
                timeout_ns = udev->u1_params.sel;

        /* The U1 timeout is encoded in 1us intervals.
         * Don't return a timeout of zero, because that's USB3_LPM_DISABLED.
         */
        if (timeout_ns == USB3_LPM_DISABLED)
                timeout_ns = 1;
        else
                timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 1000);

        /* If the necessary timeout value is bigger than what we can set in the
         * USB 3.0 hub, we have to disable hub-initiated U1.
         */
        if (timeout_ns <= USB3_LPM_U1_MAX_TIMEOUT)
                return timeout_ns;
        dev_dbg(&udev->dev, "Hub-initiated U1 disabled "
                        "due to long timeout %llu ms\n", timeout_ns);
        return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U1);
}

/* The U2 timeout should be the maximum of:
 *  - 10 ms (to avoid the bandwidth impact on the scheduler)
 *  - largest bInterval of any active periodic endpoint (to avoid going
 *    into lower power link states between intervals).
 *  - the U2 Exit Latency of the device
 */
static unsigned long long xhci_calculate_intel_u2_timeout(
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc)
{
        unsigned long long timeout_ns;
        unsigned long long u2_del_ns;

        timeout_ns = 10 * 1000 * 1000;

        if ((usb_endpoint_xfer_int(desc) || usb_endpoint_xfer_isoc(desc)) &&
                        (xhci_service_interval_to_ns(desc) > timeout_ns))
                timeout_ns = xhci_service_interval_to_ns(desc);

        u2_del_ns = le16_to_cpu(udev->bos->ss_cap->bU2DevExitLat) * 1000ULL;
        if (u2_del_ns > timeout_ns)
                timeout_ns = u2_del_ns;

        return timeout_ns;
}

/* Returns the hub-encoded U2 timeout value. */
static u16 xhci_calculate_u2_timeout(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc)
{
        unsigned long long timeout_ns;

        if (xhci->quirks & XHCI_INTEL_HOST)
                timeout_ns = xhci_calculate_intel_u2_timeout(udev, desc);
        else
                timeout_ns = udev->u2_params.sel;

        /* The U2 timeout is encoded in 256us intervals */
        timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 256 * 1000);
        /* If the necessary timeout value is bigger than what we can set in the
         * USB 3.0 hub, we have to disable hub-initiated U2.
         */
        if (timeout_ns <= USB3_LPM_U2_MAX_TIMEOUT)
                return timeout_ns;
        dev_dbg(&udev->dev, "Hub-initiated U2 disabled "
                        "due to long timeout %llu ms\n", timeout_ns);
        return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U2);
}

static u16 xhci_call_host_update_timeout_for_endpoint(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc,
                enum usb3_link_state state,
                u16 *timeout)
{
        if (state == USB3_LPM_U1)
                return xhci_calculate_u1_timeout(xhci, udev, desc);
        else if (state == USB3_LPM_U2)
                return xhci_calculate_u2_timeout(xhci, udev, desc);

        return USB3_LPM_DISABLED;
}

static int xhci_update_timeout_for_endpoint(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_endpoint_descriptor *desc,
                enum usb3_link_state state,
                u16 *timeout)
{
        u16 alt_timeout;

        alt_timeout = xhci_call_host_update_timeout_for_endpoint(xhci, udev,
                desc, state, timeout);

        /* If we found we can't enable hub-initiated LPM, or
         * the U1 or U2 exit latency was too high to allow
         * device-initiated LPM as well, just stop searching.
         */
        if (alt_timeout == USB3_LPM_DISABLED ||
                        alt_timeout == USB3_LPM_DEVICE_INITIATED) {
                *timeout = alt_timeout;
                return -E2BIG;
        }
        if (alt_timeout > *timeout)
                *timeout = alt_timeout;
        return 0;
}

static int xhci_update_timeout_for_interface(struct xhci_hcd *xhci,
                struct usb_device *udev,
                struct usb_host_interface *alt,
                enum usb3_link_state state,
                u16 *timeout)
{
        int j;

        for (j = 0; j < alt->desc.bNumEndpoints; j++) {
                if (xhci_update_timeout_for_endpoint(xhci, udev,
                                        &alt->endpoint[j].desc, state, timeout))
                        return -E2BIG;
                continue;
        }
        return 0;
}

static int xhci_check_intel_tier_policy(struct usb_device *udev,
                enum usb3_link_state state)
{
        struct usb_device *parent;
        unsigned int num_hubs;

        if (state == USB3_LPM_U2)
                return 0;

        /* Don't enable U1 if the device is on a 2nd tier hub or lower. */
        for (parent = udev->parent, num_hubs = 0; parent->parent;
                        parent = parent->parent)
                num_hubs++;

        if (num_hubs < 2)
                return 0;

        dev_dbg(&udev->dev, "Disabling U1 link state for device"
                        " below second-tier hub.\n");
        dev_dbg(&udev->dev, "Plug device into first-tier hub "
                        "to decrease power consumption.\n");
        return -E2BIG;
}

static int xhci_check_tier_policy(struct xhci_hcd *xhci,
                struct usb_device *udev,
                enum usb3_link_state state)
{
        if (xhci->quirks & XHCI_INTEL_HOST)
                return xhci_check_intel_tier_policy(udev, state);
        else
                return 0;
}

/* Returns the U1 or U2 timeout that should be enabled.
 * If the tier check or timeout setting functions return with a non-zero exit
 * code, that means the timeout value has been finalized and we shouldn't look
 * at any more endpoints.
 */
static u16 xhci_calculate_lpm_timeout(struct usb_hcd *hcd,
                        struct usb_device *udev, enum usb3_link_state state)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct usb_host_config *config;
        char *state_name;
        int i;
        u16 timeout = USB3_LPM_DISABLED;

        if (state == USB3_LPM_U1)
                state_name = "U1";
        else if (state == USB3_LPM_U2)
                state_name = "U2";
        else {
                dev_warn(&udev->dev, "Can't enable unknown link state %i\n",
                                state);
                return timeout;
        }

        if (xhci_check_tier_policy(xhci, udev, state) < 0)
                return timeout;

        /* Gather some information about the currently installed configuration
         * and alternate interface settings.
         */
        if (xhci_update_timeout_for_endpoint(xhci, udev, &udev->ep0.desc,
                        state, &timeout))
                return timeout;

        config = udev->actconfig;
        if (!config)
                return timeout;

        for (i = 0; i < config->desc.bNumInterfaces; i++) {
                struct usb_driver *driver;
                struct usb_interface *intf = config->interface[i];

                if (!intf)
                        continue;

                /* Check if any currently bound drivers want hub-initiated LPM
                 * disabled.
                 */
                if (intf->dev.driver) {
                        driver = to_usb_driver(intf->dev.driver);
                        if (driver && driver->disable_hub_initiated_lpm) {
                                dev_dbg(&udev->dev, "Hub-initiated %s disabled "
                                                "at request of driver %s\n",
                                                state_name, driver->name);
                                return xhci_get_timeout_no_hub_lpm(udev, state);
                        }
                }

                /* Not sure how this could happen... */
                if (!intf->cur_altsetting)
                        continue;

                if (xhci_update_timeout_for_interface(xhci, udev,
                                        intf->cur_altsetting,
                                        state, &timeout))
                        return timeout;
        }
        return timeout;
}

static int calculate_max_exit_latency(struct usb_device *udev,
                enum usb3_link_state state_changed,
                u16 hub_encoded_timeout)
{
        unsigned long long u1_mel_us = 0;
        unsigned long long u2_mel_us = 0;
        unsigned long long mel_us = 0;
        bool disabling_u1;
        bool disabling_u2;
        bool enabling_u1;
        bool enabling_u2;

        disabling_u1 = (state_changed == USB3_LPM_U1 &&
                        hub_encoded_timeout == USB3_LPM_DISABLED);
        disabling_u2 = (state_changed == USB3_LPM_U2 &&
                        hub_encoded_timeout == USB3_LPM_DISABLED);

        enabling_u1 = (state_changed == USB3_LPM_U1 &&
                        hub_encoded_timeout != USB3_LPM_DISABLED);
        enabling_u2 = (state_changed == USB3_LPM_U2 &&
                        hub_encoded_timeout != USB3_LPM_DISABLED);

        /* If U1 was already enabled and we're not disabling it,
         * or we're going to enable U1, account for the U1 max exit latency.
         */
        if ((udev->u1_params.timeout != USB3_LPM_DISABLED && !disabling_u1) ||
                        enabling_u1)
                u1_mel_us = DIV_ROUND_UP(udev->u1_params.mel, 1000);
        if ((udev->u2_params.timeout != USB3_LPM_DISABLED && !disabling_u2) ||
                        enabling_u2)
                u2_mel_us = DIV_ROUND_UP(udev->u2_params.mel, 1000);

        if (u1_mel_us > u2_mel_us)
                mel_us = u1_mel_us;
        else
                mel_us = u2_mel_us;
        /* xHCI host controller max exit latency field is only 16 bits wide. */
        if (mel_us > MAX_EXIT) {
                dev_warn(&udev->dev, "Link PM max exit latency of %lluus "
                                "is too big.\n", mel_us);
                return -E2BIG;
        }
        return mel_us;
}

/* Returns the USB3 hub-encoded value for the U1/U2 timeout. */
static int xhci_enable_usb3_lpm_timeout(struct usb_hcd *hcd,
                        struct usb_device *udev, enum usb3_link_state state)
{
        struct xhci_hcd *xhci;
        u16 hub_encoded_timeout;
        int mel;
        int ret;

        xhci = hcd_to_xhci(hcd);
        /* The LPM timeout values are pretty host-controller specific, so don't
         * enable hub-initiated timeouts unless the vendor has provided
         * information about their timeout algorithm.
         */
        if (!xhci || !(xhci->quirks & XHCI_LPM_SUPPORT) ||
                        !xhci->devs[udev->slot_id])
                return USB3_LPM_DISABLED;

        hub_encoded_timeout = xhci_calculate_lpm_timeout(hcd, udev, state);
        mel = calculate_max_exit_latency(udev, state, hub_encoded_timeout);
        if (mel < 0) {
                /* Max Exit Latency is too big, disable LPM. */
                hub_encoded_timeout = USB3_LPM_DISABLED;
                mel = 0;
        }

        ret = xhci_change_max_exit_latency(xhci, udev, mel);
        if (ret)
                return ret;
        return hub_encoded_timeout;
}

static int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
                        struct usb_device *udev, enum usb3_link_state state)
{
        struct xhci_hcd *xhci;
        u16 mel;

        xhci = hcd_to_xhci(hcd);
        if (!xhci || !(xhci->quirks & XHCI_LPM_SUPPORT) ||
                        !xhci->devs[udev->slot_id])
                return 0;

        mel = calculate_max_exit_latency(udev, state, USB3_LPM_DISABLED);
        return xhci_change_max_exit_latency(xhci, udev, mel);
}
#else /* CONFIG_PM */

static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd,
                                struct usb_device *udev, int enable)
{
        return 0;
}

static int xhci_update_device(struct usb_hcd *hcd, struct usb_device *udev)
{
        return 0;
}

static int xhci_enable_usb3_lpm_timeout(struct usb_hcd *hcd,
                        struct usb_device *udev, enum usb3_link_state state)
{
        return USB3_LPM_DISABLED;
}

static int xhci_disable_usb3_lpm_timeout(struct usb_hcd *hcd,
                        struct usb_device *udev, enum usb3_link_state state)
{
        return 0;
}
#endif  /* CONFIG_PM */

/*-------------------------------------------------------------------------*/

/* Once a hub descriptor is fetched for a device, we need to update the xHC's
 * internal data structures for the device.
 */
static int xhci_update_hub_device(struct usb_hcd *hcd, struct usb_device *hdev,
                        struct usb_tt *tt, gfp_t mem_flags)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        struct xhci_virt_device *vdev;
        struct xhci_command *config_cmd;
        struct xhci_input_control_ctx *ctrl_ctx;
        struct xhci_slot_ctx *slot_ctx;
        unsigned long flags;
        unsigned think_time;
        int ret;

        /* Ignore root hubs */
        if (!hdev->parent)
                return 0;

        vdev = xhci->devs[hdev->slot_id];
        if (!vdev) {
                xhci_warn(xhci, "Cannot update hub desc for unknown device.\n");
                return -EINVAL;
        }

        config_cmd = xhci_alloc_command(xhci, true, true, mem_flags);
        if (!config_cmd)
                return -ENOMEM;

        ctrl_ctx = xhci_get_input_control_ctx(config_cmd->in_ctx);
        if (!ctrl_ctx) {
                xhci_warn(xhci, "%s: Could not get input context, bad type.\n",
                                __func__);
                xhci_free_command(xhci, config_cmd);
                return -ENOMEM;
        }

        spin_lock_irqsave(&xhci->lock, flags);
        if (hdev->speed == USB_SPEED_HIGH &&
                        xhci_alloc_tt_info(xhci, vdev, hdev, tt, GFP_ATOMIC)) {
                xhci_dbg(xhci, "Could not allocate xHCI TT structure.\n");
                xhci_free_command(xhci, config_cmd);
                spin_unlock_irqrestore(&xhci->lock, flags);
                return -ENOMEM;
        }

        xhci_slot_copy(xhci, config_cmd->in_ctx, vdev->out_ctx);
        ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
        slot_ctx = xhci_get_slot_ctx(xhci, config_cmd->in_ctx);
        slot_ctx->dev_info |= cpu_to_le32(DEV_HUB);
        /*
         * refer to section 6.2.2: MTT should be 0 for full speed hub,
         * but it may be already set to 1 when setup an xHCI virtual
         * device, so clear it anyway.
         */
        if (tt->multi)
                slot_ctx->dev_info |= cpu_to_le32(DEV_MTT);
        else if (hdev->speed == USB_SPEED_FULL)
                slot_ctx->dev_info &= cpu_to_le32(~DEV_MTT);

        if (xhci->hci_version > 0x95) {
                xhci_dbg(xhci, "xHCI version %x needs hub "
                                "TT think time and number of ports\n",
                                (unsigned int) xhci->hci_version);
                slot_ctx->dev_info2 |= cpu_to_le32(XHCI_MAX_PORTS(hdev->maxchild));
                /* Set TT think time - convert from ns to FS bit times.
                 * 0 = 8 FS bit times, 1 = 16 FS bit times,
                 * 2 = 24 FS bit times, 3 = 32 FS bit times.
                 *
                 * xHCI 1.0: this field shall be 0 if the device is not a
                 * High-spped hub.
                 */
                think_time = tt->think_time;
                if (think_time != 0)
                        think_time = (think_time / 666) - 1;
                if (xhci->hci_version < 0x100 || hdev->speed == USB_SPEED_HIGH)
                        slot_ctx->tt_info |=
                                cpu_to_le32(TT_THINK_TIME(think_time));
        } else {
                xhci_dbg(xhci, "xHCI version %x doesn't need hub "
                                "TT think time or number of ports\n",
                                (unsigned int) xhci->hci_version);
        }
        slot_ctx->dev_state = 0;
        spin_unlock_irqrestore(&xhci->lock, flags);

        xhci_dbg(xhci, "Set up %s for hub device.\n",
                        (xhci->hci_version > 0x95) ?
                        "configure endpoint" : "evaluate context");

        /* Issue and wait for the configure endpoint or
         * evaluate context command.
         */
        if (xhci->hci_version > 0x95)
                ret = xhci_configure_endpoint(xhci, hdev, config_cmd,
                                false, false);
        else
                ret = xhci_configure_endpoint(xhci, hdev, config_cmd,
                                true, false);

        xhci_free_command(xhci, config_cmd);
        return ret;
}

static int xhci_get_frame(struct usb_hcd *hcd)
{
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        /* EHCI mods by the periodic size.  Why? */
        return readl(&xhci->run_regs->microframe_index) >> 3;
}

int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
{
        struct xhci_hcd         *xhci;
        /*
         * TODO: Check with DWC3 clients for sysdev according to
         * quirks
         */
        struct device           *dev = hcd->self.sysdev;
        int                     retval;

        /* Accept arbitrarily long scatter-gather lists */
        hcd->self.sg_tablesize = ~0;

        /* support to build packet from discontinuous buffers */
        hcd->self.no_sg_constraint = 1;

        /* XHCI controllers don't stop the ep queue on short packets :| */
        hcd->self.no_stop_on_short = 1;

        xhci = hcd_to_xhci(hcd);

        if (usb_hcd_is_primary_hcd(hcd)) {
                xhci->main_hcd = hcd;
                /* Mark the first roothub as being USB 2.0.
                 * The xHCI driver will register the USB 3.0 roothub.
                 */
                hcd->speed = HCD_USB2;
                hcd->self.root_hub->speed = USB_SPEED_HIGH;
                /*
                 * USB 2.0 roothub under xHCI has an integrated TT,
                 * (rate matching hub) as opposed to having an OHCI/UHCI
                 * companion controller.
                 */
                hcd->has_tt = 1;
        } else {
                if (xhci->sbrn == 0x31) {
                        xhci_info(xhci, "Host supports USB 3.1 Enhanced SuperSpeed\n");
                        hcd->speed = HCD_USB31;
                        hcd->self.root_hub->speed = USB_SPEED_SUPER_PLUS;
                }
                /* xHCI private pointer was set in xhci_pci_probe for the second
                 * registered roothub.
                 */
                return 0;
        }

        mutex_init(&xhci->mutex);
        xhci->cap_regs = hcd->regs;
        xhci->op_regs = hcd->regs +
                HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
        xhci->run_regs = hcd->regs +
                (readl(&xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
        /* Cache read-only capability registers */
        xhci->hcs_params1 = readl(&xhci->cap_regs->hcs_params1);
        xhci->hcs_params2 = readl(&xhci->cap_regs->hcs_params2);
        xhci->hcs_params3 = readl(&xhci->cap_regs->hcs_params3);
        xhci->hcc_params = readl(&xhci->cap_regs->hc_capbase);
        xhci->hci_version = HC_VERSION(xhci->hcc_params);
        xhci->hcc_params = readl(&xhci->cap_regs->hcc_params);
        if (xhci->hci_version > 0x100)
                xhci->hcc_params2 = readl(&xhci->cap_regs->hcc_params2);
        xhci_print_registers(xhci);

        xhci->quirks |= quirks;

        get_quirks(dev, xhci);

        /* In xhci controllers which follow xhci 1.0 spec gives a spurious
         * success event after a short transfer. This quirk will ignore such
         * spurious event.
         */
        if (xhci->hci_version > 0x96)
                xhci->quirks |= XHCI_SPURIOUS_SUCCESS;

        /* Make sure the HC is halted. */
        retval = xhci_halt(xhci);
        if (retval)
                return retval;

        xhci_dbg(xhci, "Resetting HCD\n");
        /* Reset the internal HC memory state and registers. */
        retval = xhci_reset(xhci);
        if (retval)
                return retval;
        xhci_dbg(xhci, "Reset complete\n");

        /*
         * On some xHCI controllers (e.g. R-Car SoCs), the AC64 bit (bit 0)
         * of HCCPARAMS1 is set to 1. However, the xHCs don't support 64-bit
         * address memory pointers actually. So, this driver clears the AC64
         * bit of xhci->hcc_params to call dma_set_coherent_mask(dev,
         * DMA_BIT_MASK(32)) in this xhci_gen_setup().
         */
        if (xhci->quirks & XHCI_NO_64BIT_SUPPORT)
                xhci->hcc_params &= ~BIT(0);

        /* Set dma_mask and coherent_dma_mask to 64-bits,
         * if xHC supports 64-bit addressing */
        if (HCC_64BIT_ADDR(xhci->hcc_params) &&
                        !dma_set_mask(dev, DMA_BIT_MASK(64))) {
                xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n");
                dma_set_coherent_mask(dev, DMA_BIT_MASK(64));
        } else {
                /*
                 * This is to avoid error in cases where a 32-bit USB
                 * controller is used on a 64-bit capable system.
                 */
                retval = dma_set_mask(dev, DMA_BIT_MASK(32));
                if (retval)
                        return retval;
                xhci_dbg(xhci, "Enabling 32-bit DMA addresses.\n");
                dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
        }

        xhci_dbg(xhci, "Calling HCD init\n");
        /* Initialize HCD and host controller data structures. */
        retval = xhci_init(hcd);
        if (retval)
                return retval;
        xhci_dbg(xhci, "Called HCD init\n");

        xhci_info(xhci, "hcc params 0x%08x hci version 0x%x quirks 0x%08x\n",
                  xhci->hcc_params, xhci->hci_version, xhci->quirks);

        return 0;
}
EXPORT_SYMBOL_GPL(xhci_gen_setup);

static const struct hc_driver xhci_hc_driver = {
        .description =          "xhci-hcd",
        .product_desc =         "xHCI Host Controller",
        .hcd_priv_size =        sizeof(struct xhci_hcd),

        /*
         * generic hardware linkage
         */
        .irq =                  xhci_irq,
        .flags =                HCD_MEMORY | HCD_USB3 | HCD_SHARED,

        /*
         * basic lifecycle operations
         */
        .reset =                NULL, /* set in xhci_init_driver() */
        .start =                xhci_run,
        .stop =                 xhci_stop,
        .shutdown =             xhci_shutdown,

        /*
         * managing i/o requests and associated device resources
         */
        .urb_enqueue =          xhci_urb_enqueue,
        .urb_dequeue =          xhci_urb_dequeue,
        .alloc_dev =            xhci_alloc_dev,
        .free_dev =             xhci_free_dev,
        .alloc_streams =        xhci_alloc_streams,
        .free_streams =         xhci_free_streams,
        .add_endpoint =         xhci_add_endpoint,
        .drop_endpoint =        xhci_drop_endpoint,
        .endpoint_reset =       xhci_endpoint_reset,
        .check_bandwidth =      xhci_check_bandwidth,
        .reset_bandwidth =      xhci_reset_bandwidth,
        .address_device =       xhci_address_device,
        .enable_device =        xhci_enable_device,
        .update_hub_device =    xhci_update_hub_device,
        .reset_device =         xhci_discover_or_reset_device,

        /*
         * scheduling support
         */
        .get_frame_number =     xhci_get_frame,

        /*
         * root hub support
         */
        .hub_control =          xhci_hub_control,
        .hub_status_data =      xhci_hub_status_data,
        .bus_suspend =          xhci_bus_suspend,
        .bus_resume =           xhci_bus_resume,

        /*
         * call back when device connected and addressed
         */
        .update_device =        xhci_update_device,
        .set_usb2_hw_lpm =      xhci_set_usb2_hardware_lpm,
        .enable_usb3_lpm_timeout =      xhci_enable_usb3_lpm_timeout,
        .disable_usb3_lpm_timeout =     xhci_disable_usb3_lpm_timeout,
        .find_raw_port_number = xhci_find_raw_port_number,
};

void xhci_init_driver(struct hc_driver *drv,
                      const struct xhci_driver_overrides *over)
{
        BUG_ON(!over);

        /* Copy the generic table to drv then apply the overrides */
        *drv = xhci_hc_driver;

        if (over) {
                drv->hcd_priv_size += over->extra_priv_size;
                if (over->reset)
                        drv->reset = over->reset;
                if (over->start)
                        drv->start = over->start;
        }
}
EXPORT_SYMBOL_GPL(xhci_init_driver);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_LICENSE("GPL");

static int __init xhci_hcd_init(void)
{
        /*
         * Check the compiler generated sizes of structures that must be laid
         * out in specific ways for hardware access.
         */
        BUILD_BUG_ON(sizeof(struct xhci_doorbell_array) != 256*32/8);
        BUILD_BUG_ON(sizeof(struct xhci_slot_ctx) != 8*32/8);
        BUILD_BUG_ON(sizeof(struct xhci_ep_ctx) != 8*32/8);
        /* xhci_device_control has eight fields, and also
         * embeds one xhci_slot_ctx and 31 xhci_ep_ctx
         */
        BUILD_BUG_ON(sizeof(struct xhci_stream_ctx) != 4*32/8);
        BUILD_BUG_ON(sizeof(union xhci_trb) != 4*32/8);
        BUILD_BUG_ON(sizeof(struct xhci_erst_entry) != 4*32/8);
        BUILD_BUG_ON(sizeof(struct xhci_cap_regs) != 8*32/8);
        BUILD_BUG_ON(sizeof(struct xhci_intr_reg) != 8*32/8);
        /* xhci_run_regs has eight fields and embeds 128 xhci_intr_regs */
        BUILD_BUG_ON(sizeof(struct xhci_run_regs) != (8+8*128)*32/8);

        if (usb_disabled())
                return -ENODEV;

        return 0;
}

/*
 * If an init function is provided, an exit function must also be provided
 * to allow module unload.
 */
static void __exit xhci_hcd_fini(void) { }

module_init(xhci_hcd_init);
module_exit(xhci_hcd_fini);