--- /dev/null
+/*
+ * Intel MID Power Management Unit (PWRMU) device driver
+ *
+ * Copyright (C) 2016, Intel Corporation
+ *
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * Intel MID Power Management Unit device driver handles the South Complex PCI
+ * devices such as GPDMA, SPI, I2C, PWM, and so on. By default PCI core
+ * modifies bits in PMCSR register in the PCI configuration space. This is not
+ * enough on some SoCs like Intel Tangier. In such case PCI core sets a new
+ * power state of the device in question through a PM hook registered in struct
+ * pci_platform_pm_ops (see drivers/pci/pci-mid.c).
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/pci.h>
+
+#include <asm/intel-mid.h>
+
+/* Registers */
+#define PM_STS 0x00
+#define PM_CMD 0x04
+#define PM_ICS 0x08
+#define PM_WKC(x) (0x10 + (x) * 4)
+#define PM_WKS(x) (0x18 + (x) * 4)
+#define PM_SSC(x) (0x20 + (x) * 4)
+#define PM_SSS(x) (0x30 + (x) * 4)
+
+/* Bits in PM_STS */
+#define PM_STS_BUSY (1 << 8)
+
+/* Bits in PM_CMD */
+#define PM_CMD_CMD(x) ((x) << 0)
+#define PM_CMD_IOC (1 << 8)
+#define PM_CMD_D3cold (1 << 21)
+
+/* List of commands */
+#define CMD_SET_CFG 0x01
+
+/* Bits in PM_ICS */
+#define PM_ICS_INT_STATUS(x) ((x) & 0xff)
+#define PM_ICS_IE (1 << 8)
+#define PM_ICS_IP (1 << 9)
+#define PM_ICS_SW_INT_STS (1 << 10)
+
+/* List of interrupts */
+#define INT_INVALID 0
+#define INT_CMD_COMPLETE 1
+#define INT_CMD_ERR 2
+#define INT_WAKE_EVENT 3
+#define INT_LSS_POWER_ERR 4
+#define INT_S0iX_MSG_ERR 5
+#define INT_NO_C6 6
+#define INT_TRIGGER_ERR 7
+#define INT_INACTIVITY 8
+
+/* South Complex devices */
+#define LSS_MAX_SHARED_DEVS 4
+#define LSS_MAX_DEVS 64
+
+#define LSS_WS_BITS 1 /* wake state width */
+#define LSS_PWS_BITS 2 /* power state width */
+
+/* Supported device IDs */
+#define PCI_DEVICE_ID_TANGIER 0x11a1
+
+struct mid_pwr_dev {
+ struct pci_dev *pdev;
+ pci_power_t state;
+};
+
+struct mid_pwr {
+ struct device *dev;
+ void __iomem *regs;
+ int irq;
+ bool available;
+
+ struct mutex lock;
+ struct mid_pwr_dev lss[LSS_MAX_DEVS][LSS_MAX_SHARED_DEVS];
+};
+
+static struct mid_pwr *midpwr;
+
+static u32 mid_pwr_get_state(struct mid_pwr *pwr, int reg)
+{
+ return readl(pwr->regs + PM_SSS(reg));
+}
+
+static void mid_pwr_set_state(struct mid_pwr *pwr, int reg, u32 value)
+{
+ writel(value, pwr->regs + PM_SSC(reg));
+}
+
+static void mid_pwr_set_wake(struct mid_pwr *pwr, int reg, u32 value)
+{
+ writel(value, pwr->regs + PM_WKC(reg));
+}
+
+static void mid_pwr_interrupt_disable(struct mid_pwr *pwr)
+{
+ writel(~PM_ICS_IE, pwr->regs + PM_ICS);
+}
+
+static bool mid_pwr_is_busy(struct mid_pwr *pwr)
+{
+ return !!(readl(pwr->regs + PM_STS) & PM_STS_BUSY);
+}
+
+/* Wait 500ms that the latest PWRMU command finished */
+static int mid_pwr_wait(struct mid_pwr *pwr)
+{
+ unsigned int count = 500000;
+ bool busy;
+
+ do {
+ busy = mid_pwr_is_busy(pwr);
+ if (!busy)
+ return 0;
+ udelay(1);
+ } while (--count);
+
+ return -EBUSY;
+}
+
+static int mid_pwr_wait_for_cmd(struct mid_pwr *pwr, u8 cmd)
+{
+ writel(PM_CMD_CMD(cmd), pwr->regs + PM_CMD);
+ return mid_pwr_wait(pwr);
+}
+
+static int __update_power_state(struct mid_pwr *pwr, int reg, int bit, int new)
+{
+ int curstate;
+ u32 power;
+ int ret;
+
+ /* Check if the device is already in desired state */
+ power = mid_pwr_get_state(pwr, reg);
+ curstate = (power >> bit) & 3;
+ if (curstate == new)
+ return 0;
+
+ /* Update the power state */
+ mid_pwr_set_state(pwr, reg, (power & ~(3 << bit)) | (new << bit));
+
+ /* Send command to SCU */
+ ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
+ if (ret)
+ return ret;
+
+ /* Check if the device is already in desired state */
+ power = mid_pwr_get_state(pwr, reg);
+ curstate = (power >> bit) & 3;
+ if (curstate != new)
+ return -EAGAIN;
+
+ return 0;
+}
+
+static pci_power_t __find_weakest_power_state(struct mid_pwr_dev *lss,
+ struct pci_dev *pdev,
+ pci_power_t state)
+{
+ pci_power_t weakest = PCI_D3hot;
+ unsigned int j;
+
+ /* Find device in cache or first free cell */
+ for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
+ if (lss[j].pdev == pdev || !lss[j].pdev)
+ break;
+ }
+
+ /* Store the desired state in cache */
+ if (j < LSS_MAX_SHARED_DEVS) {
+ lss[j].pdev = pdev;
+ lss[j].state = state;
+ } else {
+ dev_WARN(&pdev->dev, "No room for device in PWRMU LSS cache\n");
+ weakest = state;
+ }
+
+ /* Find the power state we may use */
+ for (j = 0; j < LSS_MAX_SHARED_DEVS; j++) {
+ if (lss[j].state < weakest)
+ weakest = lss[j].state;
+ }
+
+ return weakest;
+}
+
+static int __set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
+ pci_power_t state, int id, int reg, int bit)
+{
+ const char *name;
+ int ret;
+
+ state = __find_weakest_power_state(pwr->lss[id], pdev, state);
+ name = pci_power_name(state);
+
+ ret = __update_power_state(pwr, reg, bit, (__force int)state);
+ if (ret) {
+ dev_warn(&pdev->dev, "Can't set power state %s: %d\n", name, ret);
+ return ret;
+ }
+
+ dev_vdbg(&pdev->dev, "Set power state %s\n", name);
+ return 0;
+}
+
+static int mid_pwr_set_power_state(struct mid_pwr *pwr, struct pci_dev *pdev,
+ pci_power_t state)
+{
+ int id, reg, bit;
+ int ret;
+
+ id = intel_mid_pwr_get_lss_id(pdev);
+ if (id < 0)
+ return id;
+
+ reg = (id * LSS_PWS_BITS) / 32;
+ bit = (id * LSS_PWS_BITS) % 32;
+
+ /* We support states between PCI_D0 and PCI_D3hot */
+ if (state < PCI_D0)
+ state = PCI_D0;
+ if (state > PCI_D3hot)
+ state = PCI_D3hot;
+
+ mutex_lock(&pwr->lock);
+ ret = __set_power_state(pwr, pdev, state, id, reg, bit);
+ mutex_unlock(&pwr->lock);
+ return ret;
+}
+
+int intel_mid_pci_set_power_state(struct pci_dev *pdev, pci_power_t state)
+{
+ struct mid_pwr *pwr = midpwr;
+ int ret = 0;
+
+ might_sleep();
+
+ if (pwr && pwr->available)
+ ret = mid_pwr_set_power_state(pwr, pdev, state);
+ dev_vdbg(&pdev->dev, "set_power_state() returns %d\n", ret);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(intel_mid_pci_set_power_state);
+
+int intel_mid_pwr_get_lss_id(struct pci_dev *pdev)
+{
+ int vndr;
+ u8 id;
+
+ /*
+ * Mapping to PWRMU index is kept in the Logical SubSystem ID byte of
+ * Vendor capability.
+ */
+ vndr = pci_find_capability(pdev, PCI_CAP_ID_VNDR);
+ if (!vndr)
+ return -EINVAL;
+
+ /* Read the Logical SubSystem ID byte */
+ pci_read_config_byte(pdev, vndr + INTEL_MID_PWR_LSS_OFFSET, &id);
+ if (!(id & INTEL_MID_PWR_LSS_TYPE))
+ return -ENODEV;
+
+ id &= ~INTEL_MID_PWR_LSS_TYPE;
+ if (id >= LSS_MAX_DEVS)
+ return -ERANGE;
+
+ return id;
+}
+
+static irqreturn_t mid_pwr_irq_handler(int irq, void *dev_id)
+{
+ struct mid_pwr *pwr = dev_id;
+ u32 ics;
+
+ ics = readl(pwr->regs + PM_ICS);
+ if (!(ics & PM_ICS_IP))
+ return IRQ_NONE;
+
+ writel(ics | PM_ICS_IP, pwr->regs + PM_ICS);
+
+ dev_warn(pwr->dev, "Unexpected IRQ: %#x\n", PM_ICS_INT_STATUS(ics));
+ return IRQ_HANDLED;
+}
+
+struct mid_pwr_device_info {
+ int (*set_initial_state)(struct mid_pwr *pwr);
+};
+
+static int mid_pwr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+ struct mid_pwr_device_info *info = (void *)id->driver_data;
+ struct device *dev = &pdev->dev;
+ struct mid_pwr *pwr;
+ int ret;
+
+ ret = pcim_enable_device(pdev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "error: could not enable device\n");
+ return ret;
+ }
+
+ ret = pcim_iomap_regions(pdev, 1 << 0, pci_name(pdev));
+ if (ret) {
+ dev_err(&pdev->dev, "I/O memory remapping failed\n");
+ return ret;
+ }
+
+ pwr = devm_kzalloc(dev, sizeof(*pwr), GFP_KERNEL);
+ if (!pwr)
+ return -ENOMEM;
+
+ pwr->dev = dev;
+ pwr->regs = pcim_iomap_table(pdev)[0];
+ pwr->irq = pdev->irq;
+
+ mutex_init(&pwr->lock);
+
+ /* Disable interrupts */
+ mid_pwr_interrupt_disable(pwr);
+
+ if (info && info->set_initial_state) {
+ ret = info->set_initial_state(pwr);
+ if (ret)
+ dev_warn(dev, "Can't set initial state: %d\n", ret);
+ }
+
+ ret = devm_request_irq(dev, pdev->irq, mid_pwr_irq_handler,
+ IRQF_NO_SUSPEND, pci_name(pdev), pwr);
+ if (ret)
+ return ret;
+
+ pwr->available = true;
+ midpwr = pwr;
+
+ pci_set_drvdata(pdev, pwr);
+ return 0;
+}
+
+static int tng_set_initial_state(struct mid_pwr *pwr)
+{
+ unsigned int i, j;
+ int ret;
+
+ /*
+ * Enable wake events.
+ *
+ * PWRMU supports up to 32 sources for wake up the system. Ungate them
+ * all here.
+ */
+ mid_pwr_set_wake(pwr, 0, 0xffffffff);
+ mid_pwr_set_wake(pwr, 1, 0xffffffff);
+
+ /*
+ * Power off South Complex devices.
+ *
+ * There is a map (see a note below) of 64 devices with 2 bits per each
+ * on 32-bit HW registers. The following calls set all devices to one
+ * known initial state, i.e. PCI_D3hot. This is done in conjunction
+ * with PMCSR setting in arch/x86/pci/intel_mid_pci.c.
+ *
+ * NOTE: The actual device mapping is provided by a platform at run
+ * time using vendor capability of PCI configuration space.
+ */
+ mid_pwr_set_state(pwr, 0, 0xffffffff);
+ mid_pwr_set_state(pwr, 1, 0xffffffff);
+ mid_pwr_set_state(pwr, 2, 0xffffffff);
+ mid_pwr_set_state(pwr, 3, 0xffffffff);
+
+ /* Send command to SCU */
+ ret = mid_pwr_wait_for_cmd(pwr, CMD_SET_CFG);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < LSS_MAX_DEVS; i++) {
+ for (j = 0; j < LSS_MAX_SHARED_DEVS; j++)
+ pwr->lss[i][j].state = PCI_D3hot;
+ }
+
+ return 0;
+}
+
+static const struct mid_pwr_device_info tng_info = {
+ .set_initial_state = tng_set_initial_state,
+};
+
+static const struct pci_device_id mid_pwr_pci_ids[] = {
+ { PCI_VDEVICE(INTEL, PCI_DEVICE_ID_TANGIER), (kernel_ulong_t)&tng_info },
+ {}
+};
+MODULE_DEVICE_TABLE(pci, mid_pwr_pci_ids);
+
+static struct pci_driver mid_pwr_pci_driver = {
+ .name = "intel_mid_pwr",
+ .probe = mid_pwr_probe,
+ .id_table = mid_pwr_pci_ids,
+};
+
+builtin_pci_driver(mid_pwr_pci_driver);
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