--- /dev/null
+/*
+ * PCI Virtual Channel support
+ *
+ * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
+#include <linux/types.h>
+
+/**
+ * pci_vc_save_restore_dwords - Save or restore a series of dwords
+ * @dev: device
+ * @pos: starting config space position
+ * @buf: buffer to save to or restore from
+ * @dwords: number of dwords to save/restore
+ * @save: whether to save or restore
+ */
+static void pci_vc_save_restore_dwords(struct pci_dev *dev, int pos,
+ u32 *buf, int dwords, bool save)
+{
+ int i;
+
+ for (i = 0; i < dwords; i++, buf++) {
+ if (save)
+ pci_read_config_dword(dev, pos + (i * 4), buf);
+ else
+ pci_write_config_dword(dev, pos + (i * 4), *buf);
+ }
+}
+
+/**
+ * pci_vc_load_arb_table - load and wait for VC arbitration table
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ *
+ * Set Load VC Arbitration Table bit requesting hardware to apply the VC
+ * Arbitration Table (previously loaded). When the VC Arbitration Table
+ * Status clears, hardware has latched the table into VC arbitration logic.
+ */
+static void pci_vc_load_arb_table(struct pci_dev *dev, int pos)
+{
+ u16 ctrl;
+
+ pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL, &ctrl);
+ pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL,
+ ctrl | PCI_VC_PORT_CTRL_LOAD_TABLE);
+ if (pci_wait_for_pending(dev, pos + PCI_VC_PORT_STATUS,
+ PCI_VC_PORT_STATUS_TABLE))
+ return;
+
+ dev_err(&dev->dev, "VC arbitration table failed to load\n");
+}
+
+/**
+ * pci_vc_load_port_arb_table - Load and wait for VC port arbitration table
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @res: VC resource number, ie. VCn (0-7)
+ *
+ * Set Load Port Arbitration Table bit requesting hardware to apply the Port
+ * Arbitration Table (previously loaded). When the Port Arbitration Table
+ * Status clears, hardware has latched the table into port arbitration logic.
+ */
+static void pci_vc_load_port_arb_table(struct pci_dev *dev, int pos, int res)
+{
+ int ctrl_pos, status_pos;
+ u32 ctrl;
+
+ ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+ status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+
+ pci_read_config_dword(dev, ctrl_pos, &ctrl);
+ pci_write_config_dword(dev, ctrl_pos,
+ ctrl | PCI_VC_RES_CTRL_LOAD_TABLE);
+
+ if (pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_TABLE))
+ return;
+
+ dev_err(&dev->dev, "VC%d port arbitration table failed to load\n", res);
+}
+
+/**
+ * pci_vc_enable - Enable virtual channel
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @res: VC res number, ie. VCn (0-7)
+ *
+ * A VC is enabled by setting the enable bit in matching resource control
+ * registers on both sides of a link. We therefore need to find the opposite
+ * end of the link. To keep this simple we enable from the downstream device.
+ * RC devices do not have an upstream device, nor does it seem that VC9 do
+ * (spec is unclear). Once we find the upstream device, match the VC ID to
+ * get the correct resource, disable and enable on both ends.
+ */
+static void pci_vc_enable(struct pci_dev *dev, int pos, int res)
+{
+ int ctrl_pos, status_pos, id, pos2, evcc, i, ctrl_pos2, status_pos2;
+ u32 ctrl, header, reg1, ctrl2;
+ struct pci_dev *link = NULL;
+
+ /* Enable VCs from the downstream device */
+ if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
+ pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+
+ ctrl_pos = pos + PCI_VC_RES_CTRL + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+ status_pos = pos + PCI_VC_RES_STATUS + (res * PCI_CAP_VC_PER_VC_SIZEOF);
+
+ pci_read_config_dword(dev, ctrl_pos, &ctrl);
+ id = ctrl & PCI_VC_RES_CTRL_ID;
+
+ pci_read_config_dword(dev, pos, &header);
+
+ /* If there is no opposite end of the link, skip to enable */
+ if (PCI_EXT_CAP_ID(header) == PCI_EXT_CAP_ID_VC9 ||
+ pci_is_root_bus(dev->bus))
+ goto enable;
+
+ pos2 = pci_find_ext_capability(dev->bus->self, PCI_EXT_CAP_ID_VC);
+ if (!pos2)
+ goto enable;
+
+ pci_read_config_dword(dev->bus->self, pos2 + PCI_VC_PORT_REG1, ®1);
+ evcc = reg1 & PCI_VC_REG1_EVCC;
+
+ /* VC0 is hardwired enabled, so we can start with 1 */
+ for (i = 1; i < evcc + 1; i++) {
+ ctrl_pos2 = pos2 + PCI_VC_RES_CTRL +
+ (i * PCI_CAP_VC_PER_VC_SIZEOF);
+ status_pos2 = pos2 + PCI_VC_RES_STATUS +
+ (i * PCI_CAP_VC_PER_VC_SIZEOF);
+ pci_read_config_dword(dev->bus->self, ctrl_pos2, &ctrl2);
+ if ((ctrl2 & PCI_VC_RES_CTRL_ID) == id) {
+ link = dev->bus->self;
+ break;
+ }
+ }
+
+ if (!link)
+ goto enable;
+
+ /* Disable if enabled */
+ if (ctrl2 & PCI_VC_RES_CTRL_ENABLE) {
+ ctrl2 &= ~PCI_VC_RES_CTRL_ENABLE;
+ pci_write_config_dword(link, ctrl_pos2, ctrl2);
+ }
+
+ /* Enable on both ends */
+ ctrl2 |= PCI_VC_RES_CTRL_ENABLE;
+ pci_write_config_dword(link, ctrl_pos2, ctrl2);
+enable:
+ ctrl |= PCI_VC_RES_CTRL_ENABLE;
+ pci_write_config_dword(dev, ctrl_pos, ctrl);
+
+ if (!pci_wait_for_pending(dev, status_pos, PCI_VC_RES_STATUS_NEGO))
+ dev_err(&dev->dev, "VC%d negotiation stuck pending\n", id);
+
+ if (link && !pci_wait_for_pending(link, status_pos2,
+ PCI_VC_RES_STATUS_NEGO))
+ dev_err(&link->dev, "VC%d negotiation stuck pending\n", id);
+}
+
+/**
+ * pci_vc_do_save_buffer - Size, save, or restore VC state
+ * @dev: device
+ * @pos: starting position of VC capability (VC/VC9/MFVC)
+ * @save_state: buffer for save/restore
+ * @name: for error message
+ * @save: if provided a buffer, this indicates what to do with it
+ *
+ * Walking Virtual Channel config space to size, save, or restore it
+ * is complicated, so we do it all from one function to reduce code and
+ * guarantee ordering matches in the buffer. When called with NULL
+ * @save_state, return the size of the necessary save buffer. When called
+ * with a non-NULL @save_state, @save determines whether we save to the
+ * buffer or restore from it.
+ */
+static int pci_vc_do_save_buffer(struct pci_dev *dev, int pos,
+ struct pci_cap_saved_state *save_state,
+ bool save)
+{
+ u32 reg1;
+ char evcc, lpevcc, parb_size;
+ int i, len = 0;
+ u8 *buf = save_state ? (u8 *)save_state->cap.data : NULL;
+
+ /* Sanity check buffer size for save/restore */
+ if (buf && save_state->cap.size !=
+ pci_vc_do_save_buffer(dev, pos, NULL, save)) {
+ dev_err(&dev->dev,
+ "VC save buffer size does not match @0x%x\n", pos);
+ return -ENOMEM;
+ }
+
+ pci_read_config_dword(dev, pos + PCI_VC_PORT_REG1, ®1);
+ /* Extended VC Count (not counting VC0) */
+ evcc = reg1 & PCI_VC_REG1_EVCC;
+ /* Low Priority Extended VC Count (not counting VC0) */
+ lpevcc = (reg1 & PCI_VC_REG1_LPEVCC) >> 4;
+ /* Port Arbitration Table Entry Size (bits) */
+ parb_size = 1 << ((reg1 & PCI_VC_REG1_ARB_SIZE) >> 10);
+
+ /*
+ * Port VC Control Register contains VC Arbitration Select, which
+ * cannot be modified when more than one LPVC is in operation. We
+ * therefore save/restore it first, as only VC0 should be enabled
+ * after device reset.
+ */
+ if (buf) {
+ if (save)
+ pci_read_config_word(dev, pos + PCI_VC_PORT_CTRL,
+ (u16 *)buf);
+ else
+ pci_write_config_word(dev, pos + PCI_VC_PORT_CTRL,
+ *(u16 *)buf);
+ buf += 2;
+ }
+ len += 2;
+
+ /*
+ * If we have any Low Priority VCs and a VC Arbitration Table Offset
+ * in Port VC Capability Register 2 then save/restore it next.
+ */
+ if (lpevcc) {
+ u32 reg2;
+ int vcarb_offset;
+
+ pci_read_config_dword(dev, pos + PCI_VC_PORT_REG2, ®2);
+ vcarb_offset = ((reg2 & PCI_VC_REG2_ARB_OFF) >> 24) * 16;
+
+ if (vcarb_offset) {
+ int size, vcarb_phases = 0;
+
+ if (reg2 & PCI_VC_REG2_128_PHASE)
+ vcarb_phases = 128;
+ else if (reg2 & PCI_VC_REG2_64_PHASE)
+ vcarb_phases = 64;
+ else if (reg2 & PCI_VC_REG2_32_PHASE)
+ vcarb_phases = 32;
+
+ /* Fixed 4 bits per phase per lpevcc (plus VC0) */
+ size = ((lpevcc + 1) * vcarb_phases * 4) / 8;
+
+ if (size && buf) {
+ pci_vc_save_restore_dwords(dev,
+ pos + vcarb_offset,
+ (u32 *)buf,
+ size / 4, save);
+ /*
+ * On restore, we need to signal hardware to
+ * re-load the VC Arbitration Table.
+ */
+ if (!save)
+ pci_vc_load_arb_table(dev, pos);
+
+ buf += size;
+ }
+ len += size;
+ }
+ }
+
+ /*
+ * In addition to each VC Resource Control Register, we may have a
+ * Port Arbitration Table attached to each VC. The Port Arbitration
+ * Table Offset in each VC Resource Capability Register tells us if
+ * it exists. The entry size is global from the Port VC Capability
+ * Register1 above. The number of phases is determined per VC.
+ */
+ for (i = 0; i < evcc + 1; i++) {
+ u32 cap;
+ int parb_offset;
+
+ pci_read_config_dword(dev, pos + PCI_VC_RES_CAP +
+ (i * PCI_CAP_VC_PER_VC_SIZEOF), &cap);
+ parb_offset = ((cap & PCI_VC_RES_CAP_ARB_OFF) >> 24) * 16;
+ if (parb_offset) {
+ int size, parb_phases = 0;
+
+ if (cap & PCI_VC_RES_CAP_256_PHASE)
+ parb_phases = 256;
+ else if (cap & (PCI_VC_RES_CAP_128_PHASE |
+ PCI_VC_RES_CAP_128_PHASE_TB))
+ parb_phases = 128;
+ else if (cap & PCI_VC_RES_CAP_64_PHASE)
+ parb_phases = 64;
+ else if (cap & PCI_VC_RES_CAP_32_PHASE)
+ parb_phases = 32;
+
+ size = (parb_size * parb_phases) / 8;
+
+ if (size && buf) {
+ pci_vc_save_restore_dwords(dev,
+ pos + parb_offset,
+ (u32 *)buf,
+ size / 4, save);
+ buf += size;
+ }
+ len += size;
+ }
+
+ /* VC Resource Control Register */
+ if (buf) {
+ int ctrl_pos = pos + PCI_VC_RES_CTRL +
+ (i * PCI_CAP_VC_PER_VC_SIZEOF);
+ if (save)
+ pci_read_config_dword(dev, ctrl_pos,
+ (u32 *)buf);
+ else {
+ u32 tmp, ctrl = *(u32 *)buf;
+ /*
+ * For an FLR case, the VC config may remain.
+ * Preserve enable bit, restore the rest.
+ */
+ pci_read_config_dword(dev, ctrl_pos, &tmp);
+ tmp &= PCI_VC_RES_CTRL_ENABLE;
+ tmp |= ctrl & ~PCI_VC_RES_CTRL_ENABLE;
+ pci_write_config_dword(dev, ctrl_pos, tmp);
+ /* Load port arbitration table if used */
+ if (ctrl & PCI_VC_RES_CTRL_ARB_SELECT)
+ pci_vc_load_port_arb_table(dev, pos, i);
+ /* Re-enable if needed */
+ if ((ctrl ^ tmp) & PCI_VC_RES_CTRL_ENABLE)
+ pci_vc_enable(dev, pos, i);
+ }
+ buf += 4;
+ }
+ len += 4;
+ }
+
+ return buf ? 0 : len;
+}
+
+static struct {
+ u16 id;
+ const char *name;
+} vc_caps[] = { { PCI_EXT_CAP_ID_MFVC, "MFVC" },
+ { PCI_EXT_CAP_ID_VC, "VC" },
+ { PCI_EXT_CAP_ID_VC9, "VC9" } };
+
+/**
+ * pci_save_vc_state - Save VC state to pre-allocate save buffer
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability and
+ * save it to the pre-allocated save buffer.
+ */
+int pci_save_vc_state(struct pci_dev *dev)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+ int pos, ret;
+ struct pci_cap_saved_state *save_state;
+
+ pos = pci_find_ext_capability(dev, vc_caps[i].id);
+ if (!pos)
+ continue;
+
+ save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id);
+ if (!save_state) {
+ dev_err(&dev->dev, "%s buffer not found in %s\n",
+ vc_caps[i].name, __func__);
+ return -ENOMEM;
+ }
+
+ ret = pci_vc_do_save_buffer(dev, pos, save_state, true);
+ if (ret) {
+ dev_err(&dev->dev, "%s save unsuccessful %s\n",
+ vc_caps[i].name, __func__);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * pci_restore_vc_state - Restore VC state from save buffer
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability and
+ * restore it from the previously saved buffer.
+ */
+void pci_restore_vc_state(struct pci_dev *dev)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+ int pos;
+ struct pci_cap_saved_state *save_state;
+
+ pos = pci_find_ext_capability(dev, vc_caps[i].id);
+ save_state = pci_find_saved_ext_cap(dev, vc_caps[i].id);
+ if (!save_state || !pos)
+ continue;
+
+ pci_vc_do_save_buffer(dev, pos, save_state, false);
+ }
+}
+
+/**
+ * pci_allocate_vc_save_buffers - Allocate save buffers for VC caps
+ * @dev: device
+ *
+ * For each type of VC capability, VC/VC9/MFVC, find the capability, size
+ * it, and allocate a buffer for save/restore.
+ */
+
+void pci_allocate_vc_save_buffers(struct pci_dev *dev)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(vc_caps); i++) {
+ int len, pos = pci_find_ext_capability(dev, vc_caps[i].id);
+
+ if (!pos)
+ continue;
+
+ len = pci_vc_do_save_buffer(dev, pos, NULL, false);
+ if (pci_add_ext_cap_save_buffer(dev, vc_caps[i].id, len))
+ dev_err(&dev->dev,
+ "unable to preallocate %s save buffer\n",
+ vc_caps[i].name);
+ }
+}
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