zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/drivers/pci/pcie/aspm.c b/ap/os/linux/linux-3.4.x/drivers/pci/pcie/aspm.c
new file mode 100644
index 0000000..c9ce611
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/pci/pcie/aspm.c
@@ -0,0 +1,1018 @@
+/*
+ * File: drivers/pci/pcie/aspm.c
+ * Enabling PCIe link L0s/L1 state and Clock Power Management
+ *
+ * Copyright (C) 2007 Intel
+ * Copyright (C) Zhang Yanmin (yanmin.zhang@intel.com)
+ * Copyright (C) Shaohua Li (shaohua.li@intel.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
+#include <linux/errno.h>
+#include <linux/pm.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/pci-aspm.h>
+#include "../pci.h"
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "pcie_aspm."
+
+/* Note: those are not register definitions */
+#define ASPM_STATE_L0S_UP (1) /* Upstream direction L0s state */
+#define ASPM_STATE_L0S_DW (2) /* Downstream direction L0s state */
+#define ASPM_STATE_L1 (4) /* L1 state */
+#define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
+#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1)
+
+struct aspm_latency {
+ u32 l0s; /* L0s latency (nsec) */
+ u32 l1; /* L1 latency (nsec) */
+};
+
+struct pcie_link_state {
+ struct pci_dev *pdev; /* Upstream component of the Link */
+ struct pcie_link_state *root; /* pointer to the root port link */
+ struct pcie_link_state *parent; /* pointer to the parent Link state */
+ struct list_head sibling; /* node in link_list */
+ struct list_head children; /* list of child link states */
+ struct list_head link; /* node in parent's children list */
+
+ /* ASPM state */
+ u32 aspm_support:3; /* Supported ASPM state */
+ u32 aspm_enabled:3; /* Enabled ASPM state */
+ u32 aspm_capable:3; /* Capable ASPM state with latency */
+ u32 aspm_default:3; /* Default ASPM state by BIOS */
+ u32 aspm_disable:3; /* Disabled ASPM state */
+
+ /* Clock PM state */
+ u32 clkpm_capable:1; /* Clock PM capable? */
+ u32 clkpm_enabled:1; /* Current Clock PM state */
+ u32 clkpm_default:1; /* Default Clock PM state by BIOS */
+
+ /* Exit latencies */
+ struct aspm_latency latency_up; /* Upstream direction exit latency */
+ struct aspm_latency latency_dw; /* Downstream direction exit latency */
+ /*
+ * Endpoint acceptable latencies. A pcie downstream port only
+ * has one slot under it, so at most there are 8 functions.
+ */
+ struct aspm_latency acceptable[8];
+};
+
+static int aspm_disabled, aspm_force;
+static bool aspm_support_enabled = true;
+static DEFINE_MUTEX(aspm_lock);
+static LIST_HEAD(link_list);
+
+#define POLICY_DEFAULT 0 /* BIOS default setting */
+#define POLICY_PERFORMANCE 1 /* high performance */
+#define POLICY_POWERSAVE 2 /* high power saving */
+
+#ifdef CONFIG_PCIEASPM_PERFORMANCE
+static int aspm_policy = POLICY_PERFORMANCE;
+#elif defined CONFIG_PCIEASPM_POWERSAVE
+static int aspm_policy = POLICY_POWERSAVE;
+#else
+static int aspm_policy;
+#endif
+
+static const char *policy_str[] = {
+ [POLICY_DEFAULT] = "default",
+ [POLICY_PERFORMANCE] = "performance",
+ [POLICY_POWERSAVE] = "powersave"
+};
+
+#define LINK_RETRAIN_TIMEOUT HZ
+
+static int policy_to_aspm_state(struct pcie_link_state *link)
+{
+ switch (aspm_policy) {
+ case POLICY_PERFORMANCE:
+ /* Disable ASPM and Clock PM */
+ return 0;
+ case POLICY_POWERSAVE:
+ /* Enable ASPM L0s/L1 */
+ return ASPM_STATE_ALL;
+ case POLICY_DEFAULT:
+ return link->aspm_default;
+ }
+ return 0;
+}
+
+static int policy_to_clkpm_state(struct pcie_link_state *link)
+{
+ switch (aspm_policy) {
+ case POLICY_PERFORMANCE:
+ /* Disable ASPM and Clock PM */
+ return 0;
+ case POLICY_POWERSAVE:
+ /* Disable Clock PM */
+ return 1;
+ case POLICY_DEFAULT:
+ return link->clkpm_default;
+ }
+ return 0;
+}
+
+static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)
+{
+ int pos;
+ u16 reg16;
+ struct pci_dev *child;
+ struct pci_bus *linkbus = link->pdev->subordinate;
+
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ pos = pci_pcie_cap(child);
+ if (!pos)
+ return;
+ pci_read_config_word(child, pos + PCI_EXP_LNKCTL, ®16);
+ if (enable)
+ reg16 |= PCI_EXP_LNKCTL_CLKREQ_EN;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
+ pci_write_config_word(child, pos + PCI_EXP_LNKCTL, reg16);
+ }
+ link->clkpm_enabled = !!enable;
+}
+
+static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
+{
+ /* Don't enable Clock PM if the link is not Clock PM capable */
+ if (!link->clkpm_capable && enable)
+ enable = 0;
+ /* Need nothing if the specified equals to current state */
+ if (link->clkpm_enabled == enable)
+ return;
+ pcie_set_clkpm_nocheck(link, enable);
+}
+
+static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
+{
+ int pos, capable = 1, enabled = 1;
+ u32 reg32;
+ u16 reg16;
+ struct pci_dev *child;
+ struct pci_bus *linkbus = link->pdev->subordinate;
+
+ /* All functions should have the same cap and state, take the worst */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ pos = pci_pcie_cap(child);
+ if (!pos)
+ return;
+ pci_read_config_dword(child, pos + PCI_EXP_LNKCAP, ®32);
+ if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
+ capable = 0;
+ enabled = 0;
+ break;
+ }
+ pci_read_config_word(child, pos + PCI_EXP_LNKCTL, ®16);
+ if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
+ enabled = 0;
+ }
+ link->clkpm_enabled = enabled;
+ link->clkpm_default = enabled;
+ link->clkpm_capable = (blacklist) ? 0 : capable;
+}
+
+/*
+ * pcie_aspm_configure_common_clock: check if the 2 ends of a link
+ * could use common clock. If they are, configure them to use the
+ * common clock. That will reduce the ASPM state exit latency.
+ */
+static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
+{
+ int ppos, cpos, same_clock = 1;
+ u16 reg16, parent_reg, child_reg[8];
+ unsigned long start_jiffies;
+ struct pci_dev *child, *parent = link->pdev;
+ struct pci_bus *linkbus = parent->subordinate;
+ /*
+ * All functions of a slot should have the same Slot Clock
+ * Configuration, so just check one function
+ */
+ child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
+ BUG_ON(!pci_is_pcie(child));
+
+ /* Check downstream component if bit Slot Clock Configuration is 1 */
+ cpos = pci_pcie_cap(child);
+ pci_read_config_word(child, cpos + PCI_EXP_LNKSTA, ®16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Check upstream component if bit Slot Clock Configuration is 1 */
+ ppos = pci_pcie_cap(parent);
+ pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, ®16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Configure downstream component, all functions */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ cpos = pci_pcie_cap(child);
+ pci_read_config_word(child, cpos + PCI_EXP_LNKCTL, ®16);
+ child_reg[PCI_FUNC(child->devfn)] = reg16;
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pci_write_config_word(child, cpos + PCI_EXP_LNKCTL, reg16);
+ }
+
+ /* Configure upstream component */
+ pci_read_config_word(parent, ppos + PCI_EXP_LNKCTL, ®16);
+ parent_reg = reg16;
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
+
+ /* Retrain link */
+ reg16 |= PCI_EXP_LNKCTL_RL;
+ pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
+
+ /* Wait for link training end. Break out after waiting for timeout */
+ start_jiffies = jiffies;
+ for (;;) {
+ pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, ®16);
+ if (!(reg16 & PCI_EXP_LNKSTA_LT))
+ break;
+ if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
+ break;
+ msleep(1);
+ }
+ if (!(reg16 & PCI_EXP_LNKSTA_LT))
+ return;
+
+ /* Training failed. Restore common clock configurations */
+ dev_printk(KERN_ERR, &parent->dev,
+ "ASPM: Could not configure common clock\n");
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ cpos = pci_pcie_cap(child);
+ pci_write_config_word(child, cpos + PCI_EXP_LNKCTL,
+ child_reg[PCI_FUNC(child->devfn)]);
+ }
+ pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, parent_reg);
+}
+
+/* Convert L0s latency encoding to ns */
+static u32 calc_l0s_latency(u32 encoding)
+{
+ if (encoding == 0x7)
+ return (5 * 1000); /* > 4us */
+ return (64 << encoding);
+}
+
+/* Convert L0s acceptable latency encoding to ns */
+static u32 calc_l0s_acceptable(u32 encoding)
+{
+ if (encoding == 0x7)
+ return -1U;
+ return (64 << encoding);
+}
+
+/* Convert L1 latency encoding to ns */
+static u32 calc_l1_latency(u32 encoding)
+{
+ if (encoding == 0x7)
+ return (65 * 1000); /* > 64us */
+ return (1000 << encoding);
+}
+
+/* Convert L1 acceptable latency encoding to ns */
+static u32 calc_l1_acceptable(u32 encoding)
+{
+ if (encoding == 0x7)
+ return -1U;
+ return (1000 << encoding);
+}
+
+struct aspm_register_info {
+ u32 support:2;
+ u32 enabled:2;
+ u32 latency_encoding_l0s;
+ u32 latency_encoding_l1;
+};
+
+static void pcie_get_aspm_reg(struct pci_dev *pdev,
+ struct aspm_register_info *info)
+{
+ int pos;
+ u16 reg16;
+ u32 reg32;
+
+ pos = pci_pcie_cap(pdev);
+ pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, ®32);
+ info->support = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
+ info->latency_encoding_l0s = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
+ info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16);
+ info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
+}
+
+static void pcie_aspm_check_latency(struct pci_dev *endpoint)
+{
+ u32 latency, l1_switch_latency = 0;
+ struct aspm_latency *acceptable;
+ struct pcie_link_state *link;
+
+ /* Device not in D0 doesn't need latency check */
+ if ((endpoint->current_state != PCI_D0) &&
+ (endpoint->current_state != PCI_UNKNOWN))
+ return;
+
+ link = endpoint->bus->self->link_state;
+ acceptable = &link->acceptable[PCI_FUNC(endpoint->devfn)];
+
+ while (link) {
+ /* Check upstream direction L0s latency */
+ if ((link->aspm_capable & ASPM_STATE_L0S_UP) &&
+ (link->latency_up.l0s > acceptable->l0s))
+ link->aspm_capable &= ~ASPM_STATE_L0S_UP;
+
+ /* Check downstream direction L0s latency */
+ if ((link->aspm_capable & ASPM_STATE_L0S_DW) &&
+ (link->latency_dw.l0s > acceptable->l0s))
+ link->aspm_capable &= ~ASPM_STATE_L0S_DW;
+ /*
+ * Check L1 latency.
+ * Every switch on the path to root complex need 1
+ * more microsecond for L1. Spec doesn't mention L0s.
+ */
+ latency = max_t(u32, link->latency_up.l1, link->latency_dw.l1);
+ if ((link->aspm_capable & ASPM_STATE_L1) &&
+ (latency + l1_switch_latency > acceptable->l1))
+ link->aspm_capable &= ~ASPM_STATE_L1;
+ l1_switch_latency += 1000;
+
+ link = link->parent;
+ }
+}
+
+static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
+{
+ struct pci_dev *child, *parent = link->pdev;
+ struct pci_bus *linkbus = parent->subordinate;
+ struct aspm_register_info upreg, dwreg;
+
+ if (blacklist) {
+ /* Set enabled/disable so that we will disable ASPM later */
+ link->aspm_enabled = ASPM_STATE_ALL;
+ link->aspm_disable = ASPM_STATE_ALL;
+ return;
+ }
+
+ /* Configure common clock before checking latencies */
+ pcie_aspm_configure_common_clock(link);
+
+ /* Get upstream/downstream components' register state */
+ pcie_get_aspm_reg(parent, &upreg);
+ child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
+ pcie_get_aspm_reg(child, &dwreg);
+
+ /*
+ * Setup L0s state
+ *
+ * Note that we must not enable L0s in either direction on a
+ * given link unless components on both sides of the link each
+ * support L0s.
+ */
+ if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S)
+ link->aspm_support |= ASPM_STATE_L0S;
+ if (dwreg.enabled & PCIE_LINK_STATE_L0S)
+ link->aspm_enabled |= ASPM_STATE_L0S_UP;
+ if (upreg.enabled & PCIE_LINK_STATE_L0S)
+ link->aspm_enabled |= ASPM_STATE_L0S_DW;
+ link->latency_up.l0s = calc_l0s_latency(upreg.latency_encoding_l0s);
+ link->latency_dw.l0s = calc_l0s_latency(dwreg.latency_encoding_l0s);
+
+ /* Setup L1 state */
+ if (upreg.support & dwreg.support & PCIE_LINK_STATE_L1)
+ link->aspm_support |= ASPM_STATE_L1;
+ if (upreg.enabled & dwreg.enabled & PCIE_LINK_STATE_L1)
+ link->aspm_enabled |= ASPM_STATE_L1;
+ link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1);
+ link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1);
+
+ /* Save default state */
+ link->aspm_default = link->aspm_enabled;
+
+ /* Setup initial capable state. Will be updated later */
+ link->aspm_capable = link->aspm_support;
+ /*
+ * If the downstream component has pci bridge function, don't
+ * do ASPM for now.
+ */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+ link->aspm_disable = ASPM_STATE_ALL;
+ break;
+ }
+ }
+
+ /* Get and check endpoint acceptable latencies */
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ int pos;
+ u32 reg32, encoding;
+ struct aspm_latency *acceptable =
+ &link->acceptable[PCI_FUNC(child->devfn)];
+
+ if (child->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
+ child->pcie_type != PCI_EXP_TYPE_LEG_END)
+ continue;
+
+ pos = pci_pcie_cap(child);
+ pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, ®32);
+ /* Calculate endpoint L0s acceptable latency */
+ encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
+ acceptable->l0s = calc_l0s_acceptable(encoding);
+ /* Calculate endpoint L1 acceptable latency */
+ encoding = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
+ acceptable->l1 = calc_l1_acceptable(encoding);
+
+ pcie_aspm_check_latency(child);
+ }
+}
+
+static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
+{
+ u16 reg16;
+ int pos = pci_pcie_cap(pdev);
+
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16);
+ reg16 &= ~0x3;
+ reg16 |= val;
+ pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
+}
+
+static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
+{
+ u32 upstream = 0, dwstream = 0;
+ struct pci_dev *child, *parent = link->pdev;
+ struct pci_bus *linkbus = parent->subordinate;
+
+ /* Nothing to do if the link is already in the requested state */
+ state &= (link->aspm_capable & ~link->aspm_disable);
+ if (link->aspm_enabled == state)
+ return;
+ /* Convert ASPM state to upstream/downstream ASPM register state */
+ if (state & ASPM_STATE_L0S_UP)
+ dwstream |= PCIE_LINK_STATE_L0S;
+ if (state & ASPM_STATE_L0S_DW)
+ upstream |= PCIE_LINK_STATE_L0S;
+ if (state & ASPM_STATE_L1) {
+ upstream |= PCIE_LINK_STATE_L1;
+ dwstream |= PCIE_LINK_STATE_L1;
+ }
+ /*
+ * Spec 2.0 suggests all functions should be configured the
+ * same setting for ASPM. Enabling ASPM L1 should be done in
+ * upstream component first and then downstream, and vice
+ * versa for disabling ASPM L1. Spec doesn't mention L0S.
+ */
+ if (state & ASPM_STATE_L1)
+ pcie_config_aspm_dev(parent, upstream);
+ list_for_each_entry(child, &linkbus->devices, bus_list)
+ pcie_config_aspm_dev(child, dwstream);
+ if (!(state & ASPM_STATE_L1))
+ pcie_config_aspm_dev(parent, upstream);
+
+ link->aspm_enabled = state;
+}
+
+static void pcie_config_aspm_path(struct pcie_link_state *link)
+{
+ while (link) {
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+ link = link->parent;
+ }
+}
+
+static void free_link_state(struct pcie_link_state *link)
+{
+ link->pdev->link_state = NULL;
+ kfree(link);
+}
+
+static int pcie_aspm_sanity_check(struct pci_dev *pdev)
+{
+ struct pci_dev *child;
+ int pos;
+ u32 reg32;
+
+ /*
+ * Some functions in a slot might not all be PCIe functions,
+ * very strange. Disable ASPM for the whole slot
+ */
+ list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
+ pos = pci_pcie_cap(child);
+ if (!pos)
+ return -EINVAL;
+
+ /*
+ * If ASPM is disabled then we're not going to change
+ * the BIOS state. It's safe to continue even if it's a
+ * pre-1.1 device
+ */
+
+ if (aspm_disabled)
+ continue;
+
+ /*
+ * Disable ASPM for pre-1.1 PCIe device, we follow MS to use
+ * RBER bit to determine if a function is 1.1 version device
+ */
+ pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, ®32);
+ if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
+ dev_printk(KERN_INFO, &child->dev, "disabling ASPM"
+ " on pre-1.1 PCIe device. You can enable it"
+ " with 'pcie_aspm=force'\n");
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link;
+
+ link = kzalloc(sizeof(*link), GFP_KERNEL);
+ if (!link)
+ return NULL;
+ INIT_LIST_HEAD(&link->sibling);
+ INIT_LIST_HEAD(&link->children);
+ INIT_LIST_HEAD(&link->link);
+ link->pdev = pdev;
+ if (pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM) {
+ struct pcie_link_state *parent;
+ parent = pdev->bus->parent->self->link_state;
+ if (!parent) {
+ kfree(link);
+ return NULL;
+ }
+ link->parent = parent;
+ list_add(&link->link, &parent->children);
+ }
+ /* Setup a pointer to the root port link */
+ if (!link->parent)
+ link->root = link;
+ else
+ link->root = link->parent->root;
+
+ list_add(&link->sibling, &link_list);
+ pdev->link_state = link;
+ return link;
+}
+
+/*
+ * pcie_aspm_init_link_state: Initiate PCI express link state.
+ * It is called after the pcie and its children devices are scaned.
+ * @pdev: the root port or switch downstream port
+ */
+void pcie_aspm_init_link_state(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link;
+ int blacklist = !!pcie_aspm_sanity_check(pdev);
+
+ if (!aspm_support_enabled)
+ return;
+
+ if (!pci_is_pcie(pdev) || pdev->link_state)
+ return;
+ if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+
+ /* VIA has a strange chipset, root port is under a bridge */
+ if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->bus->self)
+ return;
+
+ down_read(&pci_bus_sem);
+ if (list_empty(&pdev->subordinate->devices))
+ goto out;
+
+ mutex_lock(&aspm_lock);
+ link = alloc_pcie_link_state(pdev);
+ if (!link)
+ goto unlock;
+ /*
+ * Setup initial ASPM state. Note that we need to configure
+ * upstream links also because capable state of them can be
+ * update through pcie_aspm_cap_init().
+ */
+ pcie_aspm_cap_init(link, blacklist);
+
+ /* Setup initial Clock PM state */
+ pcie_clkpm_cap_init(link, blacklist);
+
+ /*
+ * At this stage drivers haven't had an opportunity to change the
+ * link policy setting. Enabling ASPM on broken hardware can cripple
+ * it even before the driver has had a chance to disable ASPM, so
+ * default to a safe level right now. If we're enabling ASPM beyond
+ * the BIOS's expectation, we'll do so once pci_enable_device() is
+ * called.
+ */
+ if (aspm_policy != POLICY_POWERSAVE) {
+ pcie_config_aspm_path(link);
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+ }
+
+unlock:
+ mutex_unlock(&aspm_lock);
+out:
+ up_read(&pci_bus_sem);
+}
+
+/* Recheck latencies and update aspm_capable for links under the root */
+static void pcie_update_aspm_capable(struct pcie_link_state *root)
+{
+ struct pcie_link_state *link;
+ BUG_ON(root->parent);
+ list_for_each_entry(link, &link_list, sibling) {
+ if (link->root != root)
+ continue;
+ link->aspm_capable = link->aspm_support;
+ }
+ list_for_each_entry(link, &link_list, sibling) {
+ struct pci_dev *child;
+ struct pci_bus *linkbus = link->pdev->subordinate;
+ if (link->root != root)
+ continue;
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ if ((child->pcie_type != PCI_EXP_TYPE_ENDPOINT) &&
+ (child->pcie_type != PCI_EXP_TYPE_LEG_END))
+ continue;
+ pcie_aspm_check_latency(child);
+ }
+ }
+}
+
+/* @pdev: the endpoint device */
+void pcie_aspm_exit_link_state(struct pci_dev *pdev)
+{
+ struct pci_dev *parent = pdev->bus->self;
+ struct pcie_link_state *link, *root, *parent_link;
+
+ if (!pci_is_pcie(pdev) || !parent || !parent->link_state)
+ return;
+ if ((parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
+ (parent->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ /*
+ * All PCIe functions are in one slot, remove one function will remove
+ * the whole slot, so just wait until we are the last function left.
+ */
+ if (!list_is_last(&pdev->bus_list, &parent->subordinate->devices))
+ goto out;
+
+ link = parent->link_state;
+ root = link->root;
+ parent_link = link->parent;
+
+ /* All functions are removed, so just disable ASPM for the link */
+ pcie_config_aspm_link(link, 0);
+ list_del(&link->sibling);
+ list_del(&link->link);
+ /* Clock PM is for endpoint device */
+ free_link_state(link);
+
+ /* Recheck latencies and configure upstream links */
+ if (parent_link) {
+ pcie_update_aspm_capable(root);
+ pcie_config_aspm_path(parent_link);
+ }
+out:
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+/* @pdev: the root port or switch downstream port */
+void pcie_aspm_pm_state_change(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link = pdev->link_state;
+
+ if (aspm_disabled || !pci_is_pcie(pdev) || !link)
+ return;
+ if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
+ (pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+ /*
+ * Devices changed PM state, we should recheck if latency
+ * meets all functions' requirement
+ */
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ pcie_update_aspm_capable(link->root);
+ pcie_config_aspm_path(link);
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link = pdev->link_state;
+
+ if (aspm_disabled || !pci_is_pcie(pdev) || !link)
+ return;
+
+ if (aspm_policy != POLICY_POWERSAVE)
+ return;
+
+ if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
+ (pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ pcie_config_aspm_path(link);
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+/*
+ * pci_disable_link_state - disable pci device's link state, so the link will
+ * never enter specific states
+ */
+static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem,
+ bool force)
+{
+ struct pci_dev *parent = pdev->bus->self;
+ struct pcie_link_state *link;
+
+ if (aspm_disabled && !force)
+ return;
+
+ if (!pci_is_pcie(pdev))
+ return;
+
+ if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
+ pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
+ parent = pdev;
+ if (!parent || !parent->link_state)
+ return;
+
+ if (sem)
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ link = parent->link_state;
+ if (state & PCIE_LINK_STATE_L0S)
+ link->aspm_disable |= ASPM_STATE_L0S;
+ if (state & PCIE_LINK_STATE_L1)
+ link->aspm_disable |= ASPM_STATE_L1;
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+
+ if (state & PCIE_LINK_STATE_CLKPM) {
+ link->clkpm_capable = 0;
+ pcie_set_clkpm(link, 0);
+ }
+ mutex_unlock(&aspm_lock);
+ if (sem)
+ up_read(&pci_bus_sem);
+}
+
+void pci_disable_link_state_locked(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, false, false);
+}
+EXPORT_SYMBOL(pci_disable_link_state_locked);
+
+void pci_disable_link_state(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, true, false);
+}
+EXPORT_SYMBOL(pci_disable_link_state);
+
+void pcie_clear_aspm(struct pci_bus *bus)
+{
+ struct pci_dev *child;
+
+ if (aspm_force)
+ return;
+
+ /*
+ * Clear any ASPM setup that the firmware has carried out on this bus
+ */
+ list_for_each_entry(child, &bus->devices, bus_list) {
+ __pci_disable_link_state(child, PCIE_LINK_STATE_L0S |
+ PCIE_LINK_STATE_L1 |
+ PCIE_LINK_STATE_CLKPM,
+ false, true);
+ }
+}
+
+static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp)
+{
+ int i;
+ struct pcie_link_state *link;
+
+ if (aspm_disabled)
+ return -EPERM;
+ for (i = 0; i < ARRAY_SIZE(policy_str); i++)
+ if (!strncmp(val, policy_str[i], strlen(policy_str[i])))
+ break;
+ if (i >= ARRAY_SIZE(policy_str))
+ return -EINVAL;
+ if (i == aspm_policy)
+ return 0;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ aspm_policy = i;
+ list_for_each_entry(link, &link_list, sibling) {
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+ }
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+ return 0;
+}
+
+static int pcie_aspm_get_policy(char *buffer, struct kernel_param *kp)
+{
+ int i, cnt = 0;
+ for (i = 0; i < ARRAY_SIZE(policy_str); i++)
+ if (i == aspm_policy)
+ cnt += sprintf(buffer + cnt, "[%s] ", policy_str[i]);
+ else
+ cnt += sprintf(buffer + cnt, "%s ", policy_str[i]);
+ return cnt;
+}
+
+module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
+ NULL, 0644);
+
+#ifdef CONFIG_PCIEASPM_DEBUG
+static ssize_t link_state_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ struct pcie_link_state *link_state = pci_device->link_state;
+
+ return sprintf(buf, "%d\n", link_state->aspm_enabled);
+}
+
+static ssize_t link_state_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t n)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link, *root = pdev->link_state->root;
+ u32 val = buf[0] - '0', state = 0;
+
+ if (aspm_disabled)
+ return -EPERM;
+ if (n < 1 || val > 3)
+ return -EINVAL;
+
+ /* Convert requested state to ASPM state */
+ if (val & PCIE_LINK_STATE_L0S)
+ state |= ASPM_STATE_L0S;
+ if (val & PCIE_LINK_STATE_L1)
+ state |= ASPM_STATE_L1;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ list_for_each_entry(link, &link_list, sibling) {
+ if (link->root != root)
+ continue;
+ pcie_config_aspm_link(link, state);
+ }
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+ return n;
+}
+
+static ssize_t clk_ctl_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ struct pcie_link_state *link_state = pci_device->link_state;
+
+ return sprintf(buf, "%d\n", link_state->clkpm_enabled);
+}
+
+static ssize_t clk_ctl_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t n)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ int state;
+
+ if (n < 1)
+ return -EINVAL;
+ state = buf[0]-'0';
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ pcie_set_clkpm_nocheck(pdev->link_state, !!state);
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return n;
+}
+
+static DEVICE_ATTR(link_state, 0644, link_state_show, link_state_store);
+static DEVICE_ATTR(clk_ctl, 0644, clk_ctl_show, clk_ctl_store);
+
+static char power_group[] = "power";
+void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link_state = pdev->link_state;
+
+ if (!pci_is_pcie(pdev) ||
+ (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
+ return;
+
+ if (link_state->aspm_support)
+ sysfs_add_file_to_group(&pdev->dev.kobj,
+ &dev_attr_link_state.attr, power_group);
+ if (link_state->clkpm_capable)
+ sysfs_add_file_to_group(&pdev->dev.kobj,
+ &dev_attr_clk_ctl.attr, power_group);
+}
+
+void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link_state = pdev->link_state;
+
+ if (!pci_is_pcie(pdev) ||
+ (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
+ return;
+
+ if (link_state->aspm_support)
+ sysfs_remove_file_from_group(&pdev->dev.kobj,
+ &dev_attr_link_state.attr, power_group);
+ if (link_state->clkpm_capable)
+ sysfs_remove_file_from_group(&pdev->dev.kobj,
+ &dev_attr_clk_ctl.attr, power_group);
+}
+#endif
+
+static int __init pcie_aspm_disable(char *str)
+{
+ if (!strcmp(str, "off")) {
+ aspm_policy = POLICY_DEFAULT;
+ aspm_disabled = 1;
+ aspm_support_enabled = false;
+ printk(KERN_INFO "PCIe ASPM is disabled\n");
+ } else if (!strcmp(str, "force")) {
+ aspm_force = 1;
+ printk(KERN_INFO "PCIe ASPM is forcibly enabled\n");
+ }
+ return 1;
+}
+
+__setup("pcie_aspm=", pcie_aspm_disable);
+
+void pcie_no_aspm(void)
+{
+ /*
+ * Disabling ASPM is intended to prevent the kernel from modifying
+ * existing hardware state, not to clear existing state. To that end:
+ * (a) set policy to POLICY_DEFAULT in order to avoid changing state
+ * (b) prevent userspace from changing policy
+ */
+ if (!aspm_force) {
+ aspm_policy = POLICY_DEFAULT;
+ aspm_disabled = 1;
+ }
+}
+
+/**
+ * pcie_aspm_enabled - is PCIe ASPM enabled?
+ *
+ * Returns true if ASPM has not been disabled by the command-line option
+ * pcie_aspm=off.
+ **/
+int pcie_aspm_enabled(void)
+{
+ return !aspm_disabled;
+}
+EXPORT_SYMBOL(pcie_aspm_enabled);
+
+bool pcie_aspm_support_enabled(void)
+{
+ return aspm_support_enabled;
+}
+EXPORT_SYMBOL(pcie_aspm_support_enabled);