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path: root/drivers/pci/pcie/aspm.c
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Diffstat (limited to 'drivers/pci/pcie/aspm.c')
-rw-r--r--drivers/pci/pcie/aspm.c165
1 files changed, 124 insertions, 41 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 9aad608bcf3f..586b6f75910d 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -17,6 +17,7 @@
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
+#include <linux/delay.h>
#include <linux/pci-aspm.h>
#include "../pci.h"
@@ -33,6 +34,11 @@ struct endpoint_state {
struct pcie_link_state {
struct list_head sibiling;
struct pci_dev *pdev;
+ bool downstream_has_switch;
+
+ struct pcie_link_state *parent;
+ struct list_head children;
+ struct list_head link;
/* ASPM state */
unsigned int support_state;
@@ -70,6 +76,8 @@ static const char *policy_str[] = {
[POLICY_POWERSAVE] = "powersave"
};
+#define LINK_RETRAIN_TIMEOUT HZ
+
static int policy_to_aspm_state(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
@@ -125,7 +133,7 @@ static void pcie_set_clock_pm(struct pci_dev *pdev, int enable)
link_state->clk_pm_enabled = !!enable;
}
-static void pcie_check_clock_pm(struct pci_dev *pdev)
+static void pcie_check_clock_pm(struct pci_dev *pdev, int blacklist)
{
int pos;
u32 reg32;
@@ -149,10 +157,26 @@ static void pcie_check_clock_pm(struct pci_dev *pdev)
if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
enabled = 0;
}
- link_state->clk_pm_capable = capable;
link_state->clk_pm_enabled = enabled;
link_state->bios_clk_state = enabled;
- pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
+ if (!blacklist) {
+ link_state->clk_pm_capable = capable;
+ pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
+ } else {
+ link_state->clk_pm_capable = 0;
+ pcie_set_clock_pm(pdev, 0);
+ }
+}
+
+static bool pcie_aspm_downstream_has_switch(struct pci_dev *pdev)
+{
+ struct pci_dev *child_dev;
+
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ if (child_dev->pcie_type == PCI_EXP_TYPE_UPSTREAM)
+ return true;
+ }
+ return false;
}
/*
@@ -217,16 +241,18 @@ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev)
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
/* Wait for link training end */
- /* break out after waiting for 1 second */
+ /* break out after waiting for timeout */
start_jiffies = jiffies;
- while ((jiffies - start_jiffies) < HZ) {
+ for (;;) {
pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
- cpu_relax();
+ if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
+ break;
+ msleep(1);
}
/* training failed -> recover */
- if ((jiffies - start_jiffies) >= HZ) {
+ if (reg16 & PCI_EXP_LNKSTA_LT) {
dev_printk (KERN_ERR, &pdev->dev, "ASPM: Could not configure"
" common clock\n");
i = 0;
@@ -419,9 +445,9 @@ static unsigned int pcie_aspm_check_state(struct pci_dev *pdev,
{
struct pci_dev *child_dev;
- /* If no child, disable the link */
+ /* If no child, ignore the link */
if (list_empty(&pdev->subordinate->devices))
- return 0;
+ return state;
list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
if (child_dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
/*
@@ -462,6 +488,9 @@ static void __pcie_aspm_config_link(struct pci_dev *pdev, unsigned int state)
int valid = 1;
struct pcie_link_state *link_state = pdev->link_state;
+ /* If no child, disable the link */
+ if (list_empty(&pdev->subordinate->devices))
+ state = 0;
/*
* if the downstream component has pci bridge function, don't do ASPM
* now
@@ -493,20 +522,52 @@ static void __pcie_aspm_config_link(struct pci_dev *pdev, unsigned int state)
link_state->enabled_state = state;
}
+static struct pcie_link_state *get_root_port_link(struct pcie_link_state *link)
+{
+ struct pcie_link_state *root_port_link = link;
+ while (root_port_link->parent)
+ root_port_link = root_port_link->parent;
+ return root_port_link;
+}
+
+/* check the whole hierarchy, and configure each link in the hierarchy */
static void __pcie_aspm_configure_link_state(struct pci_dev *pdev,
unsigned int state)
{
struct pcie_link_state *link_state = pdev->link_state;
+ struct pcie_link_state *root_port_link = get_root_port_link(link_state);
+ struct pcie_link_state *leaf;
- if (link_state->support_state == 0)
- return;
state &= PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
- /* state 0 means disabling aspm */
- state = pcie_aspm_check_state(pdev, state);
+ /* check all links who have specific root port link */
+ list_for_each_entry(leaf, &link_list, sibiling) {
+ if (!list_empty(&leaf->children) ||
+ get_root_port_link(leaf) != root_port_link)
+ continue;
+ state = pcie_aspm_check_state(leaf->pdev, state);
+ }
+ /* check root port link too in case it hasn't children */
+ state = pcie_aspm_check_state(root_port_link->pdev, state);
+
if (link_state->enabled_state == state)
return;
- __pcie_aspm_config_link(pdev, state);
+
+ /*
+ * we must change the hierarchy. See comments in
+ * __pcie_aspm_config_link for the order
+ **/
+ if (state & PCIE_LINK_STATE_L1) {
+ list_for_each_entry(leaf, &link_list, sibiling) {
+ if (get_root_port_link(leaf) == root_port_link)
+ __pcie_aspm_config_link(leaf->pdev, state);
+ }
+ } else {
+ list_for_each_entry_reverse(leaf, &link_list, sibiling) {
+ if (get_root_port_link(leaf) == root_port_link)
+ __pcie_aspm_config_link(leaf->pdev, state);
+ }
+ }
}
/*
@@ -570,6 +631,7 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
unsigned int state;
struct pcie_link_state *link_state;
int error = 0;
+ int blacklist;
if (aspm_disabled || !pdev->is_pcie || pdev->link_state)
return;
@@ -580,29 +642,58 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
if (list_empty(&pdev->subordinate->devices))
goto out;
- if (pcie_aspm_sanity_check(pdev))
- goto out;
+ blacklist = !!pcie_aspm_sanity_check(pdev);
mutex_lock(&aspm_lock);
link_state = kzalloc(sizeof(*link_state), GFP_KERNEL);
if (!link_state)
goto unlock_out;
- pdev->link_state = link_state;
- pcie_aspm_configure_common_clock(pdev);
+ link_state->downstream_has_switch = pcie_aspm_downstream_has_switch(pdev);
+ INIT_LIST_HEAD(&link_state->children);
+ INIT_LIST_HEAD(&link_state->link);
+ if (pdev->bus->self) {/* this is a switch */
+ struct pcie_link_state *parent_link_state;
- pcie_aspm_cap_init(pdev);
+ parent_link_state = pdev->bus->parent->self->link_state;
+ if (!parent_link_state) {
+ kfree(link_state);
+ goto unlock_out;
+ }
+ list_add(&link_state->link, &parent_link_state->children);
+ link_state->parent = parent_link_state;
+ }
- /* config link state to avoid BIOS error */
- state = pcie_aspm_check_state(pdev, policy_to_aspm_state(pdev));
- __pcie_aspm_config_link(pdev, state);
+ pdev->link_state = link_state;
- pcie_check_clock_pm(pdev);
+ if (!blacklist) {
+ pcie_aspm_configure_common_clock(pdev);
+ pcie_aspm_cap_init(pdev);
+ } else {
+ link_state->enabled_state = PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
+ link_state->bios_aspm_state = 0;
+ /* Set support state to 0, so we will disable ASPM later */
+ link_state->support_state = 0;
+ }
link_state->pdev = pdev;
list_add(&link_state->sibiling, &link_list);
+ if (link_state->downstream_has_switch) {
+ /*
+ * If link has switch, delay the link config. The leaf link
+ * initialization will config the whole hierarchy. but we must
+ * make sure BIOS doesn't set unsupported link state
+ **/
+ state = pcie_aspm_check_state(pdev, link_state->bios_aspm_state);
+ __pcie_aspm_config_link(pdev, state);
+ } else
+ __pcie_aspm_configure_link_state(pdev,
+ policy_to_aspm_state(pdev));
+
+ pcie_check_clock_pm(pdev, blacklist);
+
unlock_out:
if (error)
free_link_state(pdev);
@@ -635,6 +726,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
/* All functions are removed, so just disable ASPM for the link */
__pcie_aspm_config_one_dev(parent, 0);
list_del(&link_state->sibiling);
+ list_del(&link_state->link);
/* Clock PM is for endpoint device */
free_link_state(parent);
@@ -857,24 +949,15 @@ void pcie_no_aspm(void)
aspm_disabled = 1;
}
-#ifdef CONFIG_ACPI
-#include <acpi/acpi_bus.h>
-#include <linux/pci-acpi.h>
-static void pcie_aspm_platform_init(void)
-{
- pcie_osc_support_set(OSC_ACTIVE_STATE_PWR_SUPPORT|
- OSC_CLOCK_PWR_CAPABILITY_SUPPORT);
-}
-#else
-static inline void pcie_aspm_platform_init(void) { }
-#endif
-
-static int __init pcie_aspm_init(void)
+/**
+ * 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)
{
- if (aspm_disabled)
- return 0;
- pcie_aspm_platform_init();
- return 0;
+ return !aspm_disabled;
}
+EXPORT_SYMBOL(pcie_aspm_enabled);
-fs_initcall(pcie_aspm_init);