PCI PM: Restore standard config registers of all devices early
There is a problem in our handling of suspend-resume of PCI devices that
many of them have their standard config registers restored with
interrupts enabled and they are put into the full power state with
interrupts enabled as well. This may lead to the following scenario:
* an interrupt vector is shared between two or more devices
* one device is resumed earlier and generates an interrupt
* the interrupt handler of another device tries to handle it and
attempts to access the device the config space of which hasn't been
restored yet and/or which still is in a low power state
* the system crashes as a result
To prevent this from happening we should restore the standard
configuration registers of all devices with interrupts disabled and we
should put them into the D0 power state right after that.
Unfortunately, this cannot be done using the existing
pci_set_power_state(), because it can sleep. Also, to do it we have to
make sure that the config spaces of all devices were actually saved
during suspend.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index c697f26..9de07b7 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -355,17 +355,27 @@
int i = 0;
if (drv && drv->suspend) {
+ pci_dev->state_saved = false;
+
i = drv->suspend(pci_dev, state);
suspend_report_result(drv->suspend, i);
- } else {
- pci_save_state(pci_dev);
- /*
- * This is for compatibility with existing code with legacy PM
- * support.
- */
- pci_pm_set_unknown_state(pci_dev);
+ if (i)
+ return i;
+
+ if (pci_dev->state_saved)
+ goto Fixup;
+
+ if (WARN_ON_ONCE(pci_dev->current_state != PCI_D0))
+ goto Fixup;
}
+ pci_save_state(pci_dev);
+ /*
+ * This is for compatibility with existing code with legacy PM support.
+ */
+ pci_pm_set_unknown_state(pci_dev);
+
+ Fixup:
pci_fixup_device(pci_fixup_suspend, pci_dev);
return i;
@@ -386,81 +396,34 @@
static int pci_legacy_resume_early(struct device *dev)
{
- int error = 0;
struct pci_dev * pci_dev = to_pci_dev(dev);
struct pci_driver * drv = pci_dev->driver;
- pci_fixup_device(pci_fixup_resume_early, pci_dev);
-
- if (drv && drv->resume_early)
- error = drv->resume_early(pci_dev);
- return error;
+ return drv && drv->resume_early ?
+ drv->resume_early(pci_dev) : 0;
}
static int pci_legacy_resume(struct device *dev)
{
- int error;
struct pci_dev * pci_dev = to_pci_dev(dev);
struct pci_driver * drv = pci_dev->driver;
pci_fixup_device(pci_fixup_resume, pci_dev);
- if (drv && drv->resume) {
- error = drv->resume(pci_dev);
- } else {
- /* restore the PCI config space */
- pci_restore_state(pci_dev);
- error = pci_pm_reenable_device(pci_dev);
- }
- return error;
+ return drv && drv->resume ?
+ drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);
}
/* Auxiliary functions used by the new power management framework */
-static int pci_restore_standard_config(struct pci_dev *pci_dev)
-{
- struct pci_dev *parent = pci_dev->bus->self;
- int error = 0;
-
- /* Check if the device's bus is operational */
- if (!parent || parent->current_state == PCI_D0) {
- pci_restore_state(pci_dev);
- pci_update_current_state(pci_dev, PCI_D0);
- } else {
- dev_warn(&pci_dev->dev, "unable to restore config, "
- "bridge %s in low power state D%d\n", pci_name(parent),
- parent->current_state);
- pci_dev->current_state = PCI_UNKNOWN;
- error = -EAGAIN;
- }
-
- return error;
-}
-
-static bool pci_is_bridge(struct pci_dev *pci_dev)
-{
- return !!(pci_dev->subordinate);
-}
-
static void pci_pm_default_resume_noirq(struct pci_dev *pci_dev)
{
- if (pci_restore_standard_config(pci_dev))
- pci_fixup_device(pci_fixup_resume_early, pci_dev);
+ pci_restore_standard_config(pci_dev);
+ pci_fixup_device(pci_fixup_resume_early, pci_dev);
}
static int pci_pm_default_resume(struct pci_dev *pci_dev)
{
- /*
- * pci_restore_standard_config() should have been called once already,
- * but it would have failed if the device's parent bridge had not been
- * in power state D0 at that time. Check it and try again if necessary.
- */
- if (pci_dev->current_state == PCI_UNKNOWN) {
- int error = pci_restore_standard_config(pci_dev);
- if (error)
- return error;
- }
-
pci_fixup_device(pci_fixup_resume, pci_dev);
if (!pci_is_bridge(pci_dev))
@@ -575,11 +538,11 @@
struct device_driver *drv = dev->driver;
int error = 0;
+ pci_pm_default_resume_noirq(pci_dev);
+
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_resume_early(dev);
- pci_pm_default_resume_noirq(pci_dev);
-
if (drv && drv->pm && drv->pm->resume_noirq)
error = drv->pm->resume_noirq(dev);
@@ -730,11 +693,11 @@
struct device_driver *drv = dev->driver;
int error = 0;
+ pci_pm_default_resume_noirq(pci_dev);
+
if (pci_has_legacy_pm_support(pci_dev))
return pci_legacy_resume_early(dev);
- pci_pm_default_resume_noirq(pci_dev);
-
if (drv && drv->pm && drv->pm->restore_noirq)
error = drv->pm->restore_noirq(dev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e491fde..17bd932 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,7 +22,7 @@
#include <asm/dma.h> /* isa_dma_bridge_buggy */
#include "pci.h"
-unsigned int pci_pm_d3_delay = 10;
+unsigned int pci_pm_d3_delay = PCI_PM_D3_WAIT;
#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
@@ -426,6 +426,7 @@
* given PCI device
* @dev: PCI device to handle.
* @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
+ * @wait: If 'true', wait for the device to change its power state
*
* RETURN VALUE:
* -EINVAL if the requested state is invalid.
@@ -435,7 +436,7 @@
* 0 if device's power state has been successfully changed.
*/
static int
-pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
+pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state, bool wait)
{
u16 pmcsr;
bool need_restore = false;
@@ -480,8 +481,10 @@
break;
case PCI_UNKNOWN: /* Boot-up */
if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
- && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))
+ && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET)) {
need_restore = true;
+ wait = true;
+ }
/* Fall-through: force to D0 */
default:
pmcsr = 0;
@@ -491,12 +494,15 @@
/* enter specified state */
pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
+ if (!wait)
+ return 0;
+
/* Mandatory power management transition delays */
/* see PCI PM 1.1 5.6.1 table 18 */
if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
msleep(pci_pm_d3_delay);
else if (state == PCI_D2 || dev->current_state == PCI_D2)
- udelay(200);
+ udelay(PCI_PM_D2_DELAY);
dev->current_state = state;
@@ -515,7 +521,7 @@
if (need_restore)
pci_restore_bars(dev);
- if (dev->bus->self)
+ if (wait && dev->bus->self)
pcie_aspm_pm_state_change(dev->bus->self);
return 0;
@@ -585,7 +591,7 @@
if (state == PCI_D3hot && (dev->dev_flags & PCI_DEV_FLAGS_NO_D3))
return 0;
- error = pci_raw_set_power_state(dev, state);
+ error = pci_raw_set_power_state(dev, state, true);
if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
/* Allow the platform to finalize the transition */
@@ -730,6 +736,7 @@
/* XXX: 100% dword access ok here? */
for (i = 0; i < 16; i++)
pci_read_config_dword(dev, i * 4,&dev->saved_config_space[i]);
+ dev->state_saved = true;
if ((i = pci_save_pcie_state(dev)) != 0)
return i;
if ((i = pci_save_pcix_state(dev)) != 0)
@@ -1374,6 +1381,50 @@
}
/**
+ * pci_restore_standard_config - restore standard config registers of PCI device
+ * @dev: PCI device to handle
+ *
+ * This function assumes that the device's configuration space is accessible.
+ * If the device needs to be powered up, the function will wait for it to
+ * change the state.
+ */
+int pci_restore_standard_config(struct pci_dev *dev)
+{
+ pci_power_t prev_state;
+ int error;
+
+ pci_restore_state(dev);
+ pci_update_current_state(dev, PCI_D0);
+
+ prev_state = dev->current_state;
+ if (prev_state == PCI_D0)
+ return 0;
+
+ error = pci_raw_set_power_state(dev, PCI_D0, false);
+ if (error)
+ return error;
+
+ if (pci_is_bridge(dev)) {
+ if (prev_state > PCI_D1)
+ mdelay(PCI_PM_BUS_WAIT);
+ } else {
+ switch(prev_state) {
+ case PCI_D3cold:
+ case PCI_D3hot:
+ mdelay(pci_pm_d3_delay);
+ break;
+ case PCI_D2:
+ udelay(PCI_PM_D2_DELAY);
+ break;
+ }
+ }
+
+ dev->current_state = PCI_D0;
+
+ return 0;
+}
+
+/**
* pci_enable_ari - enable ARI forwarding if hardware support it
* @dev: the PCI device
*/
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1351bb4..26ddf78a 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -49,6 +49,12 @@
extern void pci_pm_init(struct pci_dev *dev);
extern void platform_pci_wakeup_init(struct pci_dev *dev);
extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);
+extern int pci_restore_standard_config(struct pci_dev *dev);
+
+static inline bool pci_is_bridge(struct pci_dev *pci_dev)
+{
+ return !!(pci_dev->subordinate);
+}
extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);