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>

1 files changed, 57 insertions, 6 deletions

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 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable)
  *                           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 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable)
  * 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 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
 		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 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
 	/* 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 @@ pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
 	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 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 	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 @@ pci_save_state(struct pci_dev *dev)
 	/* 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 @@ void pci_allocate_cap_save_buffers(struct pci_dev *dev)
 }
 
 /**
+ * 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
  */