PCI PM: Add suspend counterpart of pci_reenable_device

PCI devices without drivers are not disabled during suspend and
hibernation, but they are enabled during resume, with the help of
pci_reenable_device(), so there is an unbalanced execution of
pcibios_enable_device() in the resume code path.

To correct this introduce function pci_disable_enabled_device()
that will disable the argument device, if it is enabled when the
function is being run, without updating the device's pci_dev
structure and use it in the suspend code path to balance the
pci_reenable_device() executed during resume.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 59 insertions, 13 deletions

diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 23bdf64411e5..57cb0015a470 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -324,9 +324,19 @@ static bool pci_has_legacy_pm_support(struct pci_dev *pci_dev)
 
 /*
  * Default "suspend" method for devices that have no driver provided suspend,
- * or not even a driver at all.
+ * or not even a driver at all (first part).
+ */
+static void pci_default_pm_suspend_early(struct pci_dev *pci_dev)
+{
+        /* If device is enabled at this point, disable it */
+        pci_disable_enabled_device(pci_dev);
+}
+
+/*
+ * Default "suspend" method for devices that have no driver provided suspend,
+ * or not even a driver at all (second part).
  */
-static void pci_default_pm_suspend(struct pci_dev *pci_dev)
+static void pci_default_pm_suspend_late(struct pci_dev *pci_dev)
 {
         pci_save_state(pci_dev);
         /*
@@ -377,7 +387,11 @@ static int pci_legacy_suspend(struct device *dev, pm_message_t state)
                 i = drv->suspend(pci_dev, state);
                 suspend_report_result(drv->suspend, i);
         } else {
-                pci_default_pm_suspend(pci_dev);
+                /*
+                 * For compatibility with existing code with legacy PM support
+                 * don't call pci_default_pm_suspend_early() here.
+                 */
+                pci_default_pm_suspend_late(pci_dev);
         }
         return i;
 }
@@ -455,7 +469,10 @@ static int pci_pm_suspend(struct device *dev)
                 }
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 error = pci_legacy_suspend(dev, PMSG_SUSPEND);
+        } else {
+                pci_default_pm_suspend_early(pci_dev);
         }
+
         pci_fixup_device(pci_fixup_suspend, pci_dev);
 
         return error;
@@ -475,7 +492,7 @@ static int pci_pm_suspend_noirq(struct device *dev)
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 error = pci_legacy_suspend_late(dev, PMSG_SUSPEND);
         } else {
-                pci_default_pm_suspend(pci_dev);
+                pci_default_pm_suspend_late(pci_dev);
         }
 
         return error;
@@ -546,6 +563,8 @@ static int pci_pm_freeze(struct device *dev)
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 error = pci_legacy_suspend(dev, PMSG_FREEZE);
                 pci_fixup_device(pci_fixup_suspend, pci_dev);
+        } else {
+                pci_default_pm_suspend_early(pci_dev);
         }
 
         return error;
@@ -565,7 +584,7 @@ static int pci_pm_freeze_noirq(struct device *dev)
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 error = pci_legacy_suspend_late(dev, PMSG_FREEZE);
         } else {
-                pci_default_pm_suspend(pci_dev);
+                pci_default_pm_suspend_late(pci_dev);
         }
 
         return error;
@@ -583,6 +602,8 @@ static int pci_pm_thaw(struct device *dev)
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 pci_fixup_device(pci_fixup_resume, pci_dev);
                 error = pci_legacy_resume(dev);
+        } else {
+                pci_default_pm_resume_late(pci_dev);
         }
 
         return error;
@@ -600,6 +621,8 @@ static int pci_pm_thaw_noirq(struct device *dev)
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 pci_fixup_device(pci_fixup_resume_early, to_pci_dev(dev));
                 error = pci_legacy_resume_early(dev);
+        } else {
+                pci_default_pm_resume_early(pci_dev);
         }
 
         return error;
@@ -618,6 +641,8 @@ static int pci_pm_poweroff(struct device *dev)
                 }
         } else if (pci_has_legacy_pm_support(pci_dev)) {
                 error = pci_legacy_suspend(dev, PMSG_HIBERNATE);
+        } else {
+                pci_default_pm_suspend_early(pci_dev);
         }
 
         pci_fixup_device(pci_fixup_suspend, pci_dev);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f3fd55df67db..6e309c8b47df 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -970,6 +970,32 @@ void pcim_pin_device(struct pci_dev *pdev)
  */
 void __attribute__ ((weak)) pcibios_disable_device (struct pci_dev *dev) {}
 
+static void do_pci_disable_device(struct pci_dev *dev)
+{
+        u16 pci_command;
+
+        pci_read_config_word(dev, PCI_COMMAND, &pci_command);
+        if (pci_command & PCI_COMMAND_MASTER) {
+                pci_command &= ~PCI_COMMAND_MASTER;
+                pci_write_config_word(dev, PCI_COMMAND, pci_command);
+        }
+
+        pcibios_disable_device(dev);
+}
+
+/**
+ * pci_disable_enabled_device - Disable device without updating enable_cnt
+ * @dev: PCI device to disable
+ *
+ * NOTE: This function is a backend of PCI power management routines and is
+ * not supposed to be called drivers.
+ */
+void pci_disable_enabled_device(struct pci_dev *dev)
+{
+        if (atomic_read(&dev->enable_cnt))
+                do_pci_disable_device(dev);
+}
+
 /**
  * pci_disable_device - Disable PCI device after use
  * @dev: PCI device to be disabled
@@ -984,7 +1010,6 @@ void
 pci_disable_device(struct pci_dev *dev)
 {
         struct pci_devres *dr;
-        u16 pci_command;
 
         dr = find_pci_dr(dev);
         if (dr)
@@ -993,14 +1018,9 @@ pci_disable_device(struct pci_dev *dev)
         if (atomic_sub_return(1, &dev->enable_cnt) != 0)
                 return;
 
-        pci_read_config_word(dev, PCI_COMMAND, &pci_command);
-        if (pci_command & PCI_COMMAND_MASTER) {
-                pci_command &= ~PCI_COMMAND_MASTER;
-                pci_write_config_word(dev, PCI_COMMAND, pci_command);
-        }
-        dev->is_busmaster = 0;
+        do_pci_disable_device(dev);
 
-        pcibios_disable_device(dev);
+        dev->is_busmaster = 0;
 }
 
 /**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 211fd418f48f..881dc15f8efd 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -44,6 +44,7 @@ struct pci_platform_pm_ops {
 };
 
 extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
+extern void pci_disable_enabled_device(struct pci_dev *dev);
 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);