1 files changed, 62 insertions, 4 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index cab05f31223f..8cf6b85968ec 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -521,6 +521,11 @@ static inline int platform_pci_run_wake(struct pci_dev *dev, bool enable)
 			pci_platform_pm->run_wake(dev, enable) : -ENODEV;
 }
 
+static inline bool platform_pci_need_resume(struct pci_dev *dev)
+{
+	return pci_platform_pm ? pci_platform_pm->need_resume(dev) : false;
+}
+
 /**
  * pci_raw_set_power_state - Use PCI PM registers to set the power state of
  *                           given PCI device
@@ -1999,6 +2004,27 @@ bool pci_dev_run_wake(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_dev_run_wake);
 
+/**
+ * pci_dev_keep_suspended - Check if the device can stay in the suspended state.
+ * @pci_dev: Device to check.
+ *
+ * Return 'true' if the device is runtime-suspended, it doesn't have to be
+ * reconfigured due to wakeup settings difference between system and runtime
+ * suspend and the current power state of it is suitable for the upcoming
+ * (system) transition.
+ */
+bool pci_dev_keep_suspended(struct pci_dev *pci_dev)
+{
+	struct device *dev = &pci_dev->dev;
+
+	if (!pm_runtime_suspended(dev)
+	    || (device_can_wakeup(dev) && !device_may_wakeup(dev))
+	    || platform_pci_need_resume(pci_dev))
+		return false;
+
+	return pci_target_state(pci_dev) == pci_dev->current_state;
+}
+
 void pci_config_pm_runtime_get(struct pci_dev *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -3271,7 +3297,8 @@ static int pci_parent_bus_reset(struct pci_dev *dev, int probe)
 {
 	struct pci_dev *pdev;
 
-	if (pci_is_root_bus(dev->bus) || dev->subordinate || !dev->bus->self)
+	if (pci_is_root_bus(dev->bus) || dev->subordinate ||
+	    !dev->bus->self || dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
 		return -ENOTTY;
 
 	list_for_each_entry(pdev, &dev->bus->devices, bus_list)
@@ -3305,7 +3332,8 @@ static int pci_dev_reset_slot_function(struct pci_dev *dev, int probe)
 {
 	struct pci_dev *pdev;
 
-	if (dev->subordinate || !dev->slot)
+	if (dev->subordinate || !dev->slot ||
+	    dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
 		return -ENOTTY;
 
 	list_for_each_entry(pdev, &dev->bus->devices, bus_list)
@@ -3557,6 +3585,20 @@ int pci_try_reset_function(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_try_reset_function);
 
+/* Do any devices on or below this bus prevent a bus reset? */
+static bool pci_bus_resetable(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+		    (dev->subordinate && !pci_bus_resetable(dev->subordinate)))
+			return false;
+	}
+
+	return true;
+}
+
 /* Lock devices from the top of the tree down */
 static void pci_bus_lock(struct pci_bus *bus)
 {
@@ -3607,6 +3649,22 @@ unlock:
 	return 0;
 }
 
+/* Do any devices on or below this slot prevent a bus reset? */
+static bool pci_slot_resetable(struct pci_slot *slot)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &slot->bus->devices, bus_list) {
+		if (!dev->slot || dev->slot != slot)
+			continue;
+		if (dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+		    (dev->subordinate && !pci_bus_resetable(dev->subordinate)))
+			return false;
+	}
+
+	return true;
+}
+
 /* Lock devices from the top of the tree down */
 static void pci_slot_lock(struct pci_slot *slot)
 {
@@ -3728,7 +3786,7 @@ static int pci_slot_reset(struct pci_slot *slot, int probe)
 {
 	int rc;
 
-	if (!slot)
+	if (!slot || !pci_slot_resetable(slot))
 		return -ENOTTY;
 
 	if (!probe)
@@ -3820,7 +3878,7 @@ EXPORT_SYMBOL_GPL(pci_try_reset_slot);
 
 static int pci_bus_reset(struct pci_bus *bus, int probe)
 {
-	if (!bus->self)
+	if (!bus->self || !pci_bus_resetable(bus))
 		return -ENOTTY;
 
 	if (probe)