PCI: set device wakeup capable flag if platform support is present

When PCI devices are initialized, we check whether they support PCI PM
caps and set the device can_wakeup flag if so. However, some devices
may have platform provided wakeup events rather than PCI PME signals, so
we need to set can_wakeup in that case too. Doing so should allow
wakeups from many more devices, especially on cost constrained systems.

Reported-by: Alan Stern <[e-mail]>
Tested-by: Joseph Chan <[e-mail]>
Acked-by: "Rafael J. Wysocki" <[e-mail]>
Signed-off-by: Jesse Barnes <[e-mail]>

drivers/pci/pci.c

···
 }
 
 /**
+ * platform_pci_wakeup_init - init platform wakeup if present
+ * @dev: PCI device
+ *
+ * Some devices don't have PCI PM caps but can still generate wakeup
+ * events through platform methods (like ACPI events).  If @dev supports
+ * platform wakeup events, set the device flag to indicate as much.  This
+ * may be redundant if the device also supports PCI PM caps, but double
+ * initialization should be safe in that case.
+ */
+void platform_pci_wakeup_init(struct pci_dev *dev)
+{
+	if (!platform_pci_can_wakeup(dev))
+		return;
+
+	device_set_wakeup_capable(&dev->dev, true);
+	device_set_wakeup_enable(&dev->dev, false);
+	platform_pci_sleep_wake(dev, false);
+}
+
+/**
  * pci_add_save_buffer - allocate buffer for saving given capability registers
  * @dev: the PCI device
  * @cap: the capability to allocate the buffer for

drivers/pci/pci.h

···
 
 extern int pci_set_platform_pm(struct pci_platform_pm_ops *ops);
 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_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);

drivers/pci/probe.c

···
 
 	/* Power Management */
 	pci_pm_init(dev);
+	platform_pci_wakeup_init(dev);
 
 	/* Vital Product Data */
 	pci_vpd_pci22_init(dev);