ACPI: PCI: PM: Rework root bus notification setup

Since pci_acpi_add_bus_pm_notifier() is only suitable for adding ACPI
PM notifiers to root buses, rename it to pci_acpi_add_root_pm_notifier()
and modify it to take an additional "root" argument, which is then used
for passing a PCI root bridge device pointer to acpi_add_pm_notifier().

That function uses it to populate the "dev" field in the context
structure attached to the ACPI device object that will receive the
ACPI "wake" notifications on behalf of the given PCI root bus.  The
context structure in question is passed to pci_acpi_wake_bus(), so
the latter can be simplified quite a bit now because the target PCI
host bridge structure address can be derived from "dev".

No intentional functional impact.

This change will also facilitate a subsequent update related to the
registration of wakeup sources.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
[ rjw: Kerneldoc comment fixup ]
Link: https://patch.msgid.link/2395263.ElGaqSPkdT@rafael.j.wysocki
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: rafaeljw

drivers/acpi/pci_root.c

@@ -738,7 +738,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	if (no_aspm)
 		pcie_no_aspm();
 
-	pci_acpi_add_bus_pm_notifier(device);
+	pci_acpi_add_root_pm_notifier(device, root);
 	device_set_wakeup_capable(root->bus->bridge, device->wakeup.flags.valid);
 
 	if (hotadd) {

drivers/pci/pci-acpi.c

@@ -847,12 +847,7 @@ bool shpchp_is_native(struct pci_dev *bridge)
  */
 static void pci_acpi_wake_bus(struct acpi_device_wakeup_context *context)
 {
-	struct acpi_device *adev;
-	struct acpi_pci_root *root;
-
-	adev = container_of(context, struct acpi_device, wakeup.context);
-	root = acpi_driver_data(adev);
-	pci_pme_wakeup_bus(root->bus);
+	pci_pme_wakeup_bus(to_pci_host_bridge(context->dev)->bus);
 }
 
 /**
@@ -885,12 +880,14 @@ static void pci_acpi_wake_dev(struct acpi_device_wakeup_context *context)
 }
 
 /**
- * pci_acpi_add_bus_pm_notifier - Register PM notifier for root PCI bus.
+ * pci_acpi_add_root_pm_notifier - Register PM notifier for root PCI bus.
  * @dev: PCI root bridge ACPI device.
+ * @root: PCI root corresponding to @dev.
  */
-acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev)
+acpi_status pci_acpi_add_root_pm_notifier(struct acpi_device *dev,
+					  struct acpi_pci_root *root)
 {
-	return acpi_add_pm_notifier(dev, NULL, pci_acpi_wake_bus);
+	return acpi_add_pm_notifier(dev, root->bus->bridge, pci_acpi_wake_bus);
 }
 
 /**

include/linux/pci-acpi.h

@@ -12,7 +12,8 @@
 #include <linux/acpi.h>
 
 #ifdef CONFIG_ACPI
-extern acpi_status pci_acpi_add_bus_pm_notifier(struct acpi_device *dev);
+extern acpi_status pci_acpi_add_root_pm_notifier(struct acpi_device *dev,
+						 struct acpi_pci_root *pci_root);
 static inline acpi_status pci_acpi_remove_bus_pm_notifier(struct acpi_device *dev)
 {
 	return acpi_remove_pm_notifier(dev);