ACPI: Introduce ACPI D3_COLD state support

If a device has _PR3, it means the device supports D3_COLD.
Add the ability to validate and enter D3_COLD state in ACPI.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/power.c

@@ -500,14 +500,14 @@ int acpi_power_transition(struct acpi_device *device, int state)
 {
 	int result;
 
-	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
+	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 		return -EINVAL;
 
 	if (device->power.state == state)
 		return 0;
 
 	if ((device->power.state < ACPI_STATE_D0)
-	    || (device->power.state > ACPI_STATE_D3))
+	    || (device->power.state > ACPI_STATE_D3_COLD))
 		return -ENODEV;
 
 	/* TBD: Resources must be ordered. */

drivers/acpi/scan.c

@@ -885,6 +885,13 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
 				acpi_bus_add_power_resource(ps->resources.handles[j]);
 		}
 
+		/* The exist of _PR3 indicates D3Cold support */
+		if (i == ACPI_STATE_D3) {
+			status = acpi_get_handle(device->handle, object_name, &handle);
+			if (ACPI_SUCCESS(status))
+				device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1;
+		}
+
 		/* Evaluate "_PSx" to see if we can do explicit sets */
 		object_name[2] = 'S';
 		status = acpi_get_handle(device->handle, object_name, &handle);