ACPI / scan: Treat power resources in a special way

ACPI power resources need to be treated in a special way by the
namespace scanning code, because they need to be ready to use as
soon as they have been discovered (even before registering ACPI
device nodes using them for power management).

For this reason, it doesn't make sense to separate the preparation
of struct acpi_device objects representing them in the device
hierarchy from the creation of struct acpi_power_resource objects
actually used for power resource manipulation.  Accordingly, it
doesn't make sense to define non-empty .add() and .remove() callbacks
in the power resources "driver" (in fact, it is questionable whether
or not it is useful to register such a "driver" at all).

Rearrange the code in scan.c and power.c so that power resources are
initialized entirely by one routine, acpi_add_power_resource(), that
also prepares their struct acpi_device objects and registers them
with the driver core, telling it to use a special release routine,
acpi_release_power_resource(), for removing objects that represent
power resources from memory.  Make the ACPI namespace scanning code
in scan.c always use acpi_add_power_resource() for preparing and
registering objects that represent power resources.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 17 insertions, 30 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 02629a810c04..952b08af91de 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -464,7 +464,7 @@ int acpi_match_device_ids(struct acpi_device *device,
 }
 EXPORT_SYMBOL(acpi_match_device_ids);
 
-static void acpi_free_ids(struct acpi_device *device)
+void acpi_free_ids(struct acpi_device *device)
 {
         struct acpi_hardware_id *id, *tmp;
 
@@ -617,7 +617,8 @@ struct bus_type acpi_bus_type = {
         .uevent         = acpi_device_uevent,
 };
 
-static int acpi_device_register(struct acpi_device *device)
+int acpi_device_register(struct acpi_device *device,
+                         void (*release)(struct device *))
 {
         int result;
         struct acpi_device_bus_id *acpi_device_bus_id, *new_bus_id;
@@ -686,7 +687,7 @@ static int acpi_device_register(struct acpi_device *device)
         if (device->parent)
                 device->dev.parent = &device->parent->dev;
         device->dev.bus = &acpi_bus_type;
-        device->dev.release = &acpi_device_release;
+        device->dev.release = release;
         result = device_register(&device->dev);
         if (result) {
                 dev_err(&device->dev, "Error registering device\n");
@@ -1022,18 +1023,12 @@ static void acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
                                 "error in _DSW or _PSW evaluation\n"));
 }
 
-static void acpi_bus_add_power_resource(acpi_handle handle);
-
 static void acpi_bus_get_power_flags(struct acpi_device *device)
 {
         acpi_status status = 0;
         acpi_handle handle = NULL;
         u32 i = 0;
 
-        /* Power resources cannot be power manageable. */
-        if (device->device_type == ACPI_BUS_TYPE_POWER)
-                return;
-
         /* Presence of _PS0|_PR0 indicates 'power manageable' */
         status = acpi_get_handle(device->handle, "_PS0", &handle);
         if (ACPI_FAILURE(status)) {
@@ -1068,8 +1063,10 @@ static void acpi_bus_get_power_flags(struct acpi_device *device)
                         int j;
 
                         device->power.flags.power_resources = 1;
-                        for (j = 0; j < ps->resources.count; j++)
-                                acpi_bus_add_power_resource(ps->resources.handles[j]);
+                        for (j = 0; j < ps->resources.count; j++) {
+                                acpi_handle rhandle = ps->resources.handles[j];
+                                acpi_add_power_resource(rhandle);
+                        }
                 }
 
                 /* Evaluate "_PSx" to see if we can do explicit sets */
@@ -1358,9 +1355,8 @@ static void acpi_device_set_id(struct acpi_device *device)
         }
 }
 
-static void acpi_init_device_object(struct acpi_device *device,
-                                     acpi_handle handle,
-                                     int type, unsigned long long sta)
+void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
+                             int type, unsigned long long sta)
 {
         INIT_LIST_HEAD(&device->pnp.ids);
         device->device_type = type;
@@ -1391,7 +1387,7 @@ static int acpi_add_single_object(struct acpi_device **child,
         acpi_bus_get_wakeup_device_flags(device);
 
         device->flags.match_driver = match_driver;
-        result = acpi_device_register(device);
+        result = acpi_device_register(device, acpi_device_release);
         if (result) {
                 acpi_device_release(&device->dev);
                 return result;
@@ -1407,19 +1403,6 @@ static int acpi_add_single_object(struct acpi_device **child,
         return 0;
 }
 
-#define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
-                          ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING)
-
-static void acpi_bus_add_power_resource(acpi_handle handle)
-{
-        struct acpi_device *device = NULL;
-
-        acpi_bus_get_device(handle, &device);
-        if (!device)
-                acpi_add_single_object(&device, handle, ACPI_BUS_TYPE_POWER,
-                                        ACPI_STA_DEFAULT, true);
-}
-
 static int acpi_bus_type_and_status(acpi_handle handle, int *type,
                                     unsigned long long *sta)
 {
@@ -1476,6 +1459,11 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
         if (result)
                 return AE_OK;
 
+        if (type == ACPI_BUS_TYPE_POWER) {
+                acpi_add_power_resource(handle);
+                return AE_OK;
+        }
+
         if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
             !(sta & ACPI_STA_DEVICE_FUNCTIONING)) {
                 struct acpi_device_wakeup wakeup;
@@ -1488,8 +1476,7 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl_not_used,
                 return AE_CTRL_DEPTH;
         }
 
-        acpi_add_single_object(&device, handle, type, sta,
-                               type == ACPI_BUS_TYPE_POWER);
+        acpi_add_single_object(&device, handle, type, sta, false);
         if (!device)
                 return AE_CTRL_DEPTH;