@@ -55,6 +55,11 @@ ACPI_MODULE_NAME("power");
#define ACPI_POWER_RESOURCE_STATE_ON 0x01
#define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
+struct acpi_power_dependent_device {
+ struct device *dev;
+ struct list_head node;
+};
+
struct acpi_power_resource {
struct acpi_device device;
struct list_head list_node;
@@ -64,6 +69,7 @@ struct acpi_power_resource {
unsigned int ref_count;
bool wakeup_enabled;
struct mutex resource_lock;
+ struct list_head dependents;
};
struct acpi_power_resource_entry {
@@ -245,8 +251,121 @@ static int acpi_power_get_list_state(struct list_head *list, int *state)
return 0;
}
+static int
+acpi_power_resource_add_dependent(struct acpi_power_resource *resource,
+ struct device *dev)
+{
+ struct acpi_power_dependent_device *dep;
+ int ret = 0;
+
+ mutex_lock(&resource->resource_lock);
+ list_for_each_entry(dep, &resource->dependents, node) {
+ /* Only add it once */
+ if (dep->dev == dev)
+ goto unlock;
+ }
+
+ dep = kzalloc(sizeof(*dep), GFP_KERNEL);
+ if (!dep) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ dep->dev = dev;
+ list_add_tail(&dep->node, &resource->dependents);
+ dev_dbg(dev, "added power dependency to [%s]\n", resource->name);
+
+unlock:
+ mutex_unlock(&resource->resource_lock);
+ return ret;
+}
+
+static void
+acpi_power_resource_remove_dependent(struct acpi_power_resource *resource,
+ struct device *dev)
+{
+ struct acpi_power_dependent_device *dep;
+
+ mutex_lock(&resource->resource_lock);
+ list_for_each_entry(dep, &resource->dependents, node) {
+ if (dep->dev == dev) {
+ list_del(&dep->node);
+ kfree(dep);
+ dev_dbg(dev, "removed power dependency to [%s]\n",
+ resource->name);
+ break;
+ }
+ }
+ mutex_unlock(&resource->resource_lock);
+}
+
+/**
+ * acpi_device_power_add_dependent - Add dependent device of this ACPI device
+ * @adev: ACPI device pointer
+ * @dev: Dependent device
+ *
+ * If @adev has non-empty _PR0 the @dev is added as dependent device to all
+ * power resources returned by it. This means that whenever these power
+ * resources are turned _ON the dependent devices get runtime resumed. This
+ * is needed for devices such as PCI to allow its driver to re-initialize
+ * it after it went to D0uninitialized.
+ *
+ * If @adev does not have _PR0 this does nothing.
+ *
+ * Returns %0 in case of success and negative errno otherwise.
+ */
+int acpi_device_power_add_dependent(struct acpi_device *adev,
+ struct device *dev)
+{
+ struct acpi_power_resource_entry *entry;
+ struct list_head *resources;
+ int ret;
+
+ if (!adev->flags.power_manageable)
+ return 0;
+
+ resources = &adev->power.states[ACPI_STATE_D0].resources;
+ list_for_each_entry(entry, resources, node) {
+ ret = acpi_power_resource_add_dependent(entry->resource, dev);
+ if (ret)
+ goto err;
+ }
+
+ return 0;
+
+err:
+ list_for_each_entry(entry, resources, node)
+ acpi_power_resource_remove_dependent(entry->resource, dev);
+
+ return ret;
+}
+
+/**
+ * acpi_device_power_remove_dependent - Remove dependent device
+ * @adev: ACPI device pointer
+ * @dev: Dependent device
+ *
+ * Does the opposite of acpi_device_power_add_dependent() and removes the
+ * dependent device if it is found. Can be called to @adev that does not
+ * have _PR0 as well.
+ */
+void acpi_device_power_remove_dependent(struct acpi_device *adev,
+ struct device *dev)
+{
+ struct acpi_power_resource_entry *entry;
+ struct list_head *resources;
+
+ if (!adev->flags.power_manageable)
+ return;
+
+ resources = &adev->power.states[ACPI_STATE_D0].resources;
+ list_for_each_entry_reverse(entry, resources, node)
+ acpi_power_resource_remove_dependent(entry->resource, dev);
+}
+
static int __acpi_power_on(struct acpi_power_resource *resource)
{
+ struct acpi_power_dependent_device *dep;
acpi_status status = AE_OK;
status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
@@ -256,6 +375,21 @@ static int __acpi_power_on(struct acpi_power_resource *resource)
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
resource->name));
+ /*
+ * If there are other dependents on this power resource we need to
+ * resume them now so that their drivers can re-initialize the
+ * hardware properly after it went back to D0.
+ */
+ if (list_empty(&resource->dependents) ||
+ list_is_singular(&resource->dependents))
+ return 0;
+
+ list_for_each_entry(dep, &resource->dependents, node) {
+ dev_dbg(dep->dev, "runtime resuming because [%s] turned on\n",
+ resource->name);
+ pm_request_resume(dep->dev);
+ }
+
return 0;
}
@@ -823,6 +957,7 @@ int acpi_add_power_resource(acpi_handle handle)
ACPI_STA_DEFAULT);
mutex_init(&resource->resource_lock);
INIT_LIST_HEAD(&resource->list_node);
+ INIT_LIST_HEAD(&resource->dependents);
resource->name = device->pnp.bus_id;
strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
@@ -526,6 +526,10 @@ int acpi_device_fix_up_power(struct acpi_device *device);
int acpi_bus_update_power(acpi_handle handle, int *state_p);
int acpi_device_update_power(struct acpi_device *device, int *state_p);
bool acpi_bus_power_manageable(acpi_handle handle);
+int acpi_device_power_add_dependent(struct acpi_device *adev,
+ struct device *dev);
+void acpi_device_power_remove_dependent(struct acpi_device *adev,
+ struct device *dev);
#ifdef CONFIG_PM
bool acpi_bus_can_wakeup(acpi_handle handle);