power.c

linux 内核源代码

		ret = acpi_power_off_device(dev->wakeup.resources.handles[i], dev);
		if (ret) {
			printk(KERN_ERR PREFIX "Transition power state\n");
			dev->wakeup.flags.valid = 0;
			return -1;
		}
	}

	return ret;
}

/* --------------------------------------------------------------------------
                             Device Power Management
   -------------------------------------------------------------------------- */

int acpi_power_get_inferred_state(struct acpi_device *device)
{
	int result = 0;
	struct acpi_handle_list *list = NULL;
	int list_state = 0;
	int i = 0;


	if (!device)
		return -EINVAL;

	device->power.state = ACPI_STATE_UNKNOWN;

	/*
	 * We know a device's inferred power state when all the resources
	 * required for a given D-state are 'on'.
	 */
	for (i = ACPI_STATE_D0; i < ACPI_STATE_D3; i++) {
		list = &device->power.states[i].resources;
		if (list->count < 1)
			continue;

		result = acpi_power_get_list_state(list, &list_state);
		if (result)
			return result;

		if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
			device->power.state = i;
			return 0;
		}
	}

	device->power.state = ACPI_STATE_D3;

	return 0;
}

int acpi_power_transition(struct acpi_device *device, int state)
{
	int result = 0;
	struct acpi_handle_list *cl = NULL;	/* Current Resources */
	struct acpi_handle_list *tl = NULL;	/* Target Resources */
	int i = 0;


	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
		return -EINVAL;

	if ((device->power.state < ACPI_STATE_D0)
	    || (device->power.state > ACPI_STATE_D3))
		return -ENODEV;

	cl = &device->power.states[device->power.state].resources;
	tl = &device->power.states[state].resources;

	if (!cl->count && !tl->count) {
		result = -ENODEV;
		goto end;
	}

	/* TBD: Resources must be ordered. */

	/*
	 * First we reference all power resources required in the target list
	 * (e.g. so the device doesn't lose power while transitioning).
	 */
	for (i = 0; i < tl->count; i++) {
		result = acpi_power_on(tl->handles[i], device);
		if (result)
			goto end;
	}

	if (device->power.state == state) {
		goto end;
	}

	/*
	 * Then we dereference all power resources used in the current list.
	 */
	for (i = 0; i < cl->count; i++) {
		result = acpi_power_off_device(cl->handles[i], device);
		if (result)
			goto end;
	}

     end:
	if (result) {
		device->power.state = ACPI_STATE_UNKNOWN;
		printk(KERN_WARNING PREFIX "Transitioning device [%s] to D%d\n",
			      device->pnp.bus_id, state);
	} else {
	/* We shouldn't change the state till all above operations succeed */
		device->power.state = state;
	}

	return result;
}

/* --------------------------------------------------------------------------
                              FS Interface (/proc)
   -------------------------------------------------------------------------- */

static struct proc_dir_entry *acpi_power_dir;

static int acpi_power_seq_show(struct seq_file *seq, void *offset)
{
	int count = 0;
	int result = 0, state;
	struct acpi_power_resource *resource = NULL;
	struct list_head *node, *next;
	struct acpi_power_reference *ref;


	resource = seq->private;

	if (!resource)
		goto end;

	result = acpi_power_get_state(resource, &state);
	if (result)
		goto end;

	seq_puts(seq, "state:                   ");
	switch (state) {
	case ACPI_POWER_RESOURCE_STATE_ON:
		seq_puts(seq, "on\n");
		break;
	case ACPI_POWER_RESOURCE_STATE_OFF:
		seq_puts(seq, "off\n");
		break;
	default:
		seq_puts(seq, "unknown\n");
		break;
	}

	mutex_lock(&resource->resource_lock);
	list_for_each_safe(node, next, &resource->reference) {
		ref = container_of(node, struct acpi_power_reference, node);
		count++;
	}
	mutex_unlock(&resource->resource_lock);

	seq_printf(seq, "system level:            S%d\n"
		   "order:                   %d\n"
		   "reference count:         %d\n",
		   resource->system_level,
		   resource->order, count);

      end:
	return 0;
}

static int acpi_power_open_fs(struct inode *inode, struct file *file)
{
	return single_open(file, acpi_power_seq_show, PDE(inode)->data);
}

static int acpi_power_add_fs(struct acpi_device *device)
{
	struct proc_dir_entry *entry = NULL;


	if (!device)
		return -EINVAL;

	if (!acpi_device_dir(device)) {
		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
						     acpi_power_dir);
		if (!acpi_device_dir(device))
			return -ENODEV;
	}

	/* 'status' [R] */
	entry = create_proc_entry(ACPI_POWER_FILE_STATUS,
				  S_IRUGO, acpi_device_dir(device));
	if (!entry)
		return -EIO;
	else {
		entry->proc_fops = &acpi_power_fops;
		entry->data = acpi_driver_data(device);
	}

	return 0;
}

static int acpi_power_remove_fs(struct acpi_device *device)
{

	if (acpi_device_dir(device)) {
		remove_proc_entry(ACPI_POWER_FILE_STATUS,
				  acpi_device_dir(device));
		remove_proc_entry(acpi_device_bid(device), acpi_power_dir);
		acpi_device_dir(device) = NULL;
	}

	return 0;
}

/* --------------------------------------------------------------------------
                                Driver Interface
   -------------------------------------------------------------------------- */

static int acpi_power_add(struct acpi_device *device)
{
	int result = 0, state;
	acpi_status status = AE_OK;
	struct acpi_power_resource *resource = NULL;
	union acpi_object acpi_object;
	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };


	if (!device)
		return -EINVAL;

	resource = kzalloc(sizeof(struct acpi_power_resource), GFP_KERNEL);
	if (!resource)
		return -ENOMEM;

	resource->device = device;
	mutex_init(&resource->resource_lock);
	INIT_LIST_HEAD(&resource->reference);
	strcpy(resource->name, device->pnp.bus_id);
	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
	acpi_driver_data(device) = resource;

	/* Evalute the object to get the system level and resource order. */
	status = acpi_evaluate_object(device->handle, NULL, NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		result = -ENODEV;
		goto end;
	}
	resource->system_level = acpi_object.power_resource.system_level;
	resource->order = acpi_object.power_resource.resource_order;

	result = acpi_power_get_state(resource, &state);
	if (result)
		goto end;

	switch (state) {
	case ACPI_POWER_RESOURCE_STATE_ON:
		device->power.state = ACPI_STATE_D0;
		break;
	case ACPI_POWER_RESOURCE_STATE_OFF:
		device->power.state = ACPI_STATE_D3;
		break;
	default:
		device->power.state = ACPI_STATE_UNKNOWN;
		break;
	}

	result = acpi_power_add_fs(device);
	if (result)
		goto end;

	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
	       acpi_device_bid(device), state ? "on" : "off");

      end:
	if (result)
		kfree(resource);

	return result;
}

static int acpi_power_remove(struct acpi_device *device, int type)
{
	struct acpi_power_resource *resource = NULL;
	struct list_head *node, *next;


	if (!device || !acpi_driver_data(device))
		return -EINVAL;

	resource = acpi_driver_data(device);

	acpi_power_remove_fs(device);

	mutex_lock(&resource->resource_lock);
	list_for_each_safe(node, next, &resource->reference) {
		struct acpi_power_reference *ref = container_of(node, struct acpi_power_reference, node);
		list_del(&ref->node);
		kfree(ref);
	}
	mutex_unlock(&resource->resource_lock);

	kfree(resource);

	return 0;
}

static int acpi_power_resume(struct acpi_device *device)
{
	int result = 0, state;
	struct acpi_power_resource *resource = NULL;
	struct acpi_power_reference *ref;

	if (!device || !acpi_driver_data(device))
		return -EINVAL;

	resource = (struct acpi_power_resource *)acpi_driver_data(device);

	result = acpi_power_get_state(resource, &state);
	if (result)
		return result;

	mutex_lock(&resource->resource_lock);
	if (state == ACPI_POWER_RESOURCE_STATE_OFF &&
	    !list_empty(&resource->reference)) {
		ref = container_of(resource->reference.next, struct acpi_power_reference, node);
		mutex_unlock(&resource->resource_lock);
		result = acpi_power_on(device->handle, ref->device);
		return result;
	}

	mutex_unlock(&resource->resource_lock);
	return 0;
}

static int __init acpi_power_init(void)
{
	int result = 0;


	if (acpi_disabled)
		return 0;

	INIT_LIST_HEAD(&acpi_power_resource_list);

	acpi_power_dir = proc_mkdir(ACPI_POWER_CLASS, acpi_root_dir);
	if (!acpi_power_dir)
		return -ENODEV;

	result = acpi_bus_register_driver(&acpi_power_driver);
	if (result < 0) {
		remove_proc_entry(ACPI_POWER_CLASS, acpi_root_dir);
		return -ENODEV;
	}

	return 0;
}

subsys_initcall(acpi_power_init);