dock.c

linux 内核源代码

 * register_dock_notifier - add yourself to the dock notifier list
 * @nb: the callers notifier block
 *
 * If a driver wishes to be notified about dock events, they can
 * use this function to put a notifier block on the dock notifier list.
 * this notifier call chain will be called after a dock event, but
 * before hotplugging any new devices.
 */
int register_dock_notifier(struct notifier_block *nb)
{
	if (!dock_station)
		return -ENODEV;

	return atomic_notifier_chain_register(&dock_notifier_list, nb);
}

EXPORT_SYMBOL_GPL(register_dock_notifier);

/**
 * unregister_dock_notifier - remove yourself from the dock notifier list
 * @nb: the callers notifier block
 */
void unregister_dock_notifier(struct notifier_block *nb)
{
	if (!dock_station)
		return;

	atomic_notifier_chain_unregister(&dock_notifier_list, nb);
}

EXPORT_SYMBOL_GPL(unregister_dock_notifier);

/**
 * register_hotplug_dock_device - register a hotplug function
 * @handle: the handle of the device
 * @handler: the acpi_notifier_handler to call after docking
 * @context: device specific data
 *
 * If a driver would like to perform a hotplug operation after a dock
 * event, they can register an acpi_notifiy_handler to be called by
 * the dock driver after _DCK is executed.
 */
int
register_hotplug_dock_device(acpi_handle handle, acpi_notify_handler handler,
			     void *context)
{
	struct dock_dependent_device *dd;

	if (!dock_station)
		return -ENODEV;

	/*
	 * make sure this handle is for a device dependent on the dock,
	 * this would include the dock station itself
	 */
	dd = find_dock_dependent_device(dock_station, handle);
	if (dd) {
		dd->handler = handler;
		dd->context = context;
		dock_add_hotplug_device(dock_station, dd);
		return 0;
	}

	return -EINVAL;
}

EXPORT_SYMBOL_GPL(register_hotplug_dock_device);

/**
 * unregister_hotplug_dock_device - remove yourself from the hotplug list
 * @handle: the acpi handle of the device
 */
void unregister_hotplug_dock_device(acpi_handle handle)
{
	struct dock_dependent_device *dd;

	if (!dock_station)
		return;

	dd = find_dock_dependent_device(dock_station, handle);
	if (dd)
		dock_del_hotplug_device(dock_station, dd);
}

EXPORT_SYMBOL_GPL(unregister_hotplug_dock_device);

/**
 * handle_eject_request - handle an undock request checking for error conditions
 *
 * Check to make sure the dock device is still present, then undock and
 * hotremove all the devices that may need removing.
 */
static int handle_eject_request(struct dock_station *ds, u32 event)
{
	if (!dock_present(ds))
		return -ENODEV;

	if (dock_in_progress(ds))
		return -EBUSY;

	/*
	 * here we need to generate the undock
	 * event prior to actually doing the undock
	 * so that the device struct still exists.
	 */
	dock_event(ds, event, UNDOCK_EVENT);
	hotplug_dock_devices(ds, ACPI_NOTIFY_EJECT_REQUEST);
	undock(ds);
	eject_dock(ds);
	if (dock_present(ds)) {
		printk(KERN_ERR PREFIX "Unable to undock!\n");
		return -EBUSY;
	}
	complete_undock(ds);
	return 0;
}

/**
 * dock_notify - act upon an acpi dock notification
 * @handle: the dock station handle
 * @event: the acpi event
 * @data: our driver data struct
 *
 * If we are notified to dock, then check to see if the dock is
 * present and then dock.  Notify all drivers of the dock event,
 * and then hotplug and devices that may need hotplugging.
 */
static void dock_notify(acpi_handle handle, u32 event, void *data)
{
	struct dock_station *ds = data;

	switch (event) {
	case ACPI_NOTIFY_BUS_CHECK:
		if (!dock_in_progress(ds) && dock_present(ds)) {
			begin_dock(ds);
			dock(ds);
			if (!dock_present(ds)) {
				printk(KERN_ERR PREFIX "Unable to dock!\n");
				break;
			}
			atomic_notifier_call_chain(&dock_notifier_list,
						   event, NULL);
			hotplug_dock_devices(ds, event);
			complete_dock(ds);
			dock_event(ds, event, DOCK_EVENT);
		}
		break;
	case ACPI_NOTIFY_DEVICE_CHECK:
	/*
         * According to acpi spec 3.0a, if a DEVICE_CHECK notification
         * is sent and _DCK is present, it is assumed to mean an
         * undock request.  This notify routine will only be called
         * for objects defining _DCK, so we will fall through to eject
         * request here.  However, we will pass an eject request through
	 * to the driver who wish to hotplug.
         */
	case ACPI_NOTIFY_EJECT_REQUEST:
		begin_undock(ds);
		if (immediate_undock)
			handle_eject_request(ds, event);
		else
			dock_event(ds, event, UNDOCK_EVENT);
		break;
	default:
		printk(KERN_ERR PREFIX "Unknown dock event %d\n", event);
	}
}

/**
 * find_dock_devices - find devices on the dock station
 * @handle: the handle of the device we are examining
 * @lvl: unused
 * @context: the dock station private data
 * @rv: unused
 *
 * This function is called by acpi_walk_namespace.  It will
 * check to see if an object has an _EJD method.  If it does, then it
 * will see if it is dependent on the dock station.
 */
static acpi_status
find_dock_devices(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	acpi_status status;
	acpi_handle tmp, parent;
	struct dock_station *ds = context;
	struct dock_dependent_device *dd;

	status = acpi_bus_get_ejd(handle, &tmp);
	if (ACPI_FAILURE(status)) {
		/* try the parent device as well */
		status = acpi_get_parent(handle, &parent);
		if (ACPI_FAILURE(status))
			goto fdd_out;
		/* see if parent is dependent on dock */
		status = acpi_bus_get_ejd(parent, &tmp);
		if (ACPI_FAILURE(status))
			goto fdd_out;
	}

	if (tmp == ds->handle) {
		dd = alloc_dock_dependent_device(handle);
		if (dd)
			add_dock_dependent_device(ds, dd);
	}
fdd_out:
	return AE_OK;
}

/*
 * show_docked - read method for "docked" file in sysfs
 */
static ssize_t show_docked(struct device *dev,
			   struct device_attribute *attr, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%d\n", dock_present(dock_station));

}
DEVICE_ATTR(docked, S_IRUGO, show_docked, NULL);

/*
 * show_flags - read method for flags file in sysfs
 */
static ssize_t show_flags(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%d\n", dock_station->flags);

}
DEVICE_ATTR(flags, S_IRUGO, show_flags, NULL);

/*
 * write_undock - write method for "undock" file in sysfs
 */
static ssize_t write_undock(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	int ret;

	if (!count)
		return -EINVAL;

	ret = handle_eject_request(dock_station, ACPI_NOTIFY_EJECT_REQUEST);
	return ret ? ret: count;
}
DEVICE_ATTR(undock, S_IWUSR, NULL, write_undock);

/*
 * show_dock_uid - read method for "uid" file in sysfs
 */
static ssize_t show_dock_uid(struct device *dev,
			     struct device_attribute *attr, char *buf)
{
	unsigned long lbuf;
	acpi_status status = acpi_evaluate_integer(dock_station->handle,
					"_UID", NULL, &lbuf);
	if (ACPI_FAILURE(status))
	    return 0;

	return snprintf(buf, PAGE_SIZE, "%lx\n", lbuf);
}
DEVICE_ATTR(uid, S_IRUGO, show_dock_uid, NULL);

/**
 * dock_add - add a new dock station
 * @handle: the dock station handle
 *
 * allocated and initialize a new dock station device.  Find all devices
 * that are on the dock station, and register for dock event notifications.
 */
static int dock_add(acpi_handle handle)
{
	int ret;
	acpi_status status;
	struct dock_dependent_device *dd;

	/* allocate & initialize the dock_station private data */
	dock_station = kzalloc(sizeof(*dock_station), GFP_KERNEL);
	if (!dock_station)
		return -ENOMEM;
	dock_station->handle = handle;
	dock_station->last_dock_time = jiffies - HZ;
	INIT_LIST_HEAD(&dock_station->dependent_devices);
	INIT_LIST_HEAD(&dock_station->hotplug_devices);
	spin_lock_init(&dock_station->dd_lock);
	mutex_init(&dock_station->hp_lock);
	ATOMIC_INIT_NOTIFIER_HEAD(&dock_notifier_list);

	/* initialize platform device stuff */
	dock_device =
		platform_device_register_simple(dock_device_name, 0, NULL, 0);
	if (IS_ERR(dock_device)) {
		kfree(dock_station);
		dock_station = NULL;
		return PTR_ERR(dock_device);
	}

	/* we want the dock device to send uevents */
	dock_device->dev.uevent_suppress = 0;

	ret = device_create_file(&dock_device->dev, &dev_attr_docked);
	if (ret) {
		printk("Error %d adding sysfs file\n", ret);
		platform_device_unregister(dock_device);
		kfree(dock_station);
		dock_station = NULL;
		return ret;
	}
	ret = device_create_file(&dock_device->dev, &dev_attr_undock);
	if (ret) {
		printk("Error %d adding sysfs file\n", ret);
		device_remove_file(&dock_device->dev, &dev_attr_docked);
		platform_device_unregister(dock_device);
		kfree(dock_station);
		dock_station = NULL;
		return ret;
	}
	ret = device_create_file(&dock_device->dev, &dev_attr_uid);
	if (ret) {
		printk("Error %d adding sysfs file\n", ret);
		device_remove_file(&dock_device->dev, &dev_attr_docked);
		device_remove_file(&dock_device->dev, &dev_attr_undock);
		platform_device_unregister(dock_device);
		kfree(dock_station);
		dock_station = NULL;
		return ret;
	}
	ret = device_create_file(&dock_device->dev, &dev_attr_flags);
	if (ret) {
		printk("Error %d adding sysfs file\n", ret);
		device_remove_file(&dock_device->dev, &dev_attr_docked);
		device_remove_file(&dock_device->dev, &dev_attr_undock);
		device_remove_file(&dock_device->dev, &dev_attr_uid);
		platform_device_unregister(dock_device);
		kfree(dock_station);
		dock_station = NULL;
		return ret;
	}

	/* Find dependent devices */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
			    ACPI_UINT32_MAX, find_dock_devices, dock_station,
			    NULL);

	/* add the dock station as a device dependent on itself */
	dd = alloc_dock_dependent_device(handle);
	if (!dd) {
		kfree(dock_station);
		dock_station = NULL;
		ret = -ENOMEM;
		goto dock_add_err_unregister;
	}
	add_dock_dependent_device(dock_station, dd);

	/* register for dock events */
	status = acpi_install_notify_handler(dock_station->handle,
					     ACPI_SYSTEM_NOTIFY,
					     dock_notify, dock_station);

	if (ACPI_FAILURE(status)) {
		printk(KERN_ERR PREFIX "Error installing notify handler\n");
		ret = -ENODEV;
		goto dock_add_err;
	}

	printk(KERN_INFO PREFIX "%s \n", ACPI_DOCK_DRIVER_DESCRIPTION);

	return 0;

dock_add_err:
	kfree(dd);
dock_add_err_unregister:
	device_remove_file(&dock_device->dev, &dev_attr_docked);
	device_remove_file(&dock_device->dev, &dev_attr_undock);
	device_remove_file(&dock_device->dev, &dev_attr_uid);
	device_remove_file(&dock_device->dev, &dev_attr_flags);
	platform_device_unregister(dock_device);
	kfree(dock_station);
	dock_station = NULL;
	return ret;
}

/**
 * dock_remove - free up resources related to the dock station
 */
static int dock_remove(void)
{
	struct dock_dependent_device *dd, *tmp;
	acpi_status status;

	if (!dock_station)
		return 0;

	/* remove dependent devices */
	list_for_each_entry_safe(dd, tmp, &dock_station->dependent_devices,
				 list)
	    kfree(dd);

	/* remove dock notify handler */
	status = acpi_remove_notify_handler(dock_station->handle,
					    ACPI_SYSTEM_NOTIFY,
					    dock_notify);
	if (ACPI_FAILURE(status))
		printk(KERN_ERR "Error removing notify handler\n");

	/* cleanup sysfs */
	device_remove_file(&dock_device->dev, &dev_attr_docked);
	device_remove_file(&dock_device->dev, &dev_attr_undock);
	device_remove_file(&dock_device->dev, &dev_attr_uid);
	device_remove_file(&dock_device->dev, &dev_attr_flags);
	platform_device_unregister(dock_device);

	/* free dock station memory */
	kfree(dock_station);
	dock_station = NULL;
	return 0;
}

/**
 * find_dock - look for a dock station
 * @handle: acpi handle of a device
 * @lvl: unused
 * @context: counter of dock stations found
 * @rv: unused
 *
 * This is called by acpi_walk_namespace to look for dock stations.
 */
static acpi_status
find_dock(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = context;
	acpi_status status = AE_OK;

	if (is_dock(handle)) {
		if (dock_add(handle) >= 0) {
			(*count)++;
			status = AE_CTRL_TERMINATE;
		}
	}
	return status;
}

static int __init dock_init(void)
{
	int num = 0;

	dock_station = NULL;

	/* look for a dock station */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
			    ACPI_UINT32_MAX, find_dock, &num, NULL);

	if (!num)
		printk(KERN_INFO "No dock devices found.\n");

	return 0;
}

static void __exit dock_exit(void)
{
	dock_remove();
}

postcore_initcall(dock_init);
module_exit(dock_exit);