Commit f8fb5766 authored by Saravana Kannan's avatar Saravana Kannan Committed by Greg Kroah-Hartman
Browse files

driver core: Make state_synced device attribute writeable 



If the file is written to and sync_state() hasn't been called for the
device yet, then call sync_state() for the device independent of the
state of its consumers.

This is useful for supplier devices that have one or more consumers that
don't have a driver but the consumers are in a state that don't use the
resources supplied by the supplier device.

This gives finer grained control than using the
fw_devlink.sync_state=timeout kernel commandline parameter.

Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20230304005355.746421-3-saravanak@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ffbe08a8

Documentation/ABI/testing/sysfs-devices-state_synced

+5 −0
Original line number Diff line number Diff line
@@ -21,4 +21,9 @@ Description: 
		at the time the kernel starts are not affected or limited in

		any way by sync_state() callbacks.



		Writing "1" to this file will force a call to the device's

		sync_state() function if it hasn't been called already. The

		sync_state() call happens independent of the state of the

		consumer devices.

drivers/base/base.h

+8 −0
Original line number Diff line number Diff line
@@ -164,6 +164,14 @@ static inline int driver_match_device(struct device_driver *drv, 
	return drv->bus->match ? drv->bus->match(dev, drv) : 1;

}



static inline void dev_sync_state(struct device *dev)

{

	if (dev->bus->sync_state)

		dev->bus->sync_state(dev);

	else if (dev->driver && dev->driver->sync_state)

		dev->driver->sync_state(dev);

}



extern int driver_add_groups(struct device_driver *drv,

			     const struct attribute_group **groups);

extern void driver_remove_groups(struct device_driver *drv,

drivers/base/core.c

+1 −4
Original line number Diff line number Diff line
@@ -1160,10 +1160,7 @@ static void device_links_flush_sync_list(struct list_head *list, 
		if (dev != dont_lock_dev)

			device_lock(dev);



		if (dev->bus->sync_state)

			dev->bus->sync_state(dev);

		else if (dev->driver && dev->driver->sync_state)

			dev->driver->sync_state(dev);

		dev_sync_state(dev);



		if (dev != dont_lock_dev)

			device_unlock(dev);

drivers/base/dd.c

+22 −1
Original line number Diff line number Diff line
@@ -510,6 +510,27 @@ EXPORT_SYMBOL_GPL(device_bind_driver); 
static atomic_t probe_count = ATOMIC_INIT(0);

static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);



static ssize_t state_synced_store(struct device *dev,

				  struct device_attribute *attr,

				  const char *buf, size_t count)

{

	int ret = 0;



	if (strcmp("1", buf))

		return -EINVAL;



	device_lock(dev);

	if (!dev->state_synced) {

		dev->state_synced = true;

		dev_sync_state(dev);

	} else {

		ret = -EINVAL;

	}

	device_unlock(dev);



	return ret ? ret : count;

}



static ssize_t state_synced_show(struct device *dev,

				 struct device_attribute *attr, char *buf)

{
@@ -521,7 +542,7 @@ static ssize_t state_synced_show(struct device *dev, 


	return sysfs_emit(buf, "%u\n", val);

}

static DEVICE_ATTR_RO(state_synced);

static DEVICE_ATTR_RW(state_synced);



static void device_unbind_cleanup(struct device *dev)

{