Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6b3cf949 authored by Saravana Kannan's avatar Saravana Kannan
Browse files

ANDROID: driver core: Add device link support for SYNC_STATE_ONLY flag 



Parent devices might need to create "proxy" device links from themselves
to supplier devices to make sure the supplier devices don't get a
sync_state() before the child consumer devices get a chance to add
device links to the supplier devices.

However, the parent device has no real dependency on the supplier device
and probing, suspend/resume or runtime PM don't need to be affected by
the supplier device.  To capture these cases, create a SYNC_STATE_ONLY
device link flag that only affects sync_state() behavior and doesn't
affect probing, suspend/resume or runtime PM.

Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
Bug: 142657042
Change-Id: Ie709d3b6cd07ac9e09d1473fc0e0a21a8146a1dc
(cherry-picked from android-mainline)
Conflicts: drivers/base/core.c
	include/linux/device.h
[Fix use of MANAGED flag]
Signed-off-by: default avatarSaravana Kannan <saravanak@google.com>
parent 2876c5dc

drivers/base/core.c

+27 −6
Original line number Diff line number Diff line
@@ -117,6 +117,9 @@ static int device_is_dependent(struct device *dev, void *target) 
		return ret;



	list_for_each_entry(link, &dev->links.consumers, s_node) {

		if (link->flags == DL_FLAG_SYNC_STATE_ONLY)

			continue;



		if (link->consumer == target)

			return 1;
@@ -142,8 +145,11 @@ static int device_reorder_to_tail(struct device *dev, void *not_used) 
		device_pm_move_last(dev);



	device_for_each_child(dev, NULL, device_reorder_to_tail);

	list_for_each_entry(link, &dev->links.consumers, s_node)

	list_for_each_entry(link, &dev->links.consumers, s_node) {

		if (link->flags == DL_FLAG_SYNC_STATE_ONLY)

			continue;

		device_reorder_to_tail(link->consumer, NULL);

	}



	return 0;

}
@@ -202,6 +208,8 @@ struct device_link *device_link_add(struct device *consumer, 
	struct device_link *link;



	if (!consumer || !supplier ||

	    (flags & DL_FLAG_SYNC_STATE_ONLY &&

	     flags != DL_FLAG_SYNC_STATE_ONLY) ||

	    ((flags & DL_FLAG_STATELESS) &&

	     (flags & DL_FLAG_AUTOREMOVE_CONSUMER)))

		return NULL;
@@ -211,11 +219,14 @@ struct device_link *device_link_add(struct device *consumer, 


	/*

	 * If the supplier has not been fully registered yet or there is a

	 * reverse dependency between the consumer and the supplier already in

	 * the graph, return NULL.

	 * reverse (non-SYNC_STATE_ONLY) dependency between the consumer and

	 * the supplier already in the graph, return NULL. If the link is a

	 * SYNC_STATE_ONLY link, we don't check for reverse dependencies

	 * because it only affects sync_state() callbacks.

	 */

	if (!device_pm_initialized(supplier)

	    || device_is_dependent(consumer, supplier)) {

	    || (!(flags & DL_FLAG_SYNC_STATE_ONLY) &&

		  device_is_dependent(consumer, supplier))) {

		link = NULL;

		goto out;

	}
@@ -223,6 +234,11 @@ struct device_link *device_link_add(struct device *consumer, 
	list_for_each_entry(link, &supplier->links.consumers, s_node)

		if (link->consumer == consumer) {

			kref_get(&link->kref);

			if (link->flags & DL_FLAG_SYNC_STATE_ONLY &&

			    !(flags & DL_FLAG_SYNC_STATE_ONLY)) {

				link->flags &= ~DL_FLAG_SYNC_STATE_ONLY;

				goto reorder;

			}

			goto out;

		}
@@ -293,6 +309,9 @@ struct device_link *device_link_add(struct device *consumer, 
		}

	}



	if (flags & DL_FLAG_SYNC_STATE_ONLY)

		goto out;

reorder:

	/*

	 * Move the consumer and all of the devices depending on it to the end

	 * of dpm_list and the devices_kset list.
@@ -503,7 +522,8 @@ int device_links_check_suppliers(struct device *dev) 
	device_links_write_lock();



	list_for_each_entry(link, &dev->links.suppliers, c_node) {

		if (link->flags & DL_FLAG_STATELESS)

		if (link->flags & DL_FLAG_STATELESS ||

		    link->flags & DL_FLAG_SYNC_STATE_ONLY)

			continue;



		if (link->status != DL_STATE_AVAILABLE) {
@@ -766,7 +786,8 @@ void device_links_unbind_consumers(struct device *dev) 
	list_for_each_entry(link, &dev->links.consumers, s_node) {

		enum device_link_state status;



		if (link->flags & DL_FLAG_STATELESS)

		if (link->flags & DL_FLAG_STATELESS ||

		    link->flags & DL_FLAG_SYNC_STATE_ONLY)

			continue;



		status = link->status;

include/linux/device.h

+2 −0
Original line number Diff line number Diff line
@@ -839,12 +839,14 @@ enum device_link_state { 
 * PM_RUNTIME: If set, the runtime PM framework will use this link.

 * RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during link creation.

 * AUTOREMOVE_SUPPLIER: Remove the link automatically on supplier driver unbind.

 * SYNC_STATE_ONLY: Link only affects sync_state() behavior.

 */

#define DL_FLAG_STATELESS		BIT(0)

#define DL_FLAG_AUTOREMOVE_CONSUMER	BIT(1)

#define DL_FLAG_PM_RUNTIME		BIT(2)

#define DL_FLAG_RPM_ACTIVE		BIT(3)

#define DL_FLAG_AUTOREMOVE_SUPPLIER	BIT(4)

#define DL_FLAG_SYNC_STATE_ONLY		BIT(7)



/**

 * struct device_link - Device link representation.