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Commit 4057ac6c authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
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V4L/DVB (13505): uvcvideo: Refactor chain scan 



Don't handle the first output terminal in a chain in a special way. Use
uvc_scan_chain_entity() like for all other entities, making the chain
scan code more generic.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent fd3e9217

drivers/media/video/uvc/uvc_driver.c

+43 −32
Original line number Diff line number Diff line
@@ -1265,13 +1265,12 @@ static int uvc_scan_chain_entity(struct uvc_video_chain *chain, 
		break;



	case UVC_TT_STREAMING:

		if (UVC_ENTITY_IS_ITERM(entity)) {

			if (uvc_trace_param & UVC_TRACE_PROBE)

				printk(" <- IT %d\n", entity->id);



		if (!UVC_ENTITY_IS_ITERM(entity)) {

			uvc_trace(UVC_TRACE_DESCR, "Unsupported input "

				"terminal %u.\n", entity->id);

			return -1;

		} else {

			if (uvc_trace_param & UVC_TRACE_PROBE)

				printk(" OT %d", entity->id);

		}



		break;
@@ -1351,10 +1350,11 @@ static int uvc_scan_chain_forward(struct uvc_video_chain *chain, 
}



static int uvc_scan_chain_backward(struct uvc_video_chain *chain,

	struct uvc_entity *entity)

	struct uvc_entity **_entity)

{

	struct uvc_entity *entity = *_entity;

	struct uvc_entity *term;

	int id = -1, i;

	int id = -EINVAL, i;



	switch (UVC_ENTITY_TYPE(entity)) {

	case UVC_VC_EXTENSION_UNIT:
@@ -1398,24 +1398,23 @@ static int uvc_scan_chain_backward(struct uvc_video_chain *chain, 


		id = 0;

		break;



	case UVC_ITT_VENDOR_SPECIFIC:

	case UVC_ITT_CAMERA:

	case UVC_ITT_MEDIA_TRANSPORT_INPUT:

	case UVC_OTT_VENDOR_SPECIFIC:

	case UVC_OTT_DISPLAY:

	case UVC_OTT_MEDIA_TRANSPORT_OUTPUT:

	case UVC_TT_STREAMING:

		id = UVC_ENTITY_IS_OTERM(entity) ? entity->output.bSourceID : 0;

		break;

	}



	if (id <= 0) {

		*_entity = NULL;

		return id;

	}



static int uvc_scan_chain(struct uvc_video_chain *chain,

			  struct uvc_entity *oterm)

{

	struct uvc_entity *entity, *prev;

	int id;



	entity = oterm;

	list_add_tail(&entity->chain, &chain->entities);

	uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain: OT %d", entity->id);



	id = entity->output.bSourceID;

	while (id != 0) {

		prev = entity;

	entity = uvc_entity_by_id(chain->dev, id);

	if (entity == NULL) {

		uvc_trace(UVC_TRACE_DESCR, "Found reference to "
@@ -1423,9 +1422,25 @@ static int uvc_scan_chain(struct uvc_video_chain *chain, 
		return -EINVAL;

	}



	*_entity = entity;

	return 0;

}



static int uvc_scan_chain(struct uvc_video_chain *chain,

			  struct uvc_entity *term)

{

	struct uvc_entity *entity, *prev;



	uvc_trace(UVC_TRACE_PROBE, "Scanning UVC chain:");



	entity = term;

	prev = NULL;



	while (entity != NULL) {

		/* Entity must not be part of an existing chain */

		if (entity->chain.next || entity->chain.prev) {

			uvc_trace(UVC_TRACE_DESCR, "Found reference to "

				"entity %d already in chain.\n", id);

				"entity %d already in chain.\n", entity->id);

			return -EINVAL;

		}
@@ -1437,14 +1452,10 @@ static int uvc_scan_chain(struct uvc_video_chain *chain, 
		if (uvc_scan_chain_forward(chain, entity, prev) < 0)

			return -EINVAL;



		/* Stop when a terminal is found. */

		if (UVC_ENTITY_IS_TERM(entity))

			break;



		/* Backward scan */

		id = uvc_scan_chain_backward(chain, entity);

		if (id < 0)

			return id;

		prev = entity;

		if (uvc_scan_chain_backward(chain, &entity) < 0)

			return -EINVAL;

	}



	return 0;