Commit a1120db3 authored by Dave Stevenson's avatar Dave Stevenson Committed by Greg Kroah-Hartman
Browse files

staging: bcm2835-camera: Do not bulk receive from service thread 



vchi_bulk_queue_receive will queue up to a default of 4
bulk receives on a connection before blocking.
If called from the VCHI service_callback thread, then
that thread is unable to service the VCHI_CALLBACK_BULK_RECEIVED
events that would enable the queue call to succeed.

Add a workqueue to schedule the call vchi_bulk_queue_receive
in an alternate context to avoid the lock up.

Signed-off-by: default avatarDave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: default avatarStefan Wahren <wahrenst@gmx.net>
Acked-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: default avatarMauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 8dedab29

drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c

+59 −42
Original line number Diff line number Diff line
@@ -117,8 +117,10 @@ struct mmal_msg_context { 


	union {

		struct {

			/* work struct for defered callback - must come first */

			/* work struct for buffer_cb callback */

			struct work_struct work;

			/* work struct for deferred callback */

			struct work_struct buffer_to_host_work;

			/* mmal instance */

			struct vchiq_mmal_instance *instance;

			/* mmal port */
@@ -167,6 +169,9 @@ struct vchiq_mmal_instance { 
	/* component to use next */

	int component_idx;

	struct vchiq_mmal_component component[VCHIQ_MMAL_MAX_COMPONENTS];



	/* ordered workqueue to process all bulk operations */

	struct workqueue_struct *bulk_wq;

};



static struct mmal_msg_context *
@@ -248,7 +253,44 @@ static void buffer_work_cb(struct work_struct *work) 
					    msg_context->u.bulk.mmal_flags,

					    msg_context->u.bulk.dts,

					    msg_context->u.bulk.pts);

}



/* workqueue scheduled callback to handle receiving buffers

 *

 * VCHI will allow up to 4 bulk receives to be scheduled before blocking.

 * If we block in the service_callback context then we can't process the

 * VCHI_CALLBACK_BULK_RECEIVED message that would otherwise allow the blocked

 * vchi_bulk_queue_receive() call to complete.

 */

static void buffer_to_host_work_cb(struct work_struct *work)

{

	struct mmal_msg_context *msg_context =

		container_of(work, struct mmal_msg_context,

			     u.bulk.buffer_to_host_work);

	struct vchiq_mmal_instance *instance = msg_context->instance;

	unsigned long len = msg_context->u.bulk.buffer_used;

	int ret;



	if (!len)

		/* Dummy receive to ensure the buffers remain in order */

		len = 8;

	/* queue the bulk submission */

	vchi_service_use(instance->handle);

	ret = vchi_bulk_queue_receive(instance->handle,

				      msg_context->u.bulk.buffer->buffer,

				      /* Actual receive needs to be a multiple

				       * of 4 bytes

				       */

				      (len + 3) & ~3,

				      VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |

				      VCHI_FLAGS_BLOCK_UNTIL_QUEUED,

				      msg_context);



	vchi_service_release(instance->handle);



	if (ret != 0)

		pr_err("%s: ctx: %p, vchi_bulk_queue_receive failed %d\n",

		       __func__, msg_context, ret);

}



/* enqueue a bulk receive for a given message context */
@@ -257,7 +299,6 @@ static int bulk_receive(struct vchiq_mmal_instance *instance, 
			struct mmal_msg_context *msg_context)

{

	unsigned long rd_len;

	int ret;



	rd_len = msg->u.buffer_from_host.buffer_header.length;
@@ -293,45 +334,10 @@ static int bulk_receive(struct vchiq_mmal_instance *instance, 
	msg_context->u.bulk.dts = msg->u.buffer_from_host.buffer_header.dts;

	msg_context->u.bulk.pts = msg->u.buffer_from_host.buffer_header.pts;



	/* queue the bulk submission */

	vchi_service_use(instance->handle);

	ret = vchi_bulk_queue_receive(instance->handle,

				      msg_context->u.bulk.buffer->buffer,

				      /* Actual receive needs to be a multiple

				       * of 4 bytes

				       */

				      (rd_len + 3) & ~3,

				      VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |

				      VCHI_FLAGS_BLOCK_UNTIL_QUEUED,

				      msg_context);



	vchi_service_release(instance->handle);



	return ret;

}



/* enque a dummy bulk receive for a given message context */

static int dummy_bulk_receive(struct vchiq_mmal_instance *instance,

			      struct mmal_msg_context *msg_context)

{

	int ret;



	/* zero length indicates this was a dummy transfer */

	msg_context->u.bulk.buffer_used = 0;



	/* queue the bulk submission */

	vchi_service_use(instance->handle);



	ret = vchi_bulk_queue_receive(instance->handle,

				      instance->bulk_scratch,

				      8,

				      VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |

				      VCHI_FLAGS_BLOCK_UNTIL_QUEUED,

				      msg_context);

	queue_work(msg_context->instance->bulk_wq,

		   &msg_context->u.bulk.buffer_to_host_work);



	vchi_service_release(instance->handle);



	return ret;

	return 0;

}



/* data in message, memcpy from packet into output buffer */
@@ -379,6 +385,8 @@ buffer_from_host(struct vchiq_mmal_instance *instance, 


	/* initialise work structure ready to schedule callback */

	INIT_WORK(&msg_context->u.bulk.work, buffer_work_cb);

	INIT_WORK(&msg_context->u.bulk.buffer_to_host_work,

		  buffer_to_host_work_cb);



	/* prep the buffer from host message */

	memset(&m, 0xbc, sizeof(m));	/* just to make debug clearer */
@@ -459,7 +467,7 @@ static void buffer_to_host_cb(struct vchiq_mmal_instance *instance, 
		if (msg->u.buffer_from_host.buffer_header.flags &

		    MMAL_BUFFER_HEADER_FLAG_EOS) {

			msg_context->u.bulk.status =

			    dummy_bulk_receive(instance, msg_context);

			    bulk_receive(instance, msg, msg_context);

			if (msg_context->u.bulk.status == 0)

				return;	/* successful bulk submission, bulk

					 * completion will trigger callback
@@ -1793,6 +1801,9 @@ int vchiq_mmal_finalise(struct vchiq_mmal_instance *instance) 


	mutex_unlock(&instance->vchiq_mutex);



	flush_workqueue(instance->bulk_wq);

	destroy_workqueue(instance->bulk_wq);



	vfree(instance->bulk_scratch);



	idr_destroy(&instance->context_map);
@@ -1855,6 +1866,11 @@ int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance) 


	params.callback_param = instance;



	instance->bulk_wq = alloc_ordered_workqueue("mmal-vchiq",

						    WQ_MEM_RECLAIM);

	if (!instance->bulk_wq)

		goto err_free;



	status = vchi_service_open(vchi_instance, &params, &instance->handle);

	if (status) {

		pr_err("Failed to open VCHI service connection (status=%d)\n",
@@ -1869,8 +1885,9 @@ int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance) 
	return 0;



err_close_services:



	vchi_service_close(instance->handle);

	destroy_workqueue(instance->bulk_wq);

err_free:

	vfree(instance->bulk_scratch);

	kfree(instance);

	return -ENODEV;

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