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

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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: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dave Stevenson 2019-06-29 14:13:18 +02:00 committed by Greg Kroah-Hartman
parent 8dedab2903
commit a1120db357
1 changed files with 59 additions and 42 deletions
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101
drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
View File

@ -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);
queue_work(msg_context->instance->bulk_wq,
&msg_context->u.bulk.buffer_to_host_work);
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);
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;