target/linux/brcm2708/patches-4.19/950-0239-staging-bcm2835-camera-Do-not-bulk-receive-from-serv.patch

   1 From 7cd2d38371edd4a04401c02c098a0e436816f3af Mon Sep 17 00:00:00 2001
   2 From: Dave Stevenson <dave.stevenson@raspberrypi.org>
   3 Date: Wed, 14 Feb 2018 17:04:26 +0000
   4 Subject: [PATCH 239/703] staging: bcm2835-camera: Do not bulk receive from
   5  service thread
   6
   7 vchi_bulk_queue_receive will queue up to a default of 4
   8 bulk receives on a connection before blocking.
   9 If called from the VCHI service_callback thread, then
  10 that thread is unable to service the VCHI_CALLBACK_BULK_RECEIVED
  11 events that would enable the queue call to succeed.
  12
  13 Add a workqueue to schedule the call vchi_bulk_queue_receive
  14 in an alternate context to avoid the lock up.
  15
  16 Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
  17 ---
  18  .../vc04_services/bcm2835-camera/mmal-vchiq.c | 101 ++++++++++--------
  19  1 file changed, 59 insertions(+), 42 deletions(-)
  20
  21 --- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
  22 +++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
  23 @@ -118,8 +118,10 @@ struct mmal_msg_context {
  24
  25         union {
  26                 struct {
  27 -                       /* work struct for defered callback - must come first */
  28 +                       /* work struct for buffer_cb callback */
  29                         struct work_struct work;
  30 +                       /* work struct for deferred callback */
  31 +                       struct work_struct buffer_to_host_work;
  32                         /* mmal instance */
  33                         struct vchiq_mmal_instance *instance;
  34                         /* mmal port */
  35 @@ -167,6 +169,9 @@ struct vchiq_mmal_instance {
  36         /* component to use next */
  37         int component_idx;
  38         struct vchiq_mmal_component component[VCHIQ_MMAL_MAX_COMPONENTS];
  39 +
  40 +       /* ordered workqueue to process all bulk operations */
  41 +       struct workqueue_struct *bulk_wq;
  42  };
  43
  44  static struct mmal_msg_context *
  45 @@ -248,7 +253,44 @@ static void buffer_work_cb(struct work_s
  46                                             msg_context->u.bulk.mmal_flags,
  47                                             msg_context->u.bulk.dts,
  48                                             msg_context->u.bulk.pts);
  49 +}
  50
  51 +/* workqueue scheduled callback to handle receiving buffers
  52 + *
  53 + * VCHI will allow up to 4 bulk receives to be scheduled before blocking.
  54 + * If we block in the service_callback context then we can't process the
  55 + * VCHI_CALLBACK_BULK_RECEIVED message that would otherwise allow the blocked
  56 + * vchi_bulk_queue_receive() call to complete.
  57 + */
  58 +static void buffer_to_host_work_cb(struct work_struct *work)
  59 +{
  60 +       struct mmal_msg_context *msg_context =
  61 +               container_of(work, struct mmal_msg_context,
  62 +                            u.bulk.buffer_to_host_work);
  63 +       struct vchiq_mmal_instance *instance = msg_context->instance;
  64 +       unsigned long len = msg_context->u.bulk.buffer_used;
  65 +       int ret;
  66 +
  67 +       if (!len)
  68 +               /* Dummy receive to ensure the buffers remain in order */
  69 +               len = 8;
  70 +       /* queue the bulk submission */
  71 +       vchi_service_use(instance->handle);
  72 +       ret = vchi_bulk_queue_receive(instance->handle,
  73 +                                     msg_context->u.bulk.buffer->buffer,
  74 +                                     /* Actual receive needs to be a multiple
  75 +                                      * of 4 bytes
  76 +                                      */
  77 +                                     (len + 3) & ~3,
  78 +                                     VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |
  79 +                                     VCHI_FLAGS_BLOCK_UNTIL_QUEUED,
  80 +                                     msg_context);
  81 +
  82 +       vchi_service_release(instance->handle);
  83 +
  84 +       if (ret != 0)
  85 +               pr_err("%s: ctx: %p, vchi_bulk_queue_receive failed %d\n",
  86 +                      __func__, msg_context, ret);
  87  }
  88
  89  /* enqueue a bulk receive for a given message context */
  90 @@ -257,7 +299,6 @@ static int bulk_receive(struct vchiq_mma
  91                         struct mmal_msg_context *msg_context)
  92  {
  93         unsigned long rd_len;
  94 -       int ret;
  95
  96         rd_len = msg->u.buffer_from_host.buffer_header.length;
  97
  98 @@ -293,45 +334,10 @@ static int bulk_receive(struct vchiq_mma
  99         msg_context->u.bulk.dts = msg->u.buffer_from_host.buffer_header.dts;
 100         msg_context->u.bulk.pts = msg->u.buffer_from_host.buffer_header.pts;
 101
 102 -       /* queue the bulk submission */
 103 -       vchi_service_use(instance->handle);
 104 -       ret = vchi_bulk_queue_receive(instance->handle,
 105 -                                     msg_context->u.bulk.buffer->buffer,
 106 -                                     /* Actual receive needs to be a multiple
 107 -                                      * of 4 bytes
 108 -                                      */
 109 -                                     (rd_len + 3) & ~3,
 110 -                                     VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |
 111 -                                     VCHI_FLAGS_BLOCK_UNTIL_QUEUED,
 112 -                                     msg_context);
 113 -
 114 -       vchi_service_release(instance->handle);
 115 +       queue_work(msg_context->instance->bulk_wq,
 116 +                  &msg_context->u.bulk.buffer_to_host_work);
 117
 118 -       return ret;
 119 -}
 120 -
 121 -/* enque a dummy bulk receive for a given message context */
 122 -static int dummy_bulk_receive(struct vchiq_mmal_instance *instance,
 123 -                             struct mmal_msg_context *msg_context)
 124 -{
 125 -       int ret;
 126 -
 127 -       /* zero length indicates this was a dummy transfer */
 128 -       msg_context->u.bulk.buffer_used = 0;
 129 -
 130 -       /* queue the bulk submission */
 131 -       vchi_service_use(instance->handle);
 132 -
 133 -       ret = vchi_bulk_queue_receive(instance->handle,
 134 -                                     instance->bulk_scratch,
 135 -                                     8,
 136 -                                     VCHI_FLAGS_CALLBACK_WHEN_OP_COMPLETE |
 137 -                                     VCHI_FLAGS_BLOCK_UNTIL_QUEUED,
 138 -                                     msg_context);
 139 -
 140 -       vchi_service_release(instance->handle);
 141 -
 142 -       return ret;
 143 +       return 0;
 144  }
 145
 146  /* data in message, memcpy from packet into output buffer */
 147 @@ -379,6 +385,8 @@ buffer_from_host(struct vchiq_mmal_insta
 148
 149         /* initialise work structure ready to schedule callback */
 150         INIT_WORK(&msg_context->u.bulk.work, buffer_work_cb);
 151 +       INIT_WORK(&msg_context->u.bulk.buffer_to_host_work,
 152 +                 buffer_to_host_work_cb);
 153
 154         /* prep the buffer from host message */
 155         memset(&m, 0xbc, sizeof(m));    /* just to make debug clearer */
 156 @@ -459,7 +467,7 @@ static void buffer_to_host_cb(struct vch
 157                 if (msg->u.buffer_from_host.buffer_header.flags &
 158                     MMAL_BUFFER_HEADER_FLAG_EOS) {
 159                         msg_context->u.bulk.status =
 160 -                           dummy_bulk_receive(instance, msg_context);
 161 +                           bulk_receive(instance, msg, msg_context);
 162                         if (msg_context->u.bulk.status == 0)
 163                                 return; /* successful bulk submission, bulk
 164                                          * completion will trigger callback
 165 @@ -1793,6 +1801,9 @@ int vchiq_mmal_finalise(struct vchiq_mma
 166
 167         mutex_unlock(&instance->vchiq_mutex);
 168
 169 +       flush_workqueue(instance->bulk_wq);
 170 +       destroy_workqueue(instance->bulk_wq);
 171 +
 172         vfree(instance->bulk_scratch);
 173
 174         idr_destroy(&instance->context_map);
 175 @@ -1862,6 +1873,11 @@ int vchiq_mmal_init(struct vchiq_mmal_in
 176
 177         params.callback_param = instance;
 178
 179 +       instance->bulk_wq = alloc_ordered_workqueue("mmal-vchiq",
 180 +                                                   WQ_MEM_RECLAIM);
 181 +       if (!instance->bulk_wq)
 182 +               goto err_free;
 183 +
 184         status = vchi_service_open(vchi_instance, &params, &instance->handle);
 185         if (status) {
 186                 pr_err("Failed to open VCHI service connection (status=%d)\n",
 187 @@ -1876,8 +1892,9 @@ int vchiq_mmal_init(struct vchiq_mmal_in
 188         return 0;
 189
 190  err_close_services:
 191 -
 192         vchi_service_close(instance->handle);
 193 +       destroy_workqueue(instance->bulk_wq);
 194 +err_free:
 195         vfree(instance->bulk_scratch);
 196         kfree(instance);
 197         return -ENODEV;