staging: most: add fair buffer distribution

[firefly-linux-kernel-4.4.55.git] / drivers / staging / most / mostcore / core.c

diff --git a/drivers/staging/most/mostcore/core.c b/drivers/staging/most/mostcore/core.c
index 0053b8cc5363a9df01207160cd73dbd01886aed6..4dfa0015f4b0d25d082a04da4532693df9775586 100644 (file)
--- a/drivers/staging/most/mostcore/core.c
+++ b/drivers/staging/most/mostcore/core.c
@@ -36,6 +36,7 @@ static struct class *most_class;
 static struct device *class_glue_dir;
 static struct ida mdev_id;
 static int modref;
+static int dummy_num_buffers;
 
 struct most_c_obj {
        struct kobject kobj;
@@ -59,6 +60,8 @@ struct most_c_obj {
        struct most_aim *second_aim;
        int first_aim_refs;
        int second_aim_refs;
+       int first_num_buffers;
+       int second_num_buffers;
        struct list_head trash_fifo;
        struct task_struct *hdm_enqueue_task;
        struct mutex stop_task_mutex;
@@ -1233,6 +1236,7 @@ static void arm_mbo(struct mbo *mbo)
        }
 
        spin_lock_irqsave(&c->fifo_lock, flags);
+       ++*mbo->num_buffers_ptr;
        list_add_tail(&mbo->list, &c->fifo);
        spin_unlock_irqrestore(&c->fifo_lock, flags);
 
@@ -1286,6 +1290,7 @@ static int arm_mbo_chain(struct most_c_obj *c, int dir,
                        goto _error1;
                }
                mbo->complete = compl;
+               mbo->num_buffers_ptr = &dummy_num_buffers;
                if (dir == MOST_CH_RX) {
                        nq_hdm_mbo(mbo);
                        atomic_inc(&c->mbo_nq_level);
@@ -1384,22 +1389,40 @@ most_c_obj *get_channel_by_iface(struct most_interface *iface, int id)
  * This attempts to get a free buffer out of the channel fifo.
  * Returns a pointer to MBO on success or NULL otherwise.
  */
-struct mbo *most_get_mbo(struct most_interface *iface, int id)
+struct mbo *most_get_mbo(struct most_interface *iface, int id,
+                        struct most_aim *aim)
 {
        struct mbo *mbo;
        struct most_c_obj *c;
        unsigned long flags;
+       int *num_buffers_ptr;
 
        c = get_channel_by_iface(iface, id);
        if (unlikely(!c))
                return NULL;
+
+       if (c->first_aim_refs && c->second_aim_refs &&
+           ((aim == c->first_aim && c->first_num_buffers <= 0) ||
+            (aim == c->second_aim && c->second_num_buffers <= 0)))
+               return NULL;
+
+       if (aim == c->first_aim)
+               num_buffers_ptr = &c->first_num_buffers;
+       else if (aim == c->second_aim)
+               num_buffers_ptr = &c->second_num_buffers;
+       else
+               num_buffers_ptr = &dummy_num_buffers;
+
        spin_lock_irqsave(&c->fifo_lock, flags);
        if (list_empty(&c->fifo)) {
                spin_unlock_irqrestore(&c->fifo_lock, flags);
                return NULL;
        }
        mbo = list_pop_mbo(&c->fifo);
+       --*num_buffers_ptr;
        spin_unlock_irqrestore(&c->fifo_lock, flags);
+
+       mbo->num_buffers_ptr = num_buffers_ptr;
        mbo->buffer_length = c->cfg.buffer_size;
        return mbo;
 }
@@ -1530,6 +1553,8 @@ int most_start_channel(struct most_interface *iface, int id,
                goto error;
 
        c->is_starving = 0;
+       c->first_num_buffers = c->cfg.num_buffers / 2;
+       c->second_num_buffers = c->cfg.num_buffers - c->first_num_buffers;
        atomic_set(&c->mbo_ref, num_buffer);
 
 out: