dmaengine/ste_dma40: add a separate queue for pending requests

tx_submit will add descriptors to the pending queue. Issue pending
will then move the pending descriptors to the transfer queue.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 24 insertions, 2 deletions

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index 8f222d4db7de..91d5ed7c79ba 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -199,6 +199,7 @@ struct d40_chan {
         struct dma_chan                  chan;
         struct tasklet_struct            tasklet;
         struct list_head                 client;
+        struct list_head                 pending_queue;
         struct list_head                 active;
         struct list_head                 queue;
         struct stedma40_chan_cfg         dma_cfg;
@@ -644,7 +645,20 @@ static struct d40_desc *d40_first_active_get(struct d40_chan *d40c)
 
 static void d40_desc_queue(struct d40_chan *d40c, struct d40_desc *desc)
 {
-        list_add_tail(&desc->node, &d40c->queue);
+        list_add_tail(&desc->node, &d40c->pending_queue);
+}
+
+static struct d40_desc *d40_first_pending(struct d40_chan *d40c)
+{
+        struct d40_desc *d;
+
+        if (list_empty(&d40c->pending_queue))
+                return NULL;
+
+        d = list_first_entry(&d40c->pending_queue,
+                             struct d40_desc,
+                             node);
+        return d;
 }
 
 static struct d40_desc *d40_first_queued(struct d40_chan *d40c)
@@ -801,6 +815,11 @@ static void d40_term_all(struct d40_chan *d40c)
                 d40_desc_free(d40c, d40d);
         }
 
+        /* Release pending descriptors */
+        while ((d40d = d40_first_pending(d40c))) {
+                d40_desc_remove(d40d);
+                d40_desc_free(d40c, d40d);
+        }
 
         d40c->pending_tx = 0;
         d40c->busy = false;
@@ -2151,7 +2170,9 @@ static void d40_issue_pending(struct dma_chan *chan)
 
         spin_lock_irqsave(&d40c->lock, flags);
 
-        /* Busy means that pending jobs are already being processed */
+        list_splice_tail_init(&d40c->pending_queue, &d40c->queue);
+
+        /* Busy means that queued jobs are already being processed */
         if (!d40c->busy)
                 (void) d40_queue_start(d40c);
 
@@ -2340,6 +2361,7 @@ static void __init d40_chan_init(struct d40_base *base, struct dma_device *dma,
 
                 INIT_LIST_HEAD(&d40c->active);
                 INIT_LIST_HEAD(&d40c->queue);
+                INIT_LIST_HEAD(&d40c->pending_queue);
                 INIT_LIST_HEAD(&d40c->client);
 
                 tasklet_init(&d40c->tasklet, dma_tasklet,