dmaengine: PL08x: split the pend_list in two

Our behaviour wasn't correct; issue_pending is supposed to be called
before any submitted descriptors are available for processing by the
DMA engine.  Split the pend_list in two, one for submitted descriptors
and another list for issued descriptors.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 28 insertions, 13 deletions

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index c278d23adee7..b6132845e65c 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -217,6 +217,7 @@ enum pl08x_dma_chan_state {
  * @cd: channel platform data
  * @runtime_addr: address for RX/TX according to the runtime config
  * @pend_list: queued transactions pending on this channel
+ * @issued_list: issued transactions for this channel
  * @done_list: list of completed transactions
  * @at: active transaction on this channel
  * @lock: a lock for this channel data
@@ -235,6 +236,7 @@ struct pl08x_dma_chan {
         const struct pl08x_channel_data *cd;
         struct dma_slave_config cfg;
         struct list_head pend_list;
+        struct list_head issued_list;
         struct list_head done_list;
         struct pl08x_txd *at;
         spinlock_t lock;
@@ -362,7 +364,7 @@ static void pl08x_start_next_txd(struct pl08x_dma_chan *plchan)
         struct pl08x_txd *txd;
         u32 val;
 
-        txd = list_first_entry(&plchan->pend_list, struct pl08x_txd, node);
+        txd = list_first_entry(&plchan->issued_list, struct pl08x_txd, node);
         list_del(&txd->node);
 
         plchan->at = txd;
@@ -525,6 +527,15 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
         }
 
         /* Sum up all queued transactions */
+        if (!list_empty(&plchan->issued_list)) {
+                struct pl08x_txd *txdi;
+                list_for_each_entry(txdi, &plchan->issued_list, node) {
+                        struct pl08x_sg *dsg;
+                        list_for_each_entry(dsg, &txd->dsg_list, node)
+                                bytes += dsg->len;
+                }
+        }
+
         if (!list_empty(&plchan->pend_list)) {
                 struct pl08x_txd *txdi;
                 list_for_each_entry(txdi, &plchan->pend_list, node) {
@@ -991,16 +1002,17 @@ static void pl08x_free_txd(struct pl08x_driver_data *pl08x,
 static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,
                                 struct pl08x_dma_chan *plchan)
 {
-        struct pl08x_txd *txdi = NULL;
-        struct pl08x_txd *next;
+        LIST_HEAD(head);
+        struct pl08x_txd *txd;
 
-        if (!list_empty(&plchan->pend_list)) {
-                list_for_each_entry_safe(txdi,
-                                         next, &plchan->pend_list, node) {
-                        pl08x_release_mux(plchan);
-                        list_del(&txdi->node);
-                        pl08x_free_txd(pl08x, txdi);
-                }
+        list_splice_tail_init(&plchan->issued_list, &head);
+        list_splice_tail_init(&plchan->pend_list, &head);
+
+        while (!list_empty(&head)) {
+                txd = list_first_entry(&head, struct pl08x_txd, node);
+                pl08x_release_mux(plchan);
+                list_del(&txd->node);
+                pl08x_free_txd(pl08x, txd);
         }
 }
 
@@ -1269,6 +1281,8 @@ static void pl08x_issue_pending(struct dma_chan *chan)
         unsigned long flags;
 
         spin_lock_irqsave(&plchan->lock, flags);
+        list_splice_tail_init(&plchan->pend_list, &plchan->issued_list);
+
         /* Something is already active, or we're waiting for a channel... */
         if (plchan->at || plchan->state == PL08X_CHAN_WAITING) {
                 spin_unlock_irqrestore(&plchan->lock, flags);
@@ -1276,7 +1290,7 @@ static void pl08x_issue_pending(struct dma_chan *chan)
         }
 
         /* Take the first element in the queue and execute it */
-        if (!list_empty(&plchan->pend_list)) {
+        if (!list_empty(&plchan->issued_list)) {
                 plchan->state = PL08X_CHAN_RUNNING;
                 pl08x_start_next_txd(plchan);
         }
@@ -1658,9 +1672,9 @@ static void pl08x_tasklet(unsigned long data)
         list_splice_tail_init(&plchan->done_list, &head);
 
         /* If a new descriptor is queued, set it up plchan->at is NULL here */
-        if (!list_empty(&plchan->pend_list)) {
+        if (!list_empty(&plchan->issued_list)) {
                 pl08x_start_next_txd(plchan);
-        } else if (plchan->phychan_hold) {
+        } else if (!list_empty(&plchan->pend_list) || plchan->phychan_hold) {
                 /*
                  * This channel is still in use - we have a new txd being
                  * prepared and will soon be queued.  Don't give up the
@@ -1841,6 +1855,7 @@ static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
 
                 spin_lock_init(&chan->lock);
                 INIT_LIST_HEAD(&chan->pend_list);
+                INIT_LIST_HEAD(&chan->issued_list);
                 INIT_LIST_HEAD(&chan->done_list);
                 tasklet_init(&chan->tasklet, pl08x_tasklet,
                              (unsigned long) chan);