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>

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index c278d23adee72a4f6d17da399818d2a2f73c29d9..b6132845e65c9bc059ed5b1f814d37dd32ea96c1 100644 (file)
--- 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);