ARM: PL08x: put txd's on the pending list in pl08x_tx_submit()

Don't place TXDs on the pending list when they're prepared - place
them on the list when they're ready to be submitted.  Also, only
place memcpy requests in the wait state when they're submitted and
don't have a physical channel associated.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 433b9e747f7569a31fb1b2bd5e9525dac9496ab2..650e2bbc7aad52b36cdfd49f812135807737fb40 100644 (file)
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -173,6 +173,11 @@ static inline struct pl08x_dma_chan *to_pl08x_chan(struct dma_chan *chan)
        return container_of(chan, struct pl08x_dma_chan, chan);
 }
 
+static inline struct pl08x_txd *to_pl08x_txd(struct dma_async_tx_descriptor *tx)
+{
+       return container_of(tx, struct pl08x_txd, tx);
+}
+
 /*
  * Physical channel handling
  */
@@ -974,11 +979,27 @@ static void release_phy_channel(struct pl08x_dma_chan *plchan)
 static dma_cookie_t pl08x_tx_submit(struct dma_async_tx_descriptor *tx)
 {
        struct pl08x_dma_chan *plchan = to_pl08x_chan(tx->chan);
+       struct pl08x_txd *txd = to_pl08x_txd(tx);
 
        plchan->chan.cookie += 1;
        if (plchan->chan.cookie < 0)
                plchan->chan.cookie = 1;
        tx->cookie = plchan->chan.cookie;
+
+       /* Put this onto the pending list */
+       list_add_tail(&txd->node, &plchan->pend_list);
+
+       /*
+        * If there was no physical channel available for this memcpy,
+        * stack the request up and indicate that the channel is waiting
+        * for a free physical channel.
+        */
+       if (!plchan->slave && !plchan->phychan) {
+               /* Do this memcpy whenever there is a channel ready */
+               plchan->state = PL08X_CHAN_WAITING;
+               plchan->waiting = txd;
+       }
+
        /* This unlock follows the lock in the prep() function */
        spin_unlock_irqrestore(&plchan->lock, plchan->lockflags);
 
@@ -1213,8 +1234,6 @@ static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan,
 
        spin_lock_irqsave(&plchan->lock, plchan->lockflags);
 
-       list_add_tail(&txd->node, &plchan->pend_list);
-
        /*
         * See if we already have a physical channel allocated,
         * else this is the time to try to get one.
@@ -1222,24 +1241,23 @@ static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan,
        ret = prep_phy_channel(plchan, txd);
        if (ret) {
                /*
-                * No physical channel available, we will
-                * stack up the memcpy channels until there is a channel
-                * available to handle it whereas slave transfers may
-                * have been denied due to platform channel muxing restrictions
-                * and since there is no guarantee that this will ever be
-                * resolved, and since the signal must be acquired AFTER
-                * acquiring the physical channel, we will let them be NACK:ed
-                * with -EBUSY here. The drivers can alway retry the prep()
-                * call if they are eager on doing this using DMA.
+                * No physical channel was available.
+                *
+                * memcpy transfers can be sorted out at submission time.
+                *
+                * Slave transfers may have been denied due to platform
+                * channel muxing restrictions.  Since there is no guarantee
+                * that this will ever be resolved, and the signal must be
+                * acquired AFTER acquiring the physical channel, we will let
+                * them be NACK:ed with -EBUSY here. The drivers can retry
+                * the prep() call if they are eager on doing this using DMA.
                 */
                if (plchan->slave) {
                        pl08x_free_txd_list(pl08x, plchan);
+                       pl08x_free_txd(pl08x, txd);
                        spin_unlock_irqrestore(&plchan->lock, plchan->lockflags);
                        return -EBUSY;
                }
-               /* Do this memcpy whenever there is a channel ready */
-               plchan->state = PL08X_CHAN_WAITING;
-               plchan->waiting = txd;
        } else
                /*
                 * Else we're all set, paused and ready to roll,