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-rw-r--r--drivers/dma/amba-pl08x.c46
1 files changed, 32 insertions, 14 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 433b9e747f75..650e2bbc7aad 100644
--- 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,