diff options
| -rw-r--r-- | drivers/dma/amba-pl08x.c | 46 |
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, |