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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>
This commit is contained in:
Russell King - ARM Linux 2011-01-03 22:44:57 +00:00 committed by Dan Williams
parent 15c17232fb
commit 501e67e82d
1 changed files with 32 additions and 14 deletions
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46
drivers/dma/amba-pl08x.c
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@ -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,