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yaml
---
r: 231608
b: refs/heads/master
c: 501e67e
h: refs/heads/master
v: v3
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Russell King - ARM Linux authored and Dan Williams committed Jan 5, 2011
1 parent 6c7ab50 commit ea42f2f
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Showing 2 changed files with 33 additions and 15 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 15c17232fbd1f7687c740c3c26f9e7f337bd9e36
refs/heads/master: 501e67e82dee68d0a594ec0549f3d6a2943c91f5
46 changes: 32 additions & 14 deletions trunk/drivers/dma/amba-pl08x.c
Original file line number Diff line number Diff line change
Expand Up @@ -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
*/
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -1213,33 +1234,30 @@ 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.
*/
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,
Expand Down

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