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dmaengine: PL08x: re-jig the starting of txds

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Rather than code the de-queue of the txd several times, move that into
the start_txd function.  Rename this to better illustrate what it's
now doing, and call this function when starting a delayed memcpy().

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2012-05-25 12:32:00 +01:00
parent 7847f6b55e
commit eab82533c9
1 changed files with 17 additions and 20 deletions
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37
drivers/dma/amba-pl08x.c
View file

@ -354,20 +354,25 @@ static int pl08x_phy_channel_busy(struct pl08x_phy_chan *ch)
* been set when the LLIs were constructed. Poke them into the hardware * been set when the LLIs were constructed. Poke them into the hardware
* and start the transfer. * and start the transfer.
*/ */
static void pl08x_start_txd(struct pl08x_dma_chan *plchan, static void pl08x_start_next_txd(struct pl08x_dma_chan *plchan)
struct pl08x_txd *txd)
{ {
struct pl08x_driver_data *pl08x = plchan->host; struct pl08x_driver_data *pl08x = plchan->host;
struct pl08x_phy_chan *phychan = plchan->phychan; struct pl08x_phy_chan *phychan = plchan->phychan;
struct pl08x_lli *lli = &txd->llis_va[0]; struct pl08x_lli *lli;
struct pl08x_txd *txd;
u32 val; u32 val;
txd = list_first_entry(&plchan->pend_list, struct pl08x_txd, node);
list_del(&txd->node);
plchan->at = txd; plchan->at = txd;
/* Wait for channel inactive */ /* Wait for channel inactive */
while (pl08x_phy_channel_busy(phychan)) while (pl08x_phy_channel_busy(phychan))
cpu_relax(); cpu_relax();
lli = &txd->llis_va[0];
dev_vdbg(&pl08x->adev->dev, dev_vdbg(&pl08x->adev->dev,
"WRITE channel %d: csrc=0x%08x, cdst=0x%08x, " "WRITE channel %d: csrc=0x%08x, cdst=0x%08x, "
"clli=0x%08x, cctl=0x%08x, ccfg=0x%08x\n", "clli=0x%08x, cctl=0x%08x, ccfg=0x%08x\n",
@ -1272,15 +1277,8 @@ static void pl08x_issue_pending(struct dma_chan *chan)
/* Take the first element in the queue and execute it */ /* Take the first element in the queue and execute it */
if (!list_empty(&plchan->pend_list)) { if (!list_empty(&plchan->pend_list)) {
struct pl08x_txd *next;
next = list_first_entry(&plchan->pend_list,
struct pl08x_txd,
node);
list_del(&next->node);
plchan->state = PL08X_CHAN_RUNNING; plchan->state = PL08X_CHAN_RUNNING;
pl08x_start_next_txd(plchan);
pl08x_start_txd(plchan, next);
} }
spin_unlock_irqrestore(&plchan->lock, flags); spin_unlock_irqrestore(&plchan->lock, flags);
@ -1661,14 +1659,7 @@ static void pl08x_tasklet(unsigned long data)
/* If a new descriptor is queued, set it up plchan->at is NULL here */ /* If a new descriptor is queued, set it up plchan->at is NULL here */
if (!list_empty(&plchan->pend_list)) { if (!list_empty(&plchan->pend_list)) {
struct pl08x_txd *next; pl08x_start_next_txd(plchan);
next = list_first_entry(&plchan->pend_list,
struct pl08x_txd,
node);
list_del(&next->node);
pl08x_start_txd(plchan, next);
} else if (plchan->phychan_hold) { } else if (plchan->phychan_hold) {
/* /*
* This channel is still in use - we have a new txd being * This channel is still in use - we have a new txd being
@ -1700,7 +1691,13 @@ static void pl08x_tasklet(unsigned long data)
BUG_ON(ret); BUG_ON(ret);
waiting->phychan_hold--; waiting->phychan_hold--;
waiting->state = PL08X_CHAN_RUNNING; waiting->state = PL08X_CHAN_RUNNING;
pl08x_issue_pending(&waiting->chan); /*
* Eww. We know this isn't going to deadlock
* but lockdep probably doens't.
*/
spin_lock(&waiting->lock);
pl08x_start_next_txd(waiting);
spin_unlock(&waiting->lock);
break; break;
} }
} }