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-rw-r--r--drivers/dma/amba-pl08x.c11
-rw-r--r--include/linux/amba/pl08x.h3
2 files changed, 14 insertions, 0 deletions
diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index 650e2bb..bf6f7d0 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -959,6 +959,7 @@ static int prep_phy_channel(struct pl08x_dma_chan *plchan,
ch->signal,
plchan->name);
+ plchan->phychan_hold++;
plchan->phychan = ch;
return 0;
@@ -998,6 +999,8 @@ static dma_cookie_t pl08x_tx_submit(struct dma_async_tx_descriptor *tx)
/* Do this memcpy whenever there is a channel ready */
plchan->state = PL08X_CHAN_WAITING;
plchan->waiting = txd;
+ } else {
+ plchan->phychan_hold--;
}
/* This unlock follows the lock in the prep() function */
@@ -1585,6 +1588,7 @@ static void pl08x_tasklet(unsigned long data)
*/
plchan->lc = txd->tx.cookie;
}
+
/*
* If a new descriptor is queued, set it up
* plchan->at is NULL here
@@ -1598,6 +1602,12 @@ static void pl08x_tasklet(unsigned long data)
list_del(&next->node);
pl08x_start_txd(plchan, next);
+ } else if (plchan->phychan_hold) {
+ /*
+ * This channel is still in use - we have a new txd being
+ * prepared and will soon be queued. Don't give up the
+ * physical channel.
+ */
} else {
struct pl08x_dma_chan *waiting = NULL;
@@ -1625,6 +1635,7 @@ static void pl08x_tasklet(unsigned long data)
ret = prep_phy_channel(waiting,
waiting->waiting);
BUG_ON(ret);
+ waiting->phychan_hold--;
waiting->state = PL08X_CHAN_RUNNING;
waiting->waiting = NULL;
pl08x_issue_pending(&waiting->chan);
diff --git a/include/linux/amba/pl08x.h b/include/linux/amba/pl08x.h
index 08a9024..95b76ea 100644
--- a/include/linux/amba/pl08x.h
+++ b/include/linux/amba/pl08x.h
@@ -151,6 +151,8 @@ enum pl08x_dma_chan_state {
* struct pl08x_dma_chan - this structure wraps a DMA ENGINE channel
* @chan: wrappped abstract channel
* @phychan: the physical channel utilized by this channel, if there is one
+ * @phychan_hold: if non-zero, hold on to the physical channel even if we
+ * have no pending entries
* @tasklet: tasklet scheduled by the IRQ to handle actual work etc
* @name: name of channel
* @cd: channel platform data
@@ -173,6 +175,7 @@ enum pl08x_dma_chan_state {
struct pl08x_dma_chan {
struct dma_chan chan;
struct pl08x_phy_chan *phychan;
+ int phychan_hold;
struct tasklet_struct tasklet;
char *name;
struct pl08x_channel_data *cd;
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