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authorIlpo Järvinen <ilpo.jarvinen@linux.intel.com>2023-05-26 13:54:34 +0300
committerVinod Koul <vkoul@kernel.org>2023-08-07 00:01:41 +0530
commit8cda3ececf07d374774f6a13e5a94bc2dc04c26c (patch)
tree5f7df1a5054a6dfc3ac66962318c9c0a81a29e61
parente2dcbc330f46afb82fd49a6dcbb10f6cdcb466ec (diff)
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dmaengine: pl330: Return DMA_PAUSED when transaction is paused
pl330_pause() does not set anything to indicate paused condition which causes pl330_tx_status() to return DMA_IN_PROGRESS. This breaks 8250 DMA flush after the fix in commit 57e9af7831dc ("serial: 8250_dma: Fix DMA Rx rearm race"). The function comment for pl330_pause() claims pause is supported but resume is not which is enough for 8250 DMA flush to work as long as DMA status reports DMA_PAUSED when appropriate. Add PAUSED state for descriptor and mark BUSY descriptors with PAUSED in pl330_pause(). Return DMA_PAUSED from pl330_tx_status() when the descriptor is PAUSED. Reported-by: Richard Tresidder <rtresidd@electromag.com.au> Tested-by: Richard Tresidder <rtresidd@electromag.com.au> Fixes: 88987d2c7534 ("dmaengine: pl330: add DMA_PAUSE feature") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-serial/f8a86ecd-64b1-573f-c2fa-59f541083f1a@electromag.com.au/ Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20230526105434.14959-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
-rw-r--r--drivers/dma/pl330.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index b4731fe6bbc1..3cf0b38387ae 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -404,6 +404,12 @@ enum desc_status {
*/
BUSY,
/*
+ * Pause was called while descriptor was BUSY. Due to hardware
+ * limitations, only termination is possible for descriptors
+ * that have been paused.
+ */
+ PAUSED,
+ /*
* Sitting on the channel work_list but xfer done
* by PL330 core
*/
@@ -2041,7 +2047,7 @@ static inline void fill_queue(struct dma_pl330_chan *pch)
list_for_each_entry(desc, &pch->work_list, node) {
/* If already submitted */
- if (desc->status == BUSY)
+ if (desc->status == BUSY || desc->status == PAUSED)
continue;
ret = pl330_submit_req(pch->thread, desc);
@@ -2326,6 +2332,7 @@ static int pl330_pause(struct dma_chan *chan)
{
struct dma_pl330_chan *pch = to_pchan(chan);
struct pl330_dmac *pl330 = pch->dmac;
+ struct dma_pl330_desc *desc;
unsigned long flags;
pm_runtime_get_sync(pl330->ddma.dev);
@@ -2335,6 +2342,10 @@ static int pl330_pause(struct dma_chan *chan)
_stop(pch->thread);
spin_unlock(&pl330->lock);
+ list_for_each_entry(desc, &pch->work_list, node) {
+ if (desc->status == BUSY)
+ desc->status = PAUSED;
+ }
spin_unlock_irqrestore(&pch->lock, flags);
pm_runtime_mark_last_busy(pl330->ddma.dev);
pm_runtime_put_autosuspend(pl330->ddma.dev);
@@ -2425,7 +2436,7 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
else if (running && desc == running)
transferred =
pl330_get_current_xferred_count(pch, desc);
- else if (desc->status == BUSY)
+ else if (desc->status == BUSY || desc->status == PAUSED)
/*
* Busy but not running means either just enqueued,
* or finished and not yet marked done
@@ -2442,6 +2453,9 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
case DONE:
ret = DMA_COMPLETE;
break;
+ case PAUSED:
+ ret = DMA_PAUSED;
+ break;
case PREP:
case BUSY:
ret = DMA_IN_PROGRESS;