diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2023-05-26 13:54:34 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2023-08-07 00:01:41 +0530 |
| commit | 8cda3ececf07d374774f6a13e5a94bc2dc04c26c (patch) | |
| tree | 5f7df1a5054a6dfc3ac66962318c9c0a81a29e61 | |
| parent | e2dcbc330f46afb82fd49a6dcbb10f6cdcb466ec (diff) | |
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.c | 18 |
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; |