dmaengine: cppi41: delete channel from pending list when stop channel

The driver defines three states for a cppi channel.
- idle: .chan_busy == 0 && not in .pending list
- pending: .chan_busy == 0 && in .pending list
- busy: .chan_busy == 1 && not in .pending list

There are cases in which the cppi channel could be in the pending state
when cppi41_dma_issue_pending() is called after cppi41_runtime_suspend()
is called.

cppi41_stop_chan() has a bug for these cases to set channels to idle state.
It only checks the .chan_busy flag, but not the .pending list, then later
when cppi41_runtime_resume() is called the channels in .pending list will
be transitioned to busy state.

Removing channels from the .pending list solves the problem.

Fixes: 975faaeb9985 ("dma: cppi41: start tear down only if channel is busy")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Bin Liu <b-liu@ti.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c
index 1497da3677109c78949cb91adf0907a30eb9b32f..e507ec36c0d3dfa107ccba439551390b9ace1add 100644 (file)
--- a/drivers/dma/ti/cppi41.c
+++ b/drivers/dma/ti/cppi41.c
@@ -723,8 +723,22 @@ static int cppi41_stop_chan(struct dma_chan *chan)
 
        desc_phys = lower_32_bits(c->desc_phys);
        desc_num = (desc_phys - cdd->descs_phys) / sizeof(struct cppi41_desc);
-       if (!cdd->chan_busy[desc_num])
+       if (!cdd->chan_busy[desc_num]) {
+               struct cppi41_channel *cc, *_ct;
+
+               /*
+                * channels might still be in the pendling list if
+                * cppi41_dma_issue_pending() is called after
+                * cppi41_runtime_suspend() is called
+                */
+               list_for_each_entry_safe(cc, _ct, &cdd->pending, node) {
+                       if (cc != c)
+                               continue;
+                       list_del(&cc->node);
+                       break;
+               }
                return 0;
+       }
 
        ret = cppi41_tear_down_chan(c);
        if (ret)