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@xxxxxxxxxxxxxxx # v3.15+
Signed-off-by: Bin Liu <b-liu@xxxxxx>
---
drivers/dma/ti/cppi41.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c
index 1497da367710..e507ec36c0d3 100644
--- 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)
--
2.17.1
