This is a note to let you know that I've just added the patch titled
soundwire: cadence: Drain the RX FIFO after an IO timeout
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
soundwire-cadence-drain-the-rx-fifo-after-an-io-time.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0a6d22b36cd519d5aa12d38362d5d46caf62e1b8
Author: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Date: Fri Dec 2 16:18:12 2022 +0000
soundwire: cadence: Drain the RX FIFO after an IO timeout
[ Upstream commit 0603a47bd3a8f439d7844b841eee1819353063e0 ]
If wait_for_completion_timeout() times-out in _cdns_xfer_msg() it
is possible that something could have been written to the RX FIFO.
In this case, we should drain the RX FIFO so that anything in it
doesn't carry over and mess up the next transfer.
Obviously, if we got to this state something went wrong, and we
don't really know the state of everything. The cleanup in this
situation cannot be bullet-proof but we should attempt to avoid
breaking future transaction, if only to reduce the amount of
error noise when debugging the failure from a kernel log.
Note that this patch only implements the draining for blocking
(non-deferred) transfers. The deferred API doesn't have any proper
handling of error conditions and would need some re-design before
implementing cleanup. That is a task for a separate patch...
Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221202161812.4186897-4-rf@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 74af111f39127..7b340f3832133 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -556,6 +556,29 @@ cdns_fill_msg_resp(struct sdw_cdns *cdns,
return SDW_CMD_OK;
}
+static void cdns_read_response(struct sdw_cdns *cdns)
+{
+ u32 num_resp, cmd_base;
+ int i;
+
+ /* RX_FIFO_AVAIL can be 2 entries more than the FIFO size */
+ BUILD_BUG_ON(ARRAY_SIZE(cdns->response_buf) < CDNS_MCP_CMD_LEN + 2);
+
+ num_resp = cdns_readl(cdns, CDNS_MCP_FIFOSTAT);
+ num_resp &= CDNS_MCP_RX_FIFO_AVAIL;
+ if (num_resp > ARRAY_SIZE(cdns->response_buf)) {
+ dev_warn(cdns->dev, "RX AVAIL %d too long\n", num_resp);
+ num_resp = ARRAY_SIZE(cdns->response_buf);
+ }
+
+ cmd_base = CDNS_MCP_CMD_BASE;
+
+ for (i = 0; i < num_resp; i++) {
+ cdns->response_buf[i] = cdns_readl(cdns, cmd_base);
+ cmd_base += CDNS_MCP_CMD_WORD_LEN;
+ }
+}
+
static enum sdw_command_response
_cdns_xfer_msg(struct sdw_cdns *cdns, struct sdw_msg *msg, int cmd,
int offset, int count, bool defer)
@@ -597,6 +620,10 @@ _cdns_xfer_msg(struct sdw_cdns *cdns, struct sdw_msg *msg, int cmd,
dev_err(cdns->dev, "IO transfer timed out, cmd %d device %d addr %x len %d\n",
cmd, msg->dev_num, msg->addr, msg->len);
msg->len = 0;
+
+ /* Drain anything in the RX_FIFO */
+ cdns_read_response(cdns);
+
return SDW_CMD_TIMEOUT;
}
@@ -765,29 +792,6 @@ EXPORT_SYMBOL(cdns_reset_page_addr);
* IRQ handling
*/
-static void cdns_read_response(struct sdw_cdns *cdns)
-{
- u32 num_resp, cmd_base;
- int i;
-
- /* RX_FIFO_AVAIL can be 2 entries more than the FIFO size */
- BUILD_BUG_ON(ARRAY_SIZE(cdns->response_buf) < CDNS_MCP_CMD_LEN + 2);
-
- num_resp = cdns_readl(cdns, CDNS_MCP_FIFOSTAT);
- num_resp &= CDNS_MCP_RX_FIFO_AVAIL;
- if (num_resp > ARRAY_SIZE(cdns->response_buf)) {
- dev_warn(cdns->dev, "RX AVAIL %d too long\n", num_resp);
- num_resp = ARRAY_SIZE(cdns->response_buf);
- }
-
- cmd_base = CDNS_MCP_CMD_BASE;
-
- for (i = 0; i < num_resp; i++) {
- cdns->response_buf[i] = cdns_readl(cdns, cmd_base);
- cmd_base += CDNS_MCP_CMD_WORD_LEN;
- }
-}
-
static int cdns_update_slave_status(struct sdw_cdns *cdns,
u64 slave_intstat)
{
