[PATCH] soundwire: qcom: fix max auto-enumeration devices

[Srinivas Kandagatla]

Controller only supports up to max of 1-11 device ids via auto-enumeration,
and it has only those many registers.

In the existing code, we can protentially cross this boundary and read incorrect
registers.

Cc: stable at vger.kernel.org
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
Fixes: a6e6581942ca ("soundwire: qcom: add auto enumeration support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
---
Thanks to Dan for reporting an overflow issue, which turned out to be
another issue, where we could read registers that do not belong to
auto-enumeration devid.
Either way this fixes both issues, one reported by Dan and other
incorrect register access.

Thanks,
Srini

 drivers/soundwire/qcom.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index 9df970eeca45..dd1365a44458 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -119,6 +119,8 @@
 #define MAX_FIFO_RD_RETRY 3
 #define SWR_OVERFLOW_RETRY_COUNT 30
 #define SWRM_LINK_STATUS_RETRY_CNT 100
+/* devid 1 - 11 */
+#define SWRM_MAX_AUTO_ENUM_DEVICES	11
 
 enum {
 	MASTER_ID_WSA = 1,
@@ -479,7 +481,7 @@ static int qcom_swrm_enumerate(struct sdw_bus *bus)
 	int i;
 	char *buf1 = (char *)&val1, *buf2 = (char *)&val2;
 
-	for (i = 1; i <= SDW_MAX_DEVICES; i++) {
+	for (i = 1; i <= SWRM_MAX_AUTO_ENUM_DEVICES; i++) {
 		/* do not continue if the status is Not Present  */
 		if (!ctrl->status[i])
 			continue;
-- 
2.25.1