soundwire: cadence: fix ACK/NAK handling

[ Upstream commit db9d9f944f95e7f3aa60ac00cbd502415152c421 ]

The existing code reports a NAK only when ACK=0
This is not aligned with the SoundWire 1.x specifications.

Table 32 in the SoundWire 1.2 specification shows that a Device shall
not set NAK=1 if ACK=1. But Table 33 shows the Combined Response
may very well be NAK=1/ACK=1, e.g. if another Device than the one
addressed reports a parity error.

NAK=1 signals a 'Command_Aborted', regardless of the ACK bit value.

Move the tests for NAK so that the NAK=1/ACK=1 combination is properly
detected according to the specification.

Fixes: 956baa1992f9a ('soundwire: cdns: Add sdw_master_ops and IO transfer support')
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210115053738.22630-5-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 9fa55164354a2245e0370d016fca8e2514e9a6b5..580660599f461ecf03df2d009108c53118847062 100644 (file)
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -484,10 +484,10 @@ cdns_fill_msg_resp(struct sdw_cdns *cdns,
                if (!(cdns->response_buf[i] & CDNS_MCP_RESP_ACK)) {
                        no_ack = 1;
                        dev_dbg_ratelimited(cdns->dev, "Msg Ack not received\n");
-                       if (cdns->response_buf[i] & CDNS_MCP_RESP_NACK) {
-                               nack = 1;
-                               dev_err_ratelimited(cdns->dev, "Msg NACK received\n");
-                       }
+               }
+               if (cdns->response_buf[i] & CDNS_MCP_RESP_NACK) {
+                       nack = 1;
+                       dev_err_ratelimited(cdns->dev, "Msg NACK received\n");
                }
        }