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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: 956baa1992 ('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>
This commit is contained in:
Pierre-Louis Bossart 2021-01-15 13:37:37 +08:00 committed by Greg Kroah-Hartman
parent fcfec32c9a
commit 3a9044ea78
1 changed files with 4 additions and 4 deletions
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8
drivers/soundwire/cadence_master.c
View File

@ -368,10 +368,10 @@ 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");
}
}