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soundwire: cadence_master: always set CMD_ACCEPT

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The Cadence IP can be configured in two different ways to deal with
CMD_IGNORED replies to broadcast commands. The CMD_ACCEPT bitfield
controls whether the command is discarded or if the IP proceeds with
the change (typically a bank switch or clock stop command).

The existing code seems to be inconsistent:
a) For some historical reason, we set this CMD_ACCEPT bitfield during
the initialization, but we don't during a resume from a clock-stoppped
state.
b) In addition, the loop used in the clock-stop sequence is quite
racy, it's possible that a device has lost sync but it's still tagged
as ATTACHED.
c) If somehow a Device loses sync and is unable to ack a broadcast
command, we do not have an error handling mechanism anyways. The IP
should go ahead and let the Device regain sync at a later time.

Make sure the CMD_ACCEPT bit is always set.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511025247.25339-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Pierre-Louis Bossart 2021-05-11 10:52:47 +08:00 committed by Vinod Koul
parent 54a6ca4fa8
commit 36eee232df
1 changed files with 2 additions and 19 deletions
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21
drivers/soundwire/cadence_master.c
View file

@ -1428,20 +1428,6 @@ int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake)
}
}
/*
* This CMD_ACCEPT should be used when there are no devices
* attached on the link when entering clock stop mode. If this is
* not set and there is a broadcast write then the command ignored
* will be treated as a failure
*/
if (!slave_present)
cdns_updatel(cdns, CDNS_MCP_CONTROL,
CDNS_MCP_CONTROL_CMD_ACCEPT,
CDNS_MCP_CONTROL_CMD_ACCEPT);
else
cdns_updatel(cdns, CDNS_MCP_CONTROL,
CDNS_MCP_CONTROL_CMD_ACCEPT, 0);
/* commit changes */
ret = cdns_config_update(cdns);
if (ret < 0) {
@ -1508,11 +1494,8 @@ int sdw_cdns_clock_restart(struct sdw_cdns *cdns, bool bus_reset)
cdns_updatel(cdns, CDNS_MCP_CONTROL,
CDNS_MCP_CONTROL_BLOCK_WAKEUP, 0);
/*
* clear CMD_ACCEPT so that the command ignored
* will be treated as a failure during a broadcast write
*/
cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_ACCEPT, 0);
cdns_updatel(cdns, CDNS_MCP_CONTROL, CDNS_MCP_CONTROL_CMD_ACCEPT,
CDNS_MCP_CONTROL_CMD_ACCEPT);
if (!bus_reset) {