[PATCH 5.11 092/342] soundwire: cadence: only prepare attached devices on clock stop

From: Greg Kroah-Hartman
Date: Mon May 10 2021 - 07:30:02 EST


From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

[ Upstream commit 58ef9356260c291a4321e07ff507f31a1d8212af ]

We sometimes see COMMAND_IGNORED responses during the clock stop
sequence. It turns out we already have information if devices are
present on a link, so we should only prepare those when they
are attached.

In addition, even when COMMAND_IGNORED are received, we should still
proceed with the clock stop. The device will not be prepared but
that's not a problem.

The only case where the clock stop will fail is if the Cadence IP
reports an error (including a timeout), or if the devices throw a
COMMAND_FAILED response.

BugLink: https://github.com/thesofproject/linux/issues/2621
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Reviewed-by: Rander Wang <rander.wang@xxxxxxxxx>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@xxxxxxxxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210323013707.21455-1-yung-chuan.liao@xxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/soundwire/cadence_master.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c
index 580660599f46..c6d421a4b91b 100644
--- a/drivers/soundwire/cadence_master.c
+++ b/drivers/soundwire/cadence_master.c
@@ -1449,10 +1449,12 @@ int sdw_cdns_clock_stop(struct sdw_cdns *cdns, bool block_wake)
}

/* Prepare slaves for clock stop */
- ret = sdw_bus_prep_clk_stop(&cdns->bus);
- if (ret < 0) {
- dev_err(cdns->dev, "prepare clock stop failed %d", ret);
- return ret;
+ if (slave_present) {
+ ret = sdw_bus_prep_clk_stop(&cdns->bus);
+ if (ret < 0 && ret != -ENODATA) {
+ dev_err(cdns->dev, "prepare clock stop failed %d\n", ret);
+ return ret;
+ }
}

/*
--
2.30.2