From: Rander Wang <rander.wang@xxxxxxxxx>
When all the links are suspended, the HDaudio controller may suspend
and the power rails to the SoundWire IP may be disabled, requiring a
complete re-initialization/enumeration on resume. However, if one or
more Masters remained active, the HDaudio controller will remain active
and the power rails will remain enabled. As a result, during the link
resume step we can check if the context was preserved by verifying if
the clock was stopped, and avoid doing a complete bus reset and
re-enumeration.
Signed-off-by: Rander Wang <rander.wang@xxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
drivers/soundwire/intel.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 2899445e2649..dbcbe2708563 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1698,6 +1698,8 @@ static int intel_resume_runtime(struct device *dev)
struct sdw_intel *sdw = cdns_to_intel(cdns);
struct sdw_bus *bus = &cdns->bus;
u32 clock_stop_quirks;
+ bool clock_stop0;
+ int status;
int ret;
if (bus->prop.hw_disabled) {
@@ -1739,11 +1741,24 @@ static int intel_resume_runtime(struct device *dev)
return ret;
}
+ /*
+ * An exception condition occurs for the CLK_STOP_BUS_RESET
+ * case if one or more masters remain active. In this condition,
+ * all the masters are powered on for they are in the same power
+ * domain. Master can preserve its context for clock stop0, so
+ * there is no need to clear slave status and reset bus.
+ */
+ clock_stop0 = sdw_cdns_is_clock_stop(&sdw->cdns);
+
/*
* make sure all Slaves are tagged as UNATTACHED and
* provide reason for reinitialization
*/
- sdw_clear_slave_status(bus, SDW_UNATTACH_REQUEST_MASTER_RESET);
+ if (!clock_stop0) {
+ status = SDW_UNATTACH_REQUEST_MASTER_RESET;
+ sdw_clear_slave_status(bus, status);
+ }
+
ret = sdw_cdns_enable_interrupt(cdns, true);
if (ret < 0) {
@@ -1751,7 +1766,7 @@ static int intel_resume_runtime(struct device *dev)
return ret;
}
- ret = sdw_cdns_clock_restart(cdns, true);
+ ret = sdw_cdns_clock_restart(cdns, !clock_stop0);
if (ret < 0) {
dev_err(dev, "unable to restart clock during resume\n");
return ret;
--
2.17.1
