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soundwire: intel: refine runtime pm for SDW_INTEL_CLK_STOP_BUS_RESET

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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@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200817152923.3259-13-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Rander Wang 2020-08-17 23:29:23 +08:00 committed by Vinod Koul
parent 61fb830bf9
commit 08abad9f45
1 changed files with 17 additions and 2 deletions
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19
drivers/soundwire/intel.c
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@ -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;