Commit 08abad9f authored by Rander Wang's avatar Rander Wang Committed by Vinod Koul
Browse files

soundwire: intel: refine runtime pm for SDW_INTEL_CLK_STOP_BUS_RESET 



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: default avatarRander Wang <rander.wang@intel.com>
Signed-off-by: default avatarBard 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: default avatarVinod Koul <vkoul@kernel.org>
parent 61fb830b

drivers/soundwire/intel.c

+17 −2
Original line number Diff line number Diff line
@@ -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;