Commit 9c49a4dd authored by Pierre-Louis Bossart's avatar Pierre-Louis Bossart Committed by Vinod Koul
Browse files

soundwire: intel: simplify sync_go sequence 



In the existing code, the SHIM_SYNC::SYNC_GO bit is set, and the code
waits for it to return to zero.

That second wait part is just wrong: the SYNC_GO bit is *write-only* so
there's no way to know if it's cleared by hardware. The code works
because the value for a read-only bit is zero, but that's really just
luck.

Simplify the sequence to a plain read-modify-write.

Signed-off-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-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/20230314015410.487311-6-yung-chuan.liao@linux.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 59e924fe

drivers/soundwire/intel.c

+2 −7
Original line number Diff line number Diff line
@@ -475,7 +475,6 @@ static int intel_shim_sync_go_unlocked(struct sdw_intel *sdw) 
{

	void __iomem *shim = sdw->link_res->shim;

	u32 sync_reg;

	int ret;



	/* Read SYNC register */

	sync_reg = intel_readl(shim, SDW_SHIM_SYNC);
@@ -487,13 +486,9 @@ static int intel_shim_sync_go_unlocked(struct sdw_intel *sdw) 
	 */

	sync_reg |= SDW_SHIM_SYNC_SYNCGO;



	ret = intel_clear_bit(shim, SDW_SHIM_SYNC, sync_reg,

			      SDW_SHIM_SYNC_SYNCGO);



	if (ret < 0)

		dev_err(sdw->cdns.dev, "SyncGO clear failed: %d\n", ret);

	intel_writel(shim, SDW_SHIM_SYNC, sync_reg);



	return ret;

	return 0;

}



static int intel_shim_sync_go(struct sdw_intel *sdw)