From: Leo Yan <leo.yan@arm.com>
Date: Fri, 15 May 2026 20:08:20 +0000 (+0100)
Subject: coresight: etm4x: Remove redundant checks in PM save and restore
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=81bf1c33f6a7b2be8523e8b3655b85ca959975cf;p=thirdparty%2Flinux.git

coresight: etm4x: Remove redundant checks in PM save and restore

ETMv4 driver save/restore callbacks still re-check conditions that are
already validated by the core layer before the callbacks are invoked.

Remove the duplicated checks and fold the two-level functions into
direct callback implementations.  The obsolete WARN_ON() checks are
removed as well.

Reviewed-by: Mike Leach <mike.leach@linaro.org>
Tested-by: James Clark <james.clark@linaro.org>
Reviewed-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Tested-by: Jie Gan <jie.gan@oss.qualcomm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-13-f88c4a3ecfe9@arm.com
---

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 5cd70f0f3710..fef1270439e9 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1853,17 +1853,14 @@ static inline bool etm4_pm_save_needed(struct etmv4_drvdata *drvdata)
 	return !!drvdata->save_state;
 }
 
-static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
+static int etm4_cpu_save(struct coresight_device *csdev)
 {
 	int i, ret = 0;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	struct etmv4_save_state *state;
-	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa;
 	struct device *etm_dev;
 
-	if (WARN_ON(!csdev))
-		return -ENODEV;
-
 	etm_dev = &csdev->dev;
 	csa = &csdev->access;
 
@@ -1995,32 +1992,13 @@ out:
 	return ret;
 }
 
-static int etm4_cpu_save(struct coresight_device *csdev)
-{
-	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-	int ret = 0;
-
-	if (!etm4_pm_save_needed(drvdata))
-		return 0;
-
-	/*
-	 * Save and restore the ETM Trace registers only if
-	 * the ETM is active.
-	 */
-	if (coresight_get_mode(drvdata->csdev))
-		ret = __etm4_cpu_save(drvdata);
-	return ret;
-}
-
-static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
+static void etm4_cpu_restore(struct coresight_device *csdev)
 {
 	int i;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 	struct etmv4_save_state *state = drvdata->save_state;
 	struct csdev_access *csa = &drvdata->csdev->access;
 
-	if (WARN_ON(!drvdata->csdev))
-		return;
-
 	etm4_cs_unlock(drvdata, csa);
 	etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);
 
@@ -2113,17 +2091,6 @@ static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 	etm4_cs_lock(drvdata, csa);
 }
 
-static void etm4_cpu_restore(struct coresight_device *csdev)
-{
-	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
-
-	if (!etm4_pm_save_needed(drvdata))
-		return;
-
-	if (coresight_get_mode(drvdata->csdev))
-		__etm4_cpu_restore(drvdata);
-}
-
 static const struct coresight_ops etm4_cs_ops = {
 	.trace_id	= coresight_etm_get_trace_id,
 	.source_ops	= &etm4_source_ops,