From bc9907750718cdaad85870c93f2c72db5c85e345 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Fri, 15 May 2026 21:08:28 +0100 Subject: [PATCH] coresight: etm3x: Set active path on target CPU Set the path pointer on the target CPU during ETM enable and disable. This ensures the device mode and path pointer are updated together and observed atomically by the CPU PM notifier. Tested-by: James Clark Reviewed-by: Yeoreum Yun Reviewed-by: James Clark Tested-by: Jie Gan Signed-off-by: Leo Yan Signed-off-by: Suzuki K Poulose Link: https://lore.kernel.org/r/20260515-arm_coresight_path_power_management_improvement-v14-21-f88c4a3ecfe9@arm.com --- .../hwtracing/coresight/coresight-etm3x-core.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c index aeeb284abdbe..c6fe8b25b855 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c @@ -441,6 +441,7 @@ static int etm_enable_hw(struct etm_drvdata *drvdata) struct etm_enable_arg { struct etm_drvdata *drvdata; + struct coresight_path *path; int rc; }; @@ -462,8 +463,12 @@ static void etm_enable_sysfs_smp_call(void *info) arg->rc = etm_enable_hw(arg->drvdata); /* The tracer didn't start */ - if (arg->rc) + if (arg->rc) { coresight_set_mode(csdev, CS_MODE_DISABLED); + return; + } + + csdev->path = arg->path; } void etm_release_trace_id(struct etm_drvdata *drvdata) @@ -492,10 +497,13 @@ static int etm_enable_perf(struct coresight_device *csdev, ret = etm_enable_hw(drvdata); /* Failed to start tracer; roll back to DISABLED mode */ - if (ret) + if (ret) { coresight_set_mode(csdev, CS_MODE_DISABLED); + return ret; + } - return ret; + csdev->path = path; + return 0; } static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path) @@ -514,6 +522,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev, struct coresight_pat */ if (cpu_online(drvdata->cpu)) { arg.drvdata = drvdata; + arg.path = path; ret = smp_call_function_single(drvdata->cpu, etm_enable_sysfs_smp_call, &arg, 1); if (!ret) @@ -583,6 +592,7 @@ static void etm_disable_sysfs_smp_call(void *info) etm_disable_hw(drvdata); + drvdata->csdev->path = NULL; coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); } @@ -607,6 +617,7 @@ static void etm_disable_perf(struct coresight_device *csdev) CS_LOCK(drvdata->csa.base); + drvdata->csdev->path = NULL; coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED); /*