From 0f00b223ea22f9e32a82a6ffb5a4de0753c99b55 Mon Sep 17 00:00:00 2001 From: German Gomez Date: Tue, 23 Aug 2022 17:06:49 +0100 Subject: coresight: etm4x: Expose default timestamp source in sysfs Add a new sysfs interface in /sys/bus/coresight/devices/etm/ts_source indicating the configured timestamp source when the ETM device driver was probed. The perf tool will use this information to detect if the trace data timestamp matches the kernel time, enabling correlation of CoreSight trace with perf events. Suggested-by: Suzuki K Poulose Signed-off-by: German Gomez Reviewed-by: Leo Yan Signed-off-by: James Clark Link: https://lore.kernel.org/r/20220823160650.455823-2-james.clark@arm.com Signed-off-by: Mathieu Poirier --- .../hwtracing/coresight/coresight-etm4x-sysfs.c | 29 ++++++++++++++++++++++ 1 file changed, 29 insertions(+) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index 6ea8181816fc..9cac848cffaf 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -2306,6 +2306,34 @@ static ssize_t cpu_show(struct device *dev, } static DEVICE_ATTR_RO(cpu); +static ssize_t ts_source_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + int val; + struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent); + + if (!drvdata->trfcr) { + val = -1; + goto out; + } + + switch (drvdata->trfcr & TRFCR_ELx_TS_MASK) { + case TRFCR_ELx_TS_VIRTUAL: + case TRFCR_ELx_TS_GUEST_PHYSICAL: + case TRFCR_ELx_TS_PHYSICAL: + val = FIELD_GET(TRFCR_ELx_TS_MASK, drvdata->trfcr); + break; + default: + val = -1; + break; + } + +out: + return sysfs_emit(buf, "%d\n", val); +} +static DEVICE_ATTR_RO(ts_source); + static struct attribute *coresight_etmv4_attrs[] = { &dev_attr_nr_pe_cmp.attr, &dev_attr_nr_addr_cmp.attr, @@ -2360,6 +2388,7 @@ static struct attribute *coresight_etmv4_attrs[] = { &dev_attr_vmid_val.attr, &dev_attr_vmid_masks.attr, &dev_attr_cpu.attr, + &dev_attr_ts_source.attr, NULL, }; -- cgit v1.2.3