When cycle counting is enabled, we use a default threshold value i.e 0x100
for the instruction trace cycle counting.
This patch makes the cycle threshold user configurable via perf event
attributes( 'cc_threshold' => event->attr.config3[11:0] ), falling back
to the current default if unspecified.
Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Cc: Mike Leach <mike.leach@xxxxxxxxxx>
Cc: James Clark <james.clark@xxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: coresight@xxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Reviewed-by: Mike Leach <mike.leach@xxxxxxxxxx>
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
drivers/hwtracing/coresight/coresight-etm-perf.c | 2 ++
drivers/hwtracing/coresight/coresight-etm4x-core.c | 9 +++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 5ca6278baff4..09f75dffae60 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -68,6 +68,7 @@ PMU_FORMAT_ATTR(preset, "config:0-3");
PMU_FORMAT_ATTR(sinkid, "config2:0-31");
/* config ID - set if a system configuration is selected */
PMU_FORMAT_ATTR(configid, "config2:32-63");
+PMU_FORMAT_ATTR(cc_threshold, "config3:0-11");
/*
@@ -101,6 +102,7 @@ static struct attribute *etm_config_formats_attr[] = {
&format_attr_preset.attr,
&format_attr_configid.attr,
&format_attr_branch_broadcast.attr,
+ &format_attr_cc_threshold.attr,
NULL,
};
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 9619d9d0bbb1..5b6a878a2ac5 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -644,7 +644,7 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
struct etmv4_config *config = &drvdata->config;
struct perf_event_attr *attr = &event->attr;
unsigned long cfg_hash;
- int preset;
+ int preset, cc_threshold;
/* Clear configuration from previous run */
memset(config, 0, sizeof(struct etmv4_config));
@@ -667,7 +667,12 @@ static int etm4_parse_event_config(struct coresight_device *csdev,
if (attr->config & BIT(ETM_OPT_CYCACC)) {
config->cfg |= TRCCONFIGR_CCI;
/* TRM: Must program this for cycacc to work */
- config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT;
+ cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK;
+ if (!cc_threshold)
+ cc_threshold = ETM_CYC_THRESHOLD_DEFAULT;
+ if (cc_threshold < drvdata->ccitmin)
+ cc_threshold = drvdata->ccitmin;
+ config->ccctlr = cc_threshold;
}
if (attr->config & BIT(ETM_OPT_TS)) {
/*
--
2.25.1
