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coresight: etm: Make cycle count threshold user configurable

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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@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: James Clark <james.clark@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230921033631.1298723-3-anshuman.khandual@arm.com
This commit is contained in:
Anshuman Khandual 2023-09-21 09:06:30 +05:30 committed by Suzuki K Poulose
parent 4aff040bcc
commit 94566c5b07
2 changed files with 9 additions and 2 deletions
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2
drivers/hwtracing/coresight/coresight-etm-perf.c
View File

@ -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,
};

9
drivers/hwtracing/coresight/coresight-etm4x-core.c
View File

@ -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)) {
/*