---------- Forwarded message ---------- From: Mike Leach mike.leach@linaro.org Date: 2 January 2017 at 22:55 Subject: [PATCH] coresight: etm4x: Fix enabling of cycle accurate tracing in perf. To: mathieu.poirier@linaro.org Cc: linux-arm-kernel@lists.infradead.org, coresignt@lists.linaro.org, Mike Leach mike.leach@linaro.org
Using perf record 'cyclacc' option in cs_etm event was not setting up cycle accurate trace correctly.
Corrects bit set in TRCCONFIGR to enable cycle accurate trace. Programs TRCCCCTLR with a valid threshold value as required by ETMv4 spec.
Signed-off-by: Mike Leach mike.leach@linaro.org --- drivers/hwtracing/coresight/coresight-etm4x.c | 7 +++++-- drivers/hwtracing/coresight/coresight-etm4x.h | 1 + 2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c index 4db8d6a..07be032 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.c +++ b/drivers/hwtracing/coresight/coresight-etm4x.c @@ -216,8 +216,11 @@ static int etm4_parse_event_config(struct etmv4_drvdata *drvdata, goto out;
/* Go from generic option to ETMv4 specifics */ - if (attr->config & BIT(ETM_OPT_CYCACC)) - config->cfg |= ETMv4_MODE_CYCACC; + if (attr->config & BIT(ETM_OPT_CYCACC)) { + config->cfg |= BIT(4); + /* TRM: Must program this for cycacc to work */ + config->ccctlr = ETM_CYC_THRESHOLD_DEFAULT; + } if (attr->config & BIT(ETM_OPT_TS)) config->cfg |= ETMv4_MODE_TIMESTAMP;
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h index ba8d3f8..8a62c6c 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x.h +++ b/drivers/hwtracing/coresight/coresight-etm4x.h @@ -146,6 +146,7 @@ #define ETM_ARCH_V4 0x40 #define ETMv4_SYNC_MASK 0x1F #define ETM_CYC_THRESHOLD_MASK 0xFFF +#define ETM_CYC_THRESHOLD_DEFAULT 256 #define ETMv4_EVENT_MASK 0xFF #define ETM_CNTR_MAX_VAL 0xFFFF #define ETM_TRACEID_MASK 0x3f -- 2.7.4