Hi James,
-----Original Message----- From: James Clark james.clark@arm.com Sent: Friday, May 31, 2024 3:47 PM To: Linu Cherian lcherian@marvell.com Cc: linux-arm-kernel@lists.infradead.org; coresight@lists.linaro.org; linux- kernel@vger.kernel.org; robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; devicetree@vger.kernel.org; Sunil Kovvuri Goutham sgoutham@marvell.com; George Cherian gcherian@marvell.com; suzuki.poulose@arm.com; mike.leach@linaro.org Subject: [EXTERNAL] Re: [PATCH v8 6/7] coresight: tmc: Stop trace capture on FlIn
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On 31/05/2024 05:27, Linu Cherian wrote:
Configure TMC ETR and ETF to flush and stop trace capture on FlIn event based on sysfs attribute, /sys/bus/coresight/devices/tmc_etXn/stop_on_flush.
Signed-off-by: Linu Cherian lcherian@marvell.com
Changelog from v7:
- Honour stop_on_flush sysfs attribute for perf sessions as well. This allows user to start trace sessions using perf method as well to use the Coresight kernel panic support.
.../hwtracing/coresight/coresight-tmc-core.c | 31
+++++++++++++++++++
.../hwtracing/coresight/coresight-tmc-etf.c | 18 ++++++++--- .../hwtracing/coresight/coresight-tmc-etr.c | 18 ++++++++--- drivers/hwtracing/coresight/coresight-tmc.h | 4 +++ 4 files changed, 61 insertions(+), 10 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index aaa9de9f4cd2..24edd9d750c3 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -452,9 +452,40 @@ static ssize_t buffer_size_store(struct device *dev,
static DEVICE_ATTR_RW(buffer_size);
+static ssize_t stop_on_flush_show(struct device *dev,
struct device_attribute *attr, char *buf) {- struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
- return sprintf(buf, "%#x\n", drvdata->stop_on_flush); }
+static ssize_t stop_on_flush_store(struct device *dev,
struct device_attribute *attr,const char *buf, size_t size)+{
- int ret;
- u8 val;
- struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
- ret = kstrtou8(buf, 0, &val);
- if (ret)
return ret;- if (val)
drvdata->stop_on_flush = true;- else
drvdata->stop_on_flush = false;- return size;
+}
+static DEVICE_ATTR_RW(stop_on_flush);
static struct attribute *coresight_tmc_attrs[] = { &dev_attr_trigger_cntr.attr, &dev_attr_buffer_size.attr,
- &dev_attr_stop_on_flush.attr, NULL,
};
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index 655c0c0ba54b..1529b9cc210a 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -19,6 +19,7 @@ static int tmc_set_etf_buffer(struct coresight_device *csdev, static int __tmc_etb_enable_hw(struct tmc_drvdata *drvdata) { int rc = 0;
u32 ffcr;
CS_UNLOCK(drvdata->base);
@@ -32,10 +33,12 @@ static int __tmc_etb_enable_hw(struct
tmc_drvdata *drvdata)
}
writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base +
TMC_MODE);
- writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT |TMC_FFCR_TRIGON_TRIGIN,drvdata->base + TMC_FFCR);
- ffcr = TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
TMC_FFCR_FON_FLIN |
TMC_FFCR_FON_TRIG_EVT | TMC_FFCR_TRIGON_TRIGIN;if (drvdata->stop_on_flush_en)
ffcr |= TMC_FFCR_STOP_ON_FLUSH;writel_relaxed(ffcr, drvdata->base + TMC_FFCR);
writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG); tmc_enable_hw(drvdata);
@@ -225,7 +228,8 @@ static int tmc_enable_etf_sink_sysfs(struct
coresight_device *csdev)
used = true; drvdata->buf = buf;}
- if (drvdata->stop_on_flush)
drvdata->stop_on_flush_en = true;Does this do anything different than only using stop_on_flush in __tmc_etr_enable_hw()?
Seems like stop_on_flush_en == stop_on_flush whenever stop_on_flush_en is read, so you might as well just read stop_on_flush and get rid of the _en copy?
Ack.