coresight: tmc: Stop trace capture on FlIn

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 <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Linu Cherian

drivers/hwtracing/coresight/coresight-tmc-core.c

@@ -532,9 +532,40 @@ 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,
 };
 

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)
+		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 +228,6 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
 		used = true;
 		drvdata->buf = buf;
 	}
-
 	ret = tmc_etb_enable_hw(drvdata);
 	if (!ret) {
 		coresight_set_mode(csdev, CS_MODE_SYSFS);

drivers/hwtracing/coresight/coresight-tmc-etr.c

@@ -1060,7 +1060,7 @@ static void tmc_sync_etr_buf(struct tmc_drvdata *drvdata)
 
 static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 {
-	u32 axictl, sts;
+	u32 axictl, sts, ffcr;
 	struct etr_buf *etr_buf = drvdata->etr_buf;
 	int rc = 0;
 
@@ -1106,10 +1106,12 @@ static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 		writel_relaxed(sts, drvdata->base + TMC_STS);
 	}
 
-	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)
+		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);
 

drivers/hwtracing/coresight/coresight-tmc.h

@@ -220,6 +220,7 @@ struct tmc_resrv_buf {
  * @pid:	Process ID of the process that owns the session that is using
  *		this component. For example this would be the pid of the Perf
  *		process.
+ * @stop_on_flush: Stop on flush trigger user configuration.
  * @buf:	Snapshot of the trace data for ETF/ETB.
  * @etr_buf:	details of buffer used in TMC-ETR
  * @len:	size of the available trace for ETF/ETB.
@@ -251,6 +252,7 @@ struct tmc_drvdata {
 	spinlock_t		spinlock;
 	pid_t			pid;
 	bool			reading;
+	bool			stop_on_flush;
 	union {
 		char		*buf;		/* TMC ETB */
 		struct etr_buf	*etr_buf;	/* TMC ETR */