coresight: trbe: Unify the enabling sequence

Unify the sequence of enabling the TRBE. We do this from
event_start and also from the TRBE IRQ handler. Lets move
this to a common helper. The only minor functional change
is returning an error when we fail to enable the TRBE.
This should be handled already.

Since we now have unique entry point to trying to enable TRBE,
move the format flag setting to the central place.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210914102641.1852544-9-suzuki.poulose@arm.comSigned-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>

drivers/hwtracing/coresight/coresight-trbe.c

@@ -629,6 +629,21 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
 	return size;
 }
 
+static int __arm_trbe_enable(struct trbe_buf *buf,
+			     struct perf_output_handle *handle)
+{
+	perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
+	buf->trbe_limit = compute_trbe_buffer_limit(handle);
+	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
+	if (buf->trbe_limit == buf->trbe_base) {
+		trbe_stop_and_truncate_event(handle);
+		return -ENOSPC;
+	}
+	*this_cpu_ptr(buf->cpudata->drvdata->handle) = handle;
+	trbe_enable_hw(buf);
+	return 0;
+}
+
 static int arm_trbe_enable(struct coresight_device *csdev, u32 mode, void *data)
 {
 	struct trbe_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -641,19 +656,11 @@ static int arm_trbe_enable(struct coresight_device *csdev, u32 mode, void *data)
 	if (mode != CS_MODE_PERF)
 		return -EINVAL;
 
-	perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
-	*this_cpu_ptr(drvdata->handle) = handle;
 	cpudata->buf = buf;
 	cpudata->mode = mode;
 	buf->cpudata = cpudata;
-	buf->trbe_limit = compute_trbe_buffer_limit(handle);
-	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
-	if (buf->trbe_limit == buf->trbe_base) {
-		trbe_stop_and_truncate_event(handle);
-		return 0;
-	}
-	trbe_enable_hw(buf);
-	return 0;
+
+	return __arm_trbe_enable(buf, handle);
 }
 
 static int arm_trbe_disable(struct coresight_device *csdev)
@@ -723,15 +730,7 @@ static void trbe_handle_overflow(struct perf_output_handle *handle)
 		*this_cpu_ptr(buf->cpudata->drvdata->handle) = NULL;
 		return;
 	}
-	perf_aux_output_flag(handle, PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW);
-	buf->trbe_limit = compute_trbe_buffer_limit(handle);
-	buf->trbe_write = buf->trbe_base + PERF_IDX2OFF(handle->head, buf);
-	if (buf->trbe_limit == buf->trbe_base) {
-		trbe_stop_and_truncate_event(handle);
-		return;
-	}
-	*this_cpu_ptr(buf->cpudata->drvdata->handle) = handle;
-	trbe_enable_hw(buf);
+	__arm_trbe_enable(buf, handle);
 }
 
 static bool is_perf_trbe(struct perf_output_handle *handle)