coresight: perf: Remove set_buffer call back

In coresight perf mode, we need to prepare the sink before
starting a session, which is done via set_buffer call back.
We then proceed to enable the tracing. If we fail to start
the session successfully, we leave the sink configuration
unchanged.  In order to make the operation atomic and to
avoid yet another call back to clear the buffer, we get
rid of the "set_buffer" call back and pass the buffer details
via enable() call back to the sink.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 25 insertions, 7 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index dba75c905e57..9fd77fdc1244 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -28,6 +28,7 @@
 
 
 #include "coresight-priv.h"
+#include "coresight-etm-perf.h"
 
 #define ETB_RAM_DEPTH_REG	0x004
 #define ETB_STATUS_REG		0x00c
@@ -90,6 +91,9 @@ struct etb_drvdata {
 	u32			trigger_cntr;
 };
 
+static int etb_set_buffer(struct coresight_device *csdev,
+			  struct perf_output_handle *handle);
+
 static unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
 {
 	u32 depth = 0;
@@ -131,12 +135,24 @@ static void etb_enable_hw(struct etb_drvdata *drvdata)
 	CS_LOCK(drvdata->base);
 }
 
-static int etb_enable(struct coresight_device *csdev, u32 mode)
+static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
 {
+	int ret = 0;
 	u32 val;
 	unsigned long flags;
 	struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
 
+	/*
+	 * We don't have an internal state to clean up if we fail to setup
+	 * the perf buffer. So we can perform the step before we turn the
+	 * ETB on and leave without cleaning up.
+	 */
+	if (mode == CS_MODE_PERF) {
+		ret = etb_set_buffer(csdev, (struct perf_output_handle *)data);
+		if (ret)
+			goto out;
+	}
+
 	val = local_cmpxchg(&drvdata->mode,
 			    CS_MODE_DISABLED, mode);
 	/*
@@ -160,8 +176,9 @@ static int etb_enable(struct coresight_device *csdev, u32 mode)
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 out:
-	dev_dbg(drvdata->dev, "ETB enabled\n");
-	return 0;
+	if (!ret)
+		dev_dbg(drvdata->dev, "ETB enabled\n");
+	return ret;
 }
 
 static void etb_disable_hw(struct etb_drvdata *drvdata)
@@ -298,12 +315,14 @@ static void etb_free_buffer(void *config)
 }
 
 static int etb_set_buffer(struct coresight_device *csdev,
-			  struct perf_output_handle *handle,
-			  void *sink_config)
+			  struct perf_output_handle *handle)
 {
 	int ret = 0;
 	unsigned long head;
-	struct cs_buffers *buf = sink_config;
+	struct cs_buffers *buf = etm_perf_sink_config(handle);
+
+	if (!buf)
+		return -EINVAL;
 
 	/* wrap head around to the amount of space we have */
 	head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
@@ -457,7 +476,6 @@ static const struct coresight_ops_sink etb_sink_ops = {
 	.disable	= etb_disable,
 	.alloc_buffer	= etb_alloc_buffer,
 	.free_buffer	= etb_free_buffer,
-	.set_buffer	= etb_set_buffer,
 	.update_buffer	= etb_update_buffer,
 };