[PATCH v2 2/2] hwtracing: hisi_ptt: Remove unnecessary trace buffer zeroing in trace_start()

["Pradhan, Sanman" <sanman.pradhan@hpe.com>]

From: Sanman Pradhan <psanman@juniper.net>

hisi_ptt_trace_start() clears all four trace buffers before enabling
tracing.

This is unnecessary. On trace stop, hisi_ptt_update_aux() copies only
the number of bytes reported in HISI_PTT_TRACE_WR_STS. On buffer-full
interrupts, it copies a full completed buffer. In both cases the driver
only consumes data written by hardware.

Remove the buffer clearing from the trace start path.

Signed-off-by: Sanman Pradhan <psanman@juniper.net>
Reviewed-by: Yicong Yang <yangyccccc@gmail.com>
---
v2:
  - No changes

 drivers/hwtracing/ptt/hisi_ptt.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
index b5d851281fbf0..a8f6986c8e1f7 100644
--- a/drivers/hwtracing/ptt/hisi_ptt.c
+++ b/drivers/hwtracing/ptt/hisi_ptt.c
@@ -194,7 +194,6 @@ static int hisi_ptt_trace_start(struct hisi_ptt *hisi_ptt)
 {
 	struct hisi_ptt_trace_ctrl *ctrl = &hisi_ptt->trace_ctrl;
 	u32 val;
-	int i;
 
 	/* Check device idle before start trace */
 	if (!hisi_ptt_wait_trace_hw_idle(hisi_ptt)) {
@@ -222,10 +221,6 @@ static int hisi_ptt_trace_start(struct hisi_ptt *hisi_ptt)
 	/* Reset the index of current buffer */
 	hisi_ptt->trace_ctrl.buf_index = 0;
 
-	/* Zero the trace buffers */
-	for (i = 0; i < HISI_PTT_TRACE_BUF_CNT; i++)
-		memset(ctrl->trace_buf[i].addr, 0, HISI_PTT_TRACE_BUF_SIZE);
-
 	/* Clear the interrupt status */
 	writel(HISI_PTT_TRACE_INT_STAT_MASK, hisi_ptt->iobase + HISI_PTT_TRACE_INT_STAT);
 	writel(0, hisi_ptt->iobase + HISI_PTT_TRACE_INT_MASK);
-- 
2.34.1