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hwtracing: hisi_ptt: Remove unnecessary trace buffer zeroing in trace_start()

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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>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20260414172451.14331-3-sanman.pradhan@hpe.com
This commit is contained in:
Sanman Pradhan 2026-04-14 17:25:22 +00:00 committed by Suzuki K Poulose
parent 75d42d9903
commit 856119909d
1 changed files with 0 additions and 5 deletions
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5
drivers/hwtracing/ptt/hisi_ptt.c
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@ -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);