[PATCH v2 06/23] coresight: trbe: Drop redundant disable from enable path

[Leo Yan]

The Arm ARM (ARM DDI 0487 M.c) rule RDJMDD says:

 | When the following conditions apply, the PE might ignore a direct or
 | external write to any of certain Trace Buffer Unit registers, other
 | than a direct write or external write to TRBLIMITR_EL1 that clears
 | the conditions:
 | • TRBLIMITR_EL1.E is 1, and either FEAT_TRBE_EXT is not implemented
 |   or the Trace Buffer Unit is using Self-hosted mode.

trbe_enable_hw() calls set_trbe_disabled() first to ensure TRBE has
already been disabled before programming any other TRBE registers.

However, TRBE is already expected to be disabled before trbe_enable_hw()
runs:

 1. CPU probe resets TRBLIMITR_EL1 via trbe_reset_local();
 2. Interrupt handling disables the buffer before re-enabling it;
 3. The normal disable path clears TRBLIMITR_EL1.E.

Calling set_trbe_disabled() from the enable path is therefore redundant.
Drop the call from trbe_enable_hw(), which only needs to program a
known-disabled TRBE.

Signed-off-by: Leo Yan <leo.yan@xxxxxxx>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index a7c1037a048f5236598f8f3a7cc4f47bff9d329c..979d0fa84c1c7b448c1ce5cd7a37dff8845795ef 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -652,7 +652,6 @@ static void trbe_enable_hw(struct trbe_buf *buf)
 	WARN_ON(buf->trbe_hw_base < buf->trbe_base);
 	WARN_ON(buf->trbe_write < buf->trbe_hw_base);
 	WARN_ON(buf->trbe_write >= buf->trbe_limit);
-	set_trbe_disabled(buf->cpudata);
 	clr_trbe_status();
 	set_trbe_base_pointer(buf->trbe_hw_base);
 	set_trbe_write_pointer(buf->trbe_write);

-- 
2.34.1