[PATCH v5 11/15] coresight: trbe: Add a helper to determine the minimum buffer size

Suzuki K Poulose
2021-10-14T22:32:06Z

For the TRBE to operate, we need a minimum space available to collect
meaningful trace session. This is currently a few bytes, but we may need
to extend this for working around errata. So, abstract this into a helper
function.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-trbe.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index b56b166b2dec..4a50309a892d 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -303,6 +303,11 @@ static unsigned long trbe_snapshot_offset(struct perf_output_handle *handle)
return buf->nr_pages * PAGE_SIZE;
}

+static u64 trbe_min_trace_buf_size(struct perf_output_handle *handle)
+{
+ return TRBE_TRACE_MIN_BUF_SIZE;
+}
+
/*
* TRBE Limit Calculation
*
@@ -473,7 +478,7 @@ static unsigned long trbe_normal_offset(struct perf_output_handle *handle)
* have space for a meaningful run, we rather pad it
* and start fresh.
*/
- if (limit && (limit - head < TRBE_TRACE_MIN_BUF_SIZE)) {
+ if (limit && ((limit - head) < trbe_min_trace_buf_size(handle))) {
trbe_pad_buf(handle, limit - head);
limit = __trbe_normal_offset(handle);
}
--
2.25.4