coresight: tmc-etr: Properly set AUX buffer head in snapshot mode (3ecb0302) · Commits · 戴 / test

Unify amongst sink drivers how the AUX ring buffer head is communicated to user space. That way the same algorithm in user space can be used to determine where the latest data is and how much of it to access. Signed-off-by:

Mathieu Poirier <mathieu.poirier@linaro.org> Reviewed-by:

Suzuki K Poulose <suzuki.poulose@arm.com> Tested-by:

Leo Yan <leo.yan@linaro.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-tmc-etr.c

+5 −6

Original line number	Diff line number	Diff line
		@@ -1501,14 +1501,13 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
		tmc_etr_sync_perf_buffer(etr_perf);

		/*
		* Update handle->head in snapshot mode. Also update the size to the
		* hardware buffer size if there was an overflow.
		* In snapshot mode we simply increment the head by the number of byte
		* that were written. User space function cs_etm_find_snapshot() will
		* figure out how many bytes to get from the AUX buffer based on the
		* position of the head.
		*/
		if (etr_perf->snapshot) {
		if (etr_perf->snapshot)
		handle->head += size;
		if (etr_buf->full)
		size = etr_buf->size;
		}

		lost \|= etr_buf->full;
		out:

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