From 3ecb03022a25b3f089b93a35f608ea7ee6a244aa Mon Sep 17 00:00:00 2001 From: Mathieu Poirier Date: Wed, 19 Jun 2019 11:29:06 -0600 Subject: [PATCH] coresight: tmc-etr: Properly set AUX buffer head in snapshot mode 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 Reviewed-by: Suzuki K Poulose Tested-by: Leo Yan Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index df6e4b0b84e93..cc8401c76c399 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -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: -- 2.30.2