Unify amongst sink drivers how the AUX ring buffer head is communicated to user space. That way the same algorithm in cs_etm_find_snapshot() 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 --- drivers/hwtracing/coresight/coresight-tmc-etf.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c index 2527b5d3b65e..d026bd04a6af 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c @@ -542,11 +542,15 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev, } }
- /* In snapshot mode we have to update the head */ - if (buf->snapshot) { - handle->head = (cur * PAGE_SIZE) + offset; - to_read = buf->nr_pages << PAGE_SHIFT; - } + /* + * 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 (buf->snapshot) + handle->head += to_read; + CS_LOCK(drvdata->base); out: spin_unlock_irqrestore(&drvdata->spinlock, flags);