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authorMathieu Poirier <mathieu.poirier@linaro.org>2019-05-09 15:47:49 -0600
committerMathieu Poirier <mathieu.poirier@linaro.org>2019-05-20 13:38:39 -0600
commit03a26d6f907c06e25103fb061f1c399d33304d4a (patch)
treeff0ff2949d7e0d44e0290c8681cefac1d56207a3
parenta188339ca5a396acc588e5851ed7e19f66b0ebd9 (diff)
coresight: etb10: 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 <mathieu.poirier@linaro.org> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Tested-by: Leo Yan <leo.yan@linaro.org>
-rw-r--r--drivers/hwtracing/coresight/coresight-etb10.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 4ee4c80a4354..60e753b1768d 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -548,13 +548,14 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev,
writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
/*
- * In snapshot mode we have to update the handle->head to point
- * to the new location.
+ * 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 = (cur * PAGE_SIZE) + offset;
- to_read = buf->nr_pages << PAGE_SHIFT;
- }
+ if (buf->snapshot)
+ handle->head += to_read;
+
__etb_enable_hw(drvdata);
CS_LOCK(drvdata->base);
out: