[V3,1/4] docs/perf: Add explanation for DDR_CAP_AXI_ID_FILTER_ENHANCED quirk

Commit Message

Joakim Zhang Nov. 1, 2019, 8:36 a.m. UTC

Add explanation for DDR_CAP_AXI_ID_FILTER_ENHANCED quirk.

Signed-off-by: Joakim Zhang <[e-mail]>
---
ChangeLog:
V1->V2:
	* improve the context a bit.
V2->V3:
	* only need select this enhanced quirk if HW supports.
---
 Documentation/admin-guide/perf/imx-ddr.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

Patch

diff --git a/Documentation/admin-guide/perf/imx-ddr.rst b/Documentation/admin-guide/perf/imx-ddr.rst
index 517a205abad6..d1347928ac39 100644
--- a/Documentation/admin-guide/perf/imx-ddr.rst
+++ b/Documentation/admin-guide/perf/imx-ddr.rst
@@ -50,3 +50,11 @@  in the driver.
   axi_id to monitor a specific id, rather than having to specify axi_mask.
   e.g.::
         perf stat -a -e imx8_ddr0/axid-read,axi_id=0x12/ cmd, which will monitor ARID=0x12
+
+* With DDR_CAP_AXI_ID_FILTER_ENHANCED quirk.
+  This is the extension of DDR_CAP_AXI_ID_FILTER quirk which is only support getting
+  bursts from DDR transaction, i.e. only can get DDR read or write requests. You
+  can select DDR_CAP_AXI_ID_FILTER_ENHANCED quirk if HW supports enhanced filter.
+  Enhanced filter means that it can count bursts and bytes from DDR transaction
+  at the same time as it implements another set of data counters. DDR PMU driver
+  always return bytes for enhanced filter due to it is more meaningful for users.