[PATCH v4 1/6] Documentation: perf: hisi: Documentation for HiSilicon SoC PMU driver

[Shaokun Zhang]

This patch adds documentation for the uncore PMUs on HiSilicon SoC.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Shaokun Zhang <zhangshaokun@xxxxxxxxxxxxx>
Signed-off-by: Anurup M <anurup.m@xxxxxxxxxx>
---
 Documentation/perf/hisi-pmu.txt | 52 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 Documentation/perf/hisi-pmu.txt

diff --git a/Documentation/perf/hisi-pmu.txt b/Documentation/perf/hisi-pmu.txt
new file mode 100644
index 0000000..f45a03d
--- /dev/null
+++ b/Documentation/perf/hisi-pmu.txt
@@ -0,0 +1,52 @@
+HiSilicon SoC uncore Performance Monitoring Unit (PMU)
+======================================================
+The HiSilicon SoC chip comprehends various independent system device PMUs
+such as L3 cache (L3C), Hydra Home Agent (HHA) and DDRC. These PMUs are
+independent and have hardware logic to gather statistics and performance
+information.
+
+HiSilicon SoC encapsulates multiple CPU and IO dies. Each CPU cluster
+(CCL) is made up of 4 cpu cores sharing one L3 cache; Each CPU die is
+called Super CPU cluster (SCCL) and is made up of 6 CCLs. Each SCCL has
+two HHAs (0 - 1) and four DDRCs (0 - 3), respectively.
+
+HiSilicon SoC uncore PMU driver
+---------------------------------------
+Each device PMU has separate registers for event counting, control and
+interrupt, and the PMU driver shall register perf PMU drivers like L3C,
+HHA and DDRC etc. The available events and configuration options shall
+be described in the sysfs, see /sys/devices/hisi_* or /sys/bus/
+event_source/devices/hisi_*.
+The "perf list" command shall list the available events from sysfs.
+
+Each L3C, HHA and DDRC in one SCCL are registered as an separate PMU with perf.
+The PMU name will appear in event listing as hisi_module <index-id>_<sccl-id>.
+where "index-id" is the index of module and "sccl-id" is the identifier of
+the SCCL.
+e.g. hisi_l3c0_1/rd_hit_cpipe is READ_HIT_CPIPE event of L3C index #0 and SCCL
+ID #1.
+e.g. hisi_hha0_1/rx_operations is RX_OPERATIONS event of HHA index #0 and SCCL
+ID #1.
+
+The driver also provides a "cpumask" sysfs attribute, which shows the CPU core
+ID used to count the uncore PMU event.
+
+Example usage of perf:
+$# perf list
+hisi_l3c0_3/rd_hit_cpipe/ [kernel PMU event]
+------------------------------------------
+hisi_l3c0_3/wr_hit_cpipe/ [kernel PMU event]
+------------------------------------------
+hisi_l3c0_1/rd_hit_cpipe/ [kernel PMU event]
+------------------------------------------
+hisi_l3c0_1/wr_hit_cpipe/ [kernel PMU event]
+------------------------------------------
+
+$# perf stat -a -e hisi_l3c0_1/rd_hit_cpipe/ sleep 5
+$# perf stat -a -e hisi_l3c0_1/config=0x02/ sleep 5
+
+The current driver does not support sampling. So "perf record" is unsupported.
+Also attach to a task is unsupported as the events are all uncore.
+
+Note: Please contact the maintainer for a complete list of events supported for
+the PMU devices in the SoC and its information if needed.
-- 
1.9.1