[PATCH v2 3/3] dt-bindings: perf: marvell: add CN20K TAD PMU support

[Geetha sowjanya]

Marvell CN20K SoCs integrate a Performance Monitoring Unit (PMU)
associated with the LLC Tag-and-Data (TAD) blocks. The PMU provides
hardware counters to monitor cache traffic and performance events
via a dedicated MMIO region.

The CN20K LLC-TAD PMU is largely similar to CN10K, but differs in the
layout of PFC/PRF register offsets relative to each TAD base. These
offsets are derived from the compatible string in the driver and are
not described through Devicetree properties.

Because of this, using "marvell,cn10k-tad-pmu" as a fallback for CN20K
would result in incorrect register programming. Therefore, add a
separate compatible string:

  "marvell,cn20k-tad-pmu"

Update the binding to document CN20K alongside CN10K.

Signed-off-by: Geetha sowjanya <gakula at marvell.com>
---
 Documentation/devicetree/bindings/perf/marvell-cn10k-tad.yaml | 17 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/Documentation/devicetree/bindings/perf/marvell-cn10k-tad.yaml b/Documentation/devicetree/bindings/perf/marvell-cn10k-tad.yaml
index 362142252667..d11121a1e2c9 100644
--- a/Documentation/devicetree/bindings/perf/marvell-cn10k-tad.yaml
+++ b/Documentation/devicetree/bindings/perf/marvell-cn10k-tad.yaml
@@ -4,23 +4,32 @@
 $id: http://devicetree.org/schemas/perf/marvell-cn10k-tad.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Marvell CN10K LLC-TAD performance monitor
+title: Marvell CN10K / CN20K LLC-TAD performance monitor
 
 maintainers:
   - Bhaskara Budiredla <bbudiredla at marvell.com>
+  - Geetha sowjanya <gakula at marvell.com>
 
 description: |
-  The Tag-and-Data units (TADs) maintain coherence and contain CN10K
-  shared on-chip last level cache (LLC). The tad pmu measures the
-  performance of last-level cache. Each tad pmu supports up to eight
-  counters.
+  The Tag-and-Data units (TADs) maintain coherence and contain the
+  shared on-chip last level cache (LLC) on Marvell CN10K and CN20K SoCs.
+  The TAD PMU measures last-level cache performance. Each TAD PMU
+  supports up to eight counters.
 
-  The DT setup comprises of number of tad blocks, the sizes of pmu
-  regions, tad blocks and overall base address of the HW.
+  The DT setup describes the number of TAD blocks, the sizes of PMU
+  regions and TAD pages, and the overall MMIO base of the hardware.
+
+  marvell,cn20k-tad-pmu is not a compatible fallback for
+  marvell,cn10k-tad-pmu (and vice versa): the driver selects different
+  PFC/PRF MMIO offsets from the compatible string, and those offsets are
+  not described by separate DT properties today.
 
 properties:
   compatible:
-    const: marvell,cn10k-tad-pmu
+    items:
+      - enum:
+          - marvell,cn10k-tad-pmu
+          - marvell,cn20k-tad-pmu
 
   reg:
     maxItems: 1
-- 
2.25.1