Messages in this thread | | | Date | Thu, 30 Jun 2022 16:59:46 +0530 | Subject | Re: [PATCH v6 1/4] dt-bindings: interconnect: qcom,msm8998-cpu-bwmon: add BWMON device | From | Rajendra Nayak <> |
| |
On 6/30/2022 4:53 PM, Krzysztof Kozlowski wrote: > On 30/06/2022 13:14, Rajendra Nayak wrote: >> >> On 6/29/2022 7:32 PM, Krzysztof Kozlowski wrote: >>> Add bindings for the Qualcomm Bandwidth Monitor device providing >>> performance data on interconnects. The bindings describe only BWMON CPU >>> (version 4), e.g. the instance which appeared for the first on Qualcomm >>> MSM8998 SoC and is also used on SDM845. This BWMON device sits between >>> CPU and Last Level Cache Controller. >>> >>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >>> Reviewed-by: Rob Herring <robh@kernel.org> >>> Acked-by: Georgi Djakov <djakov@kernel.org> >>> --- >>> .../interconnect/qcom,msm8998-llcc-bwmon.yaml | 85 +++++++++++++++++++ >>> 1 file changed, 85 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/interconnect/qcom,msm8998-llcc-bwmon.yaml >>> >>> diff --git a/Documentation/devicetree/bindings/interconnect/qcom,msm8998-llcc-bwmon.yaml b/Documentation/devicetree/bindings/interconnect/qcom,msm8998-llcc-bwmon.yaml >>> new file mode 100644 >>> index 000000000000..76e09658d615 >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/interconnect/qcom,msm8998-llcc-bwmon.yaml >>> @@ -0,0 +1,85 @@ >>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause >>> +%YAML 1.2 >>> +--- >>> +$id: http://devicetree.org/schemas/interconnect/qcom,msm8998-llcc-bwmon.yaml# >>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >>> + >>> +title: Qualcomm Interconnect Bandwidth Monitor >>> + >>> +maintainers: >>> + - Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> >>> + >>> +description: | >>> + Bandwidth Monitor measures current throughput on buses between various NoC >>> + fabrics and provides information when it crosses configured thresholds. >>> + >>> + Certain SoCs might have more than one Bandwidth Monitors, for example on SDM845:: >>> + - Measuring the bandwidth between CPUs and Last Level Cache Controller - >>> + called LLCC BWMON, >>> + - Measuring the bandwidth between Last Level Cache Controller and memory (DDR). >>> + >>> +properties: >>> + compatible: >>> + oneOf: >>> + - items: >>> + - enum: >>> + - qcom,sdm845-llcc-bwmon >>> + - const: qcom,msm8998-llcc-bwmon >>> + - const: qcom,msm8998-llcc-bwmon # BWMON v4 >>> + >>> + interconnects: >>> + maxItems: 1 >>> + >>> + interrupts: >>> + maxItems: 1 >>> + >>> + operating-points-v2: true >>> + opp-table: true >>> + >>> + reg: >>> + # BWMON v4 (currently described) and BWMON v5 use one register address >>> + # space. BWMON v2 uses two register spaces - not yet described. >>> + maxItems: 1 >>> + >>> +required: >>> + - compatible >>> + - interconnects >>> + - interrupts >>> + - operating-points-v2 >>> + - opp-table >>> + - reg >>> + >>> +additionalProperties: false >>> + >>> +examples: >>> + - | >>> + #include <dt-bindings/interconnect/qcom,sdm845.h> >>> + #include <dt-bindings/interrupt-controller/arm-gic.h> >>> + >>> + pmu@1436400 { >>> + compatible = "qcom,sdm845-llcc-bwmon", "qcom,msm8998-llcc-bwmon"; >> >> so with this compatible fallback scheme, I am trying to understand what >> do I need to do if I have to add support for another SoC for instance. >> >> I just update the binding with the new SoC compatible (lets say qcom,sc7280-llcc-bwmon) >> and in the device tree node use it as >> compatible = "qcom,sc7280-llcc-bwmon", "qcom,sdm845-llcc-bwmon", "qcom,msm8998-llcc-bwmon"; >> without any updates in the driver? > > I expect: > "qcom,sc7280-llcc-bwmon", "qcom,msm8998-llcc-bwmon"; > and you need to add sc7280 compatible to the driver. The actual proper > solution in my patch would be to use msm8998 compatible in the driver, > but I did not test MSM8998. > > Maybe we should switch to that anyway?
Right, looks like without it every new SoC compatible added would need a dummy update in the driver even though you really don't need to do anything different in the driver.
| |