RE: [EXT] Re: [RFC PATCH v3 1/7] dt-bindings: arm: coresight-tmc: Add "memory-region" property

Hi Suzuki,

-----Original Message----- From: Suzuki K Poulose suzuki.poulose@arm.com Sent: Monday, September 4, 2023 1:57 PM To: Linu Cherian lcherian@marvell.com; mike.leach@linaro.org; james.clark@arm.com; leo.yan@linaro.org Cc: linux-arm-kernel@lists.infradead.org; coresight@lists.linaro.org; linux- kernel@vger.kernel.org; robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; conor+dt@kernel.org; devicetree@vger.kernel.org; Sunil Kovvuri Goutham sgoutham@marvell.com; George Cherian gcherian@marvell.com Subject: [EXT] Re: [RFC PATCH v3 1/7] dt-bindings: arm: coresight-tmc: Add "memory-region" property

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On 04/09/2023 06:05, Linu Cherian wrote:

...

memory-region 0: Reserved trace buffer memory

TMC ETR: When available, use this reserved memory region for trace data capture. Same region is used for trace data retention after a panic or watchdog reset.

TMC ETF: When available, use this reserved memory region for trace data retention synced from internal SRAM after a panic or watchdog reset.

memory-region 1: Reserved meta data memory

TMC ETR, ETF: When available, use this memory for register snapshot retention synced from hardware registers after a panic or watchdog reset.

Instead of having to use a number to map the memory regions, could we use

memory-region-names property to describe the index ? That way it is much easier to read and is less error prone.

Names could be something like:

tmc-reserved-trace tmc-reserved-metadata

Ack. Will use names in the next version. Will take care of the suggestions from Rob.

Suzuki

...

Signed-off-by: Linu Cherian lcherian@marvell.com

.../devicetree/bindings/arm/arm,coresight-tmc.yaml | 13

+++++++++++++

...

1 file changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-tmc.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-tmc.yaml index cb8dceaca70e..dce54978554a 100644 --- a/Documentation/devicetree/bindings/arm/arm,coresight-tmc.yaml +++ b/Documentation/devicetree/bindings/arm/arm,coresight-tmc.yaml @@ -101,6 +101,17 @@ properties: and ETF configurations. $ref: /schemas/graph.yaml#/properties/port

• memory-region:
• items:

•  - description: Reserved trace buffer memory for ETR and ETF sinks.
  

•    For ETR, this reserved memory region is used for trace data capture.
  

•    Same region is used for trace data retention as well after a panic
  

•    or watchdog reset.
  

•    For ETF, this reserved memory region is used for retention of trace
  

•    data synced from internal SRAM after a panic or watchdog reset.
  

•  - description: Reserved meta data memory. Used for ETR and ETF sinks.
  

• required:
  • compatible
  • reg

@@ -115,6 +126,8 @@ examples: etr@20070000 { compatible = "arm,coresight-tmc", "arm,primecell"; reg = <0x20070000 0x1000>;

•    memory-region = <&etr_trace_mem_reserved>,
  

•                   <&etr_mdata_mem_reserved>;
  
      clocks = <&oscclk6a>;
      clock-names = "apb_pclk";