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SubjectRe: [PATCH v2 05/27] dts: bindings: Document device tree binding for CATU
On 1 May 2018 at 07:10, Rob Herring <robh@kernel.org> wrote:
> On Tue, May 01, 2018 at 10:10:35AM +0100, Suzuki K Poulose wrote:
>> Document CATU device-tree bindings. CATU augments the TMC-ETR
>> by providing an improved Scatter Gather mechanism for streaming
>> trace data to non-contiguous system RAM pages.
>>
>> Cc: devicetree@vger.kernel.org
>> Cc: frowand.list@gmail.com
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: Mathieu Poirier <mathieu.poirier@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> ---
>> .../devicetree/bindings/arm/coresight.txt | 52 ++++++++++++++++++++++
>> 1 file changed, 52 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt
>> index 15ac8e8..cdd84d0 100644
>> --- a/Documentation/devicetree/bindings/arm/coresight.txt
>> +++ b/Documentation/devicetree/bindings/arm/coresight.txt
>> @@ -39,6 +39,8 @@ its hardware characteristcs.
>>
>> - System Trace Macrocell:
>> "arm,coresight-stm", "arm,primecell"; [1]
>> + - Coresight Address Translation Unit (CATU)
>> + "arm, coresight-catu", "arm,primecell";
>
> spurious space ^
>
>>
>> * reg: physical base address and length of the register
>> set(s) of the component.
>> @@ -86,6 +88,9 @@ its hardware characteristcs.
>> * arm,buffer-size: size of contiguous buffer space for TMC ETR
>> (embedded trace router)
>>
>> +* Optional property for CATU :
>> + * interrupts : Exactly one SPI may be listed for reporting the address
>> + error
>
> Somewhere you need to define the ports for the CATU.
>
>>
>> Example:
>>
>> @@ -118,6 +123,35 @@ Example:
>> };
>> };
>>
>> + etr@20070000 {
>> + compatible = "arm,coresight-tmc", "arm,primecell";
>> + reg = <0 0x20070000 0 0x1000>;
>> +
>> + clocks = <&oscclk6a>;
>> + clock-names = "apb_pclk";
>> + ports {
>> + #address-cells = <1>;
>> + #size-cells = <0>;
>> +
>> + /* input port */
>> + port@0 {
>> + reg = <0>;
>> + etr_in_port: endpoint {
>> + slave-mode;
>> + remote-endpoint = <&replicator2_out_port0>;
>> + };
>> + };
>> +
>> + /* CATU link represented by output port */
>> + port@1 {
>> + reg = <0>;
>
> While common in the Coresight bindings, having unit-address and reg not
> match is an error. Mathieu and I discussed this a bit as dtc now warns
> on these.
>
> Either reg should be 1 here, or 'ports' needs to be split into input and
> output ports. My preference would be the former, but Mathieu objected to
> this not reflecting the the h/w numbering.

Suzuki, as we discuss this is related to your work on revamping CS
bindings for ACPI. Until that gets done and to move forward with this
set I suggest you abide to Rob's request.

>
> Rob

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