On 09/18/2020 04:35 PM, Mike Leach wrote:
On Fri, 11 Sep 2020 at 09:41, Suzuki K Poulose <suzuki.poulose@xxxxxxx> wrote:Document the bindings for ETMv4.4 and later with only system register access. Cc: devicetree@xxxxxxxxxxxxxxx Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> Cc: Mike Leach <mike.leach@xxxxxxxxxx> Reviewed-by: Rob Herring <robh@xxxxxxxxxx> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx> --- Documentation/devicetree/bindings/arm/coresight.txt | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/arm/coresight.txt b/Documentation/devicetree/bindings/arm/coresight.txt index d711676b4a51..cfe47bdda728 100644 --- a/Documentation/devicetree/bindings/arm/coresight.txt +++ b/Documentation/devicetree/bindings/arm/coresight.txt @@ -34,9 +34,13 @@ its hardware characteristcs. Program Flow Trace Macrocell: "arm,coresight-etm3x", "arm,primecell"; - - Embedded Trace Macrocell (version 4.x): + - Embedded Trace Macrocell (version 4.x), with memory mapped access. "arm,coresight-etm4x", "arm,primecell"; + - Embedded Trace Macrocell (version 4.4 and later) with system + register access only. + "arm,coresight-etm-v4.4";Any version of ETM can implement register access - including those pre ETM 4.4. Perhaps the new name should simply reflect sys reg access rather than a version.
You're right. I got it confused with the v8.4 SelfHosted Extensions, which mandates the sysreg access and makes the mem I/O obsolete. How about : "arm,coresight-etm4x-sysreg" ?
Given that the two compatibility strings should be mutually exclusive for a given device, should the bindings doc (or at least the etm4x component part) be re-written into the .yaml format so that this can be enforced?
I will take a look, haven't played with the yaml. Thanks for the review ! Suzuki
