linux-kernel - Re: [PATCH v2 1/4] dt-bindings: Correct RISC-V's timebase-frequency

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Message-ID: <5d652370-4782-23b2-9896-b9666b3cc1e7@linaro.org>
Date:   Fri, 14 Dec 2018 10:17:24 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Atish Patra <atish.patra@....com>, linux-kernel@...r.kernel.org
Cc:     Palmer Dabbelt <palmer@...ive.com>, Christoph Hellwig <hch@....de>,
        Albert Ou <aou@...s.berkeley.edu>, devicetree@...r.kernel.org,
        Dmitriy Cherkasov <dmitriy@...-tech.org>,
        linux-riscv@...ts.infradead.org,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Anup Patel <anup@...infault.org>,
        Damien Le Moal <Damien.LeMoal@....com>,
        Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH v2 1/4] dt-bindings: Correct RISC-V's timebase-frequency

On 14/12/2018 00:14, Atish Patra wrote:
> From: Palmer Dabbelt <palmer@...ive.com>
> 
> In RISC-V systems, timebase-frequency is per cpu instead of one
> instance for entire SOC as there is a individual timer per each CPU.
> Fix the DT binding accordingly.

Why not use a fixed-clock instead of this timebase property which forces
to declare a global variable to be exported from arch/riscv to
drivers/clocksource ?

In addition, please add the 'Fixes' tag

> Signed-off-by: Palmer Dabbelt <palmer@...ive.com>
> Signed-off-by: Christoph Hellwig <hch@....de>
> [Atish: Update the commit text]
> Signed-off-by: Atish Patra <atish.patra@....com>
> Reviewed-by: Rob Herring <robh@...nel.org>
> ---
>  Documentation/devicetree/bindings/riscv/cpus.txt | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/riscv/cpus.txt b/Documentation/devicetree/bindings/riscv/cpus.txt
> index adf7b7af..b0b038d6 100644
> --- a/Documentation/devicetree/bindings/riscv/cpus.txt
> +++ b/Documentation/devicetree/bindings/riscv/cpus.txt
> @@ -93,9 +93,9 @@ Linux is allowed to run on.
>          cpus {
>                  #address-cells = <1>;
>                  #size-cells = <0>;
> -                timebase-frequency = <1000000>;
>                  cpu@0 {
>                          clock-frequency = <1600000000>;
> +                        timebase-frequency = <1000000>;
>                          compatible = "sifive,rocket0", "riscv";
>                          device_type = "cpu";
>                          i-cache-block-size = <64>;
> @@ -113,6 +113,7 @@ Linux is allowed to run on.
>                  };
>                  cpu@1 {
>                          clock-frequency = <1600000000>;
> +                        timebase-frequency = <1000000>;
>                          compatible = "sifive,rocket0", "riscv";
>                          d-cache-block-size = <64>;
>                          d-cache-sets = <64>;
> @@ -145,6 +146,7 @@ Example: Spike ISA Simulator with 1 Hart
>  This device tree matches the Spike ISA golden model as run with `spike -p1`.
>  
>          cpus {
> +                timebase-frequency = <1000000>;
>                  cpu@0 {
>                          device_type = "cpu";
>                          reg = <0x00000000>;





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