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[0/3] Enable Multi Core Timer (MCT) for gs101

Message ID 20231222165355.1462740-1-peter.griffin@linaro.org
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Series Enable Multi Core Timer (MCT) for gs101 | expand

Message

Peter Griffin Dec. 22, 2023, 4:53 p.m. UTC 
Hi folks,

This series enables Multi Core Timer (MCT) for gs101. As part of enabling
MCT we also need to register cmu_misc bank of clocks early so exynos_mct can
obtain it's clock.

MCT timer is required longer term as the Arm arch timer can't wake the CPU from
suspend. This series is based off todays linux-next.

Note the dtsi change without the corresponding clock driver changes will result
in a system that doesn't boot. So ideally this would both be merged together
through Krzysztofs Samsung exynos tree. If that is OK with everyone?

regards,

Peter

Peter Griffin (3):
  dt-bindings: timer: exynos4210-mct: Add google,gs101-mct compatible
  clk: samsung: gs101: register cmu_misc clocks early
  arm64: dts: exynos: gs101: define Multi Core Timer (MCT) node

 .../timer/samsung,exynos4210-mct.yaml         |  2 ++
 arch/arm64/boot/dts/exynos/google/gs101.dtsi  | 20 +++++++++++++++++++
 drivers/clk/samsung/clk-gs101.c               | 12 ++++++++---
 3 files changed, 31 insertions(+), 3 deletions(-)

Comments

Sam Protsenko Dec. 22, 2023, 4:59 p.m. UTC | #1 
On Fri, Dec 22, 2023 at 10:54 AM Peter Griffin <peter.griffin@linaro.org> wrote:
>
> Update cmu_misc so it is registered early, as it contains
> the gate which clocks the Multi Core Timer (MCT). This clock
> is required early in boot, otherwise exynos_mct will fail
> obtaining the clock.
>
> Note this wasn't previously an issue as exynos_mct wasn't
> enabled.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> ---

Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>

>  drivers/clk/samsung/clk-gs101.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/samsung/clk-gs101.c b/drivers/clk/samsung/clk-gs101.c
> index 0964bb11657f..590119a25c18 100644
> --- a/drivers/clk/samsung/clk-gs101.c
> +++ b/drivers/clk/samsung/clk-gs101.c
> @@ -2478,6 +2478,15 @@ static const struct samsung_cmu_info misc_cmu_info __initconst = {
>         .clk_name               = "dout_cmu_misc_bus",
>  };
>
> +static void __init gs101_cmu_misc_init(struct device_node *np)
> +{
> +       exynos_arm64_register_cmu(NULL, np, &misc_cmu_info);
> +}
> +
> +/* Register CMU_MISC early, as it's needed for MCT timer */
> +CLK_OF_DECLARE(gs101_cmu_misc, "google,gs101-cmu-misc",
> +              gs101_cmu_misc_init);
> +
>  /* ---- platform_driver ----------------------------------------------------- */
>
>  static int __init gs101_cmu_probe(struct platform_device *pdev)
> @@ -2495,9 +2504,6 @@ static const struct of_device_id gs101_cmu_of_match[] = {
>         {
>                 .compatible = "google,gs101-cmu-apm",
>                 .data = &apm_cmu_info,
> -       }, {
> -               .compatible = "google,gs101-cmu-misc",
> -               .data = &misc_cmu_info,
>         }, {
>         },
>  };
> --
> 2.43.0.472.g3155946c3a-goog
>
Krzysztof Kozlowski Dec. 23, 2023, 2:14 p.m. UTC | #2 
On 22/12/2023 17:53, Peter Griffin wrote:
> Add dedicated google,gs101-mct compatible to the dt-schema for
> representing mct timer of the Google Tensor gs101 SoC.
> 
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

I assume this will go via clocksource/timer. But I am also fine taking
it via Samsung SoC tree if needed.

Best regards,
Krzysztof