linux-kernel - Re: [PATCH v2 3/4] arm64: dts: exynos: gs101: add ACPM protocol node

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Message-ID: <Z2B3V78k2ibIdLYh@google.com>
Date: Mon, 16 Dec 2024 10:54:15 -0800
From: William McVicker <willmcvicker@...gle.com>
To: Tudor Ambarus <tudor.ambarus@...aro.org>
Cc: Peter Griffin <peter.griffin@...aro.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Alim Akhtar <alim.akhtar@...sung.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, linux-arm-kernel@...ts.infradead.org,
	linux-samsung-soc@...r.kernel.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, andre.draszik@...aro.org,
	kernel-team@...roid.com, daniel.lezcano@...aro.org,
	vincent.guittot@...aro.org, ulf.hansson@...aro.org, arnd@...db.de
Subject: Re: [PATCH v2 3/4] arm64: dts: exynos: gs101: add ACPM protocol node

Hi Tudor,

On 12/12/2024, Tudor Ambarus wrote:
> Add the ACPM protocol node. ACPM protocol provides interface for all
> the client drivers making use of the features offered by the
> Active Power Management (APM) module.
> 
> Signed-off-by: Tudor Ambarus <tudor.ambarus@...aro.org>
> ---
>  arch/arm64/boot/dts/exynos/google/gs101.dtsi | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/exynos/google/gs101.dtsi b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> index 04561e15b96c..8c3f07371912 100644
> --- a/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> +++ b/arch/arm64/boot/dts/exynos/google/gs101.dtsi
> @@ -277,6 +277,28 @@ apm_sram: sram@...9000 {
>  		ranges = <0x0 0x0 0x2039000 0x40000>;
>  	};
>  
> +	firmware {
> +		acpm_ipc: power-management {
> +			compatible = "google,gs101-acpm-ipc";
> +			mboxes = <&ap2apm_mailbox 0 0
> +				  &ap2apm_mailbox 0 1
> +				  &ap2apm_mailbox 0 2
> +				  &ap2apm_mailbox 0 3
> +				  &ap2apm_mailbox 0 4
> +				  &ap2apm_mailbox 0 5
> +				  &ap2apm_mailbox 0 6
> +				  &ap2apm_mailbox 0 7
> +				  &ap2apm_mailbox 0 8
> +				  &ap2apm_mailbox 0 9
> +				  &ap2apm_mailbox 0 10
> +				  &ap2apm_mailbox 0 11
> +				  &ap2apm_mailbox 0 12
> +				  &ap2apm_mailbox 0 13
> +				  &ap2apm_mailbox 0 14>;
> +			shmem = <&apm_sram>;
> +		};
> +	};

You mentioned in the previous patch that "GS101 has 14 mailbox controllers",
but here you have 15 mailboxes. I looked at the downstream driver and see the
number of mailboxes is defined by the ACPM framework (firmware) which is read
from SRAM initdata. Dumping that, I see there are 15 ACPM channels. Have you
looked into into extracting the data from the initdata SRAM address?

Thanks,
Will