Re: [PATCH v2] ARM: dts: i.MX8MM: describe feature controller

[Marco Felsch <m.felsch@pengutronix.de>]

Hi Ahamd,

On 22-08-30, Ahmad Fatoum wrote:
> Now with i.MX8M feature controller driver support available, have the
> OCOTP provide feature control on the i.MX8MM to ensure the kernel DT
> does not cause Linux to access the VPU and its power domains,
> when barebox knows them to be unavailable.
> 
> This is needed because the upstream kernel imx8mm.dtsi only
> describes the full-featured SoC, which can lead to hangs when
> instantiating drivers for hardware that's unavailable in a
> less-featureful variant of the SoC.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> v1 was RFC patch 10/10 of:
> https://lore.barebox.org/barebox/20220818051955.2088238-11-a.fatoum@pengutronix.de/T/#u
> 
> Patches 01-08 are still applicable, this replaces the approach in v1
> with a standalone feature controller with having the OCOTP as feature
> controller, like is done for i.MX8MN in patch 08/10 of above referenced
> series.
> ---
>  arch/arm/dts/imx8mm.dtsi | 52 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/arch/arm/dts/imx8mm.dtsi b/arch/arm/dts/imx8mm.dtsi
> index cdf212820594..1e81d03d6b84 100644
> --- a/arch/arm/dts/imx8mm.dtsi
> +++ b/arch/arm/dts/imx8mm.dtsi
> @@ -1,10 +1,18 @@
>  // SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +
> +#include <dt-bindings/features/imx8m.h>
> +
>  / {
>  	aliases {
>  		gpr.reboot_mode = &reboot_mode_gpr;
>  	};
>  };
>  
> +feat: &ocotp {
> +	#feature-cells = <1>;
> +	barebox,feature-controller;
> +};

Why not just appending the node like:

/ {
	aliases {
		gpr.reboot_mode = &reboot_mode_gpr;
	};

	feat: ocotp {
		#feature-cells = <1>;
		barebox,feature-controller;
	};
};

Regards,
  Marco

> +
>  &pgc_otg1 {
>  	barebox,allow-dummy;
>  };
> @@ -24,3 +32,47 @@
>  		mode-serial = <0x00000010>, <0x40000000>;
>  	};
>  };
> +
> +&A53_1 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_CPU_DUAL>;
> +};
> +
> +&A53_2 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_CPU_QUAD>;
> +};
> +
> +&A53_3 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_CPU_QUAD>;
> +};
> +
> +&gpc {
> +	barebox,feature-gates = <&feat 0>;
> +};
> +
> +&vpu_g1 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&vpu_g2 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&vpu_blk_ctrl {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&pgc_vpumix {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&pgc_vpu_g1 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&pgc_vpu_g2 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> +
> +&pgc_vpu_h1 {
> +	barebox,feature-gates = <&feat IMX8M_FEAT_VPU>;
> +};
> -- 
> 2.30.2
> 
> 
>