Re: [PATCH v3 1/2] ARM: dts: bcm2711: force CMA into first GB of memory

From: Catalin Marinas <catalin.marinas@arm.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Eric Anholt <eric@anholt.net>, Stefan Wahren <wahrenst@gmx.net>,
	devicetree@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 1/2] ARM: dts: bcm2711: force CMA into first GB of memory
Date: Thu, 7 Nov 2019 11:20:20 +0000	[thread overview]
Message-ID: <20191107112020.GA16965@arrakis.emea.arm.com> (raw)
In-Reply-To: <20191107095611.18429-2-nsaenzjulienne@suse.de>

Hi Nicolas,

On Thu, Nov 07, 2019 at 10:56:10AM +0100, Nicolas Saenz Julienne wrote:
> diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
> index ac83dac2e6ba..667658497898 100644
> --- a/arch/arm/boot/dts/bcm2711.dtsi
> +++ b/arch/arm/boot/dts/bcm2711.dtsi
> @@ -12,6 +12,26 @@
>  
>  	interrupt-parent = <&gicv2>;
>  
> +	reserved-memory {
> +		#address-cells = <2>;
> +		#size-cells = <1>;
> +		ranges;
> +
> +		/*
> +		 * arm64 reserves the CMA by default somewhere in ZONE_DMA32,
> +		 * that's not good enough for bcm2711 as some devices can
> +		 * only address the lower 1G of memory (ZONE_DMA).
> +		 */
> +		linux,cma {
> +			compatible = "shared-dma-pool";
> +			size = <0x2000000>; /* 32MB */
> +			alloc-ranges = <0x0 0x00000000 0x40000000>;
> +			reusable;
> +			linux,cma-default;
> +		};
> +	};
> +
> +
>  	soc {
>  		/*
>  		 * Defined ranges:

Sorry, I just realised I can't merge this as it depends on a patch
that's only in -next: 7dbe8c62ceeb ("ARM: dts: Add minimal Raspberry Pi
4 support").

I'll queue the second patch in the series to fix the regression
introduces by the ZONE_DMA patches and, AFAICT, the dts update can be
queued independently.

-- 
Catalin