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Date:   Thu, 1 Oct 2020 18:15:01 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc:     robh+dt@kernel.org, hch@lst.de, robin.murphy@arm.com,
        devicetree@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-mm@kvack.org, Frank Rowand <frowand.list@gmail.com>,
        will@kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-rpi-kernel@lists.infradead.org
Subject: Re: [PATCH 1/4] of/fdt: Update zone_dma_bits when running in bcm2711
Message-ID: <20201001171500.GN21544@gaia>
References: <20201001161740.29064-1-nsaenzjulienne@suse.de>
 <20201001161740.29064-2-nsaenzjulienne@suse.de>
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Hi Nicolas,

Thanks for putting this together.

On Thu, Oct 01, 2020 at 06:17:37PM +0200, Nicolas Saenz Julienne wrote:
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 4602e467ca8b..cd0d115ef329 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -25,6 +25,7 @@
>  #include <linux/serial_core.h>
>  #include <linux/sysfs.h>
>  #include <linux/random.h>
> +#include <linux/dma-direct.h>	/* for zone_dma_bits */
>  
>  #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
>  #include <asm/page.h>
> @@ -1198,6 +1199,14 @@ void __init early_init_dt_scan_nodes(void)
>  	of_scan_flat_dt(early_init_dt_scan_memory, NULL);
>  }
>  
> +void __init early_init_dt_update_zone_dma_bits(void)
> +{
> +	unsigned long dt_root = of_get_flat_dt_root();
> +
> +	if (of_flat_dt_is_compatible(dt_root, "brcm,bcm2711"))
> +		zone_dma_bits = 30;
> +}

I think we could keep this entirely in the arm64 setup_machine_fdt() and
not pollute the core code with RPi4-specific code.

-- 
Catalin