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References: <20210719123054.6844-1-will@kernel.org> <20210719123054.6844-2-will@kernel.org>
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From:   Claire Chang <tientzu@chromium.org>
Date:   Tue, 20 Jul 2021 11:35:14 +0800
Message-ID: <CALiNf29az7Y3t8OfDKRoNkhEzh4qcD-BDRX1rP-ZhfzwXAROsA@mail.gmail.com>
Subject: Re: [PATCH 1/5] of: Return success from of_dma_set_restricted_buffer()
 when !OF_ADDRESS
To:     Will Deacon <will@kernel.org>
Cc:     "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>," <iommu@lists.linux-foundation.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Christoph Hellwig <hch@lst.de>,
        Robin Murphy <robin.murphy@arm.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Nathan Chancellor <nathan@kernel.org>
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On Mon, Jul 19, 2021 at 8:31 PM Will Deacon <will@kernel.org> wrote:
>
> When CONFIG_OF_ADDRESS=n, of_dma_set_restricted_buffer() returns -ENODEV
> and breaks the boot for sparc[64] machines. Return 0 instead, since the
> function is essentially a glorified NOP in this configuration.
>
> Cc: Claire Chang <tientzu@chromium.org>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Suggested-by: Robin Murphy <robin.murphy@arm.com>
> Tested-by: Guenter Roeck <linux@roeck-us.net>

Tested-by: Claire Chang <tientzu@chromium.org>

> Link: https://lore.kernel.org/r/20210702030807.GA2685166@roeck-us.net
> Fixes: fec9b625095f ("of: Add plumbing for restricted DMA pool")
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
>  drivers/of/of_private.h | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> index 376462798f7e..f557bd22b0cf 100644
> --- a/drivers/of/of_private.h
> +++ b/drivers/of/of_private.h
> @@ -173,7 +173,8 @@ static inline int of_dma_get_range(struct device_node *np,
>  static inline int of_dma_set_restricted_buffer(struct device *dev,
>                                                struct device_node *np)
>  {
> -       return -ENODEV;
> +       /* Do nothing, successfully. */
> +       return 0;
>  }
>  #endif
>
> --
> 2.32.0.402.g57bb445576-goog
>