Subject: Re: [PATCH 3/3] dma-mapping: move swiotlb dma-phys functions to
 common header
To: Sinan Kaya <okaya@codeaurora.org>, linux-arm-kernel@lists.infradead.org,
        timur@codeaurora.org, cov@codeaurora.org, nwatters@codeaurora.org
References: <1458252137-24497-1-git-send-email-okaya@codeaurora.org>
 <1458252137-24497-3-git-send-email-okaya@codeaurora.org>
Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org,
        linux-xtensa@linux-xtensa.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>, Max Filippov <jcmvbkbc@gmail.com>,
        Chris Metcalf <cmetcalf@ezchip.com>, "H. Peter Anvin" <hpa@zytor.com>,
        Guan Xuetao <gxt@mprc.pku.edu.cn>,
        Florian Fainelli <f.fainelli@gmail.com>, x86@kernel.org,
        Ingo Molnar <mingo@redhat.com>, Guenter Roeck <linux@roeck-us.net>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Denys Vlasenko <dvlasenk@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
        Akinobu Mita <akinobu.mita@gmail.com>,
        Geliang Tang <geliangtang@163.com>,
        Zhen Lei <thunder.leizhen@huawei.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Valentin Rothberg <valentinrothberg@gmail.com>,
        Chris Zankel <chris@zankel.net>, Tony Luck <tony.luck@intel.com>,
        linux-kernel@vger.kernel.org, Ralf Baechle <ralf@linux-mips.org>,
        "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
        Joe Perches <joe@perches.com>,
        Andrew Morton <akpm@linux-foundation.org>
From: Robin Murphy <robin.murphy@arm.com>
Message-ID: <56EBE71F.2080203@arm.com>
Date: Fri, 18 Mar 2016 11:31:43 +0000
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On 17/03/16 22:02, Sinan Kaya wrote:
> Moving the default implementation of swiotlb_dma_to_phys and
> swiotlb_phys_to_dma functions to dma-mapping.h so that we can get
> rid of the duplicate code in multiple ARCH.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
>   arch/arm64/include/asm/dma-mapping.h               | 14 --------------
>   arch/ia64/include/asm/dma-mapping.h                | 14 --------------
>   arch/mips/include/asm/mach-generic/dma-coherence.h | 16 ----------------
>   arch/tile/include/asm/dma-mapping.h                | 14 --------------
>   arch/unicore32/include/asm/dma-mapping.h           | 14 --------------
>   arch/x86/include/asm/dma-mapping.h                 | 13 -------------
>   arch/xtensa/include/asm/dma-mapping.h              | 14 --------------
>   include/linux/dma-mapping.h                        | 14 ++++++++++++++
>   8 files changed, 14 insertions(+), 99 deletions(-)

[...]

> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 728ef07..871d620 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -683,4 +683,18 @@ static inline int dma_mmap_writecombine(struct device *dev,
>   #define dma_unmap_len_set(PTR, LEN_NAME, VAL)    do { } while (0)
>   #endif
>
> +#ifndef swiotlb_phys_to_dma
> +static inline dma_addr_t swiotlb_phys_to_dma(struct device *dev, phys_addr_t paddr)
> +{
> +         return paddr;
> +}
> +#endif
> +
> +#ifndef swiotlb_dma_to_phys
> +static inline phys_addr_t swiotlb_dma_to_phys(struct device *dev, dma_addr_t daddr)
> +{
> +        return daddr;
> +}
> +#endif
> +
>   #endif
>

Could the default definition not be pushed all the way down into 
swiotlb.c (or at least swiotlb.h)?

Robin.