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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 10 Dec 2019 09:08:42 +0100
Message-ID: <CAMuHMdUsKQPvOwxARcWMqmFB7BdatZe=3bR+BG=DCaq_yMfySw@mail.gmail.com>
Subject: Re: [PATCH v5 1/4] sparc64: implement ioremap_uc
To:     Tuowen Zhao <ztuowen@gmail.com>
Cc:     Lee Jones <lee.jones@linaro.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        acelan.kao@canonical.com, "Luis R. Rodriguez" <mcgrof@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        kbuild test robot <lkp@intel.com>,
        Christoph Hellwig <hch@lst.de>
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On Thu, Oct 17, 2019 at 7:47 PM Tuowen Zhao <ztuowen@gmail.com> wrote:
> On sparc64, the whole physical IO address space is accessible using
> physically addressed loads and stores. *_uc does nothing like the
> others.
>
> Cc: <stable@vger.kernel.org>
> Reported-by: kbuild test robot <lkp@intel.com>
> Signed-off-by: Tuowen Zhao <ztuowen@gmail.com>
> ---
>  arch/sparc/include/asm/io_64.h | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/sparc/include/asm/io_64.h b/arch/sparc/include/asm/io_64.h
> index 688911051b44..f4afa301954a 100644
> --- a/arch/sparc/include/asm/io_64.h
> +++ b/arch/sparc/include/asm/io_64.h
> @@ -407,6 +407,7 @@ static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
>  }
>
>  #define ioremap_nocache(X,Y)           ioremap((X),(Y))
> +#define ioremap_uc(X,Y)                        ioremap((X),(Y))
>  #define ioremap_wc(X,Y)                        ioremap((X),(Y))
>  #define ioremap_wt(X,Y)                        ioremap((X),(Y))

Do we really need this? There is only one user of ioremap_uc(), which
Christoph is trying hard to get rid of, and the new devres helper that
triggers all of this :-(
https://lore.kernel.org/dri-devel/20191112105507.GA7122@lst.de/

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds