Re: [PATCH v2 1/4] arch/*/asm/io.h: add ioremap_cache() to all architectures

[Geert Uytterhoeven]

On Tue, Jun 2, 2015 at 10:20 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
>> > --- a/arch/mn10300/include/asm/io.h
>> > +++ b/arch/mn10300/include/asm/io.h
>> > @@ -283,6 +283,7 @@ static inline void __iomem *ioremap_nocache(unsigned long offset, unsigned long
>> >
>> >  #define ioremap_wc ioremap_nocache
>> >  #define ioremap_wt ioremap_nocache
>> > +#define ioremap_cache ioremap_nocache
>>
>> From the comment in ioremap_nocache(), ioremap() may be cacheable in
>> this arch.
>
> Right, and I guess that would be a bug. ;-)
>
> mn10300 decides caching on the address, so presumably all arguments passed into

Aha, like MIPS...

> ioremap here already have that bit set. I've checked all the resource
> definitions for mn10300, and they are all between 0xA0000000 and 0xBFFFFFFF,
> which is non-cacheable.

But ioremap() clears that bit again:

static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
{
        return (void __iomem *)(offset & ~0x20000000);
}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

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
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