Re: [PATCH] drivers/video/fbdev: use ioremap_wc() instead of __ioremap(_PAGE_NO_CACHE)

[Christophe LEROY]

Le 24/08/2018 Ã 13:05, Segher Boessenkool a ÃcritÂ:
> On Fri, Aug 24, 2018 at 10:16:22AM +0000, Christophe Leroy wrote:
> > _PAGE_NO_CACHE is a target specific flag. Prefer generic functions.
>
> >   #ifdef CONFIG_PPC
> > -	p->screen_base = __ioremap(addr, 0x200000, _PAGE_NO_CACHE);
> > +	p->screen_base = ioremap_wc(addr, 0x200000);
> >   #else
>
> But that is not the same.  I think you want ioremap_nocache?

No, ioremap_nocache() is _PAGE_NO_CACHE | _PAGE_GUARDED



/arch/powerpc/include/asm/io.h

#define ioremap_nocache(addr, size)	ioremap((addr), (size))


/arch/powerpc/mm/pgtable_32.c:

void __iomem *
ioremap_wc(phys_addr_t addr, unsigned long size)
{
	return __ioremap_caller(addr, size, _PAGE_NO_CACHE,
				__builtin_return_address(0));
}

void __iomem *
ioremap(phys_addr_t addr, unsigned long size)
{
	return __ioremap_caller(addr, size, _PAGE_NO_CACHE | _PAGE_GUARDED,
				__builtin_return_address(0));
}

Christophe