From d0d98eedee2178c803dd824bb09f52b0e2ac1811 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 13 May 2013 23:58:40 +0000 Subject: Add arch_phys_wc_{add, del} to manipulate WC MTRRs if needed Several drivers currently use mtrr_add through various #ifdef guards and/or drm wrappers. The vast majority of them want to add WC MTRRs on x86 systems and don't actually need the MTRR if PAT (i.e. ioremap_wc, etc) are working. arch_phys_wc_add and arch_phys_wc_del are new functions, available on all architectures and configurations, that add WC MTRRs on x86 if needed (and handle errors) and do nothing at all otherwise. They're also easier to use than mtrr_add and mtrr_del, so the call sites can be simplified. As an added benefit, this will avoid wasting MTRRs and possibly warning pointlessly on PAT-supporting systems. Reviewed-by: Daniel Vetter Signed-off-by: Andy Lutomirski Signed-off-by: Dave Airlie --- arch/x86/include/asm/io.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/x86/include/asm/io.h') diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index d8e8eefbe24c..34f69cb9350a 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -345,4 +345,11 @@ extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, #define IO_SPACE_LIMIT 0xffff +#ifdef CONFIG_MTRR +extern int __must_check arch_phys_wc_add(unsigned long base, + unsigned long size); +extern void arch_phys_wc_del(int handle); +#define arch_phys_wc_add arch_phys_wc_add +#endif + #endif /* _ASM_X86_IO_H */ -- cgit v1.2.3