diff options
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 0cdb7f11ce4..51cd3956c56 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -97,6 +97,9 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size, default: err = _set_memory_uc(vaddr, nrpages); break; + case _PAGE_CACHE_WC: + err = _set_memory_wc(vaddr, nrpages); + break; case _PAGE_CACHE_WB: err = _set_memory_wb(vaddr, nrpages); break; @@ -166,8 +169,13 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size, * Do not fallback to certain memory types with certain * requested type: * - request is uncached, return cannot be write-back + * - request is uncached, return cannot be write-combine + * - request is write-combine, return cannot be write-back */ if ((prot_val == _PAGE_CACHE_UC && + (new_prot_val == _PAGE_CACHE_WB || + new_prot_val == _PAGE_CACHE_WC)) || + (prot_val == _PAGE_CACHE_WC && new_prot_val == _PAGE_CACHE_WB)) { free_memtype(phys_addr, phys_addr + size); return NULL; @@ -180,6 +188,9 @@ static void __iomem *__ioremap(resource_size_t phys_addr, unsigned long size, default: prot = PAGE_KERNEL_NOCACHE; break; + case _PAGE_CACHE_WC: + prot = PAGE_KERNEL_WC; + break; case _PAGE_CACHE_WB: prot = PAGE_KERNEL; break; @@ -235,6 +246,25 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) } EXPORT_SYMBOL(ioremap_nocache); +/** + * ioremap_wc - map memory into CPU space write combined + * @offset: bus address of the memory + * @size: size of the resource to map + * + * This version of ioremap ensures that the memory is marked write combining. + * Write combining allows faster writes to some hardware devices. + * + * Must be freed with iounmap. + */ +void __iomem *ioremap_wc(unsigned long phys_addr, unsigned long size) +{ + if (pat_wc_enabled) + return __ioremap(phys_addr, size, _PAGE_CACHE_WC); + else + return ioremap_nocache(phys_addr, size); +} +EXPORT_SYMBOL(ioremap_wc); + void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) { return __ioremap(phys_addr, size, _PAGE_CACHE_WB); |