diff options
Diffstat (limited to 'arch/x86/mm/ioremap.c')
| -rw-r--r-- | arch/x86/mm/ioremap.c | 71 |
1 files changed, 63 insertions, 8 deletions
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 27ff21216dfa..cc5ccc415cc0 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -42,6 +42,9 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size, case _PAGE_CACHE_MODE_WC: err = _set_memory_wc(vaddr, nrpages); break; + case _PAGE_CACHE_MODE_WT: + err = _set_memory_wt(vaddr, nrpages); + break; case _PAGE_CACHE_MODE_WB: err = _set_memory_wb(vaddr, nrpages); break; @@ -172,6 +175,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, prot = __pgprot(pgprot_val(prot) | cachemode2protval(_PAGE_CACHE_MODE_WC)); break; + case _PAGE_CACHE_MODE_WT: + prot = __pgprot(pgprot_val(prot) | + cachemode2protval(_PAGE_CACHE_MODE_WT)); + break; case _PAGE_CACHE_MODE_WB: break; } @@ -234,10 +241,11 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) { /* * Ideally, this should be: - * pat_enabled ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS; + * pat_enabled() ? _PAGE_CACHE_MODE_UC : _PAGE_CACHE_MODE_UC_MINUS; * * Till we fix all X drivers to use ioremap_wc(), we will use - * UC MINUS. + * UC MINUS. Drivers that are certain they need or can already + * be converted over to strong UC can use ioremap_uc(). */ enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC_MINUS; @@ -247,6 +255,39 @@ void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size) EXPORT_SYMBOL(ioremap_nocache); /** + * ioremap_uc - map bus memory into CPU space as strongly uncachable + * @phys_addr: bus address of the memory + * @size: size of the resource to map + * + * ioremap_uc performs a platform specific sequence of operations to + * make bus memory CPU accessible via the readb/readw/readl/writeb/ + * writew/writel functions and the other mmio helpers. The returned + * address is not guaranteed to be usable directly as a virtual + * address. + * + * This version of ioremap ensures that the memory is marked with a strong + * preference as completely uncachable on the CPU when possible. For non-PAT + * systems this ends up setting page-attribute flags PCD=1, PWT=1. For PAT + * systems this will set the PAT entry for the pages as strong UC. This call + * will honor existing caching rules from things like the PCI bus. Note that + * there are other caches and buffers on many busses. In particular driver + * authors should read up on PCI writes. + * + * It's useful if some control registers are in such an area and + * write combining or read caching is not desirable: + * + * Must be freed with iounmap. + */ +void __iomem *ioremap_uc(resource_size_t phys_addr, unsigned long size) +{ + enum page_cache_mode pcm = _PAGE_CACHE_MODE_UC; + + return __ioremap_caller(phys_addr, size, pcm, + __builtin_return_address(0)); +} +EXPORT_SYMBOL_GPL(ioremap_uc); + +/** * ioremap_wc - map memory into CPU space write combined * @phys_addr: bus address of the memory * @size: size of the resource to map @@ -258,14 +299,28 @@ EXPORT_SYMBOL(ioremap_nocache); */ void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size) { - if (pat_enabled) - return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC, + return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WC, __builtin_return_address(0)); - else - return ioremap_nocache(phys_addr, size); } EXPORT_SYMBOL(ioremap_wc); +/** + * ioremap_wt - map memory into CPU space write through + * @phys_addr: bus address of the memory + * @size: size of the resource to map + * + * This version of ioremap ensures that the memory is marked write through. + * Write through stores data into memory while keeping the cache up-to-date. + * + * Must be freed with iounmap. + */ +void __iomem *ioremap_wt(resource_size_t phys_addr, unsigned long size) +{ + return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WT, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(ioremap_wt); + void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size) { return __ioremap_caller(phys_addr, size, _PAGE_CACHE_MODE_WB, @@ -331,7 +386,7 @@ void iounmap(volatile void __iomem *addr) } EXPORT_SYMBOL(iounmap); -int arch_ioremap_pud_supported(void) +int __init arch_ioremap_pud_supported(void) { #ifdef CONFIG_X86_64 return cpu_has_gbpages; @@ -340,7 +395,7 @@ int arch_ioremap_pud_supported(void) #endif } -int arch_ioremap_pmd_supported(void) +int __init arch_ioremap_pmd_supported(void) { return cpu_has_pse; } |