diff options
Diffstat (limited to 'arch/x86/include/asm/io.h')
| -rw-r--r-- | arch/x86/include/asm/io.h | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 1dbbdf4be9b4..919e3b19f3ca 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -5,6 +5,7 @@ #include <linux/compiler.h> #include <asm-generic/int-ll64.h> +#include <asm/page.h> #define build_mmio_read(name, size, type, reg, barrier) \ static inline type name(const volatile void __iomem *addr) \ @@ -80,6 +81,64 @@ static inline void writeq(__u64 val, volatile void __iomem *addr) #define readq readq #define writeq writeq +/** + * virt_to_phys - map virtual addresses to physical + * @address: address to remap + * + * The returned physical address is the physical (CPU) mapping for + * the memory address given. It is only valid to use this function on + * addresses directly mapped or allocated via kmalloc. + * + * This function does not give bus mappings for DMA transfers. In + * almost all conceivable cases a device driver should not be using + * this function + */ + +static inline phys_addr_t virt_to_phys(volatile void *address) +{ + return __pa(address); +} + +/** + * phys_to_virt - map physical address to virtual + * @address: address to remap + * + * The returned virtual address is a current CPU mapping for + * the memory address given. It is only valid to use this function on + * addresses that have a kernel mapping + * + * This function does not handle bus mappings for DMA transfers. In + * almost all conceivable cases a device driver should not be using + * this function + */ + +static inline void *phys_to_virt(phys_addr_t address) +{ + return __va(address); +} + +/* + * Change "struct page" to physical address. + */ +#define page_to_phys(page) ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT) + +/* + * ISA I/O bus memory addresses are 1:1 with the physical address. + */ +#define isa_virt_to_bus virt_to_phys +#define isa_page_to_bus page_to_phys +#define isa_bus_to_virt phys_to_virt + +/* + * However PCI ones are not necessarily 1:1 and therefore these interfaces + * are forbidden in portable PCI drivers. + * + * Allow them on x86 for legacy drivers, though. + */ +#define virt_to_bus virt_to_phys +#define bus_to_virt phys_to_virt + + #ifdef CONFIG_X86_32 # include "io_32.h" #else |