#include <linux/ioport.h>

分配I/O内存区，失败返回NULL，所有的I/O内存分配可以通过/proc/iomem节点查询

struct resource *request_mem_region(unsigned long start, unsigned long len, char *name);

释放I/O内存区

void release_mem_region(unsigned long start, unsigned long len);

#include <asm/io.h>

void *ioremap(unsigned long phys_addr, unsigned long size);

void *ioremap_nocache(unsigned long phys_addr, unsigned long size);

void iounmap(void *addr);

I/O内存读操作：

unsigned int ioread8(void *addr);

unsigned int ioread16(void *addr);

unsigned int ioread32(void *addr);

I/O内存写操作：

void iowrite8(u8 value, void *addr);

void iowrite16(u16 value, void *addr);

void iowrite32(u32 value, void *addr);

I/O内存块操作：

void memset_io(void *addr, u8 value, unsigned int count);

void memcpy_fromio(void *dest, void *source, unsigned int count);

void memcpy_toio(void *dest, void *source, unsigned int count);

有一组旧的接口：

unsigned readb(address);

unsigned readw(address);

unsigned readl(address);

void writeb(unsigned value, address);

void writew(unsigned value, address);

void writel(unsigned value, address);