io.h

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/*
 *  include/asm-s390/io.h
 *
 *  S390 version
 *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Martin Schwidefsky ([e-mail])
 *
 *  Derived from "include/asm-i386/io.h"
 */

#ifndef _S390_IO_H
#define _S390_IO_H

#ifdef __KERNEL__

#include <linux/vmalloc.h>
#include <asm/page.h>

#define IO_SPACE_LIMIT 0xffffffff

#define __io_virt(x)            ((void *)(PAGE_OFFSET | (unsigned long)(x)))
#define __io_phys(x)            ((unsigned long)(x) & ~PAGE_OFFSET)
/*
 * Change virtual addresses to physical addresses and vv.
 * These are pretty trivial
 */
extern inline unsigned long virt_to_phys(volatile void * address)
{
	unsigned long real_address;
	__asm__ ("   lra    %0,0(%1)\n"
                 "   jz     0f\n"
                 "   sr     %0,%0\n"
                 "0:"
                 : "=a" (real_address) : "a" (address) : "cc" );
        return real_address;
}

extern inline void * phys_to_virt(unsigned long address)
{
        return __io_virt(address);
}

extern void * __ioremap(unsigned long offset, unsigned long size, unsigned long flags);

extern inline void * ioremap (unsigned long offset, unsigned long size)
{
        return __ioremap(offset, size, 0);
}

/*
 * This one maps high address device memory and turns off caching for that area.
 * it's useful if some control registers are in such an area and write combining
 * or read caching is not desirable:
 */
extern inline void * ioremap_nocache (unsigned long offset, unsigned long size)
{
        return __ioremap(offset, size, 0);
}

extern void iounmap(void *addr);

/*
 * IO bus memory addresses are also 1:1 with the physical address
 */
#define virt_to_bus virt_to_phys
#define bus_to_virt phys_to_virt

/*
 * readX/writeX() are used to access memory mapped devices. On some
 * architectures the memory mapped IO stuff needs to be accessed
 * differently.
 */

#define readb(addr) (*(volatile unsigned char *) __io_virt(addr))
#define readw(addr) (*(volatile unsigned short *) __io_virt(addr))
#define readl(addr) (*(volatile unsigned int *) __io_virt(addr))

#define writeb(b,addr) (*(volatile unsigned char *) __io_virt(addr) = (b))
#define writew(b,addr) (*(volatile unsigned short *) __io_virt(addr) = (b))
#define writel(b,addr) (*(volatile unsigned int *) __io_virt(addr) = (b))

#define memset_io(a,b,c)        memset(__io_virt(a),(b),(c))
#define memcpy_fromio(a,b,c)    memcpy((a),__io_virt(b),(c))
#define memcpy_toio(a,b,c)      memcpy(__io_virt(a),(b),(c))

#define inb_p(addr) readb(addr)
#define inb(addr) readb(addr)

#define outb(x,addr) ((void) writeb(x,addr))
#define outb_p(x,addr) outb(x,addr)

#endif /* __KERNEL__ */

#endif