1. 根目录:
2. arch
3. x86
4. include
5. asm
6. io.h

#ifndef _ASM_X86_IO_H
#define _ASM_X86_IO_H

/*
 * This file contains the definitions for the x86 IO instructions
 * inb/inw/inl/outb/outw/outl and the "string versions" of the same
 * (insb/insw/insl/outsb/outsw/outsl). You can also use "pausing"
 * versions of the single-IO instructions (inb_p/inw_p/..).
 *
 * This file is not meant to be obfuscating: it's just complicated
 * to (a) handle it all in a way that makes gcc able to optimize it
 * as well as possible and (b) trying to avoid writing the same thing
 * over and over again with slight variations and possibly making a
 * mistake somewhere.
 */

/*
 * Thanks to James van Artsdalen for a better timing-fix than
 * the two short jumps: using outb's to a nonexistent port seems
 * to guarantee better timings even on fast machines.
 *
 * On the other hand, I'd like to be sure of a non-existent port:
 * I feel a bit unsafe about using 0x80 (should be safe, though)
 *
 *		Linus
 */

 /*
  *  Bit simplified and optimized by Jan Hubicka
  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999.
  *
  *  isa_memset_io, isa_memcpy_fromio, isa_memcpy_toio added,
  *  isa_read[wl] and isa_write[wl] fixed
  *  - Arnaldo Carvalho de Melo <acme@conectiva.com.br>
  */

#define ARCH_HAS_IOREMAP_WC

#include <linux/string.h>
#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/early_ioremap.h>

#define build_mmio_read(name, size, type, reg, barrier) \
static inline type name(const volatile void __iomem *addr) \
{ type ret; asm volatile("mov" size " %1,%0":reg (ret) \
:"m" (*(volatile type __force *)addr) barrier); return ret; }

#define build_mmio_write(name, size, type, reg, barrier) \
static inline void name(type val, volatile void __iomem *addr) \
{ asm volatile("mov" size " %0,%1": :reg (val), \
"m" (*(volatile type __force *)addr) barrier); }

build_mmio_read(readb, "b", unsigned char, "=q", :"memory")
build_mmio_read(readw, "w", unsigned short, "=r", :"memory")
build_mmio_read(readl, "l", unsigned int, "=r", :"memory")

build_mmio_read(__readb, "b", unsigned char, "=q", )
build_mmio_read(__readw, "w", unsigned short, "=r", )
build_mmio_read(__readl, "l", unsigned int, "=r", )

build_mmio_write(writeb, "b", unsigned char, "q", :"memory")
build_mmio_write(writew, "w", unsigned short, "r", :"memory")
build_mmio_write(writel, "l", unsigned int, "r", :"memory")

build_mmio_write(__writeb, "b", unsigned char, "q", )
build_mmio_write(__writew, "w", unsigned short, "r", )
build_mmio_write(__writel, "l", unsigned int, "r", )

#define readb_relaxed(a) __readb(a)
#define readw_relaxed(a) __readw(a)
#define readl_relaxed(a) __readl(a)
#define __raw_readb __readb
#define __raw_readw __readw
#define __raw_readl __readl

#define writeb_relaxed(v, a) __writeb(v, a)
#define writew_relaxed(v, a) __writew(v, a)
#define writel_relaxed(v, a) __writel(v, a)
#define __raw_writeb __writeb
#define __raw_writew __writew
#define __raw_writel __writel

#define mmiowb() barrier()

#ifdef CONFIG_X86_64

build_mmio_read(readq, "q", unsigned long, "=r", :"memory")
build_mmio_write(writeq, "q", unsigned long, "r", :"memory")

#define readq_relaxed(a)	readq(a)
#define writeq_relaxed(v, a)	writeq(v, a)

#define __raw_readq(a)		readq(a)
#define __raw_writeq(val, addr)	writeq(val, addr)

/* Let people know that we have them */
#define readq			readq
#define writeq			writeq

#endif

/**
 *	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.
 * However, we truncate the address to unsigned int to avoid undesirable
 * promitions in legacy drivers.
 */
static inline unsigned int isa_virt_to_bus(volatile void *address)
{
	return (unsigned int)virt_to_phys(address);
}
#define isa_page_to_bus(page)	((unsigned int)page_to_phys(page))
#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

/**
 * ioremap     -   map bus memory into CPU space
 * @offset:    bus address of the memory
 * @size:      size of the resource to map
 *
 * ioremap 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.
 *
 * If the area you are trying to map is a PCI BAR you should have a
 * look at pci_iomap().
 */
extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size);
extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size);
extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size,
				unsigned long prot_val);

/*
 * The default ioremap() behavior is non-cached:
 */
static inline void __iomem *ioremap(resource_size_t offset, unsigned long size)
{
	return ioremap_nocache(offset, size);
}

extern void iounmap(volatile void __iomem *addr);

extern void set_iounmap_nonlazy(void);

#ifdef __KERNEL__

#include <asm-generic/iomap.h>

#include <linux/vmalloc.h>

/*
 * Convert a virtual cached pointer to an uncached pointer
 */
#define xlate_dev_kmem_ptr(p)	p

static inline void
memset_io(volatile void __iomem *addr, unsigned char val, size_t count)
{
	memset((void __force *)addr, val, count);
}

static inline void
memcpy_fromio(void *dst, const volatile void __iomem *src, size_t count)
{
	memcpy(dst, (const void __force *)src, count);
}

static inline void
memcpy_toio(volatile void __iomem *dst, const void *src, size_t count)
{
	memcpy((void __force *)dst, src, count);
}

/*
 * ISA space is 'always mapped' on a typical x86 system, no need to
 * explicitly ioremap() it. The fact that the ISA IO space is mapped
 * to PAGE_OFFSET is pure coincidence - it does not mean ISA values
 * are physical addresses. The following constant pointer can be
 * used as the IO-area pointer (it can be iounmapped as well, so the
 * analogy with PCI is quite large):
 */
#define __ISA_IO_base ((char __iomem *)(PAGE_OFFSET))

/*
 *	Cache management
 *
 *	This needed for two cases
 *	1. Out of order aware processors
 *	2. Accidentally out of order processors (PPro errata #51)
 */

static inline void flush_write_buffers(void)
{
#if defined(CONFIG_X86_PPRO_FENCE)
	asm volatile("lock; addl $0,0(%%esp)": : :"memory");
#endif
}

#endif /* __KERNEL__ */

extern void native_io_delay(void);

extern int io_delay_type;
extern void io_delay_init(void);

#if defined(CONFIG_PARAVIRT)
#include <asm/paravirt.h>
#else

static inline void slow_down_io(void)
{
	native_io_delay();
#ifdef REALLY_SLOW_IO
	native_io_delay();
	native_io_delay();
	native_io_delay();
#endif
}

#endif

#define BUILDIO(bwl, bw, type)						\
static inline void out##bwl(unsigned type value, int port)		\
{									\
	asm volatile("out" #bwl " %" #bw "0, %w1"			\
		     : : "a"(value), "Nd"(port));			\
}									\
									\
static inline unsigned type in##bwl(int port)				\
{									\
	unsigned type value;						\
	asm volatile("in" #bwl " %w1, %" #bw "0"			\
		     : "=a"(value) : "Nd"(port));			\
	return value;							\
}									\
									\
static inline void out##bwl##_p(unsigned type value, int port)		\
{									\
	out##bwl(value, port);						\
	slow_down_io();							\
}									\
									\
static inline unsigned type in##bwl##_p(int port)			\
{									\
	unsigned type value = in##bwl(port);				\
	slow_down_io();							\
	return value;							\
}									\
									\
static inline void outs##bwl(int port, const void *addr, unsigned long count) \
{									\
	asm volatile("rep; outs" #bwl					\
		     : "+S"(addr), "+c"(count) : "d"(port));		\
}									\
									\
static inline void ins##bwl(int port, void *addr, unsigned long count)	\
{									\
	asm volatile("rep; ins" #bwl					\
		     : "+D"(addr), "+c"(count) : "d"(port));		\
}

BUILDIO(b, b, char)
BUILDIO(w, w, short)
BUILDIO(l, , int)

extern void *xlate_dev_mem_ptr(phys_addr_t phys);
extern void unxlate_dev_mem_ptr(phys_addr_t phys, void *addr);

extern int ioremap_change_attr(unsigned long vaddr, unsigned long size,
				enum page_cache_mode pcm);
extern void __iomem *ioremap_wc(resource_size_t offset, unsigned long size);

extern bool is_early_ioremap_ptep(pte_t *ptep);

#ifdef CONFIG_XEN
#include <xen/xen.h>
struct bio_vec;

extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
				      const struct bio_vec *vec2);

#define BIOVEC_PHYS_MERGEABLE(vec1, vec2)				\
	(__BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&				\
	 (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2)))
#endif	/* CONFIG_XEN */

#define IO_SPACE_LIMIT 0xffff

#ifdef CONFIG_MTRR
extern int __must_check arch_phys_wc_add(unsigned long base,
					 unsigned long size);
extern void arch_phys_wc_del(int handle);
#define arch_phys_wc_add arch_phys_wc_add
#endif

#endif /* _ASM_X86_IO_H */