path: root/include/asm-generic/io.h

/* Generic I/O port emulation.
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef __ASM_GENERIC_IO_H
#define __ASM_GENERIC_IO_H

#include <asm/page.h> /* I/O is all done through memory accesses */
#include <linux/string.h> /* for memset() and memcpy() */
#include <linux/types.h>

#ifdef CONFIG_GENERIC_IOMAP
#include <asm-generic/iomap.h>
#endif

#include <asm-generic/pci_iomap.h>

#ifndef mmiowb
#define mmiowb() do {} while (0)
#endif

#ifndef __io_br
#define __io_br()      barrier()
#endif

/* prevent prefetching of coherent DMA data ahead of a dma-complete */
#ifndef __io_ar
#ifdef rmb
#define __io_ar()      rmb()
#else
#define __io_ar()      barrier()
#endif
#endif

/* flush writes to coherent DMA data before possibly triggering a DMA read */
#ifndef __io_bw
#ifdef wmb
#define __io_bw()      wmb()
#else
#define __io_bw()      barrier()
#endif
#endif

/* serialize device access against a spin_unlock, usually handled there. */
#ifndef __io_aw
#define __io_aw()      barrier()
#endif

#ifndef __io_pbw
#define __io_pbw()     __io_bw()
#endif

#ifndef __io_paw
#define __io_paw()     __io_aw()
#endif

#ifndef __io_pbr
#define __io_pbr()     __io_br()
#endif

#ifndef __io_par
#define __io_par()     __io_ar()
#endif


/*
 * __raw_{read,write}{b,w,l,q}() access memory in native endianness.
 *
 * On some architectures memory mapped IO needs to be accessed differently.
 * On the simple architectures, we just read/write the memory location
 * directly.
 */

#ifndef __raw_readb
#define __raw_readb __raw_readb
static inline u8 __raw_readb(const volatile void __iomem *addr)
{
	return *(const volatile u8 __force *)addr;
}
#endif

#ifndef __raw_readw
#define __raw_readw __raw_readw
static inline u16 __raw_readw(const volatile void __iomem *addr)
{
	return *(const volatile u16 __force *)addr;
}
#endif

#ifndef __raw_readl
#define __raw_readl __raw_readl
static inline u32 __raw_readl(const volatile void __iomem *addr)
{
	return *(const volatile u32 __force *)addr;
}
#endif

#ifdef CONFIG_64BIT
#ifndef __raw_readq
#define __raw_readq __raw_readq
static inline u64 __raw_readq(const volatile void __iomem *addr)
{
	return *(const volatile u64 __force *)addr;
}
#endif
#endif /* CONFIG_64BIT */

#ifndef __raw_writeb
#define __raw_writeb __raw_writeb
static inline void __raw_writeb(u8 value, volatile void __iomem *addr)
{
	*(volatile u8 __force *)addr = value;
}
#endif

#ifndef __raw_writew
#define __raw_writew __raw_writew
static inline void __raw_writew(u16 value, volatile void __iomem *addr)
{
	*(volatile u16 __force *)addr = value;
}
#endif

#ifndef __raw_writel
#define __raw_writel __raw_writel
static inline void __raw_writel(u32 value, volatile void __iomem *addr)
{
	*(volatile u32 __force *)addr = value;
}
#endif

#ifdef CONFIG_64BIT
#ifndef __raw_writeq
#define __raw_writeq __raw_writeq
static inline void __raw_writeq(u64 value, volatile void __iomem *addr)
{
	*(volatile u64 __force *)addr = value;
}
#endif
#endif /* CONFIG_64BIT */

/*
 * {read,write}{b,w,l,q}() access little endian memory and return result in
 * native endianness.
 */

#ifndef readb
#define readb readb
static inline u8 readb(const volatile void __iomem *addr)
{
	u8 val;

	__io_br();
	val = __raw_readb(addr);
	__io_ar();
	return val;
}
#endif

#ifndef readw
#define readw readw
static inline u16 readw(const volatile void __iomem *addr)
{
	u16 val;

	__io_br();
	val = __le16_to_cpu(__raw_readw(addr));
	__io_ar();
	return val;
}
#endif

#ifndef readl
#define readl readl
static inline u32 readl(const volatile void __iomem *addr)
{
	u32 val;

	__io_br();
	val = __le32_to_cpu(__raw_readl(addr));
	__io_ar();
	return val;
}
#endif

#ifdef CONFIG_64BIT
#ifndef readq
#define readq readq
static inline u64 readq(const volatile void __iomem *addr)
{
	u64 val;

	__io_br();
	val = __le64_to_cpu(__raw_readq(addr));
	__io_ar();
	return val;
}
#endif
#endif /* CONFIG_64BIT */

#ifndef writeb
#define writeb writeb
static inline void writeb(u8 value, volatile void __iomem *addr)
{
	__io_bw();
	__raw_writeb(value, addr);
	__io_aw();
}
#endif

#ifndef writew
#define writew writew
static inline void writew(u16 value, volatile void __iomem *addr)
{
	__io_bw();
	__raw_writew(cpu_to_le16(value), addr);
	__io_aw();
}
#endif

#ifndef writel
#define writel writel
static inline void writel(u32 value, volatile void __iomem *addr)
{
	__io_bw();
	__raw_writel(__cpu_to_le32(