io.h

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/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994, 1995 Waldorf GmbH
 * Copyright (C) 1994 - 2000, 06 Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 * Copyright (C) 2004, 2005  MIPS Technologies, Inc.  All rights reserved.
 *	Author:	Maciej W. Rozycki <[e-mail]>
 */
#ifndef _ASM_IO_H
#define _ASM_IO_H

#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/types.h>

#include <asm/addrspace.h>
#include <asm/byteorder.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm-generic/iomap.h>
#include <asm/page.h>
#include <asm/pgtable-bits.h>
#include <asm/processor.h>
#include <asm/string.h>

#include <ioremap.h>
#include <mangle-port.h>

/*
 * Slowdown I/O port space accesses for antique hardware.
 */
#undef CONF_SLOWDOWN_IO

/*
 * Raw operations are never swapped in software.  OTOH values that raw
 * operations are working on may or may not have been swapped by the bus
 * hardware.  An example use would be for flash memory that's used for
 * execute in place.
 */
# define __raw_ioswabb(a, x)	(x)
# define __raw_ioswabw(a, x)	(x)
# define __raw_ioswabl(a, x)	(x)
# define __raw_ioswabq(a, x)	(x)
# define ____raw_ioswabq(a, x)	(x)

/* ioswab[bwlq], __mem_ioswab[bwlq] are defined in mangle-port.h */

#define IO_SPACE_LIMIT 0xffff

/*
 * On MIPS I/O ports are memory mapped, so we access them using normal
 * load/store instructions. mips_io_port_base is the virtual address to
 * which all ports are being mapped.  For sake of efficiency some code
 * assumes that this is an address that can be loaded with a single lui
 * instruction, so the lower 16 bits must be zero.  Should be true on
 * on any sane architecture; generic code does not use this assumption.
 */
extern const unsigned long mips_io_port_base;

/*
 * Gcc will generate code to load the value of mips_io_port_base after each
 * function call which may be fairly wasteful in some cases.  So we don't
 * play quite by the book.  We tell gcc mips_io_port_base is a long variable
 * which solves the code generation issue.  Now we need to violate the
 * aliasing rules a little to make initialization possible and finally we
 * will need the barrier() to fight side effects of the aliasing chat.
 * This trickery will eventually collapse under gcc's optimizer.  Oh well.
 */
static inline void set_io_port_base(unsigned long base)
{
	* (unsigned long *) &mips_io_port_base = base;
	barrier();
}

/*
 * 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
 *
 */

#define __SLOW_DOWN_IO \
	__asm__ __volatile__( \
		"sb\t$0,0x80(%0)" \
		: : "r" (mips_io_port_base));

#ifdef CONF_SLOWDOWN_IO
#ifdef REALLY_SLOW_IO
#define SLOW_DOWN_IO { __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; __SLOW_DOWN_IO; }
#else
#define SLOW_DOWN_IO __SLOW_DOWN_IO
#endif
#else
#define SLOW_DOWN_IO
#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 unsigned long virt_to_phys(volatile const void *address)
{
	return (unsigned long)address - PAGE_OFFSET + PHYS_OFFSET;
}

/*
 *     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(unsigned long address)
{
	return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
}

/*
 * ISA I/O bus memory addresses are 1:1 with the physical address.
 */
static inline unsigned long isa_virt_to_bus(volatile void * address)
{
	return (unsigned long)address - PAGE_OFFSET;
}

static inline void * isa_bus_to_virt(unsigned long address)
{
	return (void *)(address + PAGE_OFFSET);
}

#define isa_page_to_bus page_to_phys

/*
 * However PCI ones are not necessarily 1:1 and therefore these interfaces
 * are forbidden in portable PCI drivers.
 *
 * Allow them for x86 for legacy drivers, though.
 */
#define virt_to_bus virt_to_phys
#define bus_to_virt phys_to_virt

/*
 * isa_slot_offset is the address where E(ISA) busaddress 0 is mapped
 * for the processor.  This implies the assumption that there is only
 * one of these busses.
 */
extern unsigned long isa_slot_offset;

/*
 * Change "struct page" to physical address.
 */
#define page_to_phys(page)	((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)

extern void __iomem * __ioremap(phys_t offset, phys_t size, unsigned long flags);
extern void __iounmap(const volatile void __iomem *addr);

static inline void __iomem * __ioremap_mode(phys_t offset, unsigned long size,
	unsigned long flags)
{
	void __iomem *addr = plat_ioremap(offset, size, flags);

	if (addr)
		return addr;

#define __IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL))

	if (cpu_has_64bit_addresses) {
		u64 base = UNCAC_BASE;

		/*
		 * R10000 supports a 2 bit uncached attribute therefore
		 * UNCAC_BASE may not equal IO_BASE.
		 */
		if (flags == _CACHE_UNCACHED)
			base = (u64) IO_BASE;
		return (void __iomem *) (unsigned long) (base + offset);
	} else if (__builtin_constant_p(offset) &&
		   __builtin_constant_p(size) && __builtin_constant_p(flags)) {
		phys_t phys_addr, last_addr;

		phys_addr = fixup_bigphys_addr(offset, size);

		/* Don't allow wraparound or zero size. */
		last_addr = phys_addr + size - 1;
		if (!size || last_addr < phys_addr)
			return NULL;

		/*
		 * Map uncached objects in the low 512MB of address
		 * space using KSEG1.
		 */
		if (__IS_LOW512(phys_addr) && __IS_LOW512(last_addr) &&
		    flags == _CACHE_UNCACHED)
			return (void __iomem *)
				(unsigned long)CKSEG1ADDR(phys_addr);
	}

	return __ioremap(offset, size, flags);

#undef __IS_LOW512
}

/*
 * 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.
 */
#define ioremap(offset, size)						\
	__ioremap_mode((offset), (size), _CACHE_UNCACHED)

/*
 * ioremap_nocache     -   map bus memory into CPU space
 * @offset:    bus address of the memory
 * @size:      size of the resource to map
 *
 * ioremap_nocache 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.
 *
 * This version of ioremap ensures that the memory is marked uncachable
 * on the CPU as well as honouring existing caching rules from things like
 * the PCI bus. Note that there are other caches and buffers on many
 * busses. In paticular driver authors should read up on PCI writes
 *
 * It's useful if some control registers are in such an area and
 * write combining or read caching is not desirable:
 */
#define ioremap_nocache(offset, size)					\
	__ioremap_mode((offset), (size), _CACHE_UNCACHED)

/*
 * ioremap_cachable -   map bus memory into CPU space
 * @offset:         bus address of the memory
 * @size:           size of the resource to map
 *
 * ioremap_nocache 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.
 *
 * This version of ioremap ensures that the memory is marked cachable by
 * the CPU.  Also enables full write-combining.  Useful for some
 * memory-like regions on I/O busses.
 */
#define ioremap_cachable(offset, size)					\
	__ioremap_mode((offset), (size), PAGE_CACHABLE_DEFAULT)

/*
 * These two are MIPS specific ioremap variant.  ioremap_cacheable_cow
 * requests a cachable mapping, ioremap_uncached_accelerated requests a
 * mapping using the uncached accelerated mode which isn't supported on
 * all processors.
 */
#define ioremap_cacheable_cow(offset, size)				\
	__ioremap_mode((offset), (size), _CACHE_CACHABLE_COW)
#define ioremap_uncached_accelerated(offset, size)			\
	__ioremap_mode((offset), (size), _CACHE_UNCACHED_ACCELERATED)

static inline void iounmap(const volatile void __iomem *addr)
{
	if (plat_iounmap(addr))
		return;

#define __IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)

	if (cpu_has_64bit_addresses ||
	    (__builtin_constant_p(addr) && __IS_KSEG1(addr)))
		return;

	__iounmap(addr);

#undef __IS_KSEG1
}