blob: 52733416c1f313d3027fa06c66d3d9e6f8ed8b42 [file] [log] [blame]
* OpenRISC Linux
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
* OpenRISC implementation:
* Copyright (C) 2003 Matjaz Breskvar <>
* Copyright (C) 2010-2011 Jonas Bonn <>
* et al.
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
/* Why exactly do we need 2 empty pages between the top of the fixed
* addresses and the top of virtual memory? Something is using that
* memory space but not sure what right now... If you find it, leave
* a comment here.
#define FIXADDR_TOP ((unsigned long) (-2*PAGE_SIZE))
#include <linux/kernel.h>
#include <asm/page.h>
* On OpenRISC we use these special fixed_addresses for doing ioremap
* early in the boot process before memory initialization is complete.
* This is used, in particular, by the early serial console code.
* It's not really 'fixmap', per se, but fits loosely into the same
* paradigm.
enum fixed_addresses {
* FIX_IOREMAP entries are useful for mapping physical address
* space before ioremap() is useable, e.g. really early in boot
* before kmalloc() is working.
#define FIX_N_IOREMAPS 32
#define FIXADDR_SIZE (__end_of_fixed_addresses << PAGE_SHIFT)
/* FIXADDR_BOTTOM might be a better name here... */
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
* 'index to address' translation. If anyone tries to use the idx
* directly without tranlation, we catch the bug with a NULL-deference
* kernel oops. Illegal ranges of incoming indices are caught too.
static __always_inline unsigned long fix_to_virt(const unsigned int idx)
* this branch gets completely eliminated after inlining,
* except when someone tries to use fixaddr indices in an
* illegal way. (such as mixing up address types or using
* out-of-range indices).
* If it doesn't get removed, the linker will complain
* loudly with a reasonably clear error message..
if (idx >= __end_of_fixed_addresses)
return __fix_to_virt(idx);
static inline unsigned long virt_to_fix(const unsigned long vaddr)
BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
return __virt_to_fix(vaddr);