/*
* Fixmap support for Hexagon - enough to support highmem features
*
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/

#ifndef _ASM_FIXMAP_H
#define _ASM_FIXMAP_H

/*
* A lot of the fixmap info is already in mem-layout.h
*/
#include <asm/mem-layout.h>

/*
* Full fixmap support involves set_fixmap() functions, but
* these may not be needed if all we're after is an area for
* highmem kernel mappings.
*/
#define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT))
#define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)

extern void __this_fixmap_does_not_exist(void);

/**
* fix_to_virt -- "index to address" translation.
*
* If anyone tries to use the idx directly without translation,
* we catch the bug with a NULL-deference kernel oops. Illegal
* ranges of incoming indices are caught too.
*/
static 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)
__this_fixmap_does_not_exist();

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);
}

#define kmap_get_fixmap_pte(vaddr) \
pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), \
(vaddr)), (vaddr)), (vaddr))

#endif