/* MN10300 Virtual kernel memory mappings for high memory
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
* - Derived from include/asm-i386/highmem.h
*
* 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_HIGHMEM_H
#define _ASM_HIGHMEM_H

#ifdef __KERNEL__

#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/highmem.h>
#include <asm/kmap_types.h>
#include <asm/pgtable.h>

/* undef for production */
#undef HIGHMEM_DEBUG

/* declarations for highmem.c */
extern unsigned long highstart_pfn, highend_pfn;

extern pte_t *kmap_pte;
extern pgprot_t kmap_prot;
extern pte_t *pkmap_page_table;

extern void __init kmap_init(void);

/*
* Right now we initialize only a single pte table. It can be extended
* easily, subsequent pte tables have to be allocated in one physical
* chunk of RAM.
*/
#define PKMAP_BASE 0xfe000000UL
#define LAST_PKMAP 1024
#define LAST_PKMAP_MASK (LAST_PKMAP - 1)
#define PKMAP_NR(virt) ((virt - PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))

extern unsigned long kmap_high(struct page *page);
extern void kunmap_high(struct page *page);

static inline unsigned long kmap(struct page *page)
{
if (in_interrupt())
BUG();
if (page < highmem_start_page)
return page_address(page);
return kmap_high(page);
}

static inline void kunmap(struct page *page)
{
if (in_interrupt())
BUG();
if (page < highmem_start_page)
return;
kunmap_high(page);
}

/*
* The use of kmap_atomic/kunmap_atomic is discouraged - kmap/kunmap
* gives a more generic (and caching) interface. But kmap_atomic can
* be used in IRQ contexts, so in some (very limited) cases we need
* it.
*/
static inline unsigned long kmap_atomic(struct page *page)
{
unsigned long vaddr;
int idx, type;

pagefault_disable();
if (page < highmem_start_page)
return page_address(page);

type = kmap_atomic_idx_push();
idx = type + KM_TYPE_NR * smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
#if HIGHMEM_DEBUG
if (!pte_none(*(kmap_pte - idx)))
BUG();
#endif
set_pte(kmap_pte - idx, mk_pte(page, kmap_prot));
local_flush_tlb_one(vaddr);

return vaddr;
}

static inline void __kunmap_atomic(unsigned long vaddr)
{
int type;

if (vaddr < FIXADDR_START) { /* FIXME */
pagefault_enable();
return;
}

type = kmap_atomic_idx();

#if HIGHMEM_DEBUG
{
unsigned int idx;
idx = type + KM_TYPE_NR * smp_processor_id();

if (vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx))
BUG();

/*
* force other mappings to Oops if they'll try to access
* this pte without first remap it
*/
pte_clear(kmap_pte - idx);
local_flush_tlb_one(vaddr);
}
#endif

kmap_atomic_idx_pop();
pagefault_enable();
}
#endif /* __KERNEL__ */

#endif /* _ASM_HIGHMEM_H */