kmap.c
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/*
* arch/sh/mm/kmap.c
*
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
* Copyright (C) 2002 - 2009 Paul Mundt
*
* Released under the terms of the GNU GPL v2.0.
*/
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#define kmap_get_fixmap_pte(vaddr) \
pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
static pte_t *kmap_coherent_pte;
void __init kmap_coherent_init(void)
{
unsigned long vaddr;
/* cache the first coherent kmap pte */
vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
}
void *kmap_coherent(struct page *page, unsigned long addr)
{
enum fixed_addresses idx;
unsigned long vaddr;
BUG_ON(!test_bit(PG_dcache_clean, &page->flags));
pagefault_disable();
idx = FIX_CMAP_END -
(((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
(FIX_N_COLOURS * smp_processor_id()));
vaddr = __fix_to_virt(idx);
BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));
return (void *)vaddr;
}
void kunmap_coherent(void *kvaddr)
{
if (kvaddr >= (void *)FIXADDR_START) {
unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
enum fixed_addresses idx = __virt_to_fix(vaddr);
/* XXX.. Kill this later, here for sanity at the moment.. */
__flush_purge_region((void *)vaddr, PAGE_SIZE);
pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
local_flush_tlb_one(get_asid(), vaddr);
}
pagefault_enable();
}