LXR linux/arch/sh/mm/kmap.c

   1/*
   2 * arch/sh/mm/kmap.c
   3 *
   4 * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
   5 * Copyright (C) 2002 - 2009  Paul Mundt
   6 *
   7 * Released under the terms of the GNU GPL v2.0.
   8 */
   9#include <linux/mm.h>
  10#include <linux/init.h>
  11#include <linux/mutex.h>
  12#include <linux/fs.h>
  13#include <linux/highmem.h>
  14#include <linux/module.h>
  15#include <asm/mmu_context.h>
  16#include <asm/cacheflush.h>
  17
  18#define kmap_get_fixmap_pte(vaddr)                                     \
  19        pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)), (vaddr)), (vaddr))
  20
  21static pte_t *kmap_coherent_pte;
  22
  23void __init kmap_coherent_init(void)
  24{
  25        unsigned long vaddr;
  26
  27        /* cache the first coherent kmap pte */
  28        vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
  29        kmap_coherent_pte = kmap_get_fixmap_pte(vaddr);
  30}
  31
  32void *kmap_coherent(struct page *page, unsigned long addr)
  33{
  34        enum fixed_addresses idx;
  35        unsigned long vaddr;
  36
  37        BUG_ON(!test_bit(PG_dcache_clean, &page->flags));
  38
  39        preempt_disable();
  40        pagefault_disable();
  41
  42        idx = FIX_CMAP_END -
  43                (((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
  44                 (FIX_N_COLOURS * smp_processor_id()));
  45
  46        vaddr = __fix_to_virt(idx);
  47
  48        BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
  49        set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));
  50
  51        return (void *)vaddr;
  52}
  53
  54void kunmap_coherent(void *kvaddr)
  55{
  56        if (kvaddr >= (void *)FIXADDR_START) {
  57                unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
  58                enum fixed_addresses idx = __virt_to_fix(vaddr);
  59
  60                /* XXX.. Kill this later, here for sanity at the moment.. */
  61                __flush_purge_region((void *)vaddr, PAGE_SIZE);
  62
  63                pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
  64                local_flush_tlb_one(get_asid(), vaddr);
  65        }
  66
  67        pagefault_enable();
  68        preempt_enable();
  69}
  70