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
  21 static pte_t *kmap_coherent_pte;
  22
  23 void __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
  32 void *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
  54 void 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 }