arch/metag/include/asm/highmem.h

   1 #ifndef _ASM_HIGHMEM_H
   2 #define _ASM_HIGHMEM_H
   3
   4 #include <asm/cacheflush.h>
   5 #include <asm/kmap_types.h>
   6 #include <asm/fixmap.h>
   7
   8 /*
   9  * Right now we initialize only a single pte table. It can be extended
  10  * easily, subsequent pte tables have to be allocated in one physical
  11  * chunk of RAM.
  12  */
  13 /*
  14  * Ordering is (from lower to higher memory addresses):
  15  *
  16  * high_memory
  17  *                      Persistent kmap area
  18  * PKMAP_BASE
  19  *                      fixed_addresses
  20  * FIXADDR_START
  21  * FIXADDR_TOP
  22  *                      Vmalloc area
  23  * VMALLOC_START
  24  * VMALLOC_END
  25  */
  26 #define PKMAP_BASE              (FIXADDR_START - PMD_SIZE)
  27 #define LAST_PKMAP              PTRS_PER_PTE
  28 #define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  29 #define PKMAP_NR(virt)          (((virt) - PKMAP_BASE) >> PAGE_SHIFT)
  30 #define PKMAP_ADDR(nr)          (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  31
  32 #define kmap_prot               PAGE_KERNEL
  33
  34 static inline void flush_cache_kmaps(void)
  35 {
  36         flush_cache_all();
  37 }
  38
  39 /* declarations for highmem.c */
  40 extern unsigned long highstart_pfn, highend_pfn;
  41
  42 extern pte_t *pkmap_page_table;
  43
  44 extern void *kmap_high(struct page *page);
  45 extern void kunmap_high(struct page *page);
  46
  47 extern void kmap_init(void);
  48
  49 /*
  50  * The following functions are already defined by <linux/highmem.h>
  51  * when CONFIG_HIGHMEM is not set.
  52  */
  53 #ifdef CONFIG_HIGHMEM
  54 extern void *kmap(struct page *page);
  55 extern void kunmap(struct page *page);
  56 extern void *kmap_atomic(struct page *page);
  57 extern void __kunmap_atomic(void *kvaddr);
  58 extern void *kmap_atomic_pfn(unsigned long pfn);
  59 #endif
  60
  61 #endif