arch/nds32/include/asm/highmem.h

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #ifndef _ASM_HIGHMEM_H
   5 #define _ASM_HIGHMEM_H
   6
   7 #include <asm/proc-fns.h>
   8 #include <asm/kmap_types.h>
   9 #include <asm/fixmap.h>
  10 #include <asm/pgtable.h>
  11
  12 /*
  13  * Right now we initialize only a single pte table. It can be extended
  14  * easily, subsequent pte tables have to be allocated in one physical
  15  * chunk of RAM.
  16  */
  17 /*
  18  * Ordering is (from lower to higher memory addresses):
  19  *
  20  * high_memory
  21  *                      Persistent kmap area
  22  * PKMAP_BASE
  23  *                      fixed_addresses
  24  * FIXADDR_START
  25  * FIXADDR_TOP
  26  *                      Vmalloc area
  27  * VMALLOC_START
  28  * VMALLOC_END
  29  */
  30 #define PKMAP_BASE              ((FIXADDR_START - PGDIR_SIZE) & (PGDIR_MASK))
  31 #define LAST_PKMAP              PTRS_PER_PTE
  32 #define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  33 #define PKMAP_NR(virt)          (((virt) - (PKMAP_BASE)) >> PAGE_SHIFT)
  34 #define PKMAP_ADDR(nr)          (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  35 #define kmap_prot               PAGE_KERNEL
  36
  37 static inline void flush_cache_kmaps(void)
  38 {
  39         cpu_dcache_wbinval_all();
  40 }
  41
  42 /* declarations for highmem.c */
  43 extern unsigned long highstart_pfn, highend_pfn;
  44
  45 extern pte_t *pkmap_page_table;
  46
  47 extern void *kmap_high(struct page *page);
  48 extern void kunmap_high(struct page *page);
  49
  50 extern void kmap_init(void);
  51
  52 /*
  53  * The following functions are already defined by <linux/highmem.h>
  54  * when CONFIG_HIGHMEM is not set.
  55  */
  56 #ifdef CONFIG_HIGHMEM
  57 extern void *kmap(struct page *page);
  58 extern void kunmap(struct page *page);
  59 extern void *kmap_atomic(struct page *page);
  60 extern void __kunmap_atomic(void *kvaddr);
  61 extern void *kmap_atomic_pfn(unsigned long pfn);
  62 extern struct page *kmap_atomic_to_page(void *ptr);
  63 #endif
  64
  65 #endif