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
  11 /*
  12  * Right now we initialize only a single pte table. It can be extended
  13  * easily, subsequent pte tables have to be allocated in one physical
  14  * chunk of RAM.
  15  */
  16 /*
  17  * Ordering is (from lower to higher memory addresses):
  18  *
  19  * high_memory
  20  *                      Persistent kmap area
  21  * PKMAP_BASE
  22  *                      fixed_addresses
  23  * FIXADDR_START
  24  * FIXADDR_TOP
  25  *                      Vmalloc area
  26  * VMALLOC_START
  27  * VMALLOC_END
  28  */
  29 #define PKMAP_BASE              ((FIXADDR_START - PGDIR_SIZE) & (PGDIR_MASK))
  30 #define LAST_PKMAP              PTRS_PER_PTE
  31 #define LAST_PKMAP_MASK         (LAST_PKMAP - 1)
  32 #define PKMAP_NR(virt)          (((virt) - (PKMAP_BASE)) >> PAGE_SHIFT)
  33 #define PKMAP_ADDR(nr)          (PKMAP_BASE + ((nr) << PAGE_SHIFT))
  34
  35 static inline void flush_cache_kmaps(void)
  36 {
  37         cpu_dcache_wbinval_all();
  38 }
  39
  40 /* declarations for highmem.c */
  41 extern unsigned long highstart_pfn, highend_pfn;
  42
  43 extern pte_t *pkmap_page_table;
  44
  45 extern void kmap_init(void);
  46
  47 /*
  48  * The following functions are already defined by <linux/highmem.h>
  49  * when CONFIG_HIGHMEM is not set.
  50  */
  51 #ifdef CONFIG_HIGHMEM
  52 extern void *kmap_atomic_pfn(unsigned long pfn);
  53 #endif
  54
  55 #endif