arch/xtensa/mm/highmem.c

   1 /*
   2  * High memory support for Xtensa architecture
   3  *
   4  * This file is subject to the terms and conditions of the GNU General
   5  * Public License.  See the file "COPYING" in the main directory of
   6  * this archive for more details.
   7  *
   8  * Copyright (C) 2014 Cadence Design Systems Inc.
   9  */
  10
  11 #include <linux/export.h>
  12 #include <linux/highmem.h>
  13 #include <asm/tlbflush.h>
  14
  15 #if DCACHE_WAY_SIZE > PAGE_SIZE
  16 unsigned int last_pkmap_nr_arr[DCACHE_N_COLORS];
  17 wait_queue_head_t pkmap_map_wait_arr[DCACHE_N_COLORS];
  18
  19 static void __init kmap_waitqueues_init(void)
  20 {
  21         unsigned int i;
  22
  23         for (i = 0; i < ARRAY_SIZE(pkmap_map_wait_arr); ++i)
  24                 init_waitqueue_head(pkmap_map_wait_arr + i);
  25 }
  26
  27 static inline enum fixed_addresses kmap_idx(int type, unsigned long color)
  28 {
  29         int idx = (type + KM_MAX_IDX * smp_processor_id()) * DCACHE_N_COLORS;
  30
  31         /*
  32          * The fixmap operates top down, so the color offset needs to be
  33          * reverse as well.
  34          */
  35         return idx + DCACHE_N_COLORS - 1 - color;
  36 }
  37
  38 enum fixed_addresses kmap_local_map_idx(int type, unsigned long pfn)
  39 {
  40         return kmap_idx(type, DCACHE_ALIAS(pfn << PAGE_SHIFT));
  41 }
  42
  43 enum fixed_addresses kmap_local_unmap_idx(int type, unsigned long addr)
  44 {
  45         return kmap_idx(type, DCACHE_ALIAS(addr));
  46 }
  47
  48 #else
  49 static inline void kmap_waitqueues_init(void) { }
  50 #endif
  51
  52 void __init kmap_init(void)
  53 {
  54         /* Check if this memory layout is broken because PKMAP overlaps
  55          * page table.
  56          */
  57         BUILD_BUG_ON(PKMAP_BASE < TLBTEMP_BASE_1 + TLBTEMP_SIZE);
  58         kmap_waitqueues_init();
  59 }