arch/avr32/mm/init.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/gfp.h>
  11 #include <linux/mm.h>
  12 #include <linux/swap.h>
  13 #include <linux/init.h>
  14 #include <linux/mmzone.h>
  15 #include <linux/module.h>
  16 #include <linux/bootmem.h>
  17 #include <linux/pagemap.h>
  18 #include <linux/nodemask.h>
  19
  20 #include <asm/page.h>
  21 #include <asm/mmu_context.h>
  22 #include <asm/tlb.h>
  23 #include <asm/io.h>
  24 #include <asm/dma.h>
  25 #include <asm/setup.h>
  26 #include <asm/sections.h>
  27
  28 pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_data;
  29
  30 struct page *empty_zero_page;
  31 EXPORT_SYMBOL(empty_zero_page);
  32
  33 /*
  34  * Cache of MMU context last used.
  35  */
  36 unsigned long mmu_context_cache = NO_CONTEXT;
  37
  38 /*
  39  * paging_init() sets up the page tables
  40  *
  41  * This routine also unmaps the page at virtual kernel address 0, so
  42  * that we can trap those pesky NULL-reference errors in the kernel.
  43  */
  44 void __init paging_init(void)
  45 {
  46         extern unsigned long _evba;
  47         void *zero_page;
  48         int nid;
  49
  50         /*
  51          * Make sure we can handle exceptions before enabling
  52          * paging. Not that we should ever _get_ any exceptions this
  53          * early, but you never know...
  54          */
  55         printk("Exception vectors start at %p\n", &_evba);
  56         sysreg_write(EVBA, (unsigned long)&_evba);
  57
  58         /*
  59          * Since we are ready to handle exceptions now, we should let
  60          * the CPU generate them...
  61          */
  62         __asm__ __volatile__ ("csrf %0" : : "i"(SR_EM_BIT));
  63
  64         /*
  65          * Allocate the zero page. The allocator will panic if it
  66          * can't satisfy the request, so no need to check.
  67          */
  68         zero_page = alloc_bootmem_low_pages_node(NODE_DATA(0),
  69                                                  PAGE_SIZE);
  70
  71         sysreg_write(PTBR, (unsigned long)swapper_pg_dir);
  72         enable_mmu();
  73         printk ("CPU: Paging enabled\n");
  74
  75         for_each_online_node(nid) {
  76                 pg_data_t *pgdat = NODE_DATA(nid);
  77                 unsigned long zones_size[MAX_NR_ZONES];
  78                 unsigned long low, start_pfn;
  79
  80                 start_pfn = pgdat->bdata->node_min_pfn;
  81                 low = pgdat->bdata->node_low_pfn;
  82
  83                 memset(zones_size, 0, sizeof(zones_size));
  84                 zones_size[ZONE_NORMAL] = low - start_pfn;
  85
  86                 printk("Node %u: start_pfn = 0x%lx, low = 0x%lx\n",
  87                        nid, start_pfn, low);
  88
  89                 free_area_init_node(nid, zones_size, start_pfn, NULL);
  90
  91                 printk("Node %u: mem_map starts at %p\n",
  92                        pgdat->node_id, pgdat->node_mem_map);
  93         }
  94
  95         mem_map = NODE_DATA(0)->node_mem_map;
  96
  97         empty_zero_page = virt_to_page(zero_page);
  98         flush_dcache_page(empty_zero_page);
  99 }
 100
 101 void __init mem_init(void)
 102 {
 103         pg_data_t *pgdat;
 104
 105         high_memory = NULL;
 106         for_each_online_pgdat(pgdat)
 107                 high_memory = max_t(void *, high_memory,
 108                                     __va(pgdat_end_pfn(pgdat) << PAGE_SHIFT));
 109
 110         set_max_mapnr(MAP_NR(high_memory));
 111         free_all_bootmem();
 112         mem_init_print_info(NULL);
 113 }
 114
 115 void free_initmem(void)
 116 {
 117         free_initmem_default(-1);
 118 }
 119
 120 #ifdef CONFIG_BLK_DEV_INITRD
 121 void free_initrd_mem(unsigned long start, unsigned long end)
 122 {
 123         free_reserved_area((void *)start, (void *)end, -1, "initrd");
 124 }
 125 #endif