arch/powerpc/mm/init_32.c

   1 /*
   2  *  PowerPC version
   3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   4  *
   5  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
   6  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
   7  *    Copyright (C) 1996 Paul Mackerras
   8  *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
   9  *
  10  *  Derived from "arch/i386/mm/init.c"
  11  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  *
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/errno.h>
  24 #include <linux/string.h>
  25 #include <linux/types.h>
  26 #include <linux/mm.h>
  27 #include <linux/stddef.h>
  28 #include <linux/init.h>
  29 #include <linux/bootmem.h>
  30 #include <linux/highmem.h>
  31 #include <linux/initrd.h>
  32 #include <linux/pagemap.h>
  33 #include <linux/memblock.h>
  34 #include <linux/gfp.h>
  35
  36 #include <asm/pgalloc.h>
  37 #include <asm/prom.h>
  38 #include <asm/io.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/mmu.h>
  41 #include <asm/smp.h>
  42 #include <asm/machdep.h>
  43 #include <asm/btext.h>
  44 #include <asm/tlb.h>
  45 #include <asm/sections.h>
  46 #include <asm/system.h>
  47
  48 #include "mmu_decl.h"
  49
  50 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  51 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
  52 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
  53 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
  54 #endif
  55 #endif
  56 #define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  57
  58 phys_addr_t total_memory;
  59 phys_addr_t total_lowmem;
  60
  61 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  62 EXPORT_SYMBOL(memstart_addr);
  63 phys_addr_t kernstart_addr;
  64 EXPORT_SYMBOL(kernstart_addr);
  65 phys_addr_t lowmem_end_addr;
  66
  67 int boot_mapsize;
  68 #ifdef CONFIG_PPC_PMAC
  69 unsigned long agp_special_page;
  70 EXPORT_SYMBOL(agp_special_page);
  71 #endif
  72
  73 void MMU_init(void);
  74
  75 /* XXX should be in current.h  -- paulus */
  76 extern struct task_struct *current_set[NR_CPUS];
  77
  78 /*
  79  * this tells the system to map all of ram with the segregs
  80  * (i.e. page tables) instead of the bats.
  81  * -- Cort
  82  */
  83 int __map_without_bats;
  84 int __map_without_ltlbs;
  85
  86 /*
  87  * This tells the system to allow ioremapping memory marked as reserved.
  88  */
  89 int __allow_ioremap_reserved;
  90
  91 /* max amount of low RAM to map in */
  92 unsigned long __max_low_memory = MAX_LOW_MEM;
  93
  94 /*
  95  * Check for command-line options that affect what MMU_init will do.
  96  */
  97 void MMU_setup(void)
  98 {
  99         /* Check for nobats option (used in mapin_ram). */
 100         if (strstr(cmd_line, "nobats")) {
 101                 __map_without_bats = 1;
 102         }
 103
 104         if (strstr(cmd_line, "noltlbs")) {
 105                 __map_without_ltlbs = 1;
 106         }
 107 #ifdef CONFIG_DEBUG_PAGEALLOC
 108         __map_without_bats = 1;
 109         __map_without_ltlbs = 1;
 110 #endif
 111 }
 112
 113 /*
 114  * MMU_init sets up the basic memory mappings for the kernel,
 115  * including both RAM and possibly some I/O regions,
 116  * and sets up the page tables and the MMU hardware ready to go.
 117  */
 118 void __init MMU_init(void)
 119 {
 120         if (ppc_md.progress)
 121                 ppc_md.progress("MMU:enter", 0x111);
 122
 123         /* parse args from command line */
 124         MMU_setup();
 125
 126         if (memblock.memory.cnt > 1) {
 127 #ifndef CONFIG_WII
 128                 memblock.memory.cnt = 1;
 129                 memblock_analyze();
 130                 printk(KERN_WARNING "Only using first contiguous memory region");
 131 #else
 132                 wii_memory_fixups();
 133 #endif
 134         }
 135
 136         total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
 137         lowmem_end_addr = memstart_addr + total_lowmem;
 138
 139 #ifdef CONFIG_FSL_BOOKE
 140         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 141          * entries, so we need to adjust lowmem to match the amount we can map
 142          * in the fixed entries */
 143         adjust_total_lowmem();
 144 #endif /* CONFIG_FSL_BOOKE */
 145
 146         if (total_lowmem > __max_low_memory) {
 147                 total_lowmem = __max_low_memory;
 148                 lowmem_end_addr = memstart_addr + total_lowmem;
 149 #ifndef CONFIG_HIGHMEM
 150                 total_memory = total_lowmem;
 151                 memblock_enforce_memory_limit(total_lowmem);
 152                 memblock_analyze();
 153 #endif /* CONFIG_HIGHMEM */
 154         }
 155
 156         /* Initialize the MMU hardware */
 157         if (ppc_md.progress)
 158                 ppc_md.progress("MMU:hw init", 0x300);
 159         MMU_init_hw();
 160
 161         /* Map in all of RAM starting at KERNELBASE */
 162         if (ppc_md.progress)
 163                 ppc_md.progress("MMU:mapin", 0x301);
 164         mapin_ram();
 165
 166         /* Initialize early top-down ioremap allocator */
 167         ioremap_bot = IOREMAP_TOP;
 168
 169         /* Map in I/O resources */
 170         if (ppc_md.progress)
 171                 ppc_md.progress("MMU:setio", 0x302);
 172
 173         if (ppc_md.progress)
 174                 ppc_md.progress("MMU:exit", 0x211);
 175
 176         /* From now on, btext is no longer BAT mapped if it was at all */
 177 #ifdef CONFIG_BOOTX_TEXT
 178         btext_unmap();
 179 #endif
 180
 181         /* Shortly after that, the entire linear mapping will be available */
 182         memblock_set_current_limit(lowmem_end_addr);
 183 }
 184
 185 /* This is only called until mem_init is done. */
 186 void __init *early_get_page(void)
 187 {
 188         if (init_bootmem_done)
 189                 return alloc_bootmem_pages(PAGE_SIZE);
 190         else
 191                 return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
 192 }
 193
 194 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
 195 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 196                                 phys_addr_t first_memblock_size)
 197 {
 198         /* We don't currently support the first MEMBLOCK not mapping 0
 199          * physical on those processors
 200          */
 201         BUG_ON(first_memblock_base != 0);
 202
 203         /* 8xx can only access 8MB at the moment */
 204         memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
 205 }
 206 #endif /* CONFIG_8xx */