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/lmb.h>
  34
  35 #include <asm/pgalloc.h>
  36 #include <asm/prom.h>
  37 #include <asm/io.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/mmu.h>
  40 #include <asm/smp.h>
  41 #include <asm/machdep.h>
  42 #include <asm/btext.h>
  43 #include <asm/tlb.h>
  44 #include <asm/sections.h>
  45 #include <asm/system.h>
  46
  47 #include "mmu_decl.h"
  48
  49 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
  50 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
  51 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
  52 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
  53 #endif
  54 #endif
  55 #define MAX_LOW_MEM     CONFIG_LOWMEM_SIZE
  56
  57 phys_addr_t total_memory;
  58 phys_addr_t total_lowmem;
  59
  60 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  61 EXPORT_SYMBOL(memstart_addr);
  62 phys_addr_t kernstart_addr;
  63 EXPORT_SYMBOL(kernstart_addr);
  64 phys_addr_t lowmem_end_addr;
  65
  66 int boot_mapsize;
  67 #ifdef CONFIG_PPC_PMAC
  68 unsigned long agp_special_page;
  69 EXPORT_SYMBOL(agp_special_page);
  70 #endif
  71
  72 void MMU_init(void);
  73
  74 /* XXX should be in current.h  -- paulus */
  75 extern struct task_struct *current_set[NR_CPUS];
  76
  77 /*
  78  * this tells the system to map all of ram with the segregs
  79  * (i.e. page tables) instead of the bats.
  80  * -- Cort
  81  */
  82 int __map_without_bats;
  83 int __map_without_ltlbs;
  84
  85 /*
  86  * This tells the system to allow ioremapping memory marked as reserved.
  87  */
  88 int __allow_ioremap_reserved;
  89
  90 /* max amount of low RAM to map in */
  91 unsigned long __max_low_memory = MAX_LOW_MEM;
  92
  93 /*
  94  * address of the limit of what is accessible with initial MMU setup -
  95  * 256MB usually, but only 16MB on 601.
  96  */
  97 phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
  98
  99 /*
 100  * Check for command-line options that affect what MMU_init will do.
 101  */
 102 void MMU_setup(void)
 103 {
 104         /* Check for nobats option (used in mapin_ram). */
 105         if (strstr(cmd_line, "nobats")) {
 106                 __map_without_bats = 1;
 107         }
 108
 109         if (strstr(cmd_line, "noltlbs")) {
 110                 __map_without_ltlbs = 1;
 111         }
 112 #ifdef CONFIG_DEBUG_PAGEALLOC
 113         __map_without_bats = 1;
 114         __map_without_ltlbs = 1;
 115 #endif
 116 }
 117
 118 /*
 119  * MMU_init sets up the basic memory mappings for the kernel,
 120  * including both RAM and possibly some I/O regions,
 121  * and sets up the page tables and the MMU hardware ready to go.
 122  */
 123 void __init MMU_init(void)
 124 {
 125         if (ppc_md.progress)
 126                 ppc_md.progress("MMU:enter", 0x111);
 127
 128         /* 601 can only access 16MB at the moment */
 129         if (PVR_VER(mfspr(SPRN_PVR)) == 1)
 130                 __initial_memory_limit_addr = 0x01000000;
 131         /* 8xx can only access 8MB at the moment */
 132         if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
 133                 __initial_memory_limit_addr = 0x00800000;
 134
 135         /* parse args from command line */
 136         MMU_setup();
 137
 138         if (lmb.memory.cnt > 1) {
 139 #ifndef CONFIG_WII
 140                 lmb.memory.cnt = 1;
 141                 lmb_analyze();
 142                 printk(KERN_WARNING "Only using first contiguous memory region");
 143 #else
 144                 wii_memory_fixups();
 145 #endif
 146         }
 147
 148         total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
 149         lowmem_end_addr = memstart_addr + total_lowmem;
 150
 151 #ifdef CONFIG_FSL_BOOKE
 152         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 153          * entries, so we need to adjust lowmem to match the amount we can map
 154          * in the fixed entries */
 155         adjust_total_lowmem();
 156 #endif /* CONFIG_FSL_BOOKE */
 157
 158         if (total_lowmem > __max_low_memory) {
 159                 total_lowmem = __max_low_memory;
 160                 lowmem_end_addr = memstart_addr + total_lowmem;
 161 #ifndef CONFIG_HIGHMEM
 162                 total_memory = total_lowmem;
 163                 lmb_enforce_memory_limit(lowmem_end_addr);
 164                 lmb_analyze();
 165 #endif /* CONFIG_HIGHMEM */
 166         }
 167
 168         /* Initialize the MMU hardware */
 169         if (ppc_md.progress)
 170                 ppc_md.progress("MMU:hw init", 0x300);
 171         MMU_init_hw();
 172
 173         /* Map in all of RAM starting at KERNELBASE */
 174         if (ppc_md.progress)
 175                 ppc_md.progress("MMU:mapin", 0x301);
 176         mapin_ram();
 177
 178         /* Initialize early top-down ioremap allocator */
 179         ioremap_bot = IOREMAP_TOP;
 180
 181         /* Map in I/O resources */
 182         if (ppc_md.progress)
 183                 ppc_md.progress("MMU:setio", 0x302);
 184
 185         if (ppc_md.progress)
 186                 ppc_md.progress("MMU:exit", 0x211);
 187
 188         /* From now on, btext is no longer BAT mapped if it was at all */
 189 #ifdef CONFIG_BOOTX_TEXT
 190         btext_unmap();
 191 #endif
 192 }
 193
 194 /* This is only called until mem_init is done. */
 195 void __init *early_get_page(void)
 196 {
 197         void *p;
 198
 199         if (init_bootmem_done) {
 200                 p = alloc_bootmem_pages(PAGE_SIZE);
 201         } else {
 202                 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
 203                                         __initial_memory_limit_addr));
 204         }
 205         return p;
 206 }
 207
 208 /* Free up now-unused memory */
 209 static void free_sec(unsigned long start, unsigned long end, const char *name)
 210 {
 211         unsigned long cnt = 0;
 212
 213         while (start < end) {
 214                 ClearPageReserved(virt_to_page(start));
 215                 init_page_count(virt_to_page(start));
 216                 free_page(start);
 217                 cnt++;
 218                 start += PAGE_SIZE;
 219         }
 220         if (cnt) {
 221                 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
 222                 totalram_pages += cnt;
 223         }
 224 }
 225
 226 void free_initmem(void)
 227 {
 228 #define FREESEC(TYPE) \
 229         free_sec((unsigned long)(&__ ## TYPE ## _begin), \
 230                  (unsigned long)(&__ ## TYPE ## _end), \
 231                  #TYPE);
 232
 233         printk ("Freeing unused kernel memory:");
 234         FREESEC(init);
 235         printk("\n");
 236         ppc_md.progress = NULL;
 237 #undef FREESEC
 238 }
 239
 240 #ifdef CONFIG_BLK_DEV_INITRD
 241 void free_initrd_mem(unsigned long start, unsigned long end)
 242 {
 243         if (start < end)
 244                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 245         for (; start < end; start += PAGE_SIZE) {
 246                 ClearPageReserved(virt_to_page(start));
 247                 init_page_count(virt_to_page(start));
 248                 free_page(start);
 249                 totalram_pages++;
 250         }
 251 }
 252 #endif
 253