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 ammount 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 /* max amount of low RAM to map in */
  86 unsigned long __max_low_memory = MAX_LOW_MEM;
  87
  88 /*
  89  * address of the limit of what is accessible with initial MMU setup -
  90  * 256MB usually, but only 16MB on 601.
  91  */
  92 phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
  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         /* 601 can only access 16MB at the moment */
 124         if (PVR_VER(mfspr(SPRN_PVR)) == 1)
 125                 __initial_memory_limit_addr = 0x01000000;
 126         /* 8xx can only access 8MB at the moment */
 127         if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
 128                 __initial_memory_limit_addr = 0x00800000;
 129
 130         /* parse args from command line */
 131         MMU_setup();
 132
 133         if (lmb.memory.cnt > 1) {
 134                 lmb.memory.cnt = 1;
 135                 lmb_analyze();
 136                 printk(KERN_WARNING "Only using first contiguous memory region");
 137         }
 138
 139         total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
 140         lowmem_end_addr = memstart_addr + total_lowmem;
 141
 142 #ifdef CONFIG_FSL_BOOKE
 143         /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
 144          * entries, so we need to adjust lowmem to match the amount we can map
 145          * in the fixed entries */
 146         adjust_total_lowmem();
 147 #endif /* CONFIG_FSL_BOOKE */
 148
 149         if (total_lowmem > __max_low_memory) {
 150                 total_lowmem = __max_low_memory;
 151                 lowmem_end_addr = memstart_addr + total_lowmem;
 152 #ifndef CONFIG_HIGHMEM
 153                 total_memory = total_lowmem;
 154                 lmb_enforce_memory_limit(lowmem_end_addr);
 155                 lmb_analyze();
 156 #endif /* CONFIG_HIGHMEM */
 157         }
 158
 159         /* Initialize the MMU hardware */
 160         if (ppc_md.progress)
 161                 ppc_md.progress("MMU:hw init", 0x300);
 162         MMU_init_hw();
 163
 164         /* Map in all of RAM starting at KERNELBASE */
 165         if (ppc_md.progress)
 166                 ppc_md.progress("MMU:mapin", 0x301);
 167         mapin_ram();
 168
 169         /* Initialize early top-down ioremap allocator */
 170         ioremap_bot = IOREMAP_TOP;
 171
 172         /* Map in I/O resources */
 173         if (ppc_md.progress)
 174                 ppc_md.progress("MMU:setio", 0x302);
 175
 176         if (ppc_md.progress)
 177                 ppc_md.progress("MMU:exit", 0x211);
 178
 179         /* From now on, btext is no longer BAT mapped if it was at all */
 180 #ifdef CONFIG_BOOTX_TEXT
 181         btext_unmap();
 182 #endif
 183 }
 184
 185 /* This is only called until mem_init is done. */
 186 void __init *early_get_page(void)
 187 {
 188         void *p;
 189
 190         if (init_bootmem_done) {
 191                 p = alloc_bootmem_pages(PAGE_SIZE);
 192         } else {
 193                 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
 194                                         __initial_memory_limit_addr));
 195         }
 196         return p;
 197 }
 198
 199 /* Free up now-unused memory */
 200 static void free_sec(unsigned long start, unsigned long end, const char *name)
 201 {
 202         unsigned long cnt = 0;
 203
 204         while (start < end) {
 205                 ClearPageReserved(virt_to_page(start));
 206                 init_page_count(virt_to_page(start));
 207                 free_page(start);
 208                 cnt++;
 209                 start += PAGE_SIZE;
 210         }
 211         if (cnt) {
 212                 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
 213                 totalram_pages += cnt;
 214         }
 215 }
 216
 217 void free_initmem(void)
 218 {
 219 #define FREESEC(TYPE) \
 220         free_sec((unsigned long)(&__ ## TYPE ## _begin), \
 221                  (unsigned long)(&__ ## TYPE ## _end), \
 222                  #TYPE);
 223
 224         printk ("Freeing unused kernel memory:");
 225         FREESEC(init);
 226         printk("\n");
 227         ppc_md.progress = NULL;
 228 #undef FREESEC
 229 }
 230
 231 #ifdef CONFIG_BLK_DEV_INITRD
 232 void free_initrd_mem(unsigned long start, unsigned long end)
 233 {
 234         if (start < end)
 235                 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
 236         for (; start < end; start += PAGE_SIZE) {
 237                 ClearPageReserved(virt_to_page(start));
 238                 init_page_count(virt_to_page(start));
 239                 free_page(start);
 240                 totalram_pages++;
 241         }
 242 }
 243 #endif
 244