LXR linux/arch/powerpc/mm/init

   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
  57phys_addr_t total_memory;
  58phys_addr_t total_lowmem;
  59
  60phys_addr_t memstart_addr = (phys_addr_t)~0ull;
  61EXPORT_SYMBOL(memstart_addr);
  62phys_addr_t kernstart_addr;
  63EXPORT_SYMBOL(kernstart_addr);
  64phys_addr_t lowmem_end_addr;
  65
  66int boot_mapsize;
  67#ifdef CONFIG_PPC_PMAC
  68unsigned long agp_special_page;
  69EXPORT_SYMBOL(agp_special_page);
  70#endif
  71
  72void MMU_init(void);
  73
  74/* XXX should be in current.h  -- paulus */
  75extern 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 */
  82int __map_without_bats;
  83int __map_without_ltlbs;
  84
  85/* max amount of low RAM to map in */
  86unsigned 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 */
  92phys_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 */
  97void 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 */
 118void __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. */
 186void __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 */
 200static 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
 217void 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
 232void 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
 245