3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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)
10 * Derived from "arch/i386/mm/init.c"
11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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.
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>
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>
35 #include <asm/pgalloc.h>
38 #include <asm/pgtable.h>
41 #include <asm/machdep.h>
42 #include <asm/btext.h>
44 #include <asm/sections.h>
45 #include <asm/system.h>
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"
55 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
57 phys_addr_t total_memory;
58 phys_addr_t total_lowmem;
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;
67 #ifdef CONFIG_PPC_PMAC
68 unsigned long agp_special_page;
69 EXPORT_SYMBOL(agp_special_page);
74 /* XXX should be in current.h -- paulus */
75 extern struct task_struct *current_set[NR_CPUS];
78 * this tells the system to map all of ram with the segregs
79 * (i.e. page tables) instead of the bats.
82 int __map_without_bats;
83 int __map_without_ltlbs;
85 /* max amount of low RAM to map in */
86 unsigned long __max_low_memory = MAX_LOW_MEM;
89 * address of the limit of what is accessible with initial MMU setup -
90 * 256MB usually, but only 16MB on 601.
92 phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
95 * Check for command-line options that affect what MMU_init will do.
99 /* Check for nobats option (used in mapin_ram). */
100 if (strstr(cmd_line, "nobats")) {
101 __map_without_bats = 1;
104 if (strstr(cmd_line, "noltlbs")) {
105 __map_without_ltlbs = 1;
107 #ifdef CONFIG_DEBUG_PAGEALLOC
108 __map_without_bats = 1;
109 __map_without_ltlbs = 1;
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.
118 void __init MMU_init(void)
121 ppc_md.progress("MMU:enter", 0x111);
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;
130 /* parse args from command line */
133 if (lmb.memory.cnt > 1) {
137 printk(KERN_WARNING "Only using first contiguous memory region");
143 total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
144 lowmem_end_addr = memstart_addr + total_lowmem;
146 #ifdef CONFIG_FSL_BOOKE
147 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
148 * entries, so we need to adjust lowmem to match the amount we can map
149 * in the fixed entries */
150 adjust_total_lowmem();
151 #endif /* CONFIG_FSL_BOOKE */
153 if (total_lowmem > __max_low_memory) {
154 total_lowmem = __max_low_memory;
155 lowmem_end_addr = memstart_addr + total_lowmem;
156 #ifndef CONFIG_HIGHMEM
157 total_memory = total_lowmem;
158 lmb_enforce_memory_limit(lowmem_end_addr);
160 #endif /* CONFIG_HIGHMEM */
163 /* Initialize the MMU hardware */
165 ppc_md.progress("MMU:hw init", 0x300);
168 /* Map in all of RAM starting at KERNELBASE */
170 ppc_md.progress("MMU:mapin", 0x301);
173 /* Initialize early top-down ioremap allocator */
174 ioremap_bot = IOREMAP_TOP;
176 /* Map in I/O resources */
178 ppc_md.progress("MMU:setio", 0x302);
181 ppc_md.progress("MMU:exit", 0x211);
183 /* From now on, btext is no longer BAT mapped if it was at all */
184 #ifdef CONFIG_BOOTX_TEXT
189 /* This is only called until mem_init is done. */
190 void __init *early_get_page(void)
194 if (init_bootmem_done) {
195 p = alloc_bootmem_pages(PAGE_SIZE);
197 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
198 __initial_memory_limit_addr));
203 /* Free up now-unused memory */
204 static void free_sec(unsigned long start, unsigned long end, const char *name)
206 unsigned long cnt = 0;
208 while (start < end) {
209 ClearPageReserved(virt_to_page(start));
210 init_page_count(virt_to_page(start));
216 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
217 totalram_pages += cnt;
221 void free_initmem(void)
223 #define FREESEC(TYPE) \
224 free_sec((unsigned long)(&__ ## TYPE ## _begin), \
225 (unsigned long)(&__ ## TYPE ## _end), \
228 printk ("Freeing unused kernel memory:");
231 ppc_md.progress = NULL;
235 #ifdef CONFIG_BLK_DEV_INITRD
236 void free_initrd_mem(unsigned long start, unsigned long end)
239 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
240 for (; start < end; start += PAGE_SIZE) {
241 ClearPageReserved(virt_to_page(start));
242 init_page_count(virt_to_page(start));