/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#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
 58phys_addr_t total_memory;
 59phys_addr_t total_lowmem;
 60
 61phys_addr_t memstart_addr = (phys_addr_t)~0ull;
 62EXPORT_SYMBOL(memstart_addr);
 63phys_addr_t kernstart_addr;
 64EXPORT_SYMBOL(kernstart_addr);
 65phys_addr_t lowmem_end_addr;
 66
 67int boot_mapsize;
 68#ifdef CONFIG_PPC_PMAC
 69unsigned long agp_special_page;
 70EXPORT_SYMBOL(agp_special_page);
 71#endif
 72
 73void MMU_init(void);
 74
 75/* XXX should be in current.h  -- paulus */
 76extern 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 */
 83int __map_without_bats;
 84int __map_without_ltlbs;
 85
 86/*
 87 * This tells the system to allow ioremapping memory marked as reserved.
 88 */
 89int __allow_ioremap_reserved;
 90
 91/* max amount of low RAM to map in */
 92unsigned long __max_low_memory = MAX_LOW_MEM;
 93
 94/*
 95 * address of the limit of what is accessible with initial MMU setup -
 96 * 256MB usually, but only 16MB on 601.
 97 */
 98phys_addr_t __initial_memory_limit_addr = (phys_addr_t)0x10000000;
 99
100/*
101 * Check for command-line options that affect what MMU_init will do.
102 */
103void MMU_setup(void)
104{
105	/* Check for nobats option (used in mapin_ram). */
106	if (strstr(cmd_line, "nobats")) {
107		__map_without_bats = 1;
108	}
109
110	if (strstr(cmd_line, "noltlbs")) {
111		__map_without_ltlbs = 1;
112	}
113#ifdef CONFIG_DEBUG_PAGEALLOC
114	__map_without_bats = 1;
115	__map_without_ltlbs = 1;
116#endif
117}
118
119/*
120 * MMU_init sets up the basic memory mappings for the kernel,
121 * including both RAM and possibly some I/O regions,
122 * and sets up the page tables and the MMU hardware ready to go.
123 */
124void __init MMU_init(void)
125{
126	if (ppc_md.progress)
127		ppc_md.progress("MMU:enter", 0x111);
128
129	/* 601 can only access 16MB at the moment */
130	if (PVR_VER(mfspr(SPRN_PVR)) == 1)
131		__initial_memory_limit_addr = 0x01000000;
132	/* 8xx can only access 8MB at the moment */
133	if (PVR_VER(mfspr(SPRN_PVR)) == 0x50)
134		__initial_memory_limit_addr = 0x00800000;
135
136	/* parse args from command line */
137	MMU_setup();
138
139	if (lmb.memory.cnt > 1) {
140#ifndef CONFIG_WII
141		lmb.memory.cnt = 1;
142		lmb_analyze();
143		printk(KERN_WARNING "Only using first contiguous memory region");
144#else
145		wii_memory_fixups();
146#endif
147	}
148
149	total_lowmem = total_memory = lmb_end_of_DRAM() - memstart_addr;
150	lowmem_end_addr = memstart_addr + total_lowmem;
151
152#ifdef CONFIG_FSL_BOOKE
153	/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
154	 * entries, so we need to adjust lowmem to match the amount we can map
155	 * in the fixed entries */
156	adjust_total_lowmem();
157#endif /* CONFIG_FSL_BOOKE */
158
159	if (total_lowmem > __max_low_memory) {
160		total_lowmem = __max_low_memory;
161		lowmem_end_addr = memstart_addr + total_lowmem;
162#ifndef CONFIG_HIGHMEM
163		total_memory = total_lowmem;
164		lmb_enforce_memory_limit(lowmem_end_addr);
165		lmb_analyze();
166#endif /* CONFIG_HIGHMEM */
167	}
168
169	/* Initialize the MMU hardware */
170	if (ppc_md.progress)
171		ppc_md.progress("MMU:hw init", 0x300);
172	MMU_init_hw();
173
174	/* Map in all of RAM starting at KERNELBASE */
175	if (ppc_md.progress)
176		ppc_md.progress("MMU:mapin", 0x301);
177	mapin_ram();
178
179	/* Initialize early top-down ioremap allocator */
180	ioremap_bot = IOREMAP_TOP;
181
182	/* Map in I/O resources */
183	if (ppc_md.progress)
184		ppc_md.progress("MMU:setio", 0x302);
185
186	if (ppc_md.progress)
187		ppc_md.progress("MMU:exit", 0x211);
188
189	/* From now on, btext is no longer BAT mapped if it was at all */
190#ifdef CONFIG_BOOTX_TEXT
191	btext_unmap();
192#endif
193}
194
195/* This is only called until mem_init is done. */
196void __init *early_get_page(void)
197{
198	void *p;
199
200	if (init_bootmem_done) {
201		p = alloc_bootmem_pages(PAGE_SIZE);
202	} else {
203		p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
204					__initial_memory_limit_addr));
205	}
206	return p;
207}
208
209/* Free up now-unused memory */
210static void free_sec(unsigned long start, unsigned long end, const char *name)
211{
212	unsigned long cnt = 0;
213
214	while (start < end) {
215		ClearPageReserved(virt_to_page(start));
216		init_page_count(virt_to_page(start));
217		free_page(start);
218		cnt++;
219		start += PAGE_SIZE;
220 	}
221	if (cnt) {
222		printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
223		totalram_pages += cnt;
224	}
225}
226
227void free_initmem(void)
228{
229#define FREESEC(TYPE) \
230	free_sec((unsigned long)(&__ ## TYPE ## _begin), \
231		 (unsigned long)(&__ ## TYPE ## _end), \
232		 #TYPE);
233
234	printk ("Freeing unused kernel memory:");
235	FREESEC(init);
236 	printk("\n");
237	ppc_md.progress = NULL;
238#undef FREESEC
239}
240
241#ifdef CONFIG_BLK_DEV_INITRD
242void free_initrd_mem(unsigned long start, unsigned long end)
243{
244	if (start < end)
245		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
246	for (; start < end; start += PAGE_SIZE) {
247		ClearPageReserved(virt_to_page(start));
248		init_page_count(virt_to_page(start));
249		free_page(start);
250		totalram_pages++;
251	}
252}
253#endif
254