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 *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
9 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
10 *
11 *  Derived from "arch/i386/mm/init.c"
12 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
13 *
14 *  This program is free software; you can redistribute it and/or
15 *  modify it under the terms of the GNU General Public License
16 *  as published by the Free Software Foundation; either version
17 *  2 of the License, or (at your option) any later version.
18 *
19 */
20
21#include <linux/module.h>
22#include <linux/sched.h>
23#include <linux/kernel.h>
24#include <linux/errno.h>
25#include <linux/string.h>
26#include <linux/types.h>
27#include <linux/mm.h>
28#include <linux/stddef.h>
29#include <linux/init.h>
30#include <linux/bootmem.h>
31#include <linux/highmem.h>
32#include <linux/initrd.h>
33#include <linux/pagemap.h>
34
35#include <asm/pgalloc.h>
36#include <asm/prom.h>
37#include <asm/io.h>
38#include <asm/mmu_context.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/prom.h>
46#include <asm/lmb.h>
47#include <asm/sections.h>
48
49#include "mmu_decl.h"
50
51#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
52/* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
53#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
54#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
55#endif
56#endif
57#define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE
58
59DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
60
61unsigned long total_memory;
62unsigned long total_lowmem;
63
64unsigned long ppc_memstart;
65unsigned long ppc_memoffset = PAGE_OFFSET;
66
67int boot_mapsize;
68#ifdef CONFIG_PPC_PMAC
69unsigned long agp_special_page;
70EXPORT_SYMBOL(agp_special_page);
71#endif
72
73#ifdef CONFIG_HIGHMEM
74pte_t *kmap_pte;
75pgprot_t kmap_prot;
76
77EXPORT_SYMBOL(kmap_prot);
78EXPORT_SYMBOL(kmap_pte);
79#endif
80
81void MMU_init(void);
82
83extern struct task_struct *current_set[NR_CPUS];
84
85extern int init_bootmem_done;
86
87/*
88 * this tells the system to map all of ram with the segregs
89 * (i.e. page tables) instead of the bats.
90 * -- Cort
91 */
92int __map_without_bats;
93int __map_without_ltlbs;
94
95/* max amount of low RAM to map in */
96unsigned long __max_low_memory = MAX_LOW_MEM;
97
98/*
99 * limit of what is accessible with initial MMU setup -
100 * 256MB usually, but only 16MB on 601.
101 */
102unsigned long __initial_memory_limit = 0x10000000;
103
104/*
105 * Check for command-line options that affect what MMU_init will do.
106 */
107void MMU_setup(void)
108{
109	/* Check for nobats option (used in mapin_ram). */
110	if (strstr(cmd_line, "nobats")) {
111		__map_without_bats = 1;
112	}
113
114	if (strstr(cmd_line, "noltlbs")) {
115		__map_without_ltlbs = 1;
116	}
117#ifdef CONFIG_DEBUG_PAGEALLOC
118	__map_without_bats = 1;
119	__map_without_ltlbs = 1;
120#endif
121}
122
123/*
124 * MMU_init sets up the basic memory mappings for the kernel,
125 * including both RAM and possibly some I/O regions,
126 * and sets up the page tables and the MMU hardware ready to go.
127 */
128void __init MMU_init(void)
129{
130	if (ppc_md.progress)
131		ppc_md.progress("MMU:enter", 0x111);
132
133	/* 601 can only access 16MB at the moment */
134	if (PVR_VER(mfspr(SPRN_PVR)) == 1)
135		__initial_memory_limit = 0x01000000;
136
137	/* parse args from command line */
138	MMU_setup();
139
140	if (lmb.memory.cnt > 1) {
141		lmb.memory.cnt = 1;
142		lmb_analyze();
143		printk(KERN_WARNING "Only using first contiguous memory region");
144	}
145
146	total_memory = lmb_end_of_DRAM();
147	total_lowmem = total_memory;
148
149#ifdef CONFIG_FSL_BOOKE
150	/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
151	 * entries, so we need to adjust lowmem to match the amount we can map
152	 * in the fixed entries */
153	adjust_total_lowmem();
154#endif /* CONFIG_FSL_BOOKE */
155
156	if (total_lowmem > __max_low_memory) {
157		total_lowmem = __max_low_memory;
158#ifndef CONFIG_HIGHMEM
159		total_memory = total_lowmem;
160		lmb_enforce_memory_limit(total_lowmem);
161		lmb_analyze();
162#endif /* CONFIG_HIGHMEM */
163	}
164
165	/* Initialize the MMU hardware */
166	if (ppc_md.progress)
167		ppc_md.progress("MMU:hw init", 0x300);
168	MMU_init_hw();
169
170	/* Map in all of RAM starting at KERNELBASE */
171	if (ppc_md.progress)
172		ppc_md.progress("MMU:mapin", 0x301);
173	mapin_ram();
174
175#ifdef CONFIG_HIGHMEM
176	ioremap_base = PKMAP_BASE;
177#else
178	ioremap_base = 0xfe000000UL;	/* for now, could be 0xfffff000 */
179#endif /* CONFIG_HIGHMEM */
180	ioremap_bot = ioremap_base;
181
182	/* Map in I/O resources */
183	if (ppc_md.progress)
184		ppc_md.progress("MMU:setio", 0x302);
185	if (ppc_md.setup_io_mappings)
186		ppc_md.setup_io_mappings();
187
188	/* Initialize the context management stuff */
189	mmu_context_init();
190
191	if (ppc_md.progress)
192		ppc_md.progress("MMU:exit", 0x211);
193
194	/* From now on, btext is no longer BAT mapped if it was at all */
195#ifdef CONFIG_BOOTX_TEXT
196	btext_unmap();
197#endif
198}
199
200/* This is only called until mem_init is done. */
201void __init *early_get_page(void)
202{
203	void *p;
204
205	if (init_bootmem_done) {
206		p = alloc_bootmem_pages(PAGE_SIZE);
207	} else {
208		p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
209					__initial_memory_limit));
210	}
211	return p;
212}
213
214/* Free up now-unused memory */
215static void free_sec(unsigned long start, unsigned long end, const char *name)
216{
217	unsigned long cnt = 0;
218
219	while (start < end) {
220		ClearPageReserved(virt_to_page(start));
221		init_page_count(virt_to_page(start));
222		free_page(start);
223		cnt++;
224		start += PAGE_SIZE;
225 	}
226	if (cnt) {
227		printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
228		totalram_pages += cnt;
229	}
230}
231
232void free_initmem(void)
233{
234#define FREESEC(TYPE) \
235	free_sec((unsigned long)(&__ ## TYPE ## _begin), \
236		 (unsigned long)(&__ ## TYPE ## _end), \
237		 #TYPE);
238
239	printk ("Freeing unused kernel memory:");
240	FREESEC(init);
241 	printk("\n");
242	ppc_md.progress = NULL;
243#undef FREESEC
244}
245
246#ifdef CONFIG_BLK_DEV_INITRD
247void free_initrd_mem(unsigned long start, unsigned long end)
248{
249	if (start < end)
250		printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
251	for (; start < end; start += PAGE_SIZE) {
252		ClearPageReserved(virt_to_page(start));
253		init_page_count(virt_to_page(start));
254		free_page(start);
255		totalram_pages++;
256	}
257}
258#endif
259