Linux 2.6.17.7
[linux/fpc-iii.git] / arch / ppc / mm / ppc_mmu.c
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1 /*
2 * This file contains the routines for handling the MMU on those
3 * PowerPC implementations where the MMU substantially follows the
4 * architecture specification. This includes the 6xx, 7xx, 7xxx,
5 * 8260, and 83xx implementations but excludes the 8xx and 4xx.
6 * -- paulus
8 * Derived from arch/ppc/mm/init.c:
9 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
11 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
12 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
13 * Copyright (C) 1996 Paul Mackerras
14 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
16 * Derived from "arch/i386/mm/init.c"
17 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
19 * This program is free software; you can redistribute it and/or
20 * modify it under the terms of the GNU General Public License
21 * as published by the Free Software Foundation; either version
22 * 2 of the License, or (at your option) any later version.
26 #include <linux/config.h>
27 #include <linux/kernel.h>
28 #include <linux/mm.h>
29 #include <linux/init.h>
30 #include <linux/highmem.h>
32 #include <asm/prom.h>
33 #include <asm/mmu.h>
34 #include <asm/machdep.h>
36 #include "mmu_decl.h"
37 #include "mem_pieces.h"
39 PTE *Hash, *Hash_end;
40 unsigned long Hash_size, Hash_mask;
41 unsigned long _SDR1;
43 union ubat { /* BAT register values to be loaded */
44 BAT bat;
45 u32 word[2];
46 } BATS[4][2]; /* 4 pairs of IBAT, DBAT */
48 struct batrange { /* stores address ranges mapped by BATs */
49 unsigned long start;
50 unsigned long limit;
51 unsigned long phys;
52 } bat_addrs[4];
55 * Return PA for this VA if it is mapped by a BAT, or 0
57 unsigned long v_mapped_by_bats(unsigned long va)
59 int b;
60 for (b = 0; b < 4; ++b)
61 if (va >= bat_addrs[b].start && va < bat_addrs[b].limit)
62 return bat_addrs[b].phys + (va - bat_addrs[b].start);
63 return 0;
67 * Return VA for a given PA or 0 if not mapped
69 unsigned long p_mapped_by_bats(unsigned long pa)
71 int b;
72 for (b = 0; b < 4; ++b)
73 if (pa >= bat_addrs[b].phys
74 && pa < (bat_addrs[b].limit-bat_addrs[b].start)
75 +bat_addrs[b].phys)
76 return bat_addrs[b].start+(pa-bat_addrs[b].phys);
77 return 0;
80 unsigned long __init mmu_mapin_ram(void)
82 unsigned long tot, bl, done;
83 unsigned long max_size = (256<<20);
84 unsigned long align;
86 if (__map_without_bats)
87 return 0;
89 /* Set up BAT2 and if necessary BAT3 to cover RAM. */
91 /* Make sure we don't map a block larger than the
92 smallest alignment of the physical address. */
93 /* alignment of PPC_MEMSTART */
94 align = ~(PPC_MEMSTART-1) & PPC_MEMSTART;
95 /* set BAT block size to MIN(max_size, align) */
96 if (align && align < max_size)
97 max_size = align;
99 tot = total_lowmem;
100 for (bl = 128<<10; bl < max_size; bl <<= 1) {
101 if (bl * 2 > tot)
102 break;
105 setbat(2, KERNELBASE, PPC_MEMSTART, bl, _PAGE_RAM);
106 done = (unsigned long)bat_addrs[2].limit - KERNELBASE + 1;
107 if ((done < tot) && !bat_addrs[3].limit) {
108 /* use BAT3 to cover a bit more */
109 tot -= done;
110 for (bl = 128<<10; bl < max_size; bl <<= 1)
111 if (bl * 2 > tot)
112 break;
113 setbat(3, KERNELBASE+done, PPC_MEMSTART+done, bl, _PAGE_RAM);
114 done = (unsigned long)bat_addrs[3].limit - KERNELBASE + 1;
117 return done;
121 * Set up one of the I/D BAT (block address translation) register pairs.
122 * The parameters are not checked; in particular size must be a power
123 * of 2 between 128k and 256M.
125 void __init setbat(int index, unsigned long virt, unsigned long phys,
126 unsigned int size, int flags)
128 unsigned int bl;
129 int wimgxpp;
130 union ubat *bat = BATS[index];
132 if (((flags & _PAGE_NO_CACHE) == 0) &&
133 cpu_has_feature(CPU_FTR_NEED_COHERENT))
134 flags |= _PAGE_COHERENT;
136 bl = (size >> 17) - 1;
137 if (PVR_VER(mfspr(SPRN_PVR)) != 1) {
138 /* 603, 604, etc. */
139 /* Do DBAT first */
140 wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
141 | _PAGE_COHERENT | _PAGE_GUARDED);
142 wimgxpp |= (flags & _PAGE_RW)? BPP_RW: BPP_RX;
143 bat[1].word[0] = virt | (bl << 2) | 2; /* Vs=1, Vp=0 */
144 bat[1].word[1] = phys | wimgxpp;
145 #ifndef CONFIG_KGDB /* want user access for breakpoints */
146 if (flags & _PAGE_USER)
147 #endif
148 bat[1].bat.batu.vp = 1;
149 if (flags & _PAGE_GUARDED) {
150 /* G bit must be zero in IBATs */
151 bat[0].word[0] = bat[0].word[1] = 0;
152 } else {
153 /* make IBAT same as DBAT */
154 bat[0] = bat[1];
156 } else {
157 /* 601 cpu */
158 if (bl > BL_8M)
159 bl = BL_8M;
160 wimgxpp = flags & (_PAGE_WRITETHRU | _PAGE_NO_CACHE
161 | _PAGE_COHERENT);
162 wimgxpp |= (flags & _PAGE_RW)?
163 ((flags & _PAGE_USER)? PP_RWRW: PP_RWXX): PP_RXRX;
164 bat->word[0] = virt | wimgxpp | 4; /* Ks=0, Ku=1 */
165 bat->word[1] = phys | bl | 0x40; /* V=1 */
168 bat_addrs[index].start = virt;
169 bat_addrs[index].limit = virt + ((bl + 1) << 17) - 1;
170 bat_addrs[index].phys = phys;
174 * Initialize the hash table and patch the instructions in hashtable.S.
176 void __init MMU_init_hw(void)
178 unsigned int hmask, mb, mb2;
179 unsigned int n_hpteg, lg_n_hpteg;
181 extern unsigned int hash_page_patch_A[];
182 extern unsigned int hash_page_patch_B[], hash_page_patch_C[];
183 extern unsigned int hash_page[];
184 extern unsigned int flush_hash_patch_A[], flush_hash_patch_B[];
186 if (!cpu_has_feature(CPU_FTR_HPTE_TABLE)) {
188 * Put a blr (procedure return) instruction at the
189 * start of hash_page, since we can still get DSI
190 * exceptions on a 603.
192 hash_page[0] = 0x4e800020;
193 flush_icache_range((unsigned long) &hash_page[0],
194 (unsigned long) &hash_page[1]);
195 return;
198 if ( ppc_md.progress ) ppc_md.progress("hash:enter", 0x105);
200 #define LG_HPTEG_SIZE 6 /* 64 bytes per HPTEG */
201 #define SDR1_LOW_BITS ((n_hpteg - 1) >> 10)
202 #define MIN_N_HPTEG 1024 /* min 64kB hash table */
205 * Allow 1 HPTE (1/8 HPTEG) for each page of memory.
206 * This is less than the recommended amount, but then
207 * Linux ain't AIX.
209 n_hpteg = total_memory / (PAGE_SIZE * 8);
210 if (n_hpteg < MIN_N_HPTEG)
211 n_hpteg = MIN_N_HPTEG;
212 lg_n_hpteg = __ilog2(n_hpteg);
213 if (n_hpteg & (n_hpteg - 1)) {
214 ++lg_n_hpteg; /* round up if not power of 2 */
215 n_hpteg = 1 << lg_n_hpteg;
217 Hash_size = n_hpteg << LG_HPTEG_SIZE;
220 * Find some memory for the hash table.
222 if ( ppc_md.progress ) ppc_md.progress("hash:find piece", 0x322);
223 Hash = mem_pieces_find(Hash_size, Hash_size);
224 cacheable_memzero(Hash, Hash_size);
225 _SDR1 = __pa(Hash) | SDR1_LOW_BITS;
227 Hash_end = (PTE *) ((unsigned long)Hash + Hash_size);
229 printk("Total memory = %ldMB; using %ldkB for hash table (at %p)\n",
230 total_memory >> 20, Hash_size >> 10, Hash);
234 * Patch up the instructions in hashtable.S:create_hpte
236 if ( ppc_md.progress ) ppc_md.progress("hash:patch", 0x345);
237 Hash_mask = n_hpteg - 1;
238 hmask = Hash_mask >> (16 - LG_HPTEG_SIZE);
239 mb2 = mb = 32 - LG_HPTEG_SIZE - lg_n_hpteg;
240 if (lg_n_hpteg > 16)
241 mb2 = 16 - LG_HPTEG_SIZE;
243 hash_page_patch_A[0] = (hash_page_patch_A[0] & ~0xffff)
244 | ((unsigned int)(Hash) >> 16);
245 hash_page_patch_A[1] = (hash_page_patch_A[1] & ~0x7c0) | (mb << 6);
246 hash_page_patch_A[2] = (hash_page_patch_A[2] & ~0x7c0) | (mb2 << 6);
247 hash_page_patch_B[0] = (hash_page_patch_B[0] & ~0xffff) | hmask;
248 hash_page_patch_C[0] = (hash_page_patch_C[0] & ~0xffff) | hmask;
251 * Ensure that the locations we've patched have been written
252 * out from the data cache and invalidated in the instruction
253 * cache, on those machines with split caches.
255 flush_icache_range((unsigned long) &hash_page_patch_A[0],
256 (unsigned long) &hash_page_patch_C[1]);
259 * Patch up the instructions in hashtable.S:flush_hash_page
261 flush_hash_patch_A[0] = (flush_hash_patch_A[0] & ~0xffff)
262 | ((unsigned int)(Hash) >> 16);
263 flush_hash_patch_A[1] = (flush_hash_patch_A[1] & ~0x7c0) | (mb << 6);
264 flush_hash_patch_A[2] = (flush_hash_patch_A[2] & ~0x7c0) | (mb2 << 6);
265 flush_hash_patch_B[0] = (flush_hash_patch_B[0] & ~0xffff) | hmask;
266 flush_icache_range((unsigned long) &flush_hash_patch_A[0],
267 (unsigned long) &flush_hash_patch_B[1]);
269 if ( ppc_md.progress ) ppc_md.progress("hash:done", 0x205);