File: /usr/src/linux/arch/m68k/mm/motorola.c
1 /*
2 * linux/arch/m68k/motorola.c
3 *
4 * Routines specific to the Motorola MMU, originally from:
5 * linux/arch/m68k/init.c
6 * which are Copyright (C) 1995 Hamish Macdonald
7 *
8 * Moved 8/20/1999 Sam Creasey
9 */
10
11 #include <linux/config.h>
12 #include <linux/signal.h>
13 #include <linux/sched.h>
14 #include <linux/mm.h>
15 #include <linux/swap.h>
16 #include <linux/kernel.h>
17 #include <linux/string.h>
18 #include <linux/types.h>
19 #include <linux/init.h>
20 #include <linux/bootmem.h>
21 #ifdef CONFIG_BLK_DEV_RAM
22 #include <linux/blk.h>
23 #endif
24
25 #include <asm/setup.h>
26 #include <asm/uaccess.h>
27 #include <asm/page.h>
28 #include <asm/pgalloc.h>
29 #include <asm/system.h>
30 #include <asm/machdep.h>
31 #include <asm/io.h>
32 #include <asm/dma.h>
33 #ifdef CONFIG_ATARI
34 #include <asm/atari_stram.h>
35 #endif
36
37 #undef DEBUG
38
39 #ifndef mm_cachebits
40 /*
41 * Bits to add to page descriptors for "normal" caching mode.
42 * For 68020/030 this is 0.
43 * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
44 */
45 unsigned long mm_cachebits = 0;
46 #endif
47
48 static pte_t * __init kernel_page_table(void)
49 {
50 pte_t *ptablep;
51
52 ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
53
54 clear_page(ptablep);
55 __flush_page_to_ram((unsigned long) ptablep);
56 flush_tlb_kernel_page((unsigned long) ptablep);
57 nocache_page ((unsigned long)ptablep);
58
59 return ptablep;
60 }
61
62 static pmd_t *last_pgtable __initdata = NULL;
63 pmd_t *zero_pgtable __initdata = NULL;
64
65 static pmd_t * __init kernel_ptr_table(void)
66 {
67 if (!last_pgtable) {
68 unsigned long pmd, last;
69 int i;
70
71 /* Find the last ptr table that was used in head.S and
72 * reuse the remaining space in that page for further
73 * ptr tables.
74 */
75 last = (unsigned long)kernel_pg_dir;
76 for (i = 0; i < PTRS_PER_PGD; i++) {
77 if (!pgd_present(kernel_pg_dir[i]))
78 continue;
79 pmd = __pgd_page(kernel_pg_dir[i]);
80 if (pmd > last)
81 last = pmd;
82 }
83
84 last_pgtable = (pmd_t *)last;
85 #ifdef DEBUG
86 printk("kernel_ptr_init: %p\n", last_pgtable);
87 #endif
88 }
89
90 if (((unsigned long)(last_pgtable + PTRS_PER_PMD) & ~PAGE_MASK) == 0) {
91 last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
92
93 clear_page(last_pgtable);
94 __flush_page_to_ram((unsigned long)last_pgtable);
95 flush_tlb_kernel_page((unsigned long)last_pgtable);
96 nocache_page((unsigned long)last_pgtable);
97 } else
98 last_pgtable += PTRS_PER_PMD;
99
100 return last_pgtable;
101 }
102
103 static unsigned long __init
104 map_chunk (unsigned long addr, long size)
105 {
106 #define PTRTREESIZE (256*1024)
107 #define ROOTTREESIZE (32*1024*1024)
108 static unsigned long virtaddr = PAGE_OFFSET;
109 unsigned long physaddr;
110 pgd_t *pgd_dir;
111 pmd_t *pmd_dir;
112 pte_t *pte_dir;
113
114 physaddr = (addr | m68k_supervisor_cachemode |
115 _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
116 if (CPU_IS_040_OR_060)
117 physaddr |= _PAGE_GLOBAL040;
118
119 while (size > 0) {
120 #ifdef DEBUG
121 if (!(virtaddr & (PTRTREESIZE-1)))
122 printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
123 virtaddr);
124 #endif
125 pgd_dir = pgd_offset_k(virtaddr);
126 if (virtaddr && CPU_IS_020_OR_030) {
127 if (!(virtaddr & (ROOTTREESIZE-1)) &&
128 size >= ROOTTREESIZE) {
129 #ifdef DEBUG
130 printk ("[very early term]");
131 #endif
132 pgd_val(*pgd_dir) = physaddr;
133 size -= ROOTTREESIZE;
134 virtaddr += ROOTTREESIZE;
135 physaddr += ROOTTREESIZE;
136 continue;
137 }
138 }
139 if (!pgd_present(*pgd_dir)) {
140 pmd_dir = kernel_ptr_table();
141 #ifdef DEBUG
142 printk ("[new pointer %p]", pmd_dir);
143 #endif
144 pgd_set(pgd_dir, pmd_dir);
145 } else
146 pmd_dir = pmd_offset(pgd_dir, virtaddr);
147
148 if (CPU_IS_020_OR_030) {
149 if (virtaddr) {
150 #ifdef DEBUG
151 printk ("[early term]");
152 #endif
153 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
154 physaddr += PTRTREESIZE;
155 } else {
156 int i;
157 #ifdef DEBUG
158 printk ("[zero map]");
159 #endif
160 zero_pgtable = kernel_ptr_table();
161 pte_dir = (pte_t *)zero_pgtable;
162 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
163 _PAGE_TABLE | _PAGE_ACCESSED;
164 pte_val(*pte_dir++) = 0;
165 physaddr += PAGE_SIZE;
166 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
167 pte_val(*pte_dir++) = physaddr;
168 }
169 size -= PTRTREESIZE;
170 virtaddr += PTRTREESIZE;
171 } else {
172 if (!pmd_present(*pmd_dir)) {
173 #ifdef DEBUG
174 printk ("[new table]");
175 #endif
176 pte_dir = kernel_page_table();
177 pmd_set(pmd_dir, pte_dir);
178 }
179 pte_dir = pte_offset(pmd_dir, virtaddr);
180
181 if (virtaddr) {
182 if (!pte_present(*pte_dir))
183 pte_val(*pte_dir) = physaddr;
184 } else
185 pte_val(*pte_dir) = 0;
186 size -= PAGE_SIZE;
187 virtaddr += PAGE_SIZE;
188 physaddr += PAGE_SIZE;
189 }
190
191 }
192 #ifdef DEBUG
193 printk("\n");
194 #endif
195
196 return virtaddr;
197 }
198
199 extern unsigned long empty_bad_page_table;
200 extern unsigned long empty_bad_page;
201
202 /*
203 * paging_init() continues the virtual memory environment setup which
204 * was begun by the code in arch/head.S.
205 */
206 void __init paging_init(void)
207 {
208 int chunk;
209 unsigned long mem_avail = 0;
210 unsigned long zones_size[3] = { 0, };
211
212 #ifdef DEBUG
213 {
214 extern unsigned long availmem;
215 printk ("start of paging_init (%p, %lx, %lx, %lx)\n",
216 kernel_pg_dir, availmem, start_mem, end_mem);
217 }
218 #endif
219
220 /* Fix the cache mode in the page descriptors for the 680[46]0. */
221 if (CPU_IS_040_OR_060) {
222 int i;
223 #ifndef mm_cachebits
224 mm_cachebits = _PAGE_CACHE040;
225 #endif
226 for (i = 0; i < 16; i++)
227 pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
228 }
229 /* Fix the PAGE_NONE value. */
230 if (CPU_IS_040_OR_060) {
231 /* On the 680[46]0 we can use the _PAGE_SUPER bit. */
232 pgprot_val(protection_map[0]) |= _PAGE_SUPER;
233 pgprot_val(protection_map[VM_SHARED]) |= _PAGE_SUPER;
234 } else {
235 /* Otherwise we must fake it. */
236 pgprot_val(protection_map[0]) &= ~_PAGE_PRESENT;
237 pgprot_val(protection_map[0]) |= _PAGE_FAKE_SUPER;
238 pgprot_val(protection_map[VM_SHARED]) &= ~_PAGE_PRESENT;
239 pgprot_val(protection_map[VM_SHARED]) |= _PAGE_FAKE_SUPER;
240 }
241
242 /*
243 * Map the physical memory available into the kernel virtual
244 * address space. It may allocate some memory for page
245 * tables and thus modify availmem.
246 */
247
248 for (chunk = 0; chunk < m68k_num_memory; chunk++) {
249 mem_avail = map_chunk (m68k_memory[chunk].addr,
250 m68k_memory[chunk].size);
251
252 }
253
254 flush_tlb_all();
255 #ifdef DEBUG
256 printk ("memory available is %ldKB\n", mem_avail >> 10);
257 printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
258 start_mem, end_mem);
259 #endif
260
261 /*
262 * initialize the bad page table and bad page to point
263 * to a couple of allocated pages
264 */
265 empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
266 empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
267 empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
268 memset((void *)empty_zero_page, 0, PAGE_SIZE);
269
270 /*
271 * Set up SFC/DFC registers (user data space)
272 */
273 set_fs (USER_DS);
274
275 #ifdef DEBUG
276 printk ("before free_area_init\n");
277 #endif
278 zones_size[0] = (mach_max_dma_address < (unsigned long)high_memory ?
279 mach_max_dma_address : (unsigned long)high_memory);
280 zones_size[1] = (unsigned long)high_memory - zones_size[0];
281
282 zones_size[0] = (zones_size[0] - PAGE_OFFSET) >> PAGE_SHIFT;
283 zones_size[1] >>= PAGE_SHIFT;
284
285 free_area_init(zones_size);
286 }
287
288 extern char __init_begin, __init_end;
289 extern unsigned long totalram_pages;
290
291 void free_initmem(void)
292 {
293 unsigned long addr;
294
295 addr = (unsigned long)&__init_begin;
296 for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
297 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
298 set_page_count(virt_to_page(addr), 1);
299 free_page(addr);
300 totalram_pages++;
301 }
302 }
303
304
305