Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[linux-2.6] / 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/module.h>
13 #include <linux/signal.h>
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/swap.h>
17 #include <linux/kernel.h>
18 #include <linux/string.h>
19 #include <linux/types.h>
20 #include <linux/init.h>
21 #include <linux/bootmem.h>
22
23 #include <asm/setup.h>
24 #include <asm/uaccess.h>
25 #include <asm/page.h>
26 #include <asm/pgalloc.h>
27 #include <asm/system.h>
28 #include <asm/machdep.h>
29 #include <asm/io.h>
30 #include <asm/dma.h>
31 #ifdef CONFIG_ATARI
32 #include <asm/atari_stram.h>
33 #endif
34
35 #undef DEBUG
36
37 #ifndef mm_cachebits
38 /*
39  * Bits to add to page descriptors for "normal" caching mode.
40  * For 68020/030 this is 0.
41  * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
42  */
43 unsigned long mm_cachebits;
44 EXPORT_SYMBOL(mm_cachebits);
45 #endif
46
47 static pte_t * __init kernel_page_table(void)
48 {
49         pte_t *ptablep;
50
51         ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
52
53         clear_page(ptablep);
54         __flush_page_to_ram(ptablep);
55         flush_tlb_kernel_page(ptablep);
56         nocache_page(ptablep);
57
58         return ptablep;
59 }
60
61 static pmd_t *last_pgtable __initdata = NULL;
62 pmd_t *zero_pgtable __initdata = NULL;
63
64 static pmd_t * __init kernel_ptr_table(void)
65 {
66         if (!last_pgtable) {
67                 unsigned long pmd, last;
68                 int i;
69
70                 /* Find the last ptr table that was used in head.S and
71                  * reuse the remaining space in that page for further
72                  * ptr tables.
73                  */
74                 last = (unsigned long)kernel_pg_dir;
75                 for (i = 0; i < PTRS_PER_PGD; i++) {
76                         if (!pgd_present(kernel_pg_dir[i]))
77                                 continue;
78                         pmd = __pgd_page(kernel_pg_dir[i]);
79                         if (pmd > last)
80                                 last = pmd;
81                 }
82
83                 last_pgtable = (pmd_t *)last;
84 #ifdef DEBUG
85                 printk("kernel_ptr_init: %p\n", last_pgtable);
86 #endif
87         }
88
89         last_pgtable += PTRS_PER_PMD;
90         if (((unsigned long)last_pgtable & ~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(last_pgtable);
95                 flush_tlb_kernel_page(last_pgtable);
96                 nocache_page(last_pgtable);
97         }
98
99         return last_pgtable;
100 }
101
102 static unsigned long __init
103 map_chunk (unsigned long addr, long size)
104 {
105 #define PTRTREESIZE (256*1024)
106 #define ROOTTREESIZE (32*1024*1024)
107         static unsigned long virtaddr = PAGE_OFFSET;
108         unsigned long physaddr;
109         pgd_t *pgd_dir;
110         pmd_t *pmd_dir;
111         pte_t *pte_dir;
112
113         physaddr = (addr | m68k_supervisor_cachemode |
114                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
115         if (CPU_IS_040_OR_060)
116                 physaddr |= _PAGE_GLOBAL040;
117
118         while (size > 0) {
119 #ifdef DEBUG
120                 if (!(virtaddr & (PTRTREESIZE-1)))
121                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
122                                 virtaddr);
123 #endif
124                 pgd_dir = pgd_offset_k(virtaddr);
125                 if (virtaddr && CPU_IS_020_OR_030) {
126                         if (!(virtaddr & (ROOTTREESIZE-1)) &&
127                             size >= ROOTTREESIZE) {
128 #ifdef DEBUG
129                                 printk ("[very early term]");
130 #endif
131                                 pgd_val(*pgd_dir) = physaddr;
132                                 size -= ROOTTREESIZE;
133                                 virtaddr += ROOTTREESIZE;
134                                 physaddr += ROOTTREESIZE;
135                                 continue;
136                         }
137                 }
138                 if (!pgd_present(*pgd_dir)) {
139                         pmd_dir = kernel_ptr_table();
140 #ifdef DEBUG
141                         printk ("[new pointer %p]", pmd_dir);
142 #endif
143                         pgd_set(pgd_dir, pmd_dir);
144                 } else
145                         pmd_dir = pmd_offset(pgd_dir, virtaddr);
146
147                 if (CPU_IS_020_OR_030) {
148                         if (virtaddr) {
149 #ifdef DEBUG
150                                 printk ("[early term]");
151 #endif
152                                 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
153                                 physaddr += PTRTREESIZE;
154                         } else {
155                                 int i;
156 #ifdef DEBUG
157                                 printk ("[zero map]");
158 #endif
159                                 zero_pgtable = kernel_ptr_table();
160                                 pte_dir = (pte_t *)zero_pgtable;
161                                 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
162                                         _PAGE_TABLE | _PAGE_ACCESSED;
163                                 pte_val(*pte_dir++) = 0;
164                                 physaddr += PAGE_SIZE;
165                                 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
166                                         pte_val(*pte_dir++) = physaddr;
167                         }
168                         size -= PTRTREESIZE;
169                         virtaddr += PTRTREESIZE;
170                 } else {
171                         if (!pmd_present(*pmd_dir)) {
172 #ifdef DEBUG
173                                 printk ("[new table]");
174 #endif
175                                 pte_dir = kernel_page_table();
176                                 pmd_set(pmd_dir, pte_dir);
177                         }
178                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
179
180                         if (virtaddr) {
181                                 if (!pte_present(*pte_dir))
182                                         pte_val(*pte_dir) = physaddr;
183                         } else
184                                 pte_val(*pte_dir) = 0;
185                         size -= PAGE_SIZE;
186                         virtaddr += PAGE_SIZE;
187                         physaddr += PAGE_SIZE;
188                 }
189
190         }
191 #ifdef DEBUG
192         printk("\n");
193 #endif
194
195         return virtaddr;
196 }
197
198 /*
199  * paging_init() continues the virtual memory environment setup which
200  * was begun by the code in arch/head.S.
201  */
202 void __init paging_init(void)
203 {
204         int chunk;
205         unsigned long mem_avail = 0;
206         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
207
208 #ifdef DEBUG
209         {
210                 extern unsigned long availmem;
211                 printk ("start of paging_init (%p, %lx, %lx, %lx)\n",
212                         kernel_pg_dir, availmem, start_mem, end_mem);
213         }
214 #endif
215
216         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
217         if (CPU_IS_040_OR_060) {
218                 int i;
219 #ifndef mm_cachebits
220                 mm_cachebits = _PAGE_CACHE040;
221 #endif
222                 for (i = 0; i < 16; i++)
223                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
224         }
225
226         /*
227          * Map the physical memory available into the kernel virtual
228          * address space.  It may allocate some memory for page
229          * tables and thus modify availmem.
230          */
231
232         for (chunk = 0; chunk < m68k_num_memory; chunk++) {
233                 mem_avail = map_chunk (m68k_memory[chunk].addr,
234                                        m68k_memory[chunk].size);
235
236         }
237
238         flush_tlb_all();
239 #ifdef DEBUG
240         printk ("memory available is %ldKB\n", mem_avail >> 10);
241         printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
242                 start_mem, end_mem);
243 #endif
244
245         /*
246          * initialize the bad page table and bad page to point
247          * to a couple of allocated pages
248          */
249         empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
250         memset(empty_zero_page, 0, PAGE_SIZE);
251
252         /*
253          * Set up SFC/DFC registers
254          */
255         set_fs(KERNEL_DS);
256
257 #ifdef DEBUG
258         printk ("before free_area_init\n");
259 #endif
260         zones_size[ZONE_DMA] = (mach_max_dma_address < (unsigned long)high_memory ?
261                                 (mach_max_dma_address+1) : (unsigned long)high_memory);
262         zones_size[ZONE_NORMAL] = (unsigned long)high_memory - zones_size[0];
263
264         zones_size[ZONE_DMA] = (zones_size[ZONE_DMA] - PAGE_OFFSET) >> PAGE_SHIFT;
265         zones_size[ZONE_NORMAL] >>= PAGE_SHIFT;
266
267         free_area_init(zones_size);
268 }
269
270 extern char __init_begin, __init_end;
271
272 void free_initmem(void)
273 {
274         unsigned long addr;
275
276         addr = (unsigned long)&__init_begin;
277         for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
278                 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
279                 init_page_count(virt_to_page(addr));
280                 free_page(addr);
281                 totalram_pages++;
282         }
283 }
284
285