xref: /openbmc/linux/arch/m68k/mm/motorola.c (revision 9ac8d3fb)
1 /*
2  * linux/arch/m68k/mm/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/module.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 
22 #include <asm/setup.h>
23 #include <asm/uaccess.h>
24 #include <asm/page.h>
25 #include <asm/pgalloc.h>
26 #include <asm/system.h>
27 #include <asm/machdep.h>
28 #include <asm/io.h>
29 #include <asm/dma.h>
30 #ifdef CONFIG_ATARI
31 #include <asm/atari_stram.h>
32 #endif
33 
34 #undef DEBUG
35 
36 #ifndef mm_cachebits
37 /*
38  * Bits to add to page descriptors for "normal" caching mode.
39  * For 68020/030 this is 0.
40  * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
41  */
42 unsigned long mm_cachebits;
43 EXPORT_SYMBOL(mm_cachebits);
44 #endif
45 
46 /* size of memory already mapped in head.S */
47 #define INIT_MAPPED_SIZE	(4UL<<20)
48 
49 extern unsigned long availmem;
50 
51 static pte_t * __init kernel_page_table(void)
52 {
53 	pte_t *ptablep;
54 
55 	ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
56 
57 	clear_page(ptablep);
58 	__flush_page_to_ram(ptablep);
59 	flush_tlb_kernel_page(ptablep);
60 	nocache_page(ptablep);
61 
62 	return ptablep;
63 }
64 
65 static pmd_t *last_pgtable __initdata = NULL;
66 pmd_t *zero_pgtable __initdata = NULL;
67 
68 static pmd_t * __init kernel_ptr_table(void)
69 {
70 	if (!last_pgtable) {
71 		unsigned long pmd, last;
72 		int i;
73 
74 		/* Find the last ptr table that was used in head.S and
75 		 * reuse the remaining space in that page for further
76 		 * ptr tables.
77 		 */
78 		last = (unsigned long)kernel_pg_dir;
79 		for (i = 0; i < PTRS_PER_PGD; i++) {
80 			if (!pgd_present(kernel_pg_dir[i]))
81 				continue;
82 			pmd = __pgd_page(kernel_pg_dir[i]);
83 			if (pmd > last)
84 				last = pmd;
85 		}
86 
87 		last_pgtable = (pmd_t *)last;
88 #ifdef DEBUG
89 		printk("kernel_ptr_init: %p\n", last_pgtable);
90 #endif
91 	}
92 
93 	last_pgtable += PTRS_PER_PMD;
94 	if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
95 		last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
96 
97 		clear_page(last_pgtable);
98 		__flush_page_to_ram(last_pgtable);
99 		flush_tlb_kernel_page(last_pgtable);
100 		nocache_page(last_pgtable);
101 	}
102 
103 	return last_pgtable;
104 }
105 
106 static void __init map_node(int node)
107 {
108 #define PTRTREESIZE (256*1024)
109 #define ROOTTREESIZE (32*1024*1024)
110 	unsigned long physaddr, virtaddr, size;
111 	pgd_t *pgd_dir;
112 	pmd_t *pmd_dir;
113 	pte_t *pte_dir;
114 
115 	size = m68k_memory[node].size;
116 	physaddr = m68k_memory[node].addr;
117 	virtaddr = (unsigned long)phys_to_virt(physaddr);
118 	physaddr |= m68k_supervisor_cachemode |
119 		    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
120 	if (CPU_IS_040_OR_060)
121 		physaddr |= _PAGE_GLOBAL040;
122 
123 	while (size > 0) {
124 #ifdef DEBUG
125 		if (!(virtaddr & (PTRTREESIZE-1)))
126 			printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
127 				virtaddr);
128 #endif
129 		pgd_dir = pgd_offset_k(virtaddr);
130 		if (virtaddr && CPU_IS_020_OR_030) {
131 			if (!(virtaddr & (ROOTTREESIZE-1)) &&
132 			    size >= ROOTTREESIZE) {
133 #ifdef DEBUG
134 				printk ("[very early term]");
135 #endif
136 				pgd_val(*pgd_dir) = physaddr;
137 				size -= ROOTTREESIZE;
138 				virtaddr += ROOTTREESIZE;
139 				physaddr += ROOTTREESIZE;
140 				continue;
141 			}
142 		}
143 		if (!pgd_present(*pgd_dir)) {
144 			pmd_dir = kernel_ptr_table();
145 #ifdef DEBUG
146 			printk ("[new pointer %p]", pmd_dir);
147 #endif
148 			pgd_set(pgd_dir, pmd_dir);
149 		} else
150 			pmd_dir = pmd_offset(pgd_dir, virtaddr);
151 
152 		if (CPU_IS_020_OR_030) {
153 			if (virtaddr) {
154 #ifdef DEBUG
155 				printk ("[early term]");
156 #endif
157 				pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
158 				physaddr += PTRTREESIZE;
159 			} else {
160 				int i;
161 #ifdef DEBUG
162 				printk ("[zero map]");
163 #endif
164 				zero_pgtable = kernel_ptr_table();
165 				pte_dir = (pte_t *)zero_pgtable;
166 				pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
167 					_PAGE_TABLE | _PAGE_ACCESSED;
168 				pte_val(*pte_dir++) = 0;
169 				physaddr += PAGE_SIZE;
170 				for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
171 					pte_val(*pte_dir++) = physaddr;
172 			}
173 			size -= PTRTREESIZE;
174 			virtaddr += PTRTREESIZE;
175 		} else {
176 			if (!pmd_present(*pmd_dir)) {
177 #ifdef DEBUG
178 				printk ("[new table]");
179 #endif
180 				pte_dir = kernel_page_table();
181 				pmd_set(pmd_dir, pte_dir);
182 			}
183 			pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
184 
185 			if (virtaddr) {
186 				if (!pte_present(*pte_dir))
187 					pte_val(*pte_dir) = physaddr;
188 			} else
189 				pte_val(*pte_dir) = 0;
190 			size -= PAGE_SIZE;
191 			virtaddr += PAGE_SIZE;
192 			physaddr += PAGE_SIZE;
193 		}
194 
195 	}
196 #ifdef DEBUG
197 	printk("\n");
198 #endif
199 }
200 
201 /*
202  * paging_init() continues the virtual memory environment setup which
203  * was begun by the code in arch/head.S.
204  */
205 void __init paging_init(void)
206 {
207 	unsigned long zones_size[MAX_NR_ZONES] = { 0, };
208 	unsigned long min_addr, max_addr;
209 	unsigned long addr, size, end;
210 	int i;
211 
212 #ifdef DEBUG
213 	printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
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 	min_addr = m68k_memory[0].addr;
227 	max_addr = min_addr + m68k_memory[0].size;
228 	for (i = 1; i < m68k_num_memory;) {
229 		if (m68k_memory[i].addr < min_addr) {
230 			printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
231 				m68k_memory[i].addr, m68k_memory[i].size);
232 			printk("Fix your bootloader or use a memfile to make use of this area!\n");
233 			m68k_num_memory--;
234 			memmove(m68k_memory + i, m68k_memory + i + 1,
235 				(m68k_num_memory - i) * sizeof(struct mem_info));
236 			continue;
237 		}
238 		addr = m68k_memory[i].addr + m68k_memory[i].size;
239 		if (addr > max_addr)
240 			max_addr = addr;
241 		i++;
242 	}
243 	m68k_memoffset = min_addr - PAGE_OFFSET;
244 	m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
245 
246 	module_fixup(NULL, __start_fixup, __stop_fixup);
247 	flush_icache();
248 
249 	high_memory = phys_to_virt(max_addr);
250 
251 	min_low_pfn = availmem >> PAGE_SHIFT;
252 	max_low_pfn = max_addr >> PAGE_SHIFT;
253 
254 	for (i = 0; i < m68k_num_memory; i++) {
255 		addr = m68k_memory[i].addr;
256 		end = addr + m68k_memory[i].size;
257 		m68k_setup_node(i);
258 		availmem = PAGE_ALIGN(availmem);
259 		availmem += init_bootmem_node(NODE_DATA(i),
260 					      availmem >> PAGE_SHIFT,
261 					      addr >> PAGE_SHIFT,
262 					      end >> PAGE_SHIFT);
263 	}
264 
265 	/*
266 	 * Map the physical memory available into the kernel virtual
267 	 * address space. First initialize the bootmem allocator with
268 	 * the memory we already mapped, so map_node() has something
269 	 * to allocate.
270 	 */
271 	addr = m68k_memory[0].addr;
272 	size = m68k_memory[0].size;
273 	free_bootmem_node(NODE_DATA(0), availmem, min(INIT_MAPPED_SIZE, size) - (availmem - addr));
274 	map_node(0);
275 	if (size > INIT_MAPPED_SIZE)
276 		free_bootmem_node(NODE_DATA(0), addr + INIT_MAPPED_SIZE, size - INIT_MAPPED_SIZE);
277 
278 	for (i = 1; i < m68k_num_memory; i++)
279 		map_node(i);
280 
281 	flush_tlb_all();
282 
283 	/*
284 	 * initialize the bad page table and bad page to point
285 	 * to a couple of allocated pages
286 	 */
287 	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
288 
289 	/*
290 	 * Set up SFC/DFC registers
291 	 */
292 	set_fs(KERNEL_DS);
293 
294 #ifdef DEBUG
295 	printk ("before free_area_init\n");
296 #endif
297 	for (i = 0; i < m68k_num_memory; i++) {
298 		zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
299 		free_area_init_node(i, zones_size,
300 				    m68k_memory[i].addr >> PAGE_SHIFT, NULL);
301 	}
302 }
303 
304 extern char __init_begin, __init_end;
305 
306 void free_initmem(void)
307 {
308 	unsigned long addr;
309 
310 	addr = (unsigned long)&__init_begin;
311 	for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
312 		virt_to_page(addr)->flags &= ~(1 << PG_reserved);
313 		init_page_count(virt_to_page(addr));
314 		free_page(addr);
315 		totalram_pages++;
316 	}
317 }
318 
319 
320