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#include <linux/gfp.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/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#include <asm/sections.h>
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 */
43unsigned long mm_cachebits;
44EXPORT_SYMBOL(mm_cachebits);
45#endif
46
47/* size of memory already mapped in head.S */
48extern __initdata unsigned long m68k_init_mapped_size;
49
50extern unsigned long availmem;
51
52static pte_t * __init kernel_page_table(void)
53{
54	pte_t *ptablep;
55
56	ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
57
58	clear_page(ptablep);
59	__flush_page_to_ram(ptablep);
60	flush_tlb_kernel_page(ptablep);
61	nocache_page(ptablep);
62
63	return ptablep;
64}
65
66static pmd_t *last_pgtable __initdata = NULL;
67pmd_t *zero_pgtable __initdata = NULL;
68
69static pmd_t * __init kernel_ptr_table(void)
70{
71	if (!last_pgtable) {
72		unsigned long pmd, last;
73		int i;
74
75		/* Find the last ptr table that was used in head.S and
76		 * reuse the remaining space in that page for further
77		 * ptr tables.
78		 */
79		last = (unsigned long)kernel_pg_dir;
80		for (i = 0; i < PTRS_PER_PGD; i++) {
81			if (!pgd_present(kernel_pg_dir[i]))
82				continue;
83			pmd = __pgd_page(kernel_pg_dir[i]);
84			if (pmd > last)
85				last = pmd;
86		}
87
88		last_pgtable = (pmd_t *)last;
89#ifdef DEBUG
90		printk("kernel_ptr_init: %p\n", last_pgtable);
91#endif
92	}
93
94	last_pgtable += PTRS_PER_PMD;
95	if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
96		last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
97
98		clear_page(last_pgtable);
99		__flush_page_to_ram(last_pgtable);
100		flush_tlb_kernel_page(last_pgtable);
101		nocache_page(last_pgtable);
102	}
103
104	return last_pgtable;
105}
106
107static void __init map_node(int node)
108{
109#define PTRTREESIZE (256*1024)
110#define ROOTTREESIZE (32*1024*1024)
111	unsigned long physaddr, virtaddr, size;
112	pgd_t *pgd_dir;
113	pmd_t *pmd_dir;
114	pte_t *pte_dir;
115
116	size = m68k_memory[node].size;
117	physaddr = m68k_memory[node].addr;
118	virtaddr = (unsigned long)phys_to_virt(physaddr);
119	physaddr |= m68k_supervisor_cachemode |
120		    _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
121	if (CPU_IS_040_OR_060)
122		physaddr |= _PAGE_GLOBAL040;
123
124	while (size > 0) {
125#ifdef DEBUG
126		if (!(virtaddr & (PTRTREESIZE-1)))
127			printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
128				virtaddr);
129#endif
130		pgd_dir = pgd_offset_k(virtaddr);
131		if (virtaddr && CPU_IS_020_OR_030) {
132			if (!(virtaddr & (ROOTTREESIZE-1)) &&
133			    size >= ROOTTREESIZE) {
134#ifdef DEBUG
135				printk ("[very early term]");
136#endif
137				pgd_val(*pgd_dir) = physaddr;
138				size -= ROOTTREESIZE;
139				virtaddr += ROOTTREESIZE;
140				physaddr += ROOTTREESIZE;
141				continue;
142			}
143		}
144		if (!pgd_present(*pgd_dir)) {
145			pmd_dir = kernel_ptr_table();
146#ifdef DEBUG
147			printk ("[new pointer %p]", pmd_dir);
148#endif
149			pgd_set(pgd_dir, pmd_dir);
150		} else
151			pmd_dir = pmd_offset(pgd_dir, virtaddr);
152
153		if (CPU_IS_020_OR_030) {
154			if (virtaddr) {
155#ifdef DEBUG
156				printk ("[early term]");
157#endif
158				pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
159				physaddr += PTRTREESIZE;
160			} else {
161				int i;
162#ifdef DEBUG
163				printk ("[zero map]");
164#endif
165				zero_pgtable = kernel_ptr_table();
166				pte_dir = (pte_t *)zero_pgtable;
167				pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
168					_PAGE_TABLE | _PAGE_ACCESSED;
169				pte_val(*pte_dir++) = 0;
170				physaddr += PAGE_SIZE;
171				for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
172					pte_val(*pte_dir++) = physaddr;
173			}
174			size -= PTRTREESIZE;
175			virtaddr += PTRTREESIZE;
176		} else {
177			if (!pmd_present(*pmd_dir)) {
178#ifdef DEBUG
179				printk ("[new table]");
180#endif
181				pte_dir = kernel_page_table();
182				pmd_set(pmd_dir, pte_dir);
183			}
184			pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
185
186			if (virtaddr) {
187				if (!pte_present(*pte_dir))
188					pte_val(*pte_dir) = physaddr;
189			} else
190				pte_val(*pte_dir) = 0;
191			size -= PAGE_SIZE;
192			virtaddr += PAGE_SIZE;
193			physaddr += PAGE_SIZE;
194		}
195
196	}
197#ifdef DEBUG
198	printk("\n");
199#endif
200}
201
202/*
203 * paging_init() continues the virtual memory environment setup which
204 * was begun by the code in arch/head.S.
205 */
206void __init paging_init(void)
207{
208	unsigned long zones_size[MAX_NR_ZONES] = { 0, };
209	unsigned long min_addr, max_addr;
210	unsigned long addr, size, end;
211	int i;
212
213#ifdef DEBUG
214	printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
215#endif
216
217	/* Fix the cache mode in the page descriptors for the 680[46]0.  */
218	if (CPU_IS_040_OR_060) {
219		int i;
220#ifndef mm_cachebits
221		mm_cachebits = _PAGE_CACHE040;
222#endif
223		for (i = 0; i < 16; i++)
224			pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
225	}
226
227	min_addr = m68k_memory[0].addr;
228	max_addr = min_addr + m68k_memory[0].size;
229	for (i = 1; i < m68k_num_memory;) {
230		if (m68k_memory[i].addr < min_addr) {
231			printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
232				m68k_memory[i].addr, m68k_memory[i].size);
233			printk("Fix your bootloader or use a memfile to make use of this area!\n");
234			m68k_num_memory--;
235			memmove(m68k_memory + i, m68k_memory + i + 1,
236				(m68k_num_memory - i) * sizeof(struct m68k_mem_info));
237			continue;
238		}
239		addr = m68k_memory[i].addr + m68k_memory[i].size;
240		if (addr > max_addr)
241			max_addr = addr;
242		i++;
243	}
244	m68k_memoffset = min_addr - PAGE_OFFSET;
245	m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
246
247	module_fixup(NULL, __start_fixup, __stop_fixup);
248	flush_icache();
249
250	high_memory = phys_to_virt(max_addr);
251
252	min_low_pfn = availmem >> PAGE_SHIFT;
253	max_low_pfn = max_addr >> PAGE_SHIFT;
254
255	for (i = 0; i < m68k_num_memory; i++) {
256		addr = m68k_memory[i].addr;
257		end = addr + m68k_memory[i].size;
258		m68k_setup_node(i);
259		availmem = PAGE_ALIGN(availmem);
260		availmem += init_bootmem_node(NODE_DATA(i),
261					      availmem >> PAGE_SHIFT,
262					      addr >> PAGE_SHIFT,
263					      end >> PAGE_SHIFT);
264	}
265
266	/*
267	 * Map the physical memory available into the kernel virtual
268	 * address space. First initialize the bootmem allocator with
269	 * the memory we already mapped, so map_node() has something
270	 * to allocate.
271	 */
272	addr = m68k_memory[0].addr;
273	size = m68k_memory[0].size;
274	free_bootmem_node(NODE_DATA(0), availmem,
275			  min(m68k_init_mapped_size, size) - (availmem - addr));
276	map_node(0);
277	if (size > m68k_init_mapped_size)
278		free_bootmem_node(NODE_DATA(0), addr + m68k_init_mapped_size,
279				  size - m68k_init_mapped_size);
280
281	for (i = 1; i < m68k_num_memory; i++)
282		map_node(i);
283
284	flush_tlb_all();
285
286	/*
287	 * initialize the bad page table and bad page to point
288	 * to a couple of allocated pages
289	 */
290	empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
291
292	/*
293	 * Set up SFC/DFC registers
294	 */
295	set_fs(KERNEL_DS);
296
297#ifdef DEBUG
298	printk ("before free_area_init\n");
299#endif
300	for (i = 0; i < m68k_num_memory; i++) {
301		zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
302		free_area_init_node(i, zones_size,
303				    m68k_memory[i].addr >> PAGE_SHIFT, NULL);
304		if (node_present_pages(i))
305			node_set_state(i, N_NORMAL_MEMORY);
306	}
307}
308
309