arch/m68k/mm/motorola.c

   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