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 static pte_t * __init kernel_page_table(void)
  47 {
  48         pte_t *ptablep;
  49
  50         ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  51
  52         clear_page(ptablep);
  53         __flush_page_to_ram(ptablep);
  54         flush_tlb_kernel_page(ptablep);
  55         nocache_page(ptablep);
  56
  57         return ptablep;
  58 }
  59
  60 static pmd_t *last_pgtable __initdata = NULL;
  61 pmd_t *zero_pgtable __initdata = NULL;
  62
  63 static pmd_t * __init kernel_ptr_table(void)
  64 {
  65         if (!last_pgtable) {
  66                 unsigned long pmd, last;
  67                 int i;
  68
  69                 /* Find the last ptr table that was used in head.S and
  70                  * reuse the remaining space in that page for further
  71                  * ptr tables.
  72                  */
  73                 last = (unsigned long)kernel_pg_dir;
  74                 for (i = 0; i < PTRS_PER_PGD; i++) {
  75                         if (!pgd_present(kernel_pg_dir[i]))
  76                                 continue;
  77                         pmd = __pgd_page(kernel_pg_dir[i]);
  78                         if (pmd > last)
  79                                 last = pmd;
  80                 }
  81
  82                 last_pgtable = (pmd_t *)last;
  83 #ifdef DEBUG
  84                 printk("kernel_ptr_init: %p\n", last_pgtable);
  85 #endif
  86         }
  87
  88         last_pgtable += PTRS_PER_PMD;
  89         if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
  90                 last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  91
  92                 clear_page(last_pgtable);
  93                 __flush_page_to_ram(last_pgtable);
  94                 flush_tlb_kernel_page(last_pgtable);
  95                 nocache_page(last_pgtable);
  96         }
  97
  98         return last_pgtable;
  99 }
 100
 101 static unsigned long __init
 102 map_chunk (unsigned long addr, long size)
 103 {
 104 #define PTRTREESIZE (256*1024)
 105 #define ROOTTREESIZE (32*1024*1024)
 106         static unsigned long virtaddr = PAGE_OFFSET;
 107         unsigned long physaddr;
 108         pgd_t *pgd_dir;
 109         pmd_t *pmd_dir;
 110         pte_t *pte_dir;
 111
 112         physaddr = (addr | m68k_supervisor_cachemode |
 113                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
 114         if (CPU_IS_040_OR_060)
 115                 physaddr |= _PAGE_GLOBAL040;
 116
 117         while (size > 0) {
 118 #ifdef DEBUG
 119                 if (!(virtaddr & (PTRTREESIZE-1)))
 120                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 121                                 virtaddr);
 122 #endif
 123                 pgd_dir = pgd_offset_k(virtaddr);
 124                 if (virtaddr && CPU_IS_020_OR_030) {
 125                         if (!(virtaddr & (ROOTTREESIZE-1)) &&
 126                             size >= ROOTTREESIZE) {
 127 #ifdef DEBUG
 128                                 printk ("[very early term]");
 129 #endif
 130                                 pgd_val(*pgd_dir) = physaddr;
 131                                 size -= ROOTTREESIZE;
 132                                 virtaddr += ROOTTREESIZE;
 133                                 physaddr += ROOTTREESIZE;
 134                                 continue;
 135                         }
 136                 }
 137                 if (!pgd_present(*pgd_dir)) {
 138                         pmd_dir = kernel_ptr_table();
 139 #ifdef DEBUG
 140                         printk ("[new pointer %p]", pmd_dir);
 141 #endif
 142                         pgd_set(pgd_dir, pmd_dir);
 143                 } else
 144                         pmd_dir = pmd_offset(pgd_dir, virtaddr);
 145
 146                 if (CPU_IS_020_OR_030) {
 147                         if (virtaddr) {
 148 #ifdef DEBUG
 149                                 printk ("[early term]");
 150 #endif
 151                                 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
 152                                 physaddr += PTRTREESIZE;
 153                         } else {
 154                                 int i;
 155 #ifdef DEBUG
 156                                 printk ("[zero map]");
 157 #endif
 158                                 zero_pgtable = kernel_ptr_table();
 159                                 pte_dir = (pte_t *)zero_pgtable;
 160                                 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
 161                                         _PAGE_TABLE | _PAGE_ACCESSED;
 162                                 pte_val(*pte_dir++) = 0;
 163                                 physaddr += PAGE_SIZE;
 164                                 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
 165                                         pte_val(*pte_dir++) = physaddr;
 166                         }
 167                         size -= PTRTREESIZE;
 168                         virtaddr += PTRTREESIZE;
 169                 } else {
 170                         if (!pmd_present(*pmd_dir)) {
 171 #ifdef DEBUG
 172                                 printk ("[new table]");
 173 #endif
 174                                 pte_dir = kernel_page_table();
 175                                 pmd_set(pmd_dir, pte_dir);
 176                         }
 177                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 178
 179                         if (virtaddr) {
 180                                 if (!pte_present(*pte_dir))
 181                                         pte_val(*pte_dir) = physaddr;
 182                         } else
 183                                 pte_val(*pte_dir) = 0;
 184                         size -= PAGE_SIZE;
 185                         virtaddr += PAGE_SIZE;
 186                         physaddr += PAGE_SIZE;
 187                 }
 188
 189         }
 190 #ifdef DEBUG
 191         printk("\n");
 192 #endif
 193
 194         return virtaddr;
 195 }
 196
 197 /*
 198  * paging_init() continues the virtual memory environment setup which
 199  * was begun by the code in arch/head.S.
 200  */
 201 void __init paging_init(void)
 202 {
 203         int chunk;
 204         unsigned long mem_avail = 0;
 205         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
 206
 207 #ifdef DEBUG
 208         {
 209                 extern unsigned long availmem;
 210                 printk ("start of paging_init (%p, %lx, %lx, %lx)\n",
 211                         kernel_pg_dir, availmem, start_mem, end_mem);
 212         }
 213 #endif
 214
 215         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 216         if (CPU_IS_040_OR_060) {
 217                 int i;
 218 #ifndef mm_cachebits
 219                 mm_cachebits = _PAGE_CACHE040;
 220 #endif
 221                 for (i = 0; i < 16; i++)
 222                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 223         }
 224
 225         /*
 226          * Map the physical memory available into the kernel virtual
 227          * address space.  It may allocate some memory for page
 228          * tables and thus modify availmem.
 229          */
 230
 231         for (chunk = 0; chunk < m68k_num_memory; chunk++) {
 232                 mem_avail = map_chunk (m68k_memory[chunk].addr,
 233                                        m68k_memory[chunk].size);
 234
 235         }
 236
 237         flush_tlb_all();
 238 #ifdef DEBUG
 239         printk ("memory available is %ldKB\n", mem_avail >> 10);
 240         printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
 241                 start_mem, end_mem);
 242 #endif
 243
 244         /*
 245          * initialize the bad page table and bad page to point
 246          * to a couple of allocated pages
 247          */
 248         empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
 249         memset(empty_zero_page, 0, PAGE_SIZE);
 250
 251         /*
 252          * Set up SFC/DFC registers
 253          */
 254         set_fs(KERNEL_DS);
 255
 256 #ifdef DEBUG
 257         printk ("before free_area_init\n");
 258 #endif
 259         zones_size[ZONE_DMA] = (mach_max_dma_address < (unsigned long)high_memory ?
 260                                 (mach_max_dma_address+1) : (unsigned long)high_memory);
 261         zones_size[ZONE_NORMAL] = (unsigned long)high_memory - zones_size[0];
 262
 263         zones_size[ZONE_DMA] = (zones_size[ZONE_DMA] - PAGE_OFFSET) >> PAGE_SHIFT;
 264         zones_size[ZONE_NORMAL] >>= PAGE_SHIFT;
 265
 266         free_area_init(zones_size);
 267 }
 268
 269 extern char __init_begin, __init_end;
 270
 271 void free_initmem(void)
 272 {
 273         unsigned long addr;
 274
 275         addr = (unsigned long)&__init_begin;
 276         for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
 277                 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
 278                 init_page_count(virt_to_page(addr));
 279                 free_page(addr);
 280                 totalram_pages++;
 281         }
 282 }
 283
 284