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 #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  */
  43 unsigned long mm_cachebits;
  44 EXPORT_SYMBOL(mm_cachebits);
  45 #endif
  46
  47 /* size of memory already mapped in head.S */
  48 #define INIT_MAPPED_SIZE        (4UL<<20)
  49
  50 extern unsigned long availmem;
  51
  52 static 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
  66 static pmd_t *last_pgtable __initdata = NULL;
  67 pmd_t *zero_pgtable __initdata = NULL;
  68
  69 static 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
 107 static 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  */
 206 void __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 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, min(INIT_MAPPED_SIZE, size) - (availmem - addr));
 275         map_node(0);
 276         if (size > INIT_MAPPED_SIZE)
 277                 free_bootmem_node(NODE_DATA(0), addr + INIT_MAPPED_SIZE, size - INIT_MAPPED_SIZE);
 278
 279         for (i = 1; i < m68k_num_memory; i++)
 280                 map_node(i);
 281
 282         flush_tlb_all();
 283
 284         /*
 285          * initialize the bad page table and bad page to point
 286          * to a couple of allocated pages
 287          */
 288         empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
 289
 290         /*
 291          * Set up SFC/DFC registers
 292          */
 293         set_fs(KERNEL_DS);
 294
 295 #ifdef DEBUG
 296         printk ("before free_area_init\n");
 297 #endif
 298         for (i = 0; i < m68k_num_memory; i++) {
 299                 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
 300                 free_area_init_node(i, zones_size,
 301                                     m68k_memory[i].addr >> PAGE_SHIFT, NULL);
 302         }
 303 }
 304
 305 void free_initmem(void)
 306 {
 307         unsigned long addr;
 308
 309         addr = (unsigned long)__init_begin;
 310         for (; addr < (unsigned long)__init_end; addr += PAGE_SIZE) {
 311                 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
 312                 init_page_count(virt_to_page(addr));
 313                 free_page(addr);
 314                 totalram_pages++;
 315         }
 316 }
 317
 318