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 #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/system.h>
  28 #include <asm/machdep.h>
  29 #include <asm/io.h>
  30 #include <asm/dma.h>
  31 #ifdef CONFIG_ATARI
  32 #include <asm/atari_stram.h>
  33 #endif
  34 #include <asm/sections.h>
  35
  36 #undef DEBUG
  37
  38 #ifndef mm_cachebits
  39 /*
  40  * Bits to add to page descriptors for "normal" caching mode.
  41  * For 68020/030 this is 0.
  42  * For 68040, this is _PAGE_CACHE040 (cachable, copyback)
  43  */
  44 unsigned long mm_cachebits;
  45 EXPORT_SYMBOL(mm_cachebits);
  46 #endif
  47
  48 /* size of memory already mapped in head.S */
  49 #define INIT_MAPPED_SIZE        (4UL<<20)
  50
  51 extern unsigned long availmem;
  52
  53 static pte_t * __init kernel_page_table(void)
  54 {
  55         pte_t *ptablep;
  56
  57         ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  58
  59         clear_page(ptablep);
  60         __flush_page_to_ram(ptablep);
  61         flush_tlb_kernel_page(ptablep);
  62         nocache_page(ptablep);
  63
  64         return ptablep;
  65 }
  66
  67 static pmd_t *last_pgtable __initdata = NULL;
  68 pmd_t *zero_pgtable __initdata = NULL;
  69
  70 static pmd_t * __init kernel_ptr_table(void)
  71 {
  72         if (!last_pgtable) {
  73                 unsigned long pmd, last;
  74                 int i;
  75
  76                 /* Find the last ptr table that was used in head.S and
  77                  * reuse the remaining space in that page for further
  78                  * ptr tables.
  79                  */
  80                 last = (unsigned long)kernel_pg_dir;
  81                 for (i = 0; i < PTRS_PER_PGD; i++) {
  82                         if (!pgd_present(kernel_pg_dir[i]))
  83                                 continue;
  84                         pmd = __pgd_page(kernel_pg_dir[i]);
  85                         if (pmd > last)
  86                                 last = pmd;
  87                 }
  88
  89                 last_pgtable = (pmd_t *)last;
  90 #ifdef DEBUG
  91                 printk("kernel_ptr_init: %p\n", last_pgtable);
  92 #endif
  93         }
  94
  95         last_pgtable += PTRS_PER_PMD;
  96         if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
  97                 last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  98
  99                 clear_page(last_pgtable);
 100                 __flush_page_to_ram(last_pgtable);
 101                 flush_tlb_kernel_page(last_pgtable);
 102                 nocache_page(last_pgtable);
 103         }
 104
 105         return last_pgtable;
 106 }
 107
 108 static void __init map_node(int node)
 109 {
 110 #define PTRTREESIZE (256*1024)
 111 #define ROOTTREESIZE (32*1024*1024)
 112         unsigned long physaddr, virtaddr, size;
 113         pgd_t *pgd_dir;
 114         pmd_t *pmd_dir;
 115         pte_t *pte_dir;
 116
 117         size = m68k_memory[node].size;
 118         physaddr = m68k_memory[node].addr;
 119         virtaddr = (unsigned long)phys_to_virt(physaddr);
 120         physaddr |= m68k_supervisor_cachemode |
 121                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY;
 122         if (CPU_IS_040_OR_060)
 123                 physaddr |= _PAGE_GLOBAL040;
 124
 125         while (size > 0) {
 126 #ifdef DEBUG
 127                 if (!(virtaddr & (PTRTREESIZE-1)))
 128                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 129                                 virtaddr);
 130 #endif
 131                 pgd_dir = pgd_offset_k(virtaddr);
 132                 if (virtaddr && CPU_IS_020_OR_030) {
 133                         if (!(virtaddr & (ROOTTREESIZE-1)) &&
 134                             size >= ROOTTREESIZE) {
 135 #ifdef DEBUG
 136                                 printk ("[very early term]");
 137 #endif
 138                                 pgd_val(*pgd_dir) = physaddr;
 139                                 size -= ROOTTREESIZE;
 140                                 virtaddr += ROOTTREESIZE;
 141                                 physaddr += ROOTTREESIZE;
 142                                 continue;
 143                         }
 144                 }
 145                 if (!pgd_present(*pgd_dir)) {
 146                         pmd_dir = kernel_ptr_table();
 147 #ifdef DEBUG
 148                         printk ("[new pointer %p]", pmd_dir);
 149 #endif
 150                         pgd_set(pgd_dir, pmd_dir);
 151                 } else
 152                         pmd_dir = pmd_offset(pgd_dir, virtaddr);
 153
 154                 if (CPU_IS_020_OR_030) {
 155                         if (virtaddr) {
 156 #ifdef DEBUG
 157                                 printk ("[early term]");
 158 #endif
 159                                 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
 160                                 physaddr += PTRTREESIZE;
 161                         } else {
 162                                 int i;
 163 #ifdef DEBUG
 164                                 printk ("[zero map]");
 165 #endif
 166                                 zero_pgtable = kernel_ptr_table();
 167                                 pte_dir = (pte_t *)zero_pgtable;
 168                                 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
 169                                         _PAGE_TABLE | _PAGE_ACCESSED;
 170                                 pte_val(*pte_dir++) = 0;
 171                                 physaddr += PAGE_SIZE;
 172                                 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
 173                                         pte_val(*pte_dir++) = physaddr;
 174                         }
 175                         size -= PTRTREESIZE;
 176                         virtaddr += PTRTREESIZE;
 177                 } else {
 178                         if (!pmd_present(*pmd_dir)) {
 179 #ifdef DEBUG
 180                                 printk ("[new table]");
 181 #endif
 182                                 pte_dir = kernel_page_table();
 183                                 pmd_set(pmd_dir, pte_dir);
 184                         }
 185                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 186
 187                         if (virtaddr) {
 188                                 if (!pte_present(*pte_dir))
 189                                         pte_val(*pte_dir) = physaddr;
 190                         } else
 191                                 pte_val(*pte_dir) = 0;
 192                         size -= PAGE_SIZE;
 193                         virtaddr += PAGE_SIZE;
 194                         physaddr += PAGE_SIZE;
 195                 }
 196
 197         }
 198 #ifdef DEBUG
 199         printk("\n");
 200 #endif
 201 }
 202
 203 /*
 204  * paging_init() continues the virtual memory environment setup which
 205  * was begun by the code in arch/head.S.
 206  */
 207 void __init paging_init(void)
 208 {
 209         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
 210         unsigned long min_addr, max_addr;
 211         unsigned long addr, size, end;
 212         int i;
 213
 214 #ifdef DEBUG
 215         printk ("start of paging_init (%p, %lx)\n", kernel_pg_dir, availmem);
 216 #endif
 217
 218         /* Fix the cache mode in the page descriptors for the 680[46]0.  */
 219         if (CPU_IS_040_OR_060) {
 220                 int i;
 221 #ifndef mm_cachebits
 222                 mm_cachebits = _PAGE_CACHE040;
 223 #endif
 224                 for (i = 0; i < 16; i++)
 225                         pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
 226         }
 227
 228         min_addr = m68k_memory[0].addr;
 229         max_addr = min_addr + m68k_memory[0].size;
 230         for (i = 1; i < m68k_num_memory;) {
 231                 if (m68k_memory[i].addr < min_addr) {
 232                         printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
 233                                 m68k_memory[i].addr, m68k_memory[i].size);
 234                         printk("Fix your bootloader or use a memfile to make use of this area!\n");
 235                         m68k_num_memory--;
 236                         memmove(m68k_memory + i, m68k_memory + i + 1,
 237                                 (m68k_num_memory - i) * sizeof(struct mem_info));
 238                         continue;
 239                 }
 240                 addr = m68k_memory[i].addr + m68k_memory[i].size;
 241                 if (addr > max_addr)
 242                         max_addr = addr;
 243                 i++;
 244         }
 245         m68k_memoffset = min_addr - PAGE_OFFSET;
 246         m68k_virt_to_node_shift = fls(max_addr - min_addr - 1) - 6;
 247
 248         module_fixup(NULL, __start_fixup, __stop_fixup);
 249         flush_icache();
 250
 251         high_memory = phys_to_virt(max_addr);
 252
 253         min_low_pfn = availmem >> PAGE_SHIFT;
 254         max_low_pfn = max_addr >> PAGE_SHIFT;
 255
 256         for (i = 0; i < m68k_num_memory; i++) {
 257                 addr = m68k_memory[i].addr;
 258                 end = addr + m68k_memory[i].size;
 259                 m68k_setup_node(i);
 260                 availmem = PAGE_ALIGN(availmem);
 261                 availmem += init_bootmem_node(NODE_DATA(i),
 262                                               availmem >> PAGE_SHIFT,
 263                                               addr >> PAGE_SHIFT,
 264                                               end >> PAGE_SHIFT);
 265         }
 266
 267         /*
 268          * Map the physical memory available into the kernel virtual
 269          * address space. First initialize the bootmem allocator with
 270          * the memory we already mapped, so map_node() has something
 271          * to allocate.
 272          */
 273         addr = m68k_memory[0].addr;
 274         size = m68k_memory[0].size;
 275         free_bootmem_node(NODE_DATA(0), availmem, min(INIT_MAPPED_SIZE, size) - (availmem - addr));
 276         map_node(0);
 277         if (size > INIT_MAPPED_SIZE)
 278                 free_bootmem_node(NODE_DATA(0), addr + INIT_MAPPED_SIZE, size - INIT_MAPPED_SIZE);
 279
 280         for (i = 1; i < m68k_num_memory; i++)
 281                 map_node(i);
 282
 283         flush_tlb_all();
 284
 285         /*
 286          * initialize the bad page table and bad page to point
 287          * to a couple of allocated pages
 288          */
 289         empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
 290
 291         /*
 292          * Set up SFC/DFC registers
 293          */
 294         set_fs(KERNEL_DS);
 295
 296 #ifdef DEBUG
 297         printk ("before free_area_init\n");
 298 #endif
 299         for (i = 0; i < m68k_num_memory; i++) {
 300                 zones_size[ZONE_DMA] = m68k_memory[i].size >> PAGE_SHIFT;
 301                 free_area_init_node(i, zones_size,
 302                                     m68k_memory[i].addr >> PAGE_SHIFT, NULL);
 303         }
 304 }
 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