arch/m68k/mm/motorola.c

   1 /*
   2  * linux/arch/m68k/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/config.h>
  12 #include <linux/module.h>
  13 #include <linux/signal.h>
  14 #include <linux/sched.h>
  15 #include <linux/mm.h>
  16 #include <linux/swap.h>
  17 #include <linux/kernel.h>
  18 #include <linux/string.h>
  19 #include <linux/types.h>
  20 #include <linux/init.h>
  21 #include <linux/bootmem.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
  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 static pte_t * __init kernel_page_table(void)
  48 {
  49         pte_t *ptablep;
  50
  51         ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  52
  53         clear_page(ptablep);
  54         __flush_page_to_ram(ptablep);
  55         flush_tlb_kernel_page(ptablep);
  56         nocache_page(ptablep);
  57
  58         return ptablep;
  59 }
  60
  61 static pmd_t *last_pgtable __initdata = NULL;
  62 pmd_t *zero_pgtable __initdata = NULL;
  63
  64 static pmd_t * __init kernel_ptr_table(void)
  65 {
  66         if (!last_pgtable) {
  67                 unsigned long pmd, last;
  68                 int i;
  69
  70                 /* Find the last ptr table that was used in head.S and
  71                  * reuse the remaining space in that page for further
  72                  * ptr tables.
  73                  */
  74                 last = (unsigned long)kernel_pg_dir;
  75                 for (i = 0; i < PTRS_PER_PGD; i++) {
  76                         if (!pgd_present(kernel_pg_dir[i]))
  77                                 continue;
  78                         pmd = __pgd_page(kernel_pg_dir[i]);
  79                         if (pmd > last)
  80                                 last = pmd;
  81                 }
  82
  83                 last_pgtable = (pmd_t *)last;
  84 #ifdef DEBUG
  85                 printk("kernel_ptr_init: %p\n", last_pgtable);
  86 #endif
  87         }
  88
  89         last_pgtable += PTRS_PER_PMD;
  90         if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
  91                 last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  92
  93                 clear_page(last_pgtable);
  94                 __flush_page_to_ram(last_pgtable);
  95                 flush_tlb_kernel_page(last_pgtable);
  96                 nocache_page(last_pgtable);
  97         }
  98
  99         return last_pgtable;
 100 }
 101
 102 static unsigned long __init
 103 map_chunk (unsigned long addr, long size)
 104 {
 105 #define PTRTREESIZE (256*1024)
 106 #define ROOTTREESIZE (32*1024*1024)
 107         static unsigned long virtaddr = PAGE_OFFSET;
 108         unsigned long physaddr;
 109         pgd_t *pgd_dir;
 110         pmd_t *pmd_dir;
 111         pte_t *pte_dir;
 112
 113         physaddr = (addr | m68k_supervisor_cachemode |
 114                     _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
 115         if (CPU_IS_040_OR_060)
 116                 physaddr |= _PAGE_GLOBAL040;
 117
 118         while (size > 0) {
 119 #ifdef DEBUG
 120                 if (!(virtaddr & (PTRTREESIZE-1)))
 121                         printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
 122                                 virtaddr);
 123 #endif
 124                 pgd_dir = pgd_offset_k(virtaddr);
 125                 if (virtaddr && CPU_IS_020_OR_030) {
 126                         if (!(virtaddr & (ROOTTREESIZE-1)) &&
 127                             size >= ROOTTREESIZE) {
 128 #ifdef DEBUG
 129                                 printk ("[very early term]");
 130 #endif
 131                                 pgd_val(*pgd_dir) = physaddr;
 132                                 size -= ROOTTREESIZE;
 133                                 virtaddr += ROOTTREESIZE;
 134                                 physaddr += ROOTTREESIZE;
 135                                 continue;
 136                         }
 137                 }
 138                 if (!pgd_present(*pgd_dir)) {
 139                         pmd_dir = kernel_ptr_table();
 140 #ifdef DEBUG
 141                         printk ("[new pointer %p]", pmd_dir);
 142 #endif
 143                         pgd_set(pgd_dir, pmd_dir);
 144                 } else
 145                         pmd_dir = pmd_offset(pgd_dir, virtaddr);
 146
 147                 if (CPU_IS_020_OR_030) {
 148                         if (virtaddr) {
 149 #ifdef DEBUG
 150                                 printk ("[early term]");
 151 #endif
 152                                 pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
 153                                 physaddr += PTRTREESIZE;
 154                         } else {
 155                                 int i;
 156 #ifdef DEBUG
 157                                 printk ("[zero map]");
 158 #endif
 159                                 zero_pgtable = kernel_ptr_table();
 160                                 pte_dir = (pte_t *)zero_pgtable;
 161                                 pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
 162                                         _PAGE_TABLE | _PAGE_ACCESSED;
 163                                 pte_val(*pte_dir++) = 0;
 164                                 physaddr += PAGE_SIZE;
 165                                 for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
 166                                         pte_val(*pte_dir++) = physaddr;
 167                         }
 168                         size -= PTRTREESIZE;
 169                         virtaddr += PTRTREESIZE;
 170                 } else {
 171                         if (!pmd_present(*pmd_dir)) {
 172 #ifdef DEBUG
 173                                 printk ("[new table]");
 174 #endif
 175                                 pte_dir = kernel_page_table();
 176                                 pmd_set(pmd_dir, pte_dir);
 177                         }
 178                         pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
 179
 180                         if (virtaddr) {
 181                                 if (!pte_present(*pte_dir))
 182                                         pte_val(*pte_dir) = physaddr;
 183                         } else
 184                                 pte_val(*pte_dir) = 0;
 185                         size -= PAGE_SIZE;
 186                         virtaddr += PAGE_SIZE;
 187                         physaddr += PAGE_SIZE;
 188                 }
 189
 190         }
 191 #ifdef DEBUG
 192         printk("\n");
 193 #endif
 194
 195         return virtaddr;
 196 }
 197
 198 /*
 199  * paging_init() continues the virtual memory environment setup which
 200  * was begun by the code in arch/head.S.
 201  */
 202 void __init paging_init(void)
 203 {
 204         int chunk;
 205         unsigned long mem_avail = 0;
 206         unsigned long zones_size[3] = { 0, };
 207
 208 #ifdef DEBUG
 209         {
 210                 extern unsigned long availmem;
 211                 printk ("start of paging_init (%p, %lx, %lx, %lx)\n",
 212                         kernel_pg_dir, availmem, start_mem, end_mem);
 213         }
 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         /*
 227          * Map the physical memory available into the kernel virtual
 228          * address space.  It may allocate some memory for page
 229          * tables and thus modify availmem.
 230          */
 231
 232         for (chunk = 0; chunk < m68k_num_memory; chunk++) {
 233                 mem_avail = map_chunk (m68k_memory[chunk].addr,
 234                                        m68k_memory[chunk].size);
 235
 236         }
 237
 238         flush_tlb_all();
 239 #ifdef DEBUG
 240         printk ("memory available is %ldKB\n", mem_avail >> 10);
 241         printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
 242                 start_mem, end_mem);
 243 #endif
 244
 245         /*
 246          * initialize the bad page table and bad page to point
 247          * to a couple of allocated pages
 248          */
 249         empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
 250         memset(empty_zero_page, 0, PAGE_SIZE);
 251
 252         /*
 253          * Set up SFC/DFC registers
 254          */
 255         set_fs(KERNEL_DS);
 256
 257 #ifdef DEBUG
 258         printk ("before free_area_init\n");
 259 #endif
 260         zones_size[0] = (mach_max_dma_address < (unsigned long)high_memory ?
 261                          (mach_max_dma_address+1) : (unsigned long)high_memory);
 262         zones_size[1] = (unsigned long)high_memory - zones_size[0];
 263
 264         zones_size[0] = (zones_size[0] - PAGE_OFFSET) >> PAGE_SHIFT;
 265         zones_size[1] >>= PAGE_SHIFT;
 266
 267         free_area_init(zones_size);
 268 }
 269
 270 extern char __init_begin, __init_end;
 271
 272 void free_initmem(void)
 273 {
 274         unsigned long addr;
 275
 276         addr = (unsigned long)&__init_begin;
 277         for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
 278                 virt_to_page(addr)->flags &= ~(1 << PG_reserved);
 279                 set_page_count(virt_to_page(addr), 1);
 280                 free_page(addr);
 281                 totalram_pages++;
 282         }
 283 }
 284
 285