arch/m68k/atari/stram.c

   1 /*
   2  * arch/m68k/atari/stram.c: Functions for ST-RAM allocations
   3  *
   4  * Copyright 1994-97 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file COPYING in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/mm.h>
  14 #include <linux/kdev_t.h>
  15 #include <linux/major.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/pagemap.h>
  20 #include <linux/bootmem.h>
  21 #include <linux/mount.h>
  22 #include <linux/blkdev.h>
  23
  24 #include <asm/setup.h>
  25 #include <asm/machdep.h>
  26 #include <asm/page.h>
  27 #include <asm/pgtable.h>
  28 #include <asm/atarihw.h>
  29 #include <asm/atari_stram.h>
  30 #include <asm/io.h>
  31 #include <asm/semaphore.h>
  32
  33 #undef DEBUG
  34
  35 #ifdef DEBUG
  36 #define DPRINTK(fmt,args...) printk( fmt, ##args )
  37 #else
  38 #define DPRINTK(fmt,args...)
  39 #endif
  40
  41 #if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC)
  42 /* abbrev for the && above... */
  43 #define DO_PROC
  44 #include <linux/proc_fs.h>
  45 #endif
  46
  47 /*
  48  * ++roman:
  49  *
  50  * New version of ST-Ram buffer allocation. Instead of using the
  51  * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000
  52  * (1 MB granularity!), such buffers are reserved like this:
  53  *
  54  *  - If the kernel resides in ST-Ram anyway, we can take the buffer
  55  *    from behind the current kernel data space the normal way
  56  *    (incrementing start_mem).
  57  *
  58  *  - If the kernel is in TT-Ram, stram_init() initializes start and
  59  *    end of the available region. Buffers are allocated from there
  60  *    and mem_init() later marks the such used pages as reserved.
  61  *    Since each TT-Ram chunk is at least 4 MB in size, I hope there
  62  *    won't be an overrun of the ST-Ram region by normal kernel data
  63  *    space.
  64  *
  65  * For that, ST-Ram may only be allocated while kernel initialization
  66  * is going on, or exactly: before mem_init() is called. There is also
  67  * no provision now for freeing ST-Ram buffers. It seems that isn't
  68  * really needed.
  69  *
  70  */
  71
  72 /* Start and end (virtual) of ST-RAM */
  73 static void *stram_start, *stram_end;
  74
  75 /* set after memory_init() executed and allocations via start_mem aren't
  76  * possible anymore */
  77 static int mem_init_done;
  78
  79 /* set if kernel is in ST-RAM */
  80 static int kernel_in_stram;
  81
  82 typedef struct stram_block {
  83         struct stram_block *next;
  84         void *start;
  85         unsigned long size;
  86         unsigned flags;
  87         const char *owner;
  88 } BLOCK;
  89
  90 /* values for flags field */
  91 #define BLOCK_FREE      0x01    /* free structure in the BLOCKs pool */
  92 #define BLOCK_KMALLOCED 0x02    /* structure allocated by kmalloc() */
  93 #define BLOCK_GFP       0x08    /* block allocated with __get_dma_pages() */
  94
  95 /* list of allocated blocks */
  96 static BLOCK *alloc_list;
  97
  98 /* We can't always use kmalloc() to allocate BLOCK structures, since
  99  * stram_alloc() can be called rather early. So we need some pool of
 100  * statically allocated structures. 20 of them is more than enough, so in most
 101  * cases we never should need to call kmalloc(). */
 102 #define N_STATIC_BLOCKS 20
 103 static BLOCK static_blocks[N_STATIC_BLOCKS];
 104
 105 /***************************** Prototypes *****************************/
 106
 107 static BLOCK *add_region( void *addr, unsigned long size );
 108 static BLOCK *find_region( void *addr );
 109 static int remove_region( BLOCK *block );
 110
 111 /************************* End of Prototypes **************************/
 112
 113 \f
 114 /* ------------------------------------------------------------------------ */
 115 /*                                                         Public Interface                                                             */
 116 /* ------------------------------------------------------------------------ */
 117
 118 /*
 119  * This init function is called very early by atari/config.c
 120  * It initializes some internal variables needed for stram_alloc()
 121  */
 122 void __init atari_stram_init(void)
 123 {
 124         int i;
 125
 126         /* initialize static blocks */
 127         for( i = 0; i < N_STATIC_BLOCKS; ++i )
 128                 static_blocks[i].flags = BLOCK_FREE;
 129
 130         /* determine whether kernel code resides in ST-RAM (then ST-RAM is the
 131          * first memory block at virtual 0x0) */
 132         stram_start = phys_to_virt(0);
 133         kernel_in_stram = (stram_start == 0);
 134
 135         for( i = 0; i < m68k_num_memory; ++i ) {
 136                 if (m68k_memory[i].addr == 0) {
 137                         /* skip first 2kB or page (supervisor-only!) */
 138                         stram_end = stram_start + m68k_memory[i].size;
 139                         return;
 140                 }
 141         }
 142         /* Should never come here! (There is always ST-Ram!) */
 143         panic( "atari_stram_init: no ST-RAM found!" );
 144 }
 145
 146
 147 /*
 148  * This function is called from setup_arch() to reserve the pages needed for
 149  * ST-RAM management.
 150  */
 151 void __init atari_stram_reserve_pages(void *start_mem)
 152 {
 153         /* always reserve first page of ST-RAM, the first 2 kB are
 154          * supervisor-only! */
 155         if (!kernel_in_stram)
 156                 reserve_bootmem (0, PAGE_SIZE);
 157
 158 }
 159
 160 void atari_stram_mem_init_hook (void)
 161 {
 162         mem_init_done = 1;
 163 }
 164
 165
 166 /*
 167  * This is main public interface: somehow allocate a ST-RAM block
 168  *
 169  *  - If we're before mem_init(), we have to make a static allocation. The
 170  *    region is taken in the kernel data area (if the kernel is in ST-RAM) or
 171  *    from the start of ST-RAM (if the kernel is in TT-RAM) and added to the
 172  *    rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel
 173  *    address space in the latter case.
 174  *
 175  *  - If mem_init() already has been called, try with __get_dma_pages().
 176  *    This has the disadvantage that it's very hard to get more than 1 page,
 177  *    and it is likely to fail :-(
 178  *
 179  */
 180 void *atari_stram_alloc(long size, const char *owner)
 181 {
 182         void *addr = NULL;
 183         BLOCK *block;
 184         int flags;
 185
 186         DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner);
 187
 188         if (!mem_init_done)
 189                 return alloc_bootmem_low(size);
 190         else {
 191                 /* After mem_init(): can only resort to __get_dma_pages() */
 192                 addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
 193                 flags = BLOCK_GFP;
 194                 DPRINTK( "atari_stram_alloc: after mem_init, "
 195                                  "get_pages=%p\n", addr );
 196         }
 197
 198         if (addr) {
 199                 if (!(block = add_region( addr, size ))) {
 200                         /* out of memory for BLOCK structure :-( */
 201                         DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- "
 202                                          "freeing again\n" );
 203                         free_pages((unsigned long)addr, get_order(size));
 204                         return( NULL );
 205                 }
 206                 block->owner = owner;
 207                 block->flags |= flags;
 208         }
 209         return( addr );
 210 }
 211
 212 void atari_stram_free( void *addr )
 213
 214 {
 215         BLOCK *block;
 216
 217         DPRINTK( "atari_stram_free(addr=%p)\n", addr );
 218
 219         if (!(block = find_region( addr ))) {
 220                 printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p "
 221                                 "from %p\n", addr, __builtin_return_address(0) );
 222                 return;
 223         }
 224         DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, "
 225                          "flags=%02x\n", block, block->size, block->owner, block->flags );
 226
 227         if (!(block->flags & BLOCK_GFP))
 228                 goto fail;
 229
 230         DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n",
 231                 get_order(block->size));
 232         free_pages((unsigned long)addr, get_order(block->size));
 233         remove_region( block );
 234         return;
 235
 236   fail:
 237         printk( KERN_ERR "atari_stram_free: cannot free block at %p "
 238                         "(called from %p)\n", addr, __builtin_return_address(0) );
 239 }
 240
 241 \f
 242 /* ------------------------------------------------------------------------ */
 243 /*                                                        Region Management                                                             */
 244 /* ------------------------------------------------------------------------ */
 245
 246
 247 /* insert a region into the alloced list (sorted) */
 248 static BLOCK *add_region( void *addr, unsigned long size )
 249 {
 250         BLOCK **p, *n = NULL;
 251         int i;
 252
 253         for( i = 0; i < N_STATIC_BLOCKS; ++i ) {
 254                 if (static_blocks[i].flags & BLOCK_FREE) {
 255                         n = &static_blocks[i];
 256                         n->flags = 0;
 257                         break;
 258                 }
 259         }
 260         if (!n && mem_init_done) {
 261                 /* if statics block pool exhausted and we can call kmalloc() already
 262                  * (after mem_init()), try that */
 263                 n = kmalloc( sizeof(BLOCK), GFP_KERNEL );
 264                 if (n)
 265                         n->flags = BLOCK_KMALLOCED;
 266         }
 267         if (!n) {
 268                 printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" );
 269                 return( NULL );
 270         }
 271         n->start = addr;
 272         n->size  = size;
 273
 274         for( p = &alloc_list; *p; p = &((*p)->next) )
 275                 if ((*p)->start > addr) break;
 276         n->next = *p;
 277         *p = n;
 278
 279         return( n );
 280 }
 281
 282
 283 /* find a region (by start addr) in the alloced list */
 284 static BLOCK *find_region( void *addr )
 285 {
 286         BLOCK *p;
 287
 288         for( p = alloc_list; p; p = p->next ) {
 289                 if (p->start == addr)
 290                         return( p );
 291                 if (p->start > addr)
 292                         break;
 293         }
 294         return( NULL );
 295 }
 296
 297
 298 /* remove a block from the alloced list */
 299 static int remove_region( BLOCK *block )
 300 {
 301         BLOCK **p;
 302
 303         for( p = &alloc_list; *p; p = &((*p)->next) )
 304                 if (*p == block) break;
 305         if (!*p)
 306                 return( 0 );
 307
 308         *p = block->next;
 309         if (block->flags & BLOCK_KMALLOCED)
 310                 kfree( block );
 311         else
 312                 block->flags |= BLOCK_FREE;
 313         return( 1 );
 314 }
 315
 316
 317 \f
 318 /* ------------------------------------------------------------------------ */
 319 /*                                               /proc statistics file stuff                                            */
 320 /* ------------------------------------------------------------------------ */
 321
 322 #ifdef DO_PROC
 323
 324 #define PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args )
 325
 326 int get_stram_list( char *buf )
 327 {
 328         int len = 0;
 329         BLOCK *p;
 330
 331         PRINT_PROC("Total ST-RAM:      %8u kB\n",
 332                            (stram_end - stram_start) >> 10);
 333         PRINT_PROC( "Allocated regions:\n" );
 334         for( p = alloc_list; p; p = p->next ) {
 335                 if (len + 50 >= PAGE_SIZE)
 336                         break;
 337                 PRINT_PROC("0x%08lx-0x%08lx: %s (",
 338                            virt_to_phys(p->start),
 339                            virt_to_phys(p->start+p->size-1),
 340                            p->owner);
 341                 if (p->flags & BLOCK_GFP)
 342                         PRINT_PROC( "page-alloced)\n" );
 343                 else
 344                         PRINT_PROC( "??)\n" );
 345         }
 346
 347         return( len );
 348 }
 349
 350 #endif
 351
 352
 353 /*
 354  * Local variables:
 355  *  c-indent-level: 4
 356  *  tab-width: 4
 357  * End:
 358  */