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/config.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/kdev_t.h>
  16 #include <linux/major.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/bootmem.h>
  22 #include <linux/mount.h>
  23 #include <linux/blkdev.h>
  24
  25 #include <asm/setup.h>
  26 #include <asm/machdep.h>
  27 #include <asm/page.h>
  28 #include <asm/pgtable.h>
  29 #include <asm/atarihw.h>
  30 #include <asm/atari_stram.h>
  31 #include <asm/io.h>
  32 #include <asm/semaphore.h>
  33
  34 #undef DEBUG
  35
  36 #ifdef DEBUG
  37 #define DPRINTK(fmt,args...) printk( fmt, ##args )
  38 #else
  39 #define DPRINTK(fmt,args...)
  40 #endif
  41
  42 #if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC)
  43 /* abbrev for the && above... */
  44 #define DO_PROC
  45 #include <linux/proc_fs.h>
  46 #endif
  47
  48 /*
  49  * ++roman:
  50  *
  51  * New version of ST-Ram buffer allocation. Instead of using the
  52  * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000
  53  * (1 MB granularity!), such buffers are reserved like this:
  54  *
  55  *  - If the kernel resides in ST-Ram anyway, we can take the buffer
  56  *    from behind the current kernel data space the normal way
  57  *    (incrementing start_mem).
  58  *
  59  *  - If the kernel is in TT-Ram, stram_init() initializes start and
  60  *    end of the available region. Buffers are allocated from there
  61  *    and mem_init() later marks the such used pages as reserved.
  62  *    Since each TT-Ram chunk is at least 4 MB in size, I hope there
  63  *    won't be an overrun of the ST-Ram region by normal kernel data
  64  *    space.
  65  *
  66  * For that, ST-Ram may only be allocated while kernel initialization
  67  * is going on, or exactly: before mem_init() is called. There is also
  68  * no provision now for freeing ST-Ram buffers. It seems that isn't
  69  * really needed.
  70  *
  71  */
  72
  73 /* Start and end (virtual) of ST-RAM */
  74 static void *stram_start, *stram_end;
  75
  76 /* set after memory_init() executed and allocations via start_mem aren't
  77  * possible anymore */
  78 static int mem_init_done;
  79
  80 /* set if kernel is in ST-RAM */
  81 static int kernel_in_stram;
  82
  83 typedef struct stram_block {
  84         struct stram_block *next;
  85         void *start;
  86         unsigned long size;
  87         unsigned flags;
  88         const char *owner;
  89 } BLOCK;
  90
  91 /* values for flags field */
  92 #define BLOCK_FREE      0x01    /* free structure in the BLOCKs pool */
  93 #define BLOCK_KMALLOCED 0x02    /* structure allocated by kmalloc() */
  94 #define BLOCK_GFP       0x08    /* block allocated with __get_dma_pages() */
  95
  96 /* list of allocated blocks */
  97 static BLOCK *alloc_list;
  98
  99 /* We can't always use kmalloc() to allocate BLOCK structures, since
 100  * stram_alloc() can be called rather early. So we need some pool of
 101  * statically allocated structures. 20 of them is more than enough, so in most
 102  * cases we never should need to call kmalloc(). */
 103 #define N_STATIC_BLOCKS 20
 104 static BLOCK static_blocks[N_STATIC_BLOCKS];
 105
 106 /***************************** Prototypes *****************************/
 107
 108 static BLOCK *add_region( void *addr, unsigned long size );
 109 static BLOCK *find_region( void *addr );
 110 static int remove_region( BLOCK *block );
 111
 112 /************************* End of Prototypes **************************/
 113
 114 \f
 115 /* ------------------------------------------------------------------------ */
 116 /*                                                         Public Interface                                                             */
 117 /* ------------------------------------------------------------------------ */
 118
 119 /*
 120  * This init function is called very early by atari/config.c
 121  * It initializes some internal variables needed for stram_alloc()
 122  */
 123 void __init atari_stram_init(void)
 124 {
 125         int i;
 126
 127         /* initialize static blocks */
 128         for( i = 0; i < N_STATIC_BLOCKS; ++i )
 129                 static_blocks[i].flags = BLOCK_FREE;
 130
 131         /* determine whether kernel code resides in ST-RAM (then ST-RAM is the
 132          * first memory block at virtual 0x0) */
 133         stram_start = phys_to_virt(0);
 134         kernel_in_stram = (stram_start == 0);
 135
 136         for( i = 0; i < m68k_num_memory; ++i ) {
 137                 if (m68k_memory[i].addr == 0) {
 138                         /* skip first 2kB or page (supervisor-only!) */
 139                         stram_end = stram_start + m68k_memory[i].size;
 140                         return;
 141                 }
 142         }
 143         /* Should never come here! (There is always ST-Ram!) */
 144         panic( "atari_stram_init: no ST-RAM found!" );
 145 }
 146
 147
 148 /*
 149  * This function is called from setup_arch() to reserve the pages needed for
 150  * ST-RAM management.
 151  */
 152 void __init atari_stram_reserve_pages(void *start_mem)
 153 {
 154         /* always reserve first page of ST-RAM, the first 2 kB are
 155          * supervisor-only! */
 156         if (!kernel_in_stram)
 157                 reserve_bootmem (0, PAGE_SIZE);
 158
 159 }
 160
 161 void atari_stram_mem_init_hook (void)
 162 {
 163         mem_init_done = 1;
 164 }
 165
 166
 167 /*
 168  * This is main public interface: somehow allocate a ST-RAM block
 169  *
 170  *  - If we're before mem_init(), we have to make a static allocation. The
 171  *    region is taken in the kernel data area (if the kernel is in ST-RAM) or
 172  *    from the start of ST-RAM (if the kernel is in TT-RAM) and added to the
 173  *    rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel
 174  *    address space in the latter case.
 175  *
 176  *  - If mem_init() already has been called, try with __get_dma_pages().
 177  *    This has the disadvantage that it's very hard to get more than 1 page,
 178  *    and it is likely to fail :-(
 179  *
 180  */
 181 void *atari_stram_alloc(long size, const char *owner)
 182 {
 183         void *addr = NULL;
 184         BLOCK *block;
 185         int flags;
 186
 187         DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner);
 188
 189         if (!mem_init_done)
 190                 return alloc_bootmem_low(size);
 191         else {
 192                 /* After mem_init(): can only resort to __get_dma_pages() */
 193                 addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
 194                 flags = BLOCK_GFP;
 195                 DPRINTK( "atari_stram_alloc: after mem_init, "
 196                                  "get_pages=%p\n", addr );
 197         }
 198
 199         if (addr) {
 200                 if (!(block = add_region( addr, size ))) {
 201                         /* out of memory for BLOCK structure :-( */
 202                         DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- "
 203                                          "freeing again\n" );
 204                         free_pages((unsigned long)addr, get_order(size));
 205                         return( NULL );
 206                 }
 207                 block->owner = owner;
 208                 block->flags |= flags;
 209         }
 210         return( addr );
 211 }
 212
 213 void atari_stram_free( void *addr )
 214
 215 {
 216         BLOCK *block;
 217
 218         DPRINTK( "atari_stram_free(addr=%p)\n", addr );
 219
 220         if (!(block = find_region( addr ))) {
 221                 printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p "
 222                                 "from %p\n", addr, __builtin_return_address(0) );
 223                 return;
 224         }
 225         DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, "
 226                          "flags=%02x\n", block, block->size, block->owner, block->flags );
 227
 228         if (!(block->flags & BLOCK_GFP))
 229                 goto fail;
 230
 231         DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n",
 232                 get_order(block->size));
 233         free_pages((unsigned long)addr, get_order(block->size));
 234         remove_region( block );
 235         return;
 236
 237   fail:
 238         printk( KERN_ERR "atari_stram_free: cannot free block at %p "
 239                         "(called from %p)\n", addr, __builtin_return_address(0) );
 240 }
 241
 242 \f
 243 /* ------------------------------------------------------------------------ */
 244 /*                                                        Region Management                                                             */
 245 /* ------------------------------------------------------------------------ */
 246
 247
 248 /* insert a region into the alloced list (sorted) */
 249 static BLOCK *add_region( void *addr, unsigned long size )
 250 {
 251         BLOCK **p, *n = NULL;
 252         int i;
 253
 254         for( i = 0; i < N_STATIC_BLOCKS; ++i ) {
 255                 if (static_blocks[i].flags & BLOCK_FREE) {
 256                         n = &static_blocks[i];
 257                         n->flags = 0;
 258                         break;
 259                 }
 260         }
 261         if (!n && mem_init_done) {
 262                 /* if statics block pool exhausted and we can call kmalloc() already
 263                  * (after mem_init()), try that */
 264                 n = kmalloc( sizeof(BLOCK), GFP_KERNEL );
 265                 if (n)
 266                         n->flags = BLOCK_KMALLOCED;
 267         }
 268         if (!n) {
 269                 printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" );
 270                 return( NULL );
 271         }
 272         n->start = addr;
 273         n->size  = size;
 274
 275         for( p = &alloc_list; *p; p = &((*p)->next) )
 276                 if ((*p)->start > addr) break;
 277         n->next = *p;
 278         *p = n;
 279
 280         return( n );
 281 }
 282
 283
 284 /* find a region (by start addr) in the alloced list */
 285 static BLOCK *find_region( void *addr )
 286 {
 287         BLOCK *p;
 288
 289         for( p = alloc_list; p; p = p->next ) {
 290                 if (p->start == addr)
 291                         return( p );
 292                 if (p->start > addr)
 293                         break;
 294         }
 295         return( NULL );
 296 }
 297
 298
 299 /* remove a block from the alloced list */
 300 static int remove_region( BLOCK *block )
 301 {
 302         BLOCK **p;
 303
 304         for( p = &alloc_list; *p; p = &((*p)->next) )
 305                 if (*p == block) break;
 306         if (!*p)
 307                 return( 0 );
 308
 309         *p = block->next;
 310         if (block->flags & BLOCK_KMALLOCED)
 311                 kfree( block );
 312         else
 313                 block->flags |= BLOCK_FREE;
 314         return( 1 );
 315 }
 316
 317
 318 \f
 319 /* ------------------------------------------------------------------------ */
 320 /*                                               /proc statistics file stuff                                            */
 321 /* ------------------------------------------------------------------------ */
 322
 323 #ifdef DO_PROC
 324
 325 #define PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args )
 326
 327 int get_stram_list( char *buf )
 328 {
 329         int len = 0;
 330         BLOCK *p;
 331
 332         PRINT_PROC("Total ST-RAM:      %8u kB\n",
 333                            (stram_end - stram_start) >> 10);
 334         PRINT_PROC( "Allocated regions:\n" );
 335         for( p = alloc_list; p; p = p->next ) {
 336                 if (len + 50 >= PAGE_SIZE)
 337                         break;
 338                 PRINT_PROC("0x%08lx-0x%08lx: %s (",
 339                            virt_to_phys(p->start),
 340                            virt_to_phys(p->start+p->size-1),
 341                            p->owner);
 342                 if (p->flags & BLOCK_GFP)
 343                         PRINT_PROC( "page-alloced)\n" );
 344                 else
 345                         PRINT_PROC( "??)\n" );
 346         }
 347
 348         return( len );
 349 }
 350
 351 #endif
 352
 353
 354 /*
 355  * Local variables:
 356  *  c-indent-level: 4
 357  *  tab-width: 4
 358  * End:
 359  */