arch/cris/arch-v10/drivers/axisflashmap.c

   1 /*
   2  * Physical mapping layer for MTD using the Axis partitiontable format
   3  *
   4  * Copyright (c) 2001, 2002 Axis Communications AB
   5  *
   6  * This file is under the GPL.
   7  *
   8  * First partition is always sector 0 regardless of if we find a partitiontable
   9  * or not. In the start of the next sector, there can be a partitiontable that
  10  * tells us what other partitions to define. If there isn't, we use a default
  11  * partition split defined below.
  12  *
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/types.h>
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20
  21 #include <linux/mtd/concat.h>
  22 #include <linux/mtd/map.h>
  23 #include <linux/mtd/mtd.h>
  24 #include <linux/mtd/mtdram.h>
  25 #include <linux/mtd/partitions.h>
  26
  27 #include <asm/axisflashmap.h>
  28 #include <asm/mmu.h>
  29 #include <arch/sv_addr_ag.h>
  30
  31 #ifdef CONFIG_CRIS_LOW_MAP
  32 #define FLASH_UNCACHED_ADDR  KSEG_8
  33 #define FLASH_CACHED_ADDR    KSEG_5
  34 #else
  35 #define FLASH_UNCACHED_ADDR  KSEG_E
  36 #define FLASH_CACHED_ADDR    KSEG_F
  37 #endif
  38
  39 #if CONFIG_ETRAX_FLASH_BUSWIDTH==1
  40 #define flash_data __u8
  41 #elif CONFIG_ETRAX_FLASH_BUSWIDTH==2
  42 #define flash_data __u16
  43 #elif CONFIG_ETRAX_FLASH_BUSWIDTH==4
  44 #define flash_data __u32
  45 #endif
  46
  47 /* From head.S */
  48 extern unsigned long romfs_start, romfs_length, romfs_in_flash;
  49
  50 /* The master mtd for the entire flash. */
  51 struct mtd_info* axisflash_mtd = NULL;
  52
  53 /* Map driver functions. */
  54
  55 static map_word flash_read(struct map_info *map, unsigned long ofs)
  56 {
  57         map_word tmp;
  58         tmp.x[0] = *(flash_data *)(map->map_priv_1 + ofs);
  59         return tmp;
  60 }
  61
  62 static void flash_copy_from(struct map_info *map, void *to,
  63                             unsigned long from, ssize_t len)
  64 {
  65         memcpy(to, (void *)(map->map_priv_1 + from), len);
  66 }
  67
  68 static void flash_write(struct map_info *map, map_word d, unsigned long adr)
  69 {
  70         *(flash_data *)(map->map_priv_1 + adr) = (flash_data)d.x[0];
  71 }
  72
  73 /*
  74  * The map for chip select e0.
  75  *
  76  * We run into tricky coherence situations if we mix cached with uncached
  77  * accesses to we only use the uncached version here.
  78  *
  79  * The size field is the total size where the flash chips may be mapped on the
  80  * chip select. MTD probes should find all devices there and it does not matter
  81  * if there are unmapped gaps or aliases (mirrors of flash devices). The MTD
  82  * probes will ignore them.
  83  *
  84  * The start address in map_priv_1 is in virtual memory so we cannot use
  85  * MEM_CSE0_START but must rely on that FLASH_UNCACHED_ADDR is the start
  86  * address of cse0.
  87  */
  88 static struct map_info map_cse0 = {
  89         .name = "cse0",
  90         .size = MEM_CSE0_SIZE,
  91         .bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
  92         .read = flash_read,
  93         .copy_from = flash_copy_from,
  94         .write = flash_write,
  95         .map_priv_1 = FLASH_UNCACHED_ADDR
  96 };
  97
  98 /*
  99  * The map for chip select e1.
 100  *
 101  * If there was a gap between cse0 and cse1, map_priv_1 would get the wrong
 102  * address, but there isn't.
 103  */
 104 static struct map_info map_cse1 = {
 105         .name = "cse1",
 106         .size = MEM_CSE1_SIZE,
 107         .bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
 108         .read = flash_read,
 109         .copy_from = flash_copy_from,
 110         .write = flash_write,
 111         .map_priv_1 = FLASH_UNCACHED_ADDR + MEM_CSE0_SIZE
 112 };
 113
 114 /* If no partition-table was found, we use this default-set. */
 115 #define MAX_PARTITIONS         7
 116 #define NUM_DEFAULT_PARTITIONS 3
 117
 118 /*
 119  * Default flash size is 2MB. CONFIG_ETRAX_PTABLE_SECTOR is most likely the
 120  * size of one flash block and "filesystem"-partition needs 5 blocks to be able
 121  * to use JFFS.
 122  */
 123 static struct mtd_partition axis_default_partitions[NUM_DEFAULT_PARTITIONS] = {
 124         {
 125                 .name = "boot firmware",
 126                 .size = CONFIG_ETRAX_PTABLE_SECTOR,
 127                 .offset = 0
 128         },
 129         {
 130                 .name = "kernel",
 131                 .size = 0x200000 - (6 * CONFIG_ETRAX_PTABLE_SECTOR),
 132                 .offset = CONFIG_ETRAX_PTABLE_SECTOR
 133         },
 134         {
 135                 .name = "filesystem",
 136                 .size = 5 * CONFIG_ETRAX_PTABLE_SECTOR,
 137                 .offset = 0x200000 - (5 * CONFIG_ETRAX_PTABLE_SECTOR)
 138         }
 139 };
 140
 141 /* Initialize the ones normally used. */
 142 static struct mtd_partition axis_partitions[MAX_PARTITIONS] = {
 143         {
 144                 .name = "part0",
 145                 .size = CONFIG_ETRAX_PTABLE_SECTOR,
 146                 .offset = 0
 147         },
 148         {
 149                 .name = "part1",
 150                 .size = 0,
 151                 .offset = 0
 152         },
 153         {
 154                 .name = "part2",
 155                 .size = 0,
 156                 .offset = 0
 157         },
 158         {
 159                 .name = "part3",
 160                 .size = 0,
 161                 .offset = 0
 162         },
 163         {
 164                 .name = "part4",
 165                 .size = 0,
 166                 .offset = 0
 167         },
 168         {
 169                 .name = "part5",
 170                 .size = 0,
 171                 .offset = 0
 172         },
 173         {
 174                 .name = "part6",
 175                 .size = 0,
 176                 .offset = 0
 177         },
 178 };
 179
 180 /*
 181  * Probe a chip select for AMD-compatible (JEDEC) or CFI-compatible flash
 182  * chips in that order (because the amd_flash-driver is faster).
 183  */
 184 static struct mtd_info *probe_cs(struct map_info *map_cs)
 185 {
 186         struct mtd_info *mtd_cs = NULL;
 187
 188         printk(KERN_INFO
 189                "%s: Probing a 0x%08lx bytes large window at 0x%08lx.\n",
 190                map_cs->name, map_cs->size, map_cs->map_priv_1);
 191
 192 #ifdef CONFIG_MTD_CFI
 193         mtd_cs = do_map_probe("cfi_probe", map_cs);
 194 #endif
 195 #ifdef CONFIG_MTD_JEDECPROBE
 196         if (!mtd_cs)
 197                 mtd_cs = do_map_probe("jedec_probe", map_cs);
 198 #endif
 199
 200         return mtd_cs;
 201 }
 202
 203 /*
 204  * Probe each chip select individually for flash chips. If there are chips on
 205  * both cse0 and cse1, the mtd_info structs will be concatenated to one struct
 206  * so that MTD partitions can cross chip boundaries.
 207  *
 208  * The only known restriction to how you can mount your chips is that each
 209  * chip select must hold similar flash chips. But you need external hardware
 210  * to do that anyway and you can put totally different chips on cse0 and cse1
 211  * so it isn't really much of a restriction.
 212  */
 213 static struct mtd_info *flash_probe(void)
 214 {
 215         struct mtd_info *mtd_cse0;
 216         struct mtd_info *mtd_cse1;
 217         struct mtd_info *mtd_cse;
 218
 219         mtd_cse0 = probe_cs(&map_cse0);
 220         mtd_cse1 = probe_cs(&map_cse1);
 221
 222         if (!mtd_cse0 && !mtd_cse1) {
 223                 /* No chip found. */
 224                 return NULL;
 225         }
 226
 227         if (mtd_cse0 && mtd_cse1) {
 228                 struct mtd_info *mtds[] = { mtd_cse0, mtd_cse1 };
 229
 230                 /* Since the concatenation layer adds a small overhead we
 231                  * could try to figure out if the chips in cse0 and cse1 are
 232                  * identical and reprobe the whole cse0+cse1 window. But since
 233                  * flash chips are slow, the overhead is relatively small.
 234                  * So we use the MTD concatenation layer instead of further
 235                  * complicating the probing procedure.
 236                  */
 237                 mtd_cse = mtd_concat_create(mtds, ARRAY_SIZE(mtds),
 238                                             "cse0+cse1");
 239                 if (!mtd_cse) {
 240                         printk(KERN_ERR "%s and %s: Concatenation failed!\n",
 241                                map_cse0.name, map_cse1.name);
 242
 243                         /* The best we can do now is to only use what we found
 244                          * at cse0.
 245                          */
 246                         mtd_cse = mtd_cse0;
 247                         map_destroy(mtd_cse1);
 248                 }
 249         } else {
 250                 mtd_cse = mtd_cse0? mtd_cse0 : mtd_cse1;
 251         }
 252
 253         return mtd_cse;
 254 }
 255
 256 /*
 257  * Probe the flash chip(s) and, if it succeeds, read the partition-table
 258  * and register the partitions with MTD.
 259  */
 260 static int __init init_axis_flash(void)
 261 {
 262         struct mtd_info *mymtd;
 263         int err = 0;
 264         int pidx = 0;
 265         struct partitiontable_head *ptable_head = NULL;
 266         struct partitiontable_entry *ptable;
 267         int use_default_ptable = 1; /* Until proven otherwise. */
 268         const char pmsg[] = "  /dev/flash%d at 0x%08x, size 0x%08x\n";
 269
 270         if (!(mymtd = flash_probe())) {
 271                 /* There's no reason to use this module if no flash chip can
 272                  * be identified. Make sure that's understood.
 273                  */
 274                 printk(KERN_INFO "axisflashmap: Found no flash chip.\n");
 275         } else {
 276                 printk(KERN_INFO "%s: 0x%08x bytes of flash memory.\n",
 277                        mymtd->name, mymtd->size);
 278                 axisflash_mtd = mymtd;
 279         }
 280
 281         if (mymtd) {
 282                 mymtd->owner = THIS_MODULE;
 283                 ptable_head = (struct partitiontable_head *)(FLASH_CACHED_ADDR +
 284                               CONFIG_ETRAX_PTABLE_SECTOR +
 285                               PARTITION_TABLE_OFFSET);
 286         }
 287         pidx++;  /* First partition is always set to the default. */
 288
 289         if (ptable_head && (ptable_head->magic == PARTITION_TABLE_MAGIC)
 290             && (ptable_head->size <
 291                 (MAX_PARTITIONS * sizeof(struct partitiontable_entry) +
 292                 PARTITIONTABLE_END_MARKER_SIZE))
 293             && (*(unsigned long*)((void*)ptable_head + sizeof(*ptable_head) +
 294                                   ptable_head->size -
 295                                   PARTITIONTABLE_END_MARKER_SIZE)
 296                 == PARTITIONTABLE_END_MARKER)) {
 297                 /* Looks like a start, sane length and end of a
 298                  * partition table, lets check csum etc.
 299                  */
 300                 int ptable_ok = 0;
 301                 struct partitiontable_entry *max_addr =
 302                         (struct partitiontable_entry *)
 303                         ((unsigned long)ptable_head + sizeof(*ptable_head) +
 304                          ptable_head->size);
 305                 unsigned long offset = CONFIG_ETRAX_PTABLE_SECTOR;
 306                 unsigned char *p;
 307                 unsigned long csum = 0;
 308
 309                 ptable = (struct partitiontable_entry *)
 310                         ((unsigned long)ptable_head + sizeof(*ptable_head));
 311
 312                 /* Lets be PARANOID, and check the checksum. */
 313                 p = (unsigned char*) ptable;
 314
 315                 while (p <= (unsigned char*)max_addr) {
 316                         csum += *p++;
 317                         csum += *p++;
 318                         csum += *p++;
 319                         csum += *p++;
 320                 }
 321                 ptable_ok = (csum == ptable_head->checksum);
 322
 323                 /* Read the entries and use/show the info.  */
 324                 printk(KERN_INFO " Found a%s partition table at 0x%p-0x%p.\n",
 325                        (ptable_ok ? " valid" : "n invalid"), ptable_head,
 326                        max_addr);
 327
 328                 /* We have found a working bootblock.  Now read the
 329                  * partition table.  Scan the table.  It ends when
 330                  * there is 0xffffffff, that is, empty flash.
 331                  */
 332                 while (ptable_ok
 333                        && ptable->offset != 0xffffffff
 334                        && ptable < max_addr
 335                        && pidx < MAX_PARTITIONS) {
 336
 337                         axis_partitions[pidx].offset = offset + ptable->offset;
 338                         axis_partitions[pidx].size = ptable->size;
 339
 340                         printk(pmsg, pidx, axis_partitions[pidx].offset,
 341                                axis_partitions[pidx].size);
 342                         pidx++;
 343                         ptable++;
 344                 }
 345                 use_default_ptable = !ptable_ok;
 346         }
 347
 348         if (romfs_in_flash) {
 349                 /* Add an overlapping device for the root partition (romfs). */
 350
 351                 axis_partitions[pidx].name = "romfs";
 352                 axis_partitions[pidx].size = romfs_length;
 353                 axis_partitions[pidx].offset = romfs_start - FLASH_CACHED_ADDR;
 354                 axis_partitions[pidx].mask_flags |= MTD_WRITEABLE;
 355
 356                 printk(KERN_INFO
 357                        " Adding readonly flash partition for romfs image:\n");
 358                 printk(pmsg, pidx, axis_partitions[pidx].offset,
 359                        axis_partitions[pidx].size);
 360                 pidx++;
 361         }
 362
 363         if (mymtd) {
 364                 if (use_default_ptable) {
 365                         printk(KERN_INFO " Using default partition table.\n");
 366                         err = mtd_device_register(mymtd,
 367                                                   axis_default_partitions,
 368                                                   NUM_DEFAULT_PARTITIONS);
 369                 } else {
 370                         err = mtd_device_register(mymtd, axis_partitions,
 371                                                   pidx);
 372                 }
 373
 374                 if (err)
 375                         panic("axisflashmap could not add MTD partitions!\n");
 376         }
 377
 378         if (!romfs_in_flash) {
 379                 /* Create an RAM device for the root partition (romfs). */
 380
 381 #if !defined(CONFIG_MTD_MTDRAM) || (CONFIG_MTDRAM_TOTAL_SIZE != 0)
 382                 /* No use trying to boot this kernel from RAM. Panic! */
 383                 printk(KERN_EMERG "axisflashmap: Cannot create an MTD RAM "
 384                        "device due to kernel (mis)configuration!\n");
 385                 panic("This kernel cannot boot from RAM!\n");
 386 #else
 387                 struct mtd_info *mtd_ram;
 388
 389                 mtd_ram = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
 390                 if (!mtd_ram)
 391                         panic("axisflashmap couldn't allocate memory for "
 392                               "mtd_info!\n");
 393
 394                 printk(KERN_INFO " Adding RAM partition for romfs image:\n");
 395                 printk(pmsg, pidx, (unsigned)romfs_start,
 396                         (unsigned)romfs_length);
 397
 398                 err = mtdram_init_device(mtd_ram,
 399                         (void *)romfs_start,
 400                         romfs_length,
 401                         "romfs");
 402                 if (err)
 403                         panic("axisflashmap could not initialize MTD RAM "
 404                               "device!\n");
 405 #endif
 406         }
 407         return err;
 408 }
 409
 410 /* This adds the above to the kernels init-call chain. */
 411 module_init(init_axis_flash);
 412
 413 EXPORT_SYMBOL(axisflash_mtd);