1 /* 2 * Linux driver for SSFDC Flash Translation Layer (Read only) 3 * (c) 2005 Eptar srl 4 * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com> 5 * 6 * Based on NTFL and MTDBLOCK_RO drivers 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/init.h> 16 #include <linux/slab.h> 17 #include <linux/hdreg.h> 18 #include <linux/mtd/mtd.h> 19 #include <linux/mtd/nand.h> 20 #include <linux/mtd/blktrans.h> 21 22 struct ssfdcr_record { 23 struct mtd_blktrans_dev mbd; 24 int usecount; 25 unsigned char heads; 26 unsigned char sectors; 27 unsigned short cylinders; 28 int cis_block; /* block n. containing CIS/IDI */ 29 int erase_size; /* phys_block_size */ 30 unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on 31 the 128MiB) */ 32 int map_len; /* n. phys_blocks on the card */ 33 }; 34 35 #define SSFDCR_MAJOR 257 36 #define SSFDCR_PARTN_BITS 3 37 38 #define SECTOR_SIZE 512 39 #define SECTOR_SHIFT 9 40 #define OOB_SIZE 16 41 42 #define MAX_LOGIC_BLK_PER_ZONE 1000 43 #define MAX_PHYS_BLK_PER_ZONE 1024 44 45 #define KiB(x) ( (x) * 1024L ) 46 #define MiB(x) ( KiB(x) * 1024L ) 47 48 /** CHS Table 49 1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB 50 NCylinder 125 125 250 250 500 500 500 500 51 NHead 4 4 4 4 4 8 8 16 52 NSector 4 8 8 16 16 16 32 32 53 SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000 54 SectorSize 512 512 512 512 512 512 512 512 55 **/ 56 57 typedef struct { 58 unsigned long size; 59 unsigned short cyl; 60 unsigned char head; 61 unsigned char sec; 62 } chs_entry_t; 63 64 /* Must be ordered by size */ 65 static const chs_entry_t chs_table[] = { 66 { MiB( 1), 125, 4, 4 }, 67 { MiB( 2), 125, 4, 8 }, 68 { MiB( 4), 250, 4, 8 }, 69 { MiB( 8), 250, 4, 16 }, 70 { MiB( 16), 500, 4, 16 }, 71 { MiB( 32), 500, 8, 16 }, 72 { MiB( 64), 500, 8, 32 }, 73 { MiB(128), 500, 16, 32 }, 74 { 0 }, 75 }; 76 77 static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head, 78 unsigned char *sec) 79 { 80 int k; 81 int found = 0; 82 83 k = 0; 84 while (chs_table[k].size > 0 && size > chs_table[k].size) 85 k++; 86 87 if (chs_table[k].size > 0) { 88 if (cyl) 89 *cyl = chs_table[k].cyl; 90 if (head) 91 *head = chs_table[k].head; 92 if (sec) 93 *sec = chs_table[k].sec; 94 found = 1; 95 } 96 97 return found; 98 } 99 100 /* These bytes are the signature for the CIS/IDI sector */ 101 static const uint8_t cis_numbers[] = { 102 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20 103 }; 104 105 /* Read and check for a valid CIS sector */ 106 static int get_valid_cis_sector(struct mtd_info *mtd) 107 { 108 int ret, k, cis_sector; 109 size_t retlen; 110 loff_t offset; 111 uint8_t *sect_buf; 112 113 cis_sector = -1; 114 115 sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL); 116 if (!sect_buf) 117 goto out; 118 119 /* 120 * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad 121 * blocks). If the first good block doesn't contain CIS number the flash 122 * is not SSFDC formatted 123 */ 124 for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) { 125 if (!mtd->block_isbad(mtd, offset)) { 126 ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, 127 sect_buf); 128 129 /* CIS pattern match on the sector buffer */ 130 if (ret < 0 || retlen != SECTOR_SIZE) { 131 printk(KERN_WARNING 132 "SSFDC_RO:can't read CIS/IDI sector\n"); 133 } else if (!memcmp(sect_buf, cis_numbers, 134 sizeof(cis_numbers))) { 135 /* Found */ 136 cis_sector = (int)(offset >> SECTOR_SHIFT); 137 } else { 138 DEBUG(MTD_DEBUG_LEVEL1, 139 "SSFDC_RO: CIS/IDI sector not found" 140 " on %s (mtd%d)\n", mtd->name, 141 mtd->index); 142 } 143 break; 144 } 145 } 146 147 kfree(sect_buf); 148 out: 149 return cis_sector; 150 } 151 152 /* Read physical sector (wrapper to MTD_READ) */ 153 static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf, 154 int sect_no) 155 { 156 int ret; 157 size_t retlen; 158 loff_t offset = (loff_t)sect_no << SECTOR_SHIFT; 159 160 ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf); 161 if (ret < 0 || retlen != SECTOR_SIZE) 162 return -1; 163 164 return 0; 165 } 166 167 /* Read redundancy area (wrapper to MTD_READ_OOB */ 168 static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf) 169 { 170 struct mtd_oob_ops ops; 171 int ret; 172 173 ops.mode = MTD_OOB_RAW; 174 ops.ooboffs = 0; 175 ops.ooblen = OOB_SIZE; 176 ops.oobbuf = buf; 177 ops.datbuf = NULL; 178 179 ret = mtd->read_oob(mtd, offs, &ops); 180 if (ret < 0 || ops.oobretlen != OOB_SIZE) 181 return -1; 182 183 return 0; 184 } 185 186 /* Parity calculator on a word of n bit size */ 187 static int get_parity(int number, int size) 188 { 189 int k; 190 int parity; 191 192 parity = 1; 193 for (k = 0; k < size; k++) { 194 parity += (number >> k); 195 parity &= 1; 196 } 197 return parity; 198 } 199 200 /* Read and validate the logical block address field stored in the OOB */ 201 static int get_logical_address(uint8_t *oob_buf) 202 { 203 int block_address, parity; 204 int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */ 205 int j; 206 int ok = 0; 207 208 /* 209 * Look for the first valid logical address 210 * Valid address has fixed pattern on most significant bits and 211 * parity check 212 */ 213 for (j = 0; j < ARRAY_SIZE(offset); j++) { 214 block_address = ((int)oob_buf[offset[j]] << 8) | 215 oob_buf[offset[j]+1]; 216 217 /* Check for the signature bits in the address field (MSBits) */ 218 if ((block_address & ~0x7FF) == 0x1000) { 219 parity = block_address & 0x01; 220 block_address &= 0x7FF; 221 block_address >>= 1; 222 223 if (get_parity(block_address, 10) != parity) { 224 DEBUG(MTD_DEBUG_LEVEL0, 225 "SSFDC_RO: logical address field%d" 226 "parity error(0x%04X)\n", j+1, 227 block_address); 228 } else { 229 ok = 1; 230 break; 231 } 232 } 233 } 234 235 if (!ok) 236 block_address = -2; 237 238 DEBUG(MTD_DEBUG_LEVEL3, "SSFDC_RO: get_logical_address() %d\n", 239 block_address); 240 241 return block_address; 242 } 243 244 /* Build the logic block map */ 245 static int build_logical_block_map(struct ssfdcr_record *ssfdc) 246 { 247 unsigned long offset; 248 uint8_t oob_buf[OOB_SIZE]; 249 int ret, block_address, phys_block; 250 struct mtd_info *mtd = ssfdc->mbd.mtd; 251 252 DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() nblks=%d (%luK)\n", 253 ssfdc->map_len, 254 (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024); 255 256 /* Scan every physical block, skip CIS block */ 257 for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len; 258 phys_block++) { 259 offset = (unsigned long)phys_block * ssfdc->erase_size; 260 if (mtd->block_isbad(mtd, offset)) 261 continue; /* skip bad blocks */ 262 263 ret = read_raw_oob(mtd, offset, oob_buf); 264 if (ret < 0) { 265 DEBUG(MTD_DEBUG_LEVEL0, 266 "SSFDC_RO: mtd read_oob() failed at %lu\n", 267 offset); 268 return -1; 269 } 270 block_address = get_logical_address(oob_buf); 271 272 /* Skip invalid addresses */ 273 if (block_address >= 0 && 274 block_address < MAX_LOGIC_BLK_PER_ZONE) { 275 int zone_index; 276 277 zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE; 278 block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE; 279 ssfdc->logic_block_map[block_address] = 280 (unsigned short)phys_block; 281 282 DEBUG(MTD_DEBUG_LEVEL2, 283 "SSFDC_RO: build_block_map() phys_block=%d," 284 "logic_block_addr=%d, zone=%d\n", 285 phys_block, block_address, zone_index); 286 } 287 } 288 return 0; 289 } 290 291 static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 292 { 293 struct ssfdcr_record *ssfdc; 294 int cis_sector; 295 296 /* Check for small page NAND flash */ 297 if (mtd->type != MTD_NANDFLASH || mtd->oobsize != OOB_SIZE) 298 return; 299 300 /* Check for SSDFC format by reading CIS/IDI sector */ 301 cis_sector = get_valid_cis_sector(mtd); 302 if (cis_sector == -1) 303 return; 304 305 ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL); 306 if (!ssfdc) { 307 printk(KERN_WARNING 308 "SSFDC_RO: out of memory for data structures\n"); 309 return; 310 } 311 312 ssfdc->mbd.mtd = mtd; 313 ssfdc->mbd.devnum = -1; 314 ssfdc->mbd.tr = tr; 315 ssfdc->mbd.readonly = 1; 316 317 ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT); 318 ssfdc->erase_size = mtd->erasesize; 319 ssfdc->map_len = mtd->size / mtd->erasesize; 320 321 DEBUG(MTD_DEBUG_LEVEL1, 322 "SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n", 323 ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len, 324 (ssfdc->map_len + MAX_PHYS_BLK_PER_ZONE - 1) / 325 MAX_PHYS_BLK_PER_ZONE); 326 327 /* Set geometry */ 328 ssfdc->heads = 16; 329 ssfdc->sectors = 32; 330 get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors); 331 ssfdc->cylinders = (unsigned short)((mtd->size >> SECTOR_SHIFT) / 332 ((long)ssfdc->sectors * (long)ssfdc->heads)); 333 334 DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n", 335 ssfdc->cylinders, ssfdc->heads , ssfdc->sectors, 336 (long)ssfdc->cylinders * (long)ssfdc->heads * 337 (long)ssfdc->sectors); 338 339 ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders * 340 (long)ssfdc->sectors; 341 342 /* Allocate logical block map */ 343 ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) * 344 ssfdc->map_len, GFP_KERNEL); 345 if (!ssfdc->logic_block_map) { 346 printk(KERN_WARNING 347 "SSFDC_RO: out of memory for data structures\n"); 348 goto out_err; 349 } 350 memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) * 351 ssfdc->map_len); 352 353 /* Build logical block map */ 354 if (build_logical_block_map(ssfdc) < 0) 355 goto out_err; 356 357 /* Register device + partitions */ 358 if (add_mtd_blktrans_dev(&ssfdc->mbd)) 359 goto out_err; 360 361 printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n", 362 ssfdc->mbd.devnum + 'a', mtd->index, mtd->name); 363 return; 364 365 out_err: 366 kfree(ssfdc->logic_block_map); 367 kfree(ssfdc); 368 } 369 370 static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev) 371 { 372 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 373 374 DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: remove_dev (i=%d)\n", dev->devnum); 375 376 del_mtd_blktrans_dev(dev); 377 kfree(ssfdc->logic_block_map); 378 kfree(ssfdc); 379 } 380 381 static int ssfdcr_readsect(struct mtd_blktrans_dev *dev, 382 unsigned long logic_sect_no, char *buf) 383 { 384 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 385 int sectors_per_block, offset, block_address; 386 387 sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT; 388 offset = (int)(logic_sect_no % sectors_per_block); 389 block_address = (int)(logic_sect_no / sectors_per_block); 390 391 DEBUG(MTD_DEBUG_LEVEL3, 392 "SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d," 393 " block_addr=%d\n", logic_sect_no, sectors_per_block, offset, 394 block_address); 395 396 if (block_address >= ssfdc->map_len) 397 BUG(); 398 399 block_address = ssfdc->logic_block_map[block_address]; 400 401 DEBUG(MTD_DEBUG_LEVEL3, 402 "SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n", 403 block_address); 404 405 if (block_address < 0xffff) { 406 unsigned long sect_no; 407 408 sect_no = (unsigned long)block_address * sectors_per_block + 409 offset; 410 411 DEBUG(MTD_DEBUG_LEVEL3, 412 "SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n", 413 sect_no); 414 415 if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0) 416 return -EIO; 417 } else { 418 memset(buf, 0xff, SECTOR_SIZE); 419 } 420 421 return 0; 422 } 423 424 static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) 425 { 426 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 427 428 DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n", 429 ssfdc->cylinders, ssfdc->heads, ssfdc->sectors); 430 431 geo->heads = ssfdc->heads; 432 geo->sectors = ssfdc->sectors; 433 geo->cylinders = ssfdc->cylinders; 434 435 return 0; 436 } 437 438 /**************************************************************************** 439 * 440 * Module stuff 441 * 442 ****************************************************************************/ 443 444 static struct mtd_blktrans_ops ssfdcr_tr = { 445 .name = "ssfdc", 446 .major = SSFDCR_MAJOR, 447 .part_bits = SSFDCR_PARTN_BITS, 448 .blksize = SECTOR_SIZE, 449 .getgeo = ssfdcr_getgeo, 450 .readsect = ssfdcr_readsect, 451 .add_mtd = ssfdcr_add_mtd, 452 .remove_dev = ssfdcr_remove_dev, 453 .owner = THIS_MODULE, 454 }; 455 456 static int __init init_ssfdcr(void) 457 { 458 printk(KERN_INFO "SSFDC read-only Flash Translation layer\n"); 459 460 return register_mtd_blktrans(&ssfdcr_tr); 461 } 462 463 static void __exit cleanup_ssfdcr(void) 464 { 465 deregister_mtd_blktrans(&ssfdcr_tr); 466 } 467 468 module_init(init_ssfdcr); 469 module_exit(cleanup_ssfdcr); 470 471 MODULE_LICENSE("GPL"); 472 MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>"); 473 MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card"); 474