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