1 /* 2 * Linux driver for SSFDC Flash Translation Layer (Read only) 3 * © 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 pr_debug("SSFDC_RO: CIS/IDI sector not found" 139 " on %s (mtd%d)\n", mtd->name, 140 mtd->index); 141 } 142 break; 143 } 144 } 145 146 kfree(sect_buf); 147 out: 148 return cis_sector; 149 } 150 151 /* Read physical sector (wrapper to MTD_READ) */ 152 static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf, 153 int sect_no) 154 { 155 int ret; 156 size_t retlen; 157 loff_t offset = (loff_t)sect_no << SECTOR_SHIFT; 158 159 ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf); 160 if (ret < 0 || retlen != SECTOR_SIZE) 161 return -1; 162 163 return 0; 164 } 165 166 /* Read redundancy area (wrapper to MTD_READ_OOB */ 167 static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf) 168 { 169 struct mtd_oob_ops ops; 170 int ret; 171 172 ops.mode = MTD_OPS_RAW; 173 ops.ooboffs = 0; 174 ops.ooblen = OOB_SIZE; 175 ops.oobbuf = buf; 176 ops.datbuf = NULL; 177 178 ret = mtd_read_oob(mtd, offs, &ops); 179 if (ret < 0 || ops.oobretlen != OOB_SIZE) 180 return -1; 181 182 return 0; 183 } 184 185 /* Parity calculator on a word of n bit size */ 186 static int get_parity(int number, int size) 187 { 188 int k; 189 int parity; 190 191 parity = 1; 192 for (k = 0; k < size; k++) { 193 parity += (number >> k); 194 parity &= 1; 195 } 196 return parity; 197 } 198 199 /* Read and validate the logical block address field stored in the OOB */ 200 static int get_logical_address(uint8_t *oob_buf) 201 { 202 int block_address, parity; 203 int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */ 204 int j; 205 int ok = 0; 206 207 /* 208 * Look for the first valid logical address 209 * Valid address has fixed pattern on most significant bits and 210 * parity check 211 */ 212 for (j = 0; j < ARRAY_SIZE(offset); j++) { 213 block_address = ((int)oob_buf[offset[j]] << 8) | 214 oob_buf[offset[j]+1]; 215 216 /* Check for the signature bits in the address field (MSBits) */ 217 if ((block_address & ~0x7FF) == 0x1000) { 218 parity = block_address & 0x01; 219 block_address &= 0x7FF; 220 block_address >>= 1; 221 222 if (get_parity(block_address, 10) != parity) { 223 pr_debug("SSFDC_RO: logical address field%d" 224 "parity error(0x%04X)\n", j+1, 225 block_address); 226 } else { 227 ok = 1; 228 break; 229 } 230 } 231 } 232 233 if (!ok) 234 block_address = -2; 235 236 pr_debug("SSFDC_RO: get_logical_address() %d\n", 237 block_address); 238 239 return block_address; 240 } 241 242 /* Build the logic block map */ 243 static int build_logical_block_map(struct ssfdcr_record *ssfdc) 244 { 245 unsigned long offset; 246 uint8_t oob_buf[OOB_SIZE]; 247 int ret, block_address, phys_block; 248 struct mtd_info *mtd = ssfdc->mbd.mtd; 249 250 pr_debug("SSFDC_RO: build_block_map() nblks=%d (%luK)\n", 251 ssfdc->map_len, 252 (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024); 253 254 /* Scan every physical block, skip CIS block */ 255 for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len; 256 phys_block++) { 257 offset = (unsigned long)phys_block * ssfdc->erase_size; 258 if (mtd_block_isbad(mtd, offset)) 259 continue; /* skip bad blocks */ 260 261 ret = read_raw_oob(mtd, offset, oob_buf); 262 if (ret < 0) { 263 pr_debug("SSFDC_RO: mtd read_oob() failed at %lu\n", 264 offset); 265 return -1; 266 } 267 block_address = get_logical_address(oob_buf); 268 269 /* Skip invalid addresses */ 270 if (block_address >= 0 && 271 block_address < MAX_LOGIC_BLK_PER_ZONE) { 272 int zone_index; 273 274 zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE; 275 block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE; 276 ssfdc->logic_block_map[block_address] = 277 (unsigned short)phys_block; 278 279 pr_debug("SSFDC_RO: build_block_map() phys_block=%d," 280 "logic_block_addr=%d, zone=%d\n", 281 phys_block, block_address, zone_index); 282 } 283 } 284 return 0; 285 } 286 287 static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 288 { 289 struct ssfdcr_record *ssfdc; 290 int cis_sector; 291 292 /* Check for small page NAND flash */ 293 if (!mtd_type_is_nand(mtd) || mtd->oobsize != OOB_SIZE || 294 mtd->size > UINT_MAX) 295 return; 296 297 /* Check for SSDFC format by reading CIS/IDI sector */ 298 cis_sector = get_valid_cis_sector(mtd); 299 if (cis_sector == -1) 300 return; 301 302 ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL); 303 if (!ssfdc) 304 return; 305 306 ssfdc->mbd.mtd = mtd; 307 ssfdc->mbd.devnum = -1; 308 ssfdc->mbd.tr = tr; 309 ssfdc->mbd.readonly = 1; 310 311 ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT); 312 ssfdc->erase_size = mtd->erasesize; 313 ssfdc->map_len = (u32)mtd->size / mtd->erasesize; 314 315 pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n", 316 ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len, 317 DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE)); 318 319 /* Set geometry */ 320 ssfdc->heads = 16; 321 ssfdc->sectors = 32; 322 get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors); 323 ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) / 324 ((long)ssfdc->sectors * (long)ssfdc->heads)); 325 326 pr_debug("SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n", 327 ssfdc->cylinders, ssfdc->heads , ssfdc->sectors, 328 (long)ssfdc->cylinders * (long)ssfdc->heads * 329 (long)ssfdc->sectors); 330 331 ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders * 332 (long)ssfdc->sectors; 333 334 /* Allocate logical block map */ 335 ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) * 336 ssfdc->map_len, GFP_KERNEL); 337 if (!ssfdc->logic_block_map) 338 goto out_err; 339 memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) * 340 ssfdc->map_len); 341 342 /* Build logical block map */ 343 if (build_logical_block_map(ssfdc) < 0) 344 goto out_err; 345 346 /* Register device + partitions */ 347 if (add_mtd_blktrans_dev(&ssfdc->mbd)) 348 goto out_err; 349 350 printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n", 351 ssfdc->mbd.devnum + 'a', mtd->index, mtd->name); 352 return; 353 354 out_err: 355 kfree(ssfdc->logic_block_map); 356 kfree(ssfdc); 357 } 358 359 static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev) 360 { 361 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 362 363 pr_debug("SSFDC_RO: remove_dev (i=%d)\n", dev->devnum); 364 365 del_mtd_blktrans_dev(dev); 366 kfree(ssfdc->logic_block_map); 367 } 368 369 static int ssfdcr_readsect(struct mtd_blktrans_dev *dev, 370 unsigned long logic_sect_no, char *buf) 371 { 372 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 373 int sectors_per_block, offset, block_address; 374 375 sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT; 376 offset = (int)(logic_sect_no % sectors_per_block); 377 block_address = (int)(logic_sect_no / sectors_per_block); 378 379 pr_debug("SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d," 380 " block_addr=%d\n", logic_sect_no, sectors_per_block, offset, 381 block_address); 382 383 if (block_address >= ssfdc->map_len) 384 BUG(); 385 386 block_address = ssfdc->logic_block_map[block_address]; 387 388 pr_debug("SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n", 389 block_address); 390 391 if (block_address < 0xffff) { 392 unsigned long sect_no; 393 394 sect_no = (unsigned long)block_address * sectors_per_block + 395 offset; 396 397 pr_debug("SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n", 398 sect_no); 399 400 if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0) 401 return -EIO; 402 } else { 403 memset(buf, 0xff, SECTOR_SIZE); 404 } 405 406 return 0; 407 } 408 409 static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) 410 { 411 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 412 413 pr_debug("SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n", 414 ssfdc->cylinders, ssfdc->heads, ssfdc->sectors); 415 416 geo->heads = ssfdc->heads; 417 geo->sectors = ssfdc->sectors; 418 geo->cylinders = ssfdc->cylinders; 419 420 return 0; 421 } 422 423 /**************************************************************************** 424 * 425 * Module stuff 426 * 427 ****************************************************************************/ 428 429 static struct mtd_blktrans_ops ssfdcr_tr = { 430 .name = "ssfdc", 431 .major = SSFDCR_MAJOR, 432 .part_bits = SSFDCR_PARTN_BITS, 433 .blksize = SECTOR_SIZE, 434 .getgeo = ssfdcr_getgeo, 435 .readsect = ssfdcr_readsect, 436 .add_mtd = ssfdcr_add_mtd, 437 .remove_dev = ssfdcr_remove_dev, 438 .owner = THIS_MODULE, 439 }; 440 441 static int __init init_ssfdcr(void) 442 { 443 printk(KERN_INFO "SSFDC read-only Flash Translation layer\n"); 444 445 return register_mtd_blktrans(&ssfdcr_tr); 446 } 447 448 static void __exit cleanup_ssfdcr(void) 449 { 450 deregister_mtd_blktrans(&ssfdcr_tr); 451 } 452 453 module_init(init_ssfdcr); 454 module_exit(cleanup_ssfdcr); 455 456 MODULE_LICENSE("GPL"); 457 MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>"); 458 MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card"); 459