1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Linux driver for SSFDC Flash Translation Layer (Read only) 4 * © 2005 Eptar srl 5 * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com> 6 * 7 * Based on NTFL and MTDBLOCK_RO drivers 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/init.h> 13 #include <linux/slab.h> 14 #include <linux/hdreg.h> 15 #include <linux/mtd/mtd.h> 16 #include <linux/mtd/rawnand.h> 17 #include <linux/mtd/blktrans.h> 18 19 struct ssfdcr_record { 20 struct mtd_blktrans_dev mbd; 21 int usecount; 22 unsigned char heads; 23 unsigned char sectors; 24 unsigned short cylinders; 25 int cis_block; /* block n. containing CIS/IDI */ 26 int erase_size; /* phys_block_size */ 27 unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on 28 the 128MiB) */ 29 int map_len; /* n. phys_blocks on the card */ 30 }; 31 32 #define SSFDCR_MAJOR 257 33 #define SSFDCR_PARTN_BITS 3 34 35 #define SECTOR_SIZE 512 36 #define SECTOR_SHIFT 9 37 #define OOB_SIZE 16 38 39 #define MAX_LOGIC_BLK_PER_ZONE 1000 40 #define MAX_PHYS_BLK_PER_ZONE 1024 41 42 #define KiB(x) ( (x) * 1024L ) 43 #define MiB(x) ( KiB(x) * 1024L ) 44 45 /** CHS Table 46 1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB 47 NCylinder 125 125 250 250 500 500 500 500 48 NHead 4 4 4 4 4 8 8 16 49 NSector 4 8 8 16 16 16 32 32 50 SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000 51 SectorSize 512 512 512 512 512 512 512 512 52 **/ 53 54 typedef struct { 55 unsigned long size; 56 unsigned short cyl; 57 unsigned char head; 58 unsigned char sec; 59 } chs_entry_t; 60 61 /* Must be ordered by size */ 62 static const chs_entry_t chs_table[] = { 63 { MiB( 1), 125, 4, 4 }, 64 { MiB( 2), 125, 4, 8 }, 65 { MiB( 4), 250, 4, 8 }, 66 { MiB( 8), 250, 4, 16 }, 67 { MiB( 16), 500, 4, 16 }, 68 { MiB( 32), 500, 8, 16 }, 69 { MiB( 64), 500, 8, 32 }, 70 { MiB(128), 500, 16, 32 }, 71 { 0 }, 72 }; 73 74 static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head, 75 unsigned char *sec) 76 { 77 int k; 78 int found = 0; 79 80 k = 0; 81 while (chs_table[k].size > 0 && size > chs_table[k].size) 82 k++; 83 84 if (chs_table[k].size > 0) { 85 if (cyl) 86 *cyl = chs_table[k].cyl; 87 if (head) 88 *head = chs_table[k].head; 89 if (sec) 90 *sec = chs_table[k].sec; 91 found = 1; 92 } 93 94 return found; 95 } 96 97 /* These bytes are the signature for the CIS/IDI sector */ 98 static const uint8_t cis_numbers[] = { 99 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20 100 }; 101 102 /* Read and check for a valid CIS sector */ 103 static int get_valid_cis_sector(struct mtd_info *mtd) 104 { 105 int ret, k, cis_sector; 106 size_t retlen; 107 loff_t offset; 108 uint8_t *sect_buf; 109 110 cis_sector = -1; 111 112 sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL); 113 if (!sect_buf) 114 goto out; 115 116 /* 117 * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad 118 * blocks). If the first good block doesn't contain CIS number the flash 119 * is not SSFDC formatted 120 */ 121 for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) { 122 if (mtd_block_isbad(mtd, offset)) { 123 ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, 124 sect_buf); 125 126 /* CIS pattern match on the sector buffer */ 127 if (ret < 0 || retlen != SECTOR_SIZE) { 128 printk(KERN_WARNING 129 "SSFDC_RO:can't read CIS/IDI sector\n"); 130 } else if (!memcmp(sect_buf, cis_numbers, 131 sizeof(cis_numbers))) { 132 /* Found */ 133 cis_sector = (int)(offset >> SECTOR_SHIFT); 134 } else { 135 pr_debug("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 kfree(sect_buf); 144 out: 145 return cis_sector; 146 } 147 148 /* Read physical sector (wrapper to MTD_READ) */ 149 static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf, 150 int sect_no) 151 { 152 int ret; 153 size_t retlen; 154 loff_t offset = (loff_t)sect_no << SECTOR_SHIFT; 155 156 ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf); 157 if (ret < 0 || retlen != SECTOR_SIZE) 158 return -1; 159 160 return 0; 161 } 162 163 /* Read redundancy area (wrapper to MTD_READ_OOB */ 164 static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf) 165 { 166 struct mtd_oob_ops ops = { }; 167 int ret; 168 169 ops.mode = MTD_OPS_RAW; 170 ops.ooboffs = 0; 171 ops.ooblen = OOB_SIZE; 172 ops.oobbuf = buf; 173 ops.datbuf = NULL; 174 175 ret = mtd_read_oob(mtd, offs, &ops); 176 if (ret < 0 || ops.oobretlen != OOB_SIZE) 177 return -1; 178 179 return 0; 180 } 181 182 /* Parity calculator on a word of n bit size */ 183 static int get_parity(int number, int size) 184 { 185 int k; 186 int parity; 187 188 parity = 1; 189 for (k = 0; k < size; k++) { 190 parity += (number >> k); 191 parity &= 1; 192 } 193 return parity; 194 } 195 196 /* Read and validate the logical block address field stored in the OOB */ 197 static int get_logical_address(uint8_t *oob_buf) 198 { 199 int block_address, parity; 200 int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */ 201 int j; 202 int ok = 0; 203 204 /* 205 * Look for the first valid logical address 206 * Valid address has fixed pattern on most significant bits and 207 * parity check 208 */ 209 for (j = 0; j < ARRAY_SIZE(offset); j++) { 210 block_address = ((int)oob_buf[offset[j]] << 8) | 211 oob_buf[offset[j]+1]; 212 213 /* Check for the signature bits in the address field (MSBits) */ 214 if ((block_address & ~0x7FF) == 0x1000) { 215 parity = block_address & 0x01; 216 block_address &= 0x7FF; 217 block_address >>= 1; 218 219 if (get_parity(block_address, 10) != parity) { 220 pr_debug("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 pr_debug("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 pr_debug("SSFDC_RO: build_block_map() nblks=%d (%luK)\n", 248 ssfdc->map_len, 249 (unsigned long)ssfdc->map_len * 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 pr_debug("SSFDC_RO: mtd read_oob() failed at %lu\n", 261 offset); 262 return -1; 263 } 264 block_address = get_logical_address(oob_buf); 265 266 /* Skip invalid addresses */ 267 if (block_address >= 0 && 268 block_address < MAX_LOGIC_BLK_PER_ZONE) { 269 int zone_index; 270 271 zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE; 272 block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE; 273 ssfdc->logic_block_map[block_address] = 274 (unsigned short)phys_block; 275 276 pr_debug("SSFDC_RO: build_block_map() phys_block=%d," 277 "logic_block_addr=%d, zone=%d\n", 278 phys_block, block_address, zone_index); 279 } 280 } 281 return 0; 282 } 283 284 static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 285 { 286 struct ssfdcr_record *ssfdc; 287 int cis_sector; 288 289 /* Check for small page NAND flash */ 290 if (!mtd_type_is_nand(mtd) || mtd->oobsize != OOB_SIZE || 291 mtd->size > UINT_MAX) 292 return; 293 294 /* Check for SSDFC format by reading CIS/IDI sector */ 295 cis_sector = get_valid_cis_sector(mtd); 296 if (cis_sector == -1) 297 return; 298 299 ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL); 300 if (!ssfdc) 301 return; 302 303 ssfdc->mbd.mtd = mtd; 304 ssfdc->mbd.devnum = -1; 305 ssfdc->mbd.tr = tr; 306 ssfdc->mbd.readonly = 1; 307 308 ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT); 309 ssfdc->erase_size = mtd->erasesize; 310 ssfdc->map_len = (u32)mtd->size / mtd->erasesize; 311 312 pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n", 313 ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len, 314 DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE)); 315 316 /* Set geometry */ 317 ssfdc->heads = 16; 318 ssfdc->sectors = 32; 319 get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors); 320 ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) / 321 ((long)ssfdc->sectors * (long)ssfdc->heads)); 322 323 pr_debug("SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n", 324 ssfdc->cylinders, ssfdc->heads , ssfdc->sectors, 325 (long)ssfdc->cylinders * (long)ssfdc->heads * 326 (long)ssfdc->sectors); 327 328 ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders * 329 (long)ssfdc->sectors; 330 331 /* Allocate logical block map */ 332 ssfdc->logic_block_map = 333 kmalloc_array(ssfdc->map_len, 334 sizeof(ssfdc->logic_block_map[0]), GFP_KERNEL); 335 if (!ssfdc->logic_block_map) 336 goto out_err; 337 memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) * 338 ssfdc->map_len); 339 340 /* Build logical block map */ 341 if (build_logical_block_map(ssfdc) < 0) 342 goto out_err; 343 344 /* Register device + partitions */ 345 if (add_mtd_blktrans_dev(&ssfdc->mbd)) 346 goto out_err; 347 348 printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n", 349 ssfdc->mbd.devnum + 'a', mtd->index, mtd->name); 350 return; 351 352 out_err: 353 kfree(ssfdc->logic_block_map); 354 kfree(ssfdc); 355 } 356 357 static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev) 358 { 359 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 360 361 pr_debug("SSFDC_RO: remove_dev (i=%d)\n", dev->devnum); 362 363 del_mtd_blktrans_dev(dev); 364 kfree(ssfdc->logic_block_map); 365 } 366 367 static int ssfdcr_readsect(struct mtd_blktrans_dev *dev, 368 unsigned long logic_sect_no, char *buf) 369 { 370 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 371 int sectors_per_block, offset, block_address; 372 373 sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT; 374 offset = (int)(logic_sect_no % sectors_per_block); 375 block_address = (int)(logic_sect_no / sectors_per_block); 376 377 pr_debug("SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d," 378 " block_addr=%d\n", logic_sect_no, sectors_per_block, offset, 379 block_address); 380 381 BUG_ON(block_address >= ssfdc->map_len); 382 383 block_address = ssfdc->logic_block_map[block_address]; 384 385 pr_debug("SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n", 386 block_address); 387 388 if (block_address < 0xffff) { 389 unsigned long sect_no; 390 391 sect_no = (unsigned long)block_address * sectors_per_block + 392 offset; 393 394 pr_debug("SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n", 395 sect_no); 396 397 if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0) 398 return -EIO; 399 } else { 400 memset(buf, 0xff, SECTOR_SIZE); 401 } 402 403 return 0; 404 } 405 406 static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo) 407 { 408 struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev; 409 410 pr_debug("SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n", 411 ssfdc->cylinders, ssfdc->heads, ssfdc->sectors); 412 413 geo->heads = ssfdc->heads; 414 geo->sectors = ssfdc->sectors; 415 geo->cylinders = ssfdc->cylinders; 416 417 return 0; 418 } 419 420 /**************************************************************************** 421 * 422 * Module stuff 423 * 424 ****************************************************************************/ 425 426 static struct mtd_blktrans_ops ssfdcr_tr = { 427 .name = "ssfdc", 428 .major = SSFDCR_MAJOR, 429 .part_bits = SSFDCR_PARTN_BITS, 430 .blksize = SECTOR_SIZE, 431 .getgeo = ssfdcr_getgeo, 432 .readsect = ssfdcr_readsect, 433 .add_mtd = ssfdcr_add_mtd, 434 .remove_dev = ssfdcr_remove_dev, 435 .owner = THIS_MODULE, 436 }; 437 438 static int __init init_ssfdcr(void) 439 { 440 printk(KERN_INFO "SSFDC read-only Flash Translation layer\n"); 441 442 return register_mtd_blktrans(&ssfdcr_tr); 443 } 444 445 static void __exit cleanup_ssfdcr(void) 446 { 447 deregister_mtd_blktrans(&ssfdcr_tr); 448 } 449 450 module_init(init_ssfdcr); 451 module_exit(cleanup_ssfdcr); 452 453 MODULE_LICENSE("GPL"); 454 MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>"); 455 MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card"); 456