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 unsigned char heads; 22 unsigned char sectors; 23 unsigned short cylinders; 24 int cis_block; /* block n. containing CIS/IDI */ 25 int erase_size; /* phys_block_size */ 26 unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on 27 the 128MiB) */ 28 int map_len; /* n. phys_blocks on the card */ 29 }; 30 31 #define SSFDCR_MAJOR 257 32 #define SSFDCR_PARTN_BITS 3 33 34 #define SECTOR_SIZE 512 35 #define SECTOR_SHIFT 9 36 #define OOB_SIZE 16 37 38 #define MAX_LOGIC_BLK_PER_ZONE 1000 39 #define MAX_PHYS_BLK_PER_ZONE 1024 40 41 #define KiB(x) ( (x) * 1024L ) 42 #define MiB(x) ( KiB(x) * 1024L ) 43 44 /** CHS Table 45 1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB 46 NCylinder 125 125 250 250 500 500 500 500 47 NHead 4 4 4 4 4 8 8 16 48 NSector 4 8 8 16 16 16 32 32 49 SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,000 50 SectorSize 512 512 512 512 512 512 512 512 51 **/ 52 53 typedef struct { 54 unsigned long size; 55 unsigned short cyl; 56 unsigned char head; 57 unsigned char sec; 58 } chs_entry_t; 59 60 /* Must be ordered by size */ 61 static const chs_entry_t chs_table[] = { 62 { MiB( 1), 125, 4, 4 }, 63 { MiB( 2), 125, 4, 8 }, 64 { MiB( 4), 250, 4, 8 }, 65 { MiB( 8), 250, 4, 16 }, 66 { MiB( 16), 500, 4, 16 }, 67 { MiB( 32), 500, 8, 16 }, 68 { MiB( 64), 500, 8, 32 }, 69 { MiB(128), 500, 16, 32 }, 70 { 0 }, 71 }; 72 73 static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head, 74 unsigned char *sec) 75 { 76 int k; 77 int found = 0; 78 79 k = 0; 80 while (chs_table[k].size > 0 && size > chs_table[k].size) 81 k++; 82 83 if (chs_table[k].size > 0) { 84 if (cyl) 85 *cyl = chs_table[k].cyl; 86 if (head) 87 *head = chs_table[k].head; 88 if (sec) 89 *sec = chs_table[k].sec; 90 found = 1; 91 } 92 93 return found; 94 } 95 96 /* These bytes are the signature for the CIS/IDI sector */ 97 static const uint8_t cis_numbers[] = { 98 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20 99 }; 100 101 /* Read and check for a valid CIS sector */ 102 static int get_valid_cis_sector(struct mtd_info *mtd) 103 { 104 int ret, k, cis_sector; 105 size_t retlen; 106 loff_t offset; 107 uint8_t *sect_buf; 108 109 cis_sector = -1; 110 111 sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL); 112 if (!sect_buf) 113 goto out; 114 115 /* 116 * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad 117 * blocks). If the first good block doesn't contain CIS number the flash 118 * is not SSFDC formatted 119 */ 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 pr_debug("SSFDC_RO: CIS/IDI sector not found" 135 " on %s (mtd%d)\n", mtd->name, 136 mtd->index); 137 } 138 break; 139 } 140 } 141 142 kfree(sect_buf); 143 out: 144 return cis_sector; 145 } 146 147 /* Read physical sector (wrapper to MTD_READ) */ 148 static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf, 149 int sect_no) 150 { 151 int ret; 152 size_t retlen; 153 loff_t offset = (loff_t)sect_no << SECTOR_SHIFT; 154 155 ret = mtd_read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf); 156 if (ret < 0 || retlen != SECTOR_SIZE) 157 return -1; 158 159 return 0; 160 } 161 162 /* Read redundancy area (wrapper to MTD_READ_OOB */ 163 static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf) 164 { 165 struct mtd_oob_ops ops = { }; 166 int ret; 167 168 ops.mode = MTD_OPS_RAW; 169 ops.ooboffs = 0; 170 ops.ooblen = OOB_SIZE; 171 ops.oobbuf = buf; 172 ops.datbuf = NULL; 173 174 ret = mtd_read_oob(mtd, offs, &ops); 175 if (ret < 0 || ops.oobretlen != 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 pr_debug("SSFDC_RO: logical address field%d" 220 "parity error(0x%04X)\n", j+1, 221 block_address); 222 } else { 223 ok = 1; 224 break; 225 } 226 } 227 } 228 229 if (!ok) 230 block_address = -2; 231 232 pr_debug("SSFDC_RO: get_logical_address() %d\n", 233 block_address); 234 235 return block_address; 236 } 237 238 /* Build the logic block map */ 239 static int build_logical_block_map(struct ssfdcr_record *ssfdc) 240 { 241 unsigned long offset; 242 uint8_t oob_buf[OOB_SIZE]; 243 int ret, block_address, phys_block; 244 struct mtd_info *mtd = ssfdc->mbd.mtd; 245 246 pr_debug("SSFDC_RO: build_block_map() nblks=%d (%luK)\n", 247 ssfdc->map_len, 248 (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024); 249 250 /* Scan every physical block, skip CIS block */ 251 for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len; 252 phys_block++) { 253 offset = (unsigned long)phys_block * ssfdc->erase_size; 254 if (mtd_block_isbad(mtd, offset)) 255 continue; /* skip bad blocks */ 256 257 ret = read_raw_oob(mtd, offset, oob_buf); 258 if (ret < 0) { 259 pr_debug("SSFDC_RO: mtd read_oob() failed at %lu\n", 260 offset); 261 return -1; 262 } 263 block_address = get_logical_address(oob_buf); 264 265 /* Skip invalid addresses */ 266 if (block_address >= 0 && 267 block_address < MAX_LOGIC_BLK_PER_ZONE) { 268 int zone_index; 269 270 zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE; 271 block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE; 272 ssfdc->logic_block_map[block_address] = 273 (unsigned short)phys_block; 274 275 pr_debug("SSFDC_RO: build_block_map() phys_block=%d," 276 "logic_block_addr=%d, zone=%d\n", 277 phys_block, block_address, zone_index); 278 } 279 } 280 return 0; 281 } 282 283 static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd) 284 { 285 struct ssfdcr_record *ssfdc; 286 int cis_sector; 287 288 /* Check for small page NAND flash */ 289 if (!mtd_type_is_nand(mtd) || mtd->oobsize != OOB_SIZE || 290 mtd->size > UINT_MAX) 291 return; 292 293 /* Check for SSDFC format by reading CIS/IDI sector */ 294 cis_sector = get_valid_cis_sector(mtd); 295 if (cis_sector == -1) 296 return; 297 298 ssfdc = kzalloc(sizeof(*ssfdc), GFP_KERNEL); 299 if (!ssfdc) 300 return; 301 302 ssfdc->mbd.mtd = mtd; 303 ssfdc->mbd.devnum = -1; 304 ssfdc->mbd.tr = tr; 305 ssfdc->mbd.readonly = 1; 306 307 ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT); 308 ssfdc->erase_size = mtd->erasesize; 309 ssfdc->map_len = (u32)mtd->size / mtd->erasesize; 310 311 pr_debug("SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n", 312 ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len, 313 DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE)); 314 315 /* Set geometry */ 316 ssfdc->heads = 16; 317 ssfdc->sectors = 32; 318 get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors); 319 ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) / 320 ((long)ssfdc->sectors * (long)ssfdc->heads)); 321 322 pr_debug("SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n", 323 ssfdc->cylinders, ssfdc->heads , ssfdc->sectors, 324 (long)ssfdc->cylinders * (long)ssfdc->heads * 325 (long)ssfdc->sectors); 326 327 ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders * 328 (long)ssfdc->sectors; 329 330 /* Allocate logical block map */ 331 ssfdc->logic_block_map = 332 kmalloc_array(ssfdc->map_len, 333 sizeof(ssfdc->logic_block_map[0]), GFP_KERNEL); 334 if (!ssfdc->logic_block_map) 335 goto out_free_ssfdc; 336 memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) * 337 ssfdc->map_len); 338 339 /* Build logical block map */ 340 if (build_logical_block_map(ssfdc) < 0) 341 goto out_err; 342 343 /* Register device + partitions */ 344 if (add_mtd_blktrans_dev(&ssfdc->mbd)) 345 goto out_err; 346 347 printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n", 348 ssfdc->mbd.devnum + 'a', mtd->index, mtd->name); 349 return; 350 351 out_err: 352 kfree(ssfdc->logic_block_map); 353 out_free_ssfdc: 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