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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Linux driver for SSFDC Flash Translation Layer (Read only)4 * © 2005 Eptar srl5 * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>6 *7 * Based on NTFL and MTDBLOCK_RO drivers8 */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 19struct 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 on27 the 128MiB) */28 int map_len; /* n. phys_blocks on the card */29};30 31#define SSFDCR_MAJOR 25732#define SSFDCR_PARTN_BITS 333 34#define SECTOR_SIZE 51235#define SECTOR_SHIFT 936#define OOB_SIZE 1637 38#define MAX_LOGIC_BLK_PER_ZONE 100039#define MAX_PHYS_BLK_PER_ZONE 102440 41#define KiB(x) ( (x) * 1024L )42#define MiB(x) ( KiB(x) * 1024L )43 44/** CHS Table45 1MiB 2MiB 4MiB 8MiB 16MiB 32MiB 64MiB 128MiB46NCylinder 125 125 250 250 500 500 500 50047NHead 4 4 4 4 4 8 8 1648NSector 4 8 8 16 16 16 32 3249SumSector 2,000 4,000 8,000 16,000 32,000 64,000 128,000 256,00050SectorSize 512 512 512 512 512 512 512 51251**/52 53typedef 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 */61static 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 73static 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 */97static const uint8_t cis_numbers[] = {98 0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x2099};100 101/* Read and check for a valid CIS sector */102static 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 bad117 * blocks). If the first good block doesn't contain CIS number the flash118 * is not SSFDC formatted119 */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_WARNING128 "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) */148static 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 */163static 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 */182static 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 */196static 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 address205 * Valid address has fixed pattern on most significant bits and206 * parity check207 */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 */239static 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 283static 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 351out_err:352 kfree(ssfdc->logic_block_map);353out_free_ssfdc:354 kfree(ssfdc);355}356 357static 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 367static 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 406static 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 stuff423 *424 ****************************************************************************/425 426static 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 438static 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 445static void __exit cleanup_ssfdcr(void)446{447 deregister_mtd_blktrans(&ssfdcr_tr);448}449 450module_init(init_ssfdcr);451module_exit(cleanup_ssfdcr);452 453MODULE_LICENSE("GPL");454MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");455MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");456