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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 != MTD_NANDFLASH || 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 |
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