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, ofs: offset)) { |
122 | ret = mtd_read(mtd, from: offset, SECTOR_SIZE, retlen: &retlen, |
123 | buf: 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(p: sect_buf, q: cis_numbers, |
130 | size: 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(objp: 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, from: offset, SECTOR_SIZE, retlen: &retlen, buf: 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, from: offs, ops: &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(number: block_address, size: 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, ofs: offset)) |
255 | continue; /* skip bad blocks */ |
256 | |
257 | ret = read_raw_oob(mtd, offs: offset, buf: 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(size: 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(size: mtd->size, NULL, head: &ssfdc->heads, sec: &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(n: ssfdc->map_len, |
333 | size: 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(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(objp: ssfdc->logic_block_map); |
353 | out_free_ssfdc: |
354 | kfree(objp: 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(objp: 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(mtd: ssfdc->mbd.mtd, sect_buf: 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(tr: &ssfdcr_tr); |
443 | } |
444 | |
445 | static void __exit cleanup_ssfdcr(void) |
446 | { |
447 | deregister_mtd_blktrans(tr: &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 | |