1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2009 - Maxim Levitsky
4  * SmartMedia/xD translation layer
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/random.h>
10 #include <linux/hdreg.h>
11 #include <linux/kthread.h>
12 #include <linux/freezer.h>
13 #include <linux/sysfs.h>
14 #include <linux/bitops.h>
15 #include <linux/slab.h>
16 #include <linux/mtd/nand-ecc-sw-hamming.h>
17 #include "nand/raw/sm_common.h"
18 #include "sm_ftl.h"
19 
20 
21 
22 static struct workqueue_struct *cache_flush_workqueue;
23 
24 static int cache_timeout = 1000;
25 module_param(cache_timeout, int, S_IRUGO);
26 MODULE_PARM_DESC(cache_timeout,
27 	"Timeout (in ms) for cache flush (1000 ms default");
28 
29 static int debug;
30 module_param(debug, int, S_IRUGO | S_IWUSR);
31 MODULE_PARM_DESC(debug, "Debug level (0-2)");
32 
33 
34 /* ------------------- sysfs attributes ---------------------------------- */
35 struct sm_sysfs_attribute {
36 	struct device_attribute dev_attr;
37 	char *data;
38 	int len;
39 };
40 
sm_attr_show(struct device * dev,struct device_attribute * attr,char * buf)41 static ssize_t sm_attr_show(struct device *dev, struct device_attribute *attr,
42 		     char *buf)
43 {
44 	struct sm_sysfs_attribute *sm_attr =
45 		container_of(attr, struct sm_sysfs_attribute, dev_attr);
46 
47 	strncpy(buf, sm_attr->data, sm_attr->len);
48 	return sm_attr->len;
49 }
50 
51 
52 #define NUM_ATTRIBUTES 1
53 #define SM_CIS_VENDOR_OFFSET 0x59
sm_create_sysfs_attributes(struct sm_ftl * ftl)54 static struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl)
55 {
56 	struct attribute_group *attr_group;
57 	struct attribute **attributes;
58 	struct sm_sysfs_attribute *vendor_attribute;
59 	char *vendor;
60 
61 	vendor = kstrndup(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
62 			  SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET, GFP_KERNEL);
63 	if (!vendor)
64 		goto error1;
65 
66 	/* Initialize sysfs attributes */
67 	vendor_attribute =
68 		kzalloc(sizeof(struct sm_sysfs_attribute), GFP_KERNEL);
69 	if (!vendor_attribute)
70 		goto error2;
71 
72 	sysfs_attr_init(&vendor_attribute->dev_attr.attr);
73 
74 	vendor_attribute->data = vendor;
75 	vendor_attribute->len = strlen(vendor);
76 	vendor_attribute->dev_attr.attr.name = "vendor";
77 	vendor_attribute->dev_attr.attr.mode = S_IRUGO;
78 	vendor_attribute->dev_attr.show = sm_attr_show;
79 
80 
81 	/* Create array of pointers to the attributes */
82 	attributes = kcalloc(NUM_ATTRIBUTES + 1, sizeof(struct attribute *),
83 								GFP_KERNEL);
84 	if (!attributes)
85 		goto error3;
86 	attributes[0] = &vendor_attribute->dev_attr.attr;
87 
88 	/* Finally create the attribute group */
89 	attr_group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
90 	if (!attr_group)
91 		goto error4;
92 	attr_group->attrs = attributes;
93 	return attr_group;
94 error4:
95 	kfree(attributes);
96 error3:
97 	kfree(vendor_attribute);
98 error2:
99 	kfree(vendor);
100 error1:
101 	return NULL;
102 }
103 
sm_delete_sysfs_attributes(struct sm_ftl * ftl)104 static void sm_delete_sysfs_attributes(struct sm_ftl *ftl)
105 {
106 	struct attribute **attributes = ftl->disk_attributes->attrs;
107 	int i;
108 
109 	for (i = 0; attributes[i] ; i++) {
110 
111 		struct device_attribute *dev_attr = container_of(attributes[i],
112 			struct device_attribute, attr);
113 
114 		struct sm_sysfs_attribute *sm_attr =
115 			container_of(dev_attr,
116 				struct sm_sysfs_attribute, dev_attr);
117 
118 		kfree(sm_attr->data);
119 		kfree(sm_attr);
120 	}
121 
122 	kfree(ftl->disk_attributes->attrs);
123 	kfree(ftl->disk_attributes);
124 }
125 
126 
127 /* ----------------------- oob helpers -------------------------------------- */
128 
sm_get_lba(uint8_t * lba)129 static int sm_get_lba(uint8_t *lba)
130 {
131 	/* check fixed bits */
132 	if ((lba[0] & 0xF8) != 0x10)
133 		return -2;
134 
135 	/* check parity - endianness doesn't matter */
136 	if (hweight16(*(uint16_t *)lba) & 1)
137 		return -2;
138 
139 	return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
140 }
141 
142 
143 /*
144  * Read LBA associated with block
145  * returns -1, if block is erased
146  * returns -2 if error happens
147  */
sm_read_lba(struct sm_oob * oob)148 static int sm_read_lba(struct sm_oob *oob)
149 {
150 	static const uint32_t erased_pattern[4] = {
151 		0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
152 
153 	uint16_t lba_test;
154 	int lba;
155 
156 	/* First test for erased block */
157 	if (!memcmp(oob, erased_pattern, SM_OOB_SIZE))
158 		return -1;
159 
160 	/* Now check is both copies of the LBA differ too much */
161 	lba_test = *(uint16_t *)oob->lba_copy1 ^ *(uint16_t*)oob->lba_copy2;
162 	if (lba_test && !is_power_of_2(lba_test))
163 		return -2;
164 
165 	/* And read it */
166 	lba = sm_get_lba(oob->lba_copy1);
167 
168 	if (lba == -2)
169 		lba = sm_get_lba(oob->lba_copy2);
170 
171 	return lba;
172 }
173 
sm_write_lba(struct sm_oob * oob,uint16_t lba)174 static void sm_write_lba(struct sm_oob *oob, uint16_t lba)
175 {
176 	uint8_t tmp[2];
177 
178 	WARN_ON(lba >= 1000);
179 
180 	tmp[0] = 0x10 | ((lba >> 7) & 0x07);
181 	tmp[1] = (lba << 1) & 0xFF;
182 
183 	if (hweight16(*(uint16_t *)tmp) & 0x01)
184 		tmp[1] |= 1;
185 
186 	oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
187 	oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
188 }
189 
190 
191 /* Make offset from parts */
sm_mkoffset(struct sm_ftl * ftl,int zone,int block,int boffset)192 static loff_t sm_mkoffset(struct sm_ftl *ftl, int zone, int block, int boffset)
193 {
194 	WARN_ON(boffset & (SM_SECTOR_SIZE - 1));
195 	WARN_ON(zone < 0 || zone >= ftl->zone_count);
196 	WARN_ON(block >= ftl->zone_size);
197 	WARN_ON(boffset >= ftl->block_size);
198 
199 	if (block == -1)
200 		return -1;
201 
202 	return (zone * SM_MAX_ZONE_SIZE + block) * ftl->block_size + boffset;
203 }
204 
205 /* Breaks offset into parts */
sm_break_offset(struct sm_ftl * ftl,loff_t loffset,int * zone,int * block,int * boffset)206 static void sm_break_offset(struct sm_ftl *ftl, loff_t loffset,
207 			    int *zone, int *block, int *boffset)
208 {
209 	u64 offset = loffset;
210 	*boffset = do_div(offset, ftl->block_size);
211 	*block = do_div(offset, ftl->max_lba);
212 	*zone = offset >= ftl->zone_count ? -1 : offset;
213 }
214 
215 /* ---------------------- low level IO ------------------------------------- */
216 
sm_correct_sector(uint8_t * buffer,struct sm_oob * oob)217 static int sm_correct_sector(uint8_t *buffer, struct sm_oob *oob)
218 {
219 	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
220 	uint8_t ecc[3];
221 
222 	ecc_sw_hamming_calculate(buffer, SM_SMALL_PAGE, ecc, sm_order);
223 	if (ecc_sw_hamming_correct(buffer, ecc, oob->ecc1, SM_SMALL_PAGE,
224 				   sm_order) < 0)
225 		return -EIO;
226 
227 	buffer += SM_SMALL_PAGE;
228 
229 	ecc_sw_hamming_calculate(buffer, SM_SMALL_PAGE, ecc, sm_order);
230 	if (ecc_sw_hamming_correct(buffer, ecc, oob->ecc2, SM_SMALL_PAGE,
231 				   sm_order) < 0)
232 		return -EIO;
233 	return 0;
234 }
235 
236 /* Reads a sector + oob*/
sm_read_sector(struct sm_ftl * ftl,int zone,int block,int boffset,uint8_t * buffer,struct sm_oob * oob)237 static int sm_read_sector(struct sm_ftl *ftl,
238 			  int zone, int block, int boffset,
239 			  uint8_t *buffer, struct sm_oob *oob)
240 {
241 	struct mtd_info *mtd = ftl->trans->mtd;
242 	struct mtd_oob_ops ops = { };
243 	struct sm_oob tmp_oob;
244 	int ret = -EIO;
245 	int try = 0;
246 
247 	/* FTL can contain -1 entries that are by default filled with bits */
248 	if (block == -1) {
249 		if (buffer)
250 			memset(buffer, 0xFF, SM_SECTOR_SIZE);
251 		return 0;
252 	}
253 
254 	/* User might not need the oob, but we do for data verification */
255 	if (!oob)
256 		oob = &tmp_oob;
257 
258 	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
259 	ops.ooboffs = 0;
260 	ops.ooblen = SM_OOB_SIZE;
261 	ops.oobbuf = (void *)oob;
262 	ops.len = SM_SECTOR_SIZE;
263 	ops.datbuf = buffer;
264 
265 again:
266 	if (try++) {
267 		/* Avoid infinite recursion on CIS reads, sm_recheck_media
268 		 * won't help anyway
269 		 */
270 		if (zone == 0 && block == ftl->cis_block && boffset ==
271 			ftl->cis_boffset)
272 			return ret;
273 
274 		/* Test if media is stable */
275 		if (try == 3 || sm_recheck_media(ftl))
276 			return ret;
277 	}
278 
279 	/* Unfortunately, oob read will _always_ succeed,
280 	 * despite card removal.....
281 	 */
282 	ret = mtd_read_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
283 
284 	/* Test for unknown errors */
285 	if (ret != 0 && !mtd_is_bitflip_or_eccerr(ret)) {
286 		dbg("read of block %d at zone %d, failed due to error (%d)",
287 			block, zone, ret);
288 		goto again;
289 	}
290 
291 	/* Do a basic test on the oob, to guard against returned garbage */
292 	if (oob->reserved != 0xFFFFFFFF && !is_power_of_2(~oob->reserved))
293 		goto again;
294 
295 	/* This should never happen, unless there is a bug in the mtd driver */
296 	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
297 	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
298 
299 	if (!buffer)
300 		return 0;
301 
302 	/* Test if sector marked as bad */
303 	if (!sm_sector_valid(oob)) {
304 		dbg("read of block %d at zone %d, failed because it is marked"
305 			" as bad" , block, zone);
306 		goto again;
307 	}
308 
309 	/* Test ECC*/
310 	if (mtd_is_eccerr(ret) ||
311 		(ftl->smallpagenand && sm_correct_sector(buffer, oob))) {
312 
313 		dbg("read of block %d at zone %d, failed due to ECC error",
314 			block, zone);
315 		goto again;
316 	}
317 
318 	return 0;
319 }
320 
321 /* Writes a sector to media */
sm_write_sector(struct sm_ftl * ftl,int zone,int block,int boffset,uint8_t * buffer,struct sm_oob * oob)322 static int sm_write_sector(struct sm_ftl *ftl,
323 			   int zone, int block, int boffset,
324 			   uint8_t *buffer, struct sm_oob *oob)
325 {
326 	struct mtd_oob_ops ops = { };
327 	struct mtd_info *mtd = ftl->trans->mtd;
328 	int ret;
329 
330 	BUG_ON(ftl->readonly);
331 
332 	if (zone == 0 && (block == ftl->cis_block || block == 0)) {
333 		dbg("attempted to write the CIS!");
334 		return -EIO;
335 	}
336 
337 	if (ftl->unstable)
338 		return -EIO;
339 
340 	ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
341 	ops.len = SM_SECTOR_SIZE;
342 	ops.datbuf = buffer;
343 	ops.ooboffs = 0;
344 	ops.ooblen = SM_OOB_SIZE;
345 	ops.oobbuf = (void *)oob;
346 
347 	ret = mtd_write_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
348 
349 	/* Now we assume that hardware will catch write bitflip errors */
350 
351 	if (ret) {
352 		dbg("write to block %d at zone %d, failed with error %d",
353 			block, zone, ret);
354 
355 		sm_recheck_media(ftl);
356 		return ret;
357 	}
358 
359 	/* This should never happen, unless there is a bug in the driver */
360 	WARN_ON(ops.oobretlen != SM_OOB_SIZE);
361 	WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
362 
363 	return 0;
364 }
365 
366 /* ------------------------ block IO ------------------------------------- */
367 
368 /* Write a block using data and lba, and invalid sector bitmap */
sm_write_block(struct sm_ftl * ftl,uint8_t * buf,int zone,int block,int lba,unsigned long invalid_bitmap)369 static int sm_write_block(struct sm_ftl *ftl, uint8_t *buf,
370 			  int zone, int block, int lba,
371 			  unsigned long invalid_bitmap)
372 {
373 	bool sm_order = IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_HAMMING_SMC);
374 	struct sm_oob oob;
375 	int boffset;
376 	int retry = 0;
377 
378 	/* Initialize the oob with requested values */
379 	memset(&oob, 0xFF, SM_OOB_SIZE);
380 	sm_write_lba(&oob, lba);
381 restart:
382 	if (ftl->unstable)
383 		return -EIO;
384 
385 	for (boffset = 0; boffset < ftl->block_size;
386 				boffset += SM_SECTOR_SIZE) {
387 
388 		oob.data_status = 0xFF;
389 
390 		if (test_bit(boffset / SM_SECTOR_SIZE, &invalid_bitmap)) {
391 
392 			sm_printk("sector %d of block at LBA %d of zone %d"
393 				" couldn't be read, marking it as invalid",
394 				boffset / SM_SECTOR_SIZE, lba, zone);
395 
396 			oob.data_status = 0;
397 		}
398 
399 		if (ftl->smallpagenand) {
400 			ecc_sw_hamming_calculate(buf + boffset,
401 						 SM_SMALL_PAGE, oob.ecc1,
402 						 sm_order);
403 
404 			ecc_sw_hamming_calculate(buf + boffset + SM_SMALL_PAGE,
405 						 SM_SMALL_PAGE, oob.ecc2,
406 						 sm_order);
407 		}
408 		if (!sm_write_sector(ftl, zone, block, boffset,
409 							buf + boffset, &oob))
410 			continue;
411 
412 		if (!retry) {
413 
414 			/* If write fails. try to erase the block */
415 			/* This is safe, because we never write in blocks
416 			 * that contain valuable data.
417 			 * This is intended to repair block that are marked
418 			 * as erased, but that isn't fully erased
419 			 */
420 
421 			if (sm_erase_block(ftl, zone, block, 0))
422 				return -EIO;
423 
424 			retry = 1;
425 			goto restart;
426 		} else {
427 			sm_mark_block_bad(ftl, zone, block);
428 			return -EIO;
429 		}
430 	}
431 	return 0;
432 }
433 
434 
435 /* Mark whole block at offset 'offs' as bad. */
sm_mark_block_bad(struct sm_ftl * ftl,int zone,int block)436 static void sm_mark_block_bad(struct sm_ftl *ftl, int zone, int block)
437 {
438 	struct sm_oob oob;
439 	int boffset;
440 
441 	memset(&oob, 0xFF, SM_OOB_SIZE);
442 	oob.block_status = 0xF0;
443 
444 	if (ftl->unstable)
445 		return;
446 
447 	if (sm_recheck_media(ftl))
448 		return;
449 
450 	sm_printk("marking block %d of zone %d as bad", block, zone);
451 
452 	/* We aren't checking the return value, because we don't care */
453 	/* This also fails on fake xD cards, but I guess these won't expose
454 	 * any bad blocks till fail completely
455 	 */
456 	for (boffset = 0; boffset < ftl->block_size; boffset += SM_SECTOR_SIZE)
457 		sm_write_sector(ftl, zone, block, boffset, NULL, &oob);
458 }
459 
460 /*
461  * Erase a block within a zone
462  * If erase succeeds, it updates free block fifo, otherwise marks block as bad
463  */
sm_erase_block(struct sm_ftl * ftl,int zone_num,uint16_t block,int put_free)464 static int sm_erase_block(struct sm_ftl *ftl, int zone_num, uint16_t block,
465 			  int put_free)
466 {
467 	struct ftl_zone *zone = &ftl->zones[zone_num];
468 	struct mtd_info *mtd = ftl->trans->mtd;
469 	struct erase_info erase;
470 
471 	erase.addr = sm_mkoffset(ftl, zone_num, block, 0);
472 	erase.len = ftl->block_size;
473 
474 	if (ftl->unstable)
475 		return -EIO;
476 
477 	BUG_ON(ftl->readonly);
478 
479 	if (zone_num == 0 && (block == ftl->cis_block || block == 0)) {
480 		sm_printk("attempted to erase the CIS!");
481 		return -EIO;
482 	}
483 
484 	if (mtd_erase(mtd, &erase)) {
485 		sm_printk("erase of block %d in zone %d failed",
486 							block, zone_num);
487 		goto error;
488 	}
489 
490 	if (put_free)
491 		kfifo_in(&zone->free_sectors,
492 			(const unsigned char *)&block, sizeof(block));
493 
494 	return 0;
495 error:
496 	sm_mark_block_bad(ftl, zone_num, block);
497 	return -EIO;
498 }
499 
500 /* Thoroughly test that block is valid. */
sm_check_block(struct sm_ftl * ftl,int zone,int block)501 static int sm_check_block(struct sm_ftl *ftl, int zone, int block)
502 {
503 	int boffset;
504 	struct sm_oob oob;
505 	int lbas[] = { -3, 0, 0, 0 };
506 	int i = 0;
507 	int test_lba;
508 
509 
510 	/* First just check that block doesn't look fishy */
511 	/* Only blocks that are valid or are sliced in two parts, are
512 	 * accepted
513 	 */
514 	for (boffset = 0; boffset < ftl->block_size;
515 					boffset += SM_SECTOR_SIZE) {
516 
517 		/* This shouldn't happen anyway */
518 		if (sm_read_sector(ftl, zone, block, boffset, NULL, &oob))
519 			return -2;
520 
521 		test_lba = sm_read_lba(&oob);
522 
523 		if (lbas[i] != test_lba)
524 			lbas[++i] = test_lba;
525 
526 		/* If we found three different LBAs, something is fishy */
527 		if (i == 3)
528 			return -EIO;
529 	}
530 
531 	/* If the block is sliced (partially erased usually) erase it */
532 	if (i == 2) {
533 		sm_erase_block(ftl, zone, block, 1);
534 		return 1;
535 	}
536 
537 	return 0;
538 }
539 
540 /* ----------------- media scanning --------------------------------- */
541 static const struct chs_entry chs_table[] = {
542 	{ 1,    125,  4,  4  },
543 	{ 2,    125,  4,  8  },
544 	{ 4,    250,  4,  8  },
545 	{ 8,    250,  4,  16 },
546 	{ 16,   500,  4,  16 },
547 	{ 32,   500,  8,  16 },
548 	{ 64,   500,  8,  32 },
549 	{ 128,  500,  16, 32 },
550 	{ 256,  1000, 16, 32 },
551 	{ 512,  1015, 32, 63 },
552 	{ 1024, 985,  33, 63 },
553 	{ 2048, 985,  33, 63 },
554 	{ 0 },
555 };
556 
557 
558 static const uint8_t cis_signature[] = {
559 	0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
560 };
561 /* Find out media parameters.
562  * This ideally has to be based on nand id, but for now device size is enough
563  */
sm_get_media_info(struct sm_ftl * ftl,struct mtd_info * mtd)564 static int sm_get_media_info(struct sm_ftl *ftl, struct mtd_info *mtd)
565 {
566 	int i;
567 	int size_in_megs = mtd->size / (1024 * 1024);
568 
569 	ftl->readonly = mtd->type == MTD_ROM;
570 
571 	/* Manual settings for very old devices */
572 	ftl->zone_count = 1;
573 	ftl->smallpagenand = 0;
574 
575 	switch (size_in_megs) {
576 	case 1:
577 		/* 1 MiB flash/rom SmartMedia card (256 byte pages)*/
578 		ftl->zone_size = 256;
579 		ftl->max_lba = 250;
580 		ftl->block_size = 8 * SM_SECTOR_SIZE;
581 		ftl->smallpagenand = 1;
582 
583 		break;
584 	case 2:
585 		/* 2 MiB flash SmartMedia (256 byte pages)*/
586 		if (mtd->writesize == SM_SMALL_PAGE) {
587 			ftl->zone_size = 512;
588 			ftl->max_lba = 500;
589 			ftl->block_size = 8 * SM_SECTOR_SIZE;
590 			ftl->smallpagenand = 1;
591 		/* 2 MiB rom SmartMedia */
592 		} else {
593 
594 			if (!ftl->readonly)
595 				return -ENODEV;
596 
597 			ftl->zone_size = 256;
598 			ftl->max_lba = 250;
599 			ftl->block_size = 16 * SM_SECTOR_SIZE;
600 		}
601 		break;
602 	case 4:
603 		/* 4 MiB flash/rom SmartMedia device */
604 		ftl->zone_size = 512;
605 		ftl->max_lba = 500;
606 		ftl->block_size = 16 * SM_SECTOR_SIZE;
607 		break;
608 	case 8:
609 		/* 8 MiB flash/rom SmartMedia device */
610 		ftl->zone_size = 1024;
611 		ftl->max_lba = 1000;
612 		ftl->block_size = 16 * SM_SECTOR_SIZE;
613 	}
614 
615 	/* Minimum xD size is 16MiB. Also, all xD cards have standard zone
616 	 * sizes. SmartMedia cards exist up to 128 MiB and have same layout
617 	 */
618 	if (size_in_megs >= 16) {
619 		ftl->zone_count = size_in_megs / 16;
620 		ftl->zone_size = 1024;
621 		ftl->max_lba = 1000;
622 		ftl->block_size = 32 * SM_SECTOR_SIZE;
623 	}
624 
625 	/* Test for proper write,erase and oob sizes */
626 	if (mtd->erasesize > ftl->block_size)
627 		return -ENODEV;
628 
629 	if (mtd->writesize > SM_SECTOR_SIZE)
630 		return -ENODEV;
631 
632 	if (ftl->smallpagenand && mtd->oobsize < SM_SMALL_OOB_SIZE)
633 		return -ENODEV;
634 
635 	if (!ftl->smallpagenand && mtd->oobsize < SM_OOB_SIZE)
636 		return -ENODEV;
637 
638 	/* We use OOB */
639 	if (!mtd_has_oob(mtd))
640 		return -ENODEV;
641 
642 	/* Find geometry information */
643 	for (i = 0 ; i < ARRAY_SIZE(chs_table) ; i++) {
644 		if (chs_table[i].size == size_in_megs) {
645 			ftl->cylinders = chs_table[i].cyl;
646 			ftl->heads = chs_table[i].head;
647 			ftl->sectors = chs_table[i].sec;
648 			return 0;
649 		}
650 	}
651 
652 	sm_printk("media has unknown size : %dMiB", size_in_megs);
653 	ftl->cylinders = 985;
654 	ftl->heads =  33;
655 	ftl->sectors = 63;
656 	return 0;
657 }
658 
659 /* Validate the CIS */
sm_read_cis(struct sm_ftl * ftl)660 static int sm_read_cis(struct sm_ftl *ftl)
661 {
662 	struct sm_oob oob;
663 
664 	if (sm_read_sector(ftl,
665 		0, ftl->cis_block, ftl->cis_boffset, ftl->cis_buffer, &oob))
666 			return -EIO;
667 
668 	if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
669 		return -EIO;
670 
671 	if (!memcmp(ftl->cis_buffer + ftl->cis_page_offset,
672 			cis_signature, sizeof(cis_signature))) {
673 		return 0;
674 	}
675 
676 	return -EIO;
677 }
678 
679 /* Scan the media for the CIS */
sm_find_cis(struct sm_ftl * ftl)680 static int sm_find_cis(struct sm_ftl *ftl)
681 {
682 	struct sm_oob oob;
683 	int block, boffset;
684 	int block_found = 0;
685 	int cis_found = 0;
686 
687 	/* Search for first valid block */
688 	for (block = 0 ; block < ftl->zone_size - ftl->max_lba ; block++) {
689 
690 		if (sm_read_sector(ftl, 0, block, 0, NULL, &oob))
691 			continue;
692 
693 		if (!sm_block_valid(&oob))
694 			continue;
695 		block_found = 1;
696 		break;
697 	}
698 
699 	if (!block_found)
700 		return -EIO;
701 
702 	/* Search for first valid sector in this block */
703 	for (boffset = 0 ; boffset < ftl->block_size;
704 						boffset += SM_SECTOR_SIZE) {
705 
706 		if (sm_read_sector(ftl, 0, block, boffset, NULL, &oob))
707 			continue;
708 
709 		if (!sm_sector_valid(&oob))
710 			continue;
711 		break;
712 	}
713 
714 	if (boffset == ftl->block_size)
715 		return -EIO;
716 
717 	ftl->cis_block = block;
718 	ftl->cis_boffset = boffset;
719 	ftl->cis_page_offset = 0;
720 
721 	cis_found = !sm_read_cis(ftl);
722 
723 	if (!cis_found) {
724 		ftl->cis_page_offset = SM_SMALL_PAGE;
725 		cis_found = !sm_read_cis(ftl);
726 	}
727 
728 	if (cis_found) {
729 		dbg("CIS block found at offset %x",
730 			block * ftl->block_size +
731 				boffset + ftl->cis_page_offset);
732 		return 0;
733 	}
734 	return -EIO;
735 }
736 
737 /* Basic test to determine if underlying mtd device if functional */
sm_recheck_media(struct sm_ftl * ftl)738 static int sm_recheck_media(struct sm_ftl *ftl)
739 {
740 	if (sm_read_cis(ftl)) {
741 
742 		if (!ftl->unstable) {
743 			sm_printk("media unstable, not allowing writes");
744 			ftl->unstable = 1;
745 		}
746 		return -EIO;
747 	}
748 	return 0;
749 }
750 
751 /* Initialize a FTL zone */
sm_init_zone(struct sm_ftl * ftl,int zone_num)752 static int sm_init_zone(struct sm_ftl *ftl, int zone_num)
753 {
754 	struct ftl_zone *zone = &ftl->zones[zone_num];
755 	struct sm_oob oob;
756 	uint16_t block;
757 	int lba;
758 	int i = 0;
759 	int len;
760 
761 	dbg("initializing zone %d", zone_num);
762 
763 	/* Allocate memory for FTL table */
764 	zone->lba_to_phys_table = kmalloc_array(ftl->max_lba, 2, GFP_KERNEL);
765 
766 	if (!zone->lba_to_phys_table)
767 		return -ENOMEM;
768 	memset(zone->lba_to_phys_table, -1, ftl->max_lba * 2);
769 
770 
771 	/* Allocate memory for free sectors FIFO */
772 	if (kfifo_alloc(&zone->free_sectors, ftl->zone_size * 2, GFP_KERNEL)) {
773 		kfree(zone->lba_to_phys_table);
774 		return -ENOMEM;
775 	}
776 
777 	/* Now scan the zone */
778 	for (block = 0 ; block < ftl->zone_size ; block++) {
779 
780 		/* Skip blocks till the CIS (including) */
781 		if (zone_num == 0 && block <= ftl->cis_block)
782 			continue;
783 
784 		/* Read the oob of first sector */
785 		if (sm_read_sector(ftl, zone_num, block, 0, NULL, &oob)) {
786 			kfifo_free(&zone->free_sectors);
787 			kfree(zone->lba_to_phys_table);
788 			return -EIO;
789 		}
790 
791 		/* Test to see if block is erased. It is enough to test
792 		 * first sector, because erase happens in one shot
793 		 */
794 		if (sm_block_erased(&oob)) {
795 			kfifo_in(&zone->free_sectors,
796 				(unsigned char *)&block, 2);
797 			continue;
798 		}
799 
800 		/* If block is marked as bad, skip it */
801 		/* This assumes we can trust first sector*/
802 		/* However the way the block valid status is defined, ensures
803 		 * very low probability of failure here
804 		 */
805 		if (!sm_block_valid(&oob)) {
806 			dbg("PH %04d <-> <marked bad>", block);
807 			continue;
808 		}
809 
810 
811 		lba = sm_read_lba(&oob);
812 
813 		/* Invalid LBA means that block is damaged. */
814 		/* We can try to erase it, or mark it as bad, but
815 		 * lets leave that to recovery application
816 		 */
817 		if (lba == -2 || lba >= ftl->max_lba) {
818 			dbg("PH %04d <-> LBA %04d(bad)", block, lba);
819 			continue;
820 		}
821 
822 
823 		/* If there is no collision,
824 		 * just put the sector in the FTL table
825 		 */
826 		if (zone->lba_to_phys_table[lba] < 0) {
827 			dbg_verbose("PH %04d <-> LBA %04d", block, lba);
828 			zone->lba_to_phys_table[lba] = block;
829 			continue;
830 		}
831 
832 		sm_printk("collision"
833 			" of LBA %d between blocks %d and %d in zone %d",
834 			lba, zone->lba_to_phys_table[lba], block, zone_num);
835 
836 		/* Test that this block is valid*/
837 		if (sm_check_block(ftl, zone_num, block))
838 			continue;
839 
840 		/* Test now the old block */
841 		if (sm_check_block(ftl, zone_num,
842 					zone->lba_to_phys_table[lba])) {
843 			zone->lba_to_phys_table[lba] = block;
844 			continue;
845 		}
846 
847 		/* If both blocks are valid and share same LBA, it means that
848 		 * they hold different versions of same data. It not
849 		 * known which is more recent, thus just erase one of them
850 		 */
851 		sm_printk("both blocks are valid, erasing the later");
852 		sm_erase_block(ftl, zone_num, block, 1);
853 	}
854 
855 	dbg("zone initialized");
856 	zone->initialized = 1;
857 
858 	/* No free sectors, means that the zone is heavily damaged, write won't
859 	 * work, but it can still can be (partially) read
860 	 */
861 	if (!kfifo_len(&zone->free_sectors)) {
862 		sm_printk("no free blocks in zone %d", zone_num);
863 		return 0;
864 	}
865 
866 	/* Randomize first block we write to */
867 	get_random_bytes(&i, 2);
868 	i %= (kfifo_len(&zone->free_sectors) / 2);
869 
870 	while (i--) {
871 		len = kfifo_out(&zone->free_sectors,
872 					(unsigned char *)&block, 2);
873 		WARN_ON(len != 2);
874 		kfifo_in(&zone->free_sectors, (const unsigned char *)&block, 2);
875 	}
876 	return 0;
877 }
878 
879 /* Get and automatically initialize an FTL mapping for one zone */
sm_get_zone(struct sm_ftl * ftl,int zone_num)880 static struct ftl_zone *sm_get_zone(struct sm_ftl *ftl, int zone_num)
881 {
882 	struct ftl_zone *zone;
883 	int error;
884 
885 	BUG_ON(zone_num >= ftl->zone_count);
886 	zone = &ftl->zones[zone_num];
887 
888 	if (!zone->initialized) {
889 		error = sm_init_zone(ftl, zone_num);
890 
891 		if (error)
892 			return ERR_PTR(error);
893 	}
894 	return zone;
895 }
896 
897 
898 /* ----------------- cache handling ------------------------------------------*/
899 
900 /* Initialize the one block cache */
sm_cache_init(struct sm_ftl * ftl)901 static void sm_cache_init(struct sm_ftl *ftl)
902 {
903 	ftl->cache_data_invalid_bitmap = 0xFFFFFFFF;
904 	ftl->cache_clean = 1;
905 	ftl->cache_zone = -1;
906 	ftl->cache_block = -1;
907 	/*memset(ftl->cache_data, 0xAA, ftl->block_size);*/
908 }
909 
910 /* Put sector in one block cache */
sm_cache_put(struct sm_ftl * ftl,char * buffer,int boffset)911 static void sm_cache_put(struct sm_ftl *ftl, char *buffer, int boffset)
912 {
913 	memcpy(ftl->cache_data + boffset, buffer, SM_SECTOR_SIZE);
914 	clear_bit(boffset / SM_SECTOR_SIZE, &ftl->cache_data_invalid_bitmap);
915 	ftl->cache_clean = 0;
916 }
917 
918 /* Read a sector from the cache */
sm_cache_get(struct sm_ftl * ftl,char * buffer,int boffset)919 static int sm_cache_get(struct sm_ftl *ftl, char *buffer, int boffset)
920 {
921 	if (test_bit(boffset / SM_SECTOR_SIZE,
922 		&ftl->cache_data_invalid_bitmap))
923 			return -1;
924 
925 	memcpy(buffer, ftl->cache_data + boffset, SM_SECTOR_SIZE);
926 	return 0;
927 }
928 
929 /* Write the cache to hardware */
sm_cache_flush(struct sm_ftl * ftl)930 static int sm_cache_flush(struct sm_ftl *ftl)
931 {
932 	struct ftl_zone *zone;
933 
934 	int sector_num;
935 	uint16_t write_sector;
936 	int zone_num = ftl->cache_zone;
937 	int block_num;
938 
939 	if (ftl->cache_clean)
940 		return 0;
941 
942 	if (ftl->unstable)
943 		return -EIO;
944 
945 	BUG_ON(zone_num < 0);
946 	zone = &ftl->zones[zone_num];
947 	block_num = zone->lba_to_phys_table[ftl->cache_block];
948 
949 
950 	/* Try to read all unread areas of the cache block*/
951 	for_each_set_bit(sector_num, &ftl->cache_data_invalid_bitmap,
952 		ftl->block_size / SM_SECTOR_SIZE) {
953 
954 		if (!sm_read_sector(ftl,
955 			zone_num, block_num, sector_num * SM_SECTOR_SIZE,
956 			ftl->cache_data + sector_num * SM_SECTOR_SIZE, NULL))
957 				clear_bit(sector_num,
958 					&ftl->cache_data_invalid_bitmap);
959 	}
960 restart:
961 
962 	if (ftl->unstable)
963 		return -EIO;
964 
965 	/* If there are no spare blocks, */
966 	/* we could still continue by erasing/writing the current block,
967 	 * but for such worn out media it doesn't worth the trouble,
968 	 * and the dangers
969 	 */
970 	if (kfifo_out(&zone->free_sectors,
971 				(unsigned char *)&write_sector, 2) != 2) {
972 		dbg("no free sectors for write!");
973 		return -EIO;
974 	}
975 
976 
977 	if (sm_write_block(ftl, ftl->cache_data, zone_num, write_sector,
978 		ftl->cache_block, ftl->cache_data_invalid_bitmap))
979 			goto restart;
980 
981 	/* Update the FTL table */
982 	zone->lba_to_phys_table[ftl->cache_block] = write_sector;
983 
984 	/* Write succesfull, so erase and free the old block */
985 	if (block_num > 0)
986 		sm_erase_block(ftl, zone_num, block_num, 1);
987 
988 	sm_cache_init(ftl);
989 	return 0;
990 }
991 
992 
993 /* flush timer, runs a second after last write */
sm_cache_flush_timer(struct timer_list * t)994 static void sm_cache_flush_timer(struct timer_list *t)
995 {
996 	struct sm_ftl *ftl = from_timer(ftl, t, timer);
997 	queue_work(cache_flush_workqueue, &ftl->flush_work);
998 }
999 
1000 /* cache flush work, kicked by timer */
sm_cache_flush_work(struct work_struct * work)1001 static void sm_cache_flush_work(struct work_struct *work)
1002 {
1003 	struct sm_ftl *ftl = container_of(work, struct sm_ftl, flush_work);
1004 	mutex_lock(&ftl->mutex);
1005 	sm_cache_flush(ftl);
1006 	mutex_unlock(&ftl->mutex);
1007 	return;
1008 }
1009 
1010 /* ---------------- outside interface -------------------------------------- */
1011 
1012 /* outside interface: read a sector */
sm_read(struct mtd_blktrans_dev * dev,unsigned long sect_no,char * buf)1013 static int sm_read(struct mtd_blktrans_dev *dev,
1014 		   unsigned long sect_no, char *buf)
1015 {
1016 	struct sm_ftl *ftl = dev->priv;
1017 	struct ftl_zone *zone;
1018 	int error = 0, in_cache = 0;
1019 	int zone_num, block, boffset;
1020 
1021 	sm_break_offset(ftl, sect_no << 9, &zone_num, &block, &boffset);
1022 	mutex_lock(&ftl->mutex);
1023 
1024 
1025 	zone = sm_get_zone(ftl, zone_num);
1026 	if (IS_ERR(zone)) {
1027 		error = PTR_ERR(zone);
1028 		goto unlock;
1029 	}
1030 
1031 	/* Have to look at cache first */
1032 	if (ftl->cache_zone == zone_num && ftl->cache_block == block) {
1033 		in_cache = 1;
1034 		if (!sm_cache_get(ftl, buf, boffset))
1035 			goto unlock;
1036 	}
1037 
1038 	/* Translate the block and return if doesn't exist in the table */
1039 	block = zone->lba_to_phys_table[block];
1040 
1041 	if (block == -1) {
1042 		memset(buf, 0xFF, SM_SECTOR_SIZE);
1043 		goto unlock;
1044 	}
1045 
1046 	if (sm_read_sector(ftl, zone_num, block, boffset, buf, NULL)) {
1047 		error = -EIO;
1048 		goto unlock;
1049 	}
1050 
1051 	if (in_cache)
1052 		sm_cache_put(ftl, buf, boffset);
1053 unlock:
1054 	mutex_unlock(&ftl->mutex);
1055 	return error;
1056 }
1057 
1058 /* outside interface: write a sector */
sm_write(struct mtd_blktrans_dev * dev,unsigned long sec_no,char * buf)1059 static int sm_write(struct mtd_blktrans_dev *dev,
1060 				unsigned long sec_no, char *buf)
1061 {
1062 	struct sm_ftl *ftl = dev->priv;
1063 	struct ftl_zone *zone;
1064 	int error = 0, zone_num, block, boffset;
1065 
1066 	BUG_ON(ftl->readonly);
1067 	sm_break_offset(ftl, sec_no << 9, &zone_num, &block, &boffset);
1068 
1069 	/* No need in flush thread running now */
1070 	del_timer(&ftl->timer);
1071 	mutex_lock(&ftl->mutex);
1072 
1073 	zone = sm_get_zone(ftl, zone_num);
1074 	if (IS_ERR(zone)) {
1075 		error = PTR_ERR(zone);
1076 		goto unlock;
1077 	}
1078 
1079 	/* If entry is not in cache, flush it */
1080 	if (ftl->cache_block != block || ftl->cache_zone != zone_num) {
1081 
1082 		error = sm_cache_flush(ftl);
1083 		if (error)
1084 			goto unlock;
1085 
1086 		ftl->cache_block = block;
1087 		ftl->cache_zone = zone_num;
1088 	}
1089 
1090 	sm_cache_put(ftl, buf, boffset);
1091 unlock:
1092 	mod_timer(&ftl->timer, jiffies + msecs_to_jiffies(cache_timeout));
1093 	mutex_unlock(&ftl->mutex);
1094 	return error;
1095 }
1096 
1097 /* outside interface: flush everything */
sm_flush(struct mtd_blktrans_dev * dev)1098 static int sm_flush(struct mtd_blktrans_dev *dev)
1099 {
1100 	struct sm_ftl *ftl = dev->priv;
1101 	int retval;
1102 
1103 	mutex_lock(&ftl->mutex);
1104 	retval =  sm_cache_flush(ftl);
1105 	mutex_unlock(&ftl->mutex);
1106 	return retval;
1107 }
1108 
1109 /* outside interface: device is released */
sm_release(struct mtd_blktrans_dev * dev)1110 static void sm_release(struct mtd_blktrans_dev *dev)
1111 {
1112 	struct sm_ftl *ftl = dev->priv;
1113 
1114 	del_timer_sync(&ftl->timer);
1115 	cancel_work_sync(&ftl->flush_work);
1116 	mutex_lock(&ftl->mutex);
1117 	sm_cache_flush(ftl);
1118 	mutex_unlock(&ftl->mutex);
1119 }
1120 
1121 /* outside interface: get geometry */
sm_getgeo(struct mtd_blktrans_dev * dev,struct hd_geometry * geo)1122 static int sm_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
1123 {
1124 	struct sm_ftl *ftl = dev->priv;
1125 	geo->heads = ftl->heads;
1126 	geo->sectors = ftl->sectors;
1127 	geo->cylinders = ftl->cylinders;
1128 	return 0;
1129 }
1130 
1131 /* external interface: main initialization function */
sm_add_mtd(struct mtd_blktrans_ops * tr,struct mtd_info * mtd)1132 static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1133 {
1134 	struct mtd_blktrans_dev *trans;
1135 	struct sm_ftl *ftl;
1136 
1137 	/* Allocate & initialize our private structure */
1138 	ftl = kzalloc(sizeof(struct sm_ftl), GFP_KERNEL);
1139 	if (!ftl)
1140 		goto error1;
1141 
1142 
1143 	mutex_init(&ftl->mutex);
1144 	timer_setup(&ftl->timer, sm_cache_flush_timer, 0);
1145 	INIT_WORK(&ftl->flush_work, sm_cache_flush_work);
1146 
1147 	/* Read media information */
1148 	if (sm_get_media_info(ftl, mtd)) {
1149 		dbg("found unsupported mtd device, aborting");
1150 		goto error2;
1151 	}
1152 
1153 
1154 	/* Allocate temporary CIS buffer for read retry support */
1155 	ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
1156 	if (!ftl->cis_buffer)
1157 		goto error2;
1158 
1159 	/* Allocate zone array, it will be initialized on demand */
1160 	ftl->zones = kcalloc(ftl->zone_count, sizeof(struct ftl_zone),
1161 								GFP_KERNEL);
1162 	if (!ftl->zones)
1163 		goto error3;
1164 
1165 	/* Allocate the cache*/
1166 	ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);
1167 
1168 	if (!ftl->cache_data)
1169 		goto error4;
1170 
1171 	sm_cache_init(ftl);
1172 
1173 
1174 	/* Allocate upper layer structure and initialize it */
1175 	trans = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1176 	if (!trans)
1177 		goto error5;
1178 
1179 	ftl->trans = trans;
1180 	trans->priv = ftl;
1181 
1182 	trans->tr = tr;
1183 	trans->mtd = mtd;
1184 	trans->devnum = -1;
1185 	trans->size = (ftl->block_size * ftl->max_lba * ftl->zone_count) >> 9;
1186 	trans->readonly = ftl->readonly;
1187 
1188 	if (sm_find_cis(ftl)) {
1189 		dbg("CIS not found on mtd device, aborting");
1190 		goto error6;
1191 	}
1192 
1193 	ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
1194 	if (!ftl->disk_attributes)
1195 		goto error6;
1196 	trans->disk_attributes = ftl->disk_attributes;
1197 
1198 	sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
1199 		(int)(mtd->size / (1024 * 1024)), mtd->index);
1200 
1201 	dbg("FTL layout:");
1202 	dbg("%d zone(s), each consists of %d blocks (+%d spares)",
1203 		ftl->zone_count, ftl->max_lba,
1204 		ftl->zone_size - ftl->max_lba);
1205 	dbg("each block consists of %d bytes",
1206 		ftl->block_size);
1207 
1208 
1209 	/* Register device*/
1210 	if (add_mtd_blktrans_dev(trans)) {
1211 		dbg("error in mtdblktrans layer");
1212 		goto error6;
1213 	}
1214 	return;
1215 error6:
1216 	kfree(trans);
1217 error5:
1218 	kfree(ftl->cache_data);
1219 error4:
1220 	kfree(ftl->zones);
1221 error3:
1222 	kfree(ftl->cis_buffer);
1223 error2:
1224 	kfree(ftl);
1225 error1:
1226 	return;
1227 }
1228 
1229 /* main interface: device {surprise,} removal */
sm_remove_dev(struct mtd_blktrans_dev * dev)1230 static void sm_remove_dev(struct mtd_blktrans_dev *dev)
1231 {
1232 	struct sm_ftl *ftl = dev->priv;
1233 	int i;
1234 
1235 	del_mtd_blktrans_dev(dev);
1236 	ftl->trans = NULL;
1237 
1238 	for (i = 0 ; i < ftl->zone_count; i++) {
1239 
1240 		if (!ftl->zones[i].initialized)
1241 			continue;
1242 
1243 		kfree(ftl->zones[i].lba_to_phys_table);
1244 		kfifo_free(&ftl->zones[i].free_sectors);
1245 	}
1246 
1247 	sm_delete_sysfs_attributes(ftl);
1248 	kfree(ftl->cis_buffer);
1249 	kfree(ftl->zones);
1250 	kfree(ftl->cache_data);
1251 	kfree(ftl);
1252 }
1253 
1254 static struct mtd_blktrans_ops sm_ftl_ops = {
1255 	.name		= "smblk",
1256 	.major		= 0,
1257 	.part_bits	= SM_FTL_PARTN_BITS,
1258 	.blksize	= SM_SECTOR_SIZE,
1259 	.getgeo		= sm_getgeo,
1260 
1261 	.add_mtd	= sm_add_mtd,
1262 	.remove_dev	= sm_remove_dev,
1263 
1264 	.readsect	= sm_read,
1265 	.writesect	= sm_write,
1266 
1267 	.flush		= sm_flush,
1268 	.release	= sm_release,
1269 
1270 	.owner		= THIS_MODULE,
1271 };
1272 
sm_module_init(void)1273 static __init int sm_module_init(void)
1274 {
1275 	int error = 0;
1276 
1277 	cache_flush_workqueue = create_freezable_workqueue("smflush");
1278 	if (!cache_flush_workqueue)
1279 		return -ENOMEM;
1280 
1281 	error = register_mtd_blktrans(&sm_ftl_ops);
1282 	if (error)
1283 		destroy_workqueue(cache_flush_workqueue);
1284 	return error;
1285 
1286 }
1287 
sm_module_exit(void)1288 static void __exit sm_module_exit(void)
1289 {
1290 	destroy_workqueue(cache_flush_workqueue);
1291 	deregister_mtd_blktrans(&sm_ftl_ops);
1292 }
1293 
1294 module_init(sm_module_init);
1295 module_exit(sm_module_exit);
1296 
1297 MODULE_LICENSE("GPL");
1298 MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
1299 MODULE_DESCRIPTION("Smartmedia/xD mtd translation layer");
1300