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/drivers/mtd/ssfdc.c

https://bitbucket.org/ndreys/linux-sunxi
C | 472 lines | 335 code | 83 blank | 54 comment | 47 complexity | fca5253e782eb435b70d5ab6319cff98 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * Linux driver for SSFDC Flash Translation Layer (Read only)
  3 * Š 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
 22struct 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
 50NCylinder	125	125	250	250	500	500	500	500
 51NHead		4	4	4	4	4	8	8	16
 52NSector		4	8	8	16	16	16	32	32
 53SumSector	2,000	4,000	8,000	16,000	32,000	64,000	128,000	256,000
 54SectorSize	512	512	512	512	512	512	512	512
 55**/
 56
 57typedef 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 */
 65static 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
 77static 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 */
101static 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 */
106static 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				DEBUG(MTD_DEBUG_LEVEL1,
139					"SSFDC_RO: CIS/IDI sector not found"
140					" on %s (mtd%d)\n", mtd->name,
141					mtd->index);
142			}
143			break;
144		}
145	}
146
147	kfree(sect_buf);
148 out:
149	return cis_sector;
150}
151
152/* Read physical sector (wrapper to MTD_READ) */
153static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf,
154				int sect_no)
155{
156	int ret;
157	size_t retlen;
158	loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;
159
160	ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
161	if (ret < 0 || retlen != SECTOR_SIZE)
162		return -1;
163
164	return 0;
165}
166
167/* Read redundancy area (wrapper to MTD_READ_OOB */
168static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
169{
170	struct mtd_oob_ops ops;
171	int ret;
172
173	ops.mode = MTD_OOB_RAW;
174	ops.ooboffs = 0;
175	ops.ooblen = OOB_SIZE;
176	ops.oobbuf = buf;
177	ops.datbuf = NULL;
178
179	ret = mtd->read_oob(mtd, offs, &ops);
180	if (ret < 0 || ops.oobretlen != OOB_SIZE)
181		return -1;
182
183	return 0;
184}
185
186/* Parity calculator on a word of n bit size */
187static int get_parity(int number, int size)
188{
189 	int k;
190	int parity;
191
192	parity = 1;
193	for (k = 0; k < size; k++) {
194		parity += (number >> k);
195		parity &= 1;
196	}
197	return parity;
198}
199
200/* Read and validate the logical block address field stored in the OOB */
201static int get_logical_address(uint8_t *oob_buf)
202{
203	int block_address, parity;
204	int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
205	int j;
206	int ok = 0;
207
208	/*
209	 * Look for the first valid logical address
210	 * Valid address has fixed pattern on most significant bits and
211	 * parity check
212	 */
213	for (j = 0; j < ARRAY_SIZE(offset); j++) {
214		block_address = ((int)oob_buf[offset[j]] << 8) |
215			oob_buf[offset[j]+1];
216
217		/* Check for the signature bits in the address field (MSBits) */
218		if ((block_address & ~0x7FF) == 0x1000) {
219			parity = block_address & 0x01;
220			block_address &= 0x7FF;
221			block_address >>= 1;
222
223			if (get_parity(block_address, 10) != parity) {
224				DEBUG(MTD_DEBUG_LEVEL0,
225					"SSFDC_RO: logical address field%d"
226					"parity error(0x%04X)\n", j+1,
227					block_address);
228			} else {
229				ok = 1;
230				break;
231			}
232		}
233	}
234
235	if (!ok)
236		block_address = -2;
237
238	DEBUG(MTD_DEBUG_LEVEL3, "SSFDC_RO: get_logical_address() %d\n",
239		block_address);
240
241	return block_address;
242}
243
244/* Build the logic block map */
245static int build_logical_block_map(struct ssfdcr_record *ssfdc)
246{
247	unsigned long offset;
248	uint8_t oob_buf[OOB_SIZE];
249	int ret, block_address, phys_block;
250	struct mtd_info *mtd = ssfdc->mbd.mtd;
251
252	DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
253	      ssfdc->map_len,
254	      (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);
255
256	/* Scan every physical block, skip CIS block */
257	for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
258			phys_block++) {
259		offset = (unsigned long)phys_block * ssfdc->erase_size;
260		if (mtd->block_isbad(mtd, offset))
261			continue;	/* skip bad blocks */
262
263		ret = read_raw_oob(mtd, offset, oob_buf);
264		if (ret < 0) {
265			DEBUG(MTD_DEBUG_LEVEL0,
266				"SSFDC_RO: mtd read_oob() failed at %lu\n",
267				offset);
268			return -1;
269		}
270		block_address = get_logical_address(oob_buf);
271
272		/* Skip invalid addresses */
273		if (block_address >= 0 &&
274				block_address < MAX_LOGIC_BLK_PER_ZONE) {
275			int zone_index;
276
277			zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
278			block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
279			ssfdc->logic_block_map[block_address] =
280				(unsigned short)phys_block;
281
282			DEBUG(MTD_DEBUG_LEVEL2,
283				"SSFDC_RO: build_block_map() phys_block=%d,"
284				"logic_block_addr=%d, zone=%d\n",
285				phys_block, block_address, zone_index);
286		}
287	}
288	return 0;
289}
290
291static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
292{
293	struct ssfdcr_record *ssfdc;
294	int cis_sector;
295
296	/* Check for small page NAND flash */
297	if (mtd->type != MTD_NANDFLASH || mtd->oobsize != OOB_SIZE ||
298	    mtd->size > UINT_MAX)
299		return;
300
301	/* Check for SSDFC format by reading CIS/IDI sector */
302	cis_sector = get_valid_cis_sector(mtd);
303	if (cis_sector == -1)
304		return;
305
306	ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
307	if (!ssfdc) {
308		printk(KERN_WARNING
309			"SSFDC_RO: out of memory for data structures\n");
310		return;
311	}
312
313	ssfdc->mbd.mtd = mtd;
314	ssfdc->mbd.devnum = -1;
315	ssfdc->mbd.tr = tr;
316	ssfdc->mbd.readonly = 1;
317
318	ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
319	ssfdc->erase_size = mtd->erasesize;
320	ssfdc->map_len = (u32)mtd->size / mtd->erasesize;
321
322	DEBUG(MTD_DEBUG_LEVEL1,
323		"SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
324		ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
325		DIV_ROUND_UP(ssfdc->map_len, MAX_PHYS_BLK_PER_ZONE));
326
327	/* Set geometry */
328	ssfdc->heads = 16;
329	ssfdc->sectors = 32;
330	get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
331	ssfdc->cylinders = (unsigned short)(((u32)mtd->size >> SECTOR_SHIFT) /
332			((long)ssfdc->sectors * (long)ssfdc->heads));
333
334	DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
335		ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
336		(long)ssfdc->cylinders * (long)ssfdc->heads *
337		(long)ssfdc->sectors);
338
339	ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
340				(long)ssfdc->sectors;
341
342	/* Allocate logical block map */
343	ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
344					 ssfdc->map_len, GFP_KERNEL);
345	if (!ssfdc->logic_block_map) {
346		printk(KERN_WARNING
347			"SSFDC_RO: out of memory for data structures\n");
348		goto out_err;
349	}
350	memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
351		ssfdc->map_len);
352
353	/* Build logical block map */
354	if (build_logical_block_map(ssfdc) < 0)
355		goto out_err;
356
357	/* Register device + partitions */
358	if (add_mtd_blktrans_dev(&ssfdc->mbd))
359		goto out_err;
360
361	printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
362		ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
363	return;
364
365out_err:
366	kfree(ssfdc->logic_block_map);
367        kfree(ssfdc);
368}
369
370static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
371{
372	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
373
374	DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);
375
376	del_mtd_blktrans_dev(dev);
377	kfree(ssfdc->logic_block_map);
378}
379
380static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
381				unsigned long logic_sect_no, char *buf)
382{
383	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
384	int sectors_per_block, offset, block_address;
385
386	sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
387	offset = (int)(logic_sect_no % sectors_per_block);
388	block_address = (int)(logic_sect_no / sectors_per_block);
389
390	DEBUG(MTD_DEBUG_LEVEL3,
391		"SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
392		" block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
393		block_address);
394
395	if (block_address >= ssfdc->map_len)
396		BUG();
397
398	block_address = ssfdc->logic_block_map[block_address];
399
400	DEBUG(MTD_DEBUG_LEVEL3,
401		"SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
402		block_address);
403
404	if (block_address < 0xffff) {
405		unsigned long sect_no;
406
407		sect_no = (unsigned long)block_address * sectors_per_block +
408				offset;
409
410		DEBUG(MTD_DEBUG_LEVEL3,
411			"SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
412			sect_no);
413
414		if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
415			return -EIO;
416	} else {
417		memset(buf, 0xff, SECTOR_SIZE);
418	}
419
420	return 0;
421}
422
423static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev,  struct hd_geometry *geo)
424{
425	struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
426
427	DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
428			ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);
429
430	geo->heads = ssfdc->heads;
431	geo->sectors = ssfdc->sectors;
432	geo->cylinders = ssfdc->cylinders;
433
434	return 0;
435}
436
437/****************************************************************************
438 *
439 * Module stuff
440 *
441 ****************************************************************************/
442
443static struct mtd_blktrans_ops ssfdcr_tr = {
444	.name		= "ssfdc",
445	.major		= SSFDCR_MAJOR,
446	.part_bits	= SSFDCR_PARTN_BITS,
447	.blksize	= SECTOR_SIZE,
448	.getgeo		= ssfdcr_getgeo,
449	.readsect	= ssfdcr_readsect,
450	.add_mtd	= ssfdcr_add_mtd,
451	.remove_dev	= ssfdcr_remove_dev,
452	.owner		= THIS_MODULE,
453};
454
455static int __init init_ssfdcr(void)
456{
457	printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");
458
459	return register_mtd_blktrans(&ssfdcr_tr);
460}
461
462static void __exit cleanup_ssfdcr(void)
463{
464	deregister_mtd_blktrans(&ssfdcr_tr);
465}
466
467module_init(init_ssfdcr);
468module_exit(cleanup_ssfdcr);
469
470MODULE_LICENSE("GPL");
471MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
472MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");