ia64/linux-2.6.18-xen.hg

view drivers/mtd/onenand/onenand_bbt.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /*
2 * linux/drivers/mtd/onenand/onenand_bbt.c
3 *
4 * Bad Block Table support for the OneNAND driver
5 *
6 * Copyright(c) 2005 Samsung Electronics
7 * Kyungmin Park <kyungmin.park@samsung.com>
8 *
9 * Derived from nand_bbt.c
10 *
11 * TODO:
12 * Split BBT core and chip specific BBT.
13 */
15 #include <linux/slab.h>
16 #include <linux/mtd/mtd.h>
17 #include <linux/mtd/onenand.h>
18 #include <linux/mtd/compatmac.h>
20 extern int onenand_do_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
21 size_t *retlen, u_char *buf);
23 /**
24 * check_short_pattern - [GENERIC] check if a pattern is in the buffer
25 * @param buf the buffer to search
26 * @param len the length of buffer to search
27 * @param paglen the pagelength
28 * @param td search pattern descriptor
29 *
30 * Check for a pattern at the given place. Used to search bad block
31 * tables and good / bad block identifiers. Same as check_pattern, but
32 * no optional empty check and the pattern is expected to start
33 * at offset 0.
34 *
35 */
36 static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
37 {
38 int i;
39 uint8_t *p = buf;
41 /* Compare the pattern */
42 for (i = 0; i < td->len; i++) {
43 if (p[i] != td->pattern[i])
44 return -1;
45 }
46 return 0;
47 }
49 /**
50 * create_bbt - [GENERIC] Create a bad block table by scanning the device
51 * @param mtd MTD device structure
52 * @param buf temporary buffer
53 * @param bd descriptor for the good/bad block search pattern
54 * @param chip create the table for a specific chip, -1 read all chips.
55 * Applies only if NAND_BBT_PERCHIP option is set
56 *
57 * Create a bad block table by scanning the device
58 * for the given good/bad block identify pattern
59 */
60 static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
61 {
62 struct onenand_chip *this = mtd->priv;
63 struct bbm_info *bbm = this->bbm;
64 int i, j, numblocks, len, scanlen;
65 int startblock;
66 loff_t from;
67 size_t readlen, ooblen;
69 printk(KERN_INFO "Scanning device for bad blocks\n");
71 len = 1;
73 /* We need only read few bytes from the OOB area */
74 scanlen = ooblen = 0;
75 readlen = bd->len;
77 /* chip == -1 case only */
78 /* Note that numblocks is 2 * (real numblocks) here;
79 * see i += 2 below as it makses shifting and masking less painful
80 */
81 numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);
82 startblock = 0;
83 from = 0;
85 for (i = startblock; i < numblocks; ) {
86 int ret;
88 for (j = 0; j < len; j++) {
89 size_t retlen;
91 /* No need to read pages fully,
92 * just read required OOB bytes */
93 ret = onenand_do_read_oob(mtd, from + j * mtd->writesize + bd->offs,
94 readlen, &retlen, &buf[0]);
96 if (ret)
97 return ret;
99 if (check_short_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
100 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
101 printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",
102 i >> 1, (unsigned int) from);
103 break;
104 }
105 }
106 i += 2;
107 from += (1 << bbm->bbt_erase_shift);
108 }
110 return 0;
111 }
114 /**
115 * onenand_memory_bbt - [GENERIC] create a memory based bad block table
116 * @param mtd MTD device structure
117 * @param bd descriptor for the good/bad block search pattern
118 *
119 * The function creates a memory based bbt by scanning the device
120 * for manufacturer / software marked good / bad blocks
121 */
122 static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
123 {
124 struct onenand_chip *this = mtd->priv;
126 bd->options &= ~NAND_BBT_SCANEMPTY;
127 return create_bbt(mtd, this->page_buf, bd, -1);
128 }
130 /**
131 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
132 * @param mtd MTD device structure
133 * @param offs offset in the device
134 * @param allowbbt allow access to bad block table region
135 */
136 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
137 {
138 struct onenand_chip *this = mtd->priv;
139 struct bbm_info *bbm = this->bbm;
140 int block;
141 uint8_t res;
143 /* Get block number * 2 */
144 block = (int) (offs >> (bbm->bbt_erase_shift - 1));
145 res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
147 DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
148 (unsigned int) offs, block >> 1, res);
150 switch ((int) res) {
151 case 0x00: return 0;
152 case 0x01: return 1;
153 case 0x02: return allowbbt ? 0 : 1;
154 }
156 return 1;
157 }
159 /**
160 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
161 * @param mtd MTD device structure
162 * @param bd descriptor for the good/bad block search pattern
163 *
164 * The function checks, if a bad block table(s) is/are already
165 * available. If not it scans the device for manufacturer
166 * marked good / bad blocks and writes the bad block table(s) to
167 * the selected place.
168 *
169 * The bad block table memory is allocated here. It must be freed
170 * by calling the onenand_free_bbt function.
171 *
172 */
173 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
174 {
175 struct onenand_chip *this = mtd->priv;
176 struct bbm_info *bbm = this->bbm;
177 int len, ret = 0;
179 len = mtd->size >> (this->erase_shift + 2);
180 /* Allocate memory (2bit per block) */
181 bbm->bbt = kmalloc(len, GFP_KERNEL);
182 if (!bbm->bbt) {
183 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
184 return -ENOMEM;
185 }
186 /* Clear the memory bad block table */
187 memset(bbm->bbt, 0x00, len);
189 /* Set the bad block position */
190 bbm->badblockpos = ONENAND_BADBLOCK_POS;
192 /* Set erase shift */
193 bbm->bbt_erase_shift = this->erase_shift;
195 if (!bbm->isbad_bbt)
196 bbm->isbad_bbt = onenand_isbad_bbt;
198 /* Scan the device to build a memory based bad block table */
199 if ((ret = onenand_memory_bbt(mtd, bd))) {
200 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
201 kfree(bbm->bbt);
202 bbm->bbt = NULL;
203 }
205 return ret;
206 }
208 /*
209 * Define some generic bad / good block scan pattern which are used
210 * while scanning a device for factory marked good / bad blocks.
211 */
212 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
214 static struct nand_bbt_descr largepage_memorybased = {
215 .options = 0,
216 .offs = 0,
217 .len = 2,
218 .pattern = scan_ff_pattern,
219 };
221 /**
222 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
223 * @param mtd MTD device structure
224 *
225 * This function selects the default bad block table
226 * support for the device and calls the onenand_scan_bbt function
227 */
228 int onenand_default_bbt(struct mtd_info *mtd)
229 {
230 struct onenand_chip *this = mtd->priv;
231 struct bbm_info *bbm;
233 this->bbm = kmalloc(sizeof(struct bbm_info), GFP_KERNEL);
234 if (!this->bbm)
235 return -ENOMEM;
237 bbm = this->bbm;
239 memset(bbm, 0, sizeof(struct bbm_info));
241 /* 1KB page has same configuration as 2KB page */
242 if (!bbm->badblock_pattern)
243 bbm->badblock_pattern = &largepage_memorybased;
245 return onenand_scan_bbt(mtd, bbm->badblock_pattern);
246 }
248 EXPORT_SYMBOL(onenand_scan_bbt);
249 EXPORT_SYMBOL(onenand_default_bbt);