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1 /*
2  *  linux/include/linux/mtd/bbm.h
3  *
4  *  NAND family Bad Block Management (BBM) header file
5  *    - Bad Block Table (BBT) implementation
6  *
7  *  Copyright (c) 2005 Samsung Electronics
8  *  Kyungmin Park <kyungmin.park@samsung.com>
9  *
10  *  Copyright (c) 2000-2005
11  *  Thomas Gleixner <tglx@linuxtronix.de>
12  *
13  */
14 #ifndef __LINUX_MTD_BBM_H
15 #define __LINUX_MTD_BBM_H
16 
17 /* The maximum number of NAND chips in an array */
18 #define NAND_MAX_CHIPS		8
19 
20 /**
21  * struct nand_bbt_descr - bad block table descriptor
22  * @options:		options for this descriptor
23  * @pages:		the page(s) where we find the bbt, used with
24  * 			option BBT_ABSPAGE when bbt is searched,
25  * 			then we store the found bbts pages here.
26  *			Its an array and supports up to 8 chips now
27  * @offs:		offset of the pattern in the oob area of the page
28  * @veroffs:		offset of the bbt version counter in the oob area of the page
29  * @version:		version read from the bbt page during scan
30  * @len:		length of the pattern, if 0 no pattern check is performed
31  * @maxblocks:		maximum number of blocks to search for a bbt. This
32  *			number of blocks is reserved at the end of the device
33  *			where the tables are written.
34  * @reserved_block_code: if non-0, this pattern denotes a reserved
35  *			(rather than bad) block in the stored bbt
36  * @pattern:		pattern to identify bad block table or factory marked
37  *			good / bad blocks, can be NULL, if len = 0
38  *
39  * Descriptor for the bad block table marker and the descriptor for the
40  * pattern which identifies good and bad blocks. The assumption is made
41  * that the pattern and the version count are always located in the oob area
42  * of the first block.
43  */
44 struct nand_bbt_descr {
45 	int options;
46 	int pages[NAND_MAX_CHIPS];
47 	int offs;
48 	int veroffs;
49 	uint8_t version[NAND_MAX_CHIPS];
50 	int len;
51 	int maxblocks;
52 	int reserved_block_code;
53 	uint8_t *pattern;
54 };
55 
56 /* Options for the bad block table descriptors */
57 
58 /* The number of bits used per block in the bbt on the device */
59 #define NAND_BBT_NRBITS_MSK	0x0000000F
60 #define NAND_BBT_1BIT		0x00000001
61 #define NAND_BBT_2BIT		0x00000002
62 #define NAND_BBT_4BIT		0x00000004
63 #define NAND_BBT_8BIT		0x00000008
64 /* The bad block table is in the last good block of the device */
65 #define NAND_BBT_LASTBLOCK	0x00000010
66 /* The bbt is at the given page, else we must scan for the bbt */
67 #define NAND_BBT_ABSPAGE	0x00000020
68 /* The bbt is at the given page, else we must scan for the bbt */
69 #define NAND_BBT_SEARCH		0x00000040
70 /* bbt is stored per chip on multichip devices */
71 #define NAND_BBT_PERCHIP	0x00000080
72 /* bbt has a version counter at offset veroffs */
73 #define NAND_BBT_VERSION	0x00000100
74 /* Create a bbt if none axists */
75 #define NAND_BBT_CREATE		0x00000200
76 /* Search good / bad pattern through all pages of a block */
77 #define NAND_BBT_SCANALLPAGES	0x00000400
78 /* Scan block empty during good / bad block scan */
79 #define NAND_BBT_SCANEMPTY	0x00000800
80 /* Write bbt if neccecary */
81 #define NAND_BBT_WRITE		0x00001000
82 /* Read and write back block contents when writing bbt */
83 #define NAND_BBT_SAVECONTENT	0x00002000
84 /* Search good / bad pattern on the first and the second page */
85 #define NAND_BBT_SCAN2NDPAGE	0x00004000
86 
87 /* The maximum number of blocks to scan for a bbt */
88 #define NAND_BBT_SCAN_MAXBLOCKS	4
89 
90 /*
91  * Constants for oob configuration
92  */
93 #define ONENAND_BADBLOCK_POS	0
94 
95 /**
96  * struct bbm_info - [GENERIC] Bad Block Table data structure
97  * @bbt_erase_shift:	[INTERN] number of address bits in a bbt entry
98  * @badblockpos:	[INTERN] position of the bad block marker in the oob area
99  * @options:		options for this descriptor
100  * @bbt:		[INTERN] bad block table pointer
101  * @isbad_bbt:		function to determine if a block is bad
102  * @badblock_pattern:	[REPLACEABLE] bad block scan pattern used for
103  *			initial bad block scan
104  * @priv:		[OPTIONAL] pointer to private bbm date
105  */
106 struct bbm_info {
107 	int bbt_erase_shift;
108 	int badblockpos;
109 	int options;
110 
111 	uint8_t *bbt;
112 
113 	int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt);
114 
115 	/* TODO Add more NAND specific fileds */
116 	struct nand_bbt_descr *badblock_pattern;
117 
118 	void *priv;
119 };
120 
121 /* OneNAND BBT interface */
122 extern int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
123 extern int onenand_default_bbt(struct mtd_info *mtd);
124 
125 #endif	/* __LINUX_MTD_BBM_H */
126