3  *   Bad block table support for the NAND driver
13  * When nand_scan_bbt is called, then it tries to find the bad block table
17  * Once a new bad block is discovered then the "factory" information is updated
24  * If the tables are not versioned, then we "or" the bad block information.
27  * good / bad blocks and the bad block tables are created.
32  * The auto generated bad block table is located in the last good blocks
41  * The table uses 2 bits per block
42  * 11b:		block is good
43  * 00b:		block is factory marked bad
44  * 01b, 10b:	block is marked bad due to wear
46  * The memory bad block table uses the following scheme:
47  * 00b:		block is good
48  * 01b:		block is marked bad due to wear
49  * 10b:		block is reserved (to protect the bbt area)
50  * 11b:		block is factory marked bad
52  * Multichip devices like DOC store the bad block info per floor.
55  * - bbts start at a page boundary, if autolocated on a block boundary
56  * - the space necessary for a bbt in FLASH does not exceed a block boundary
79 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)  in bbt_get_entry()  argument
81 	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];  in bbt_get_entry()
82 	entry >>= (block & BBT_ENTRY_MASK) * 2;  in bbt_get_entry()
86 static inline void bbt_mark_entry(struct nand_chip *chip, int block,  in bbt_mark_entry()  argument
89 	uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);  in bbt_mark_entry()
90 	chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;  in bbt_mark_entry()
107  * Check for a pattern at the given place. Used to search bad block tables and
108  * good / bad block identifiers.
127  * Check for a pattern at the given place. Used to search bad block tables and
128  * good / bad block identifiers. Same as check_pattern, but no optional empty
159  * read_bbt - [GENERIC] Read the bad block table starting from page
165  * @offs: block number offset in the table
167  * Read the bad block table starting from page.
220 					pr_info("nand_read_bbt: reserved block at 0x%012llx\n",  in read_bbt()
232 				pr_info("nand_read_bbt: bad block at 0x%012llx\n",  in read_bbt()
252  * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
255  * @td: descriptor for the bad block table
259  * Read the bad block table for all chips starting at a given page. We assume
377  * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
380  * @td: descriptor for the bad block table
381  * @md:	descriptor for the bad block table mirror
383  * Read the bad block table(s) for all chips starting at a given page. We
396 		pr_info("Bad block table at page %d, version 0x%02X\n",  in read_abs_bbts()
405 		pr_info("Bad block table at page %d, version 0x%02X\n",  in read_abs_bbts()
410 /* Scan a given block partially */
442  * create_bbt - [GENERIC] Create a bad block table by scanning the device
445  * @bd: descriptor for the good/bad block search pattern
449  * Create a bad block table by scanning the device for the given good/bad block
508  * search_bbt - [GENERIC] scan the device for a specific bad block table
511  * @td: descriptor for the bad block table
513  * Read the bad block table by searching for a given ident pattern. Search is
515  * downwards. The search starts always at the start of a block. If the option
517  * the bad block information of this chip. This is necessary to provide support
520  * The bbt ident pattern resides in the oob area of the first page in a block.
526 	int startblock, block, dir;  in search_bbt()  local
555 		for (block = 0; block < td->maxblocks; block++) {  in search_bbt()
557 			int actblock = startblock + dir * block;  in search_bbt()
576 			pr_warn("Bad block table not found for chip %d\n", i);  in search_bbt()
578 			pr_info("Bad block table found at page %d, version 0x%02X\n",  in search_bbt()
585  * search_read_bbts - [GENERIC] scan the device for bad block table(s)
588  * @td: descriptor for the bad block table
589  * @md: descriptor for the bad block table mirror
591  * Search and read the bad block table(s).
606  * write_bbt - [GENERIC] (Re)write the bad block table
609  * @td: descriptor for the bad block table
610  * @md: descriptor for the bad block table mirror
613  * (Re)write the bad block table.
637 	/* Write bad block table per chip rather than per device? */  in write_bbt()
665 		 * Automatic placement of the bad block table. Search direction  in write_bbt()
677 			int block = startblock + dir * i;  in write_bbt()  local
678 			/* Check, if the block is bad */  in write_bbt()
679 			switch (bbt_get_entry(this, block)) {  in write_bbt()
684 			page = block <<  in write_bbt()
686 			/* Check, if the block is used by the mirror table */  in write_bbt()
690 		pr_err("No space left to write bad block table\n");  in write_bbt()
715 		/* Must we save the block contents? */  in write_bbt()
717 			/* Make it block aligned */  in write_bbt()
723 					pr_info("nand_bbt: error reading block for writing the bad block table\n");  in write_bbt()
726 				pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");  in write_bbt()
797 		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",  in write_bbt()
806 	pr_warn("nand_bbt: error while writing bad block table %d\n", res);  in write_bbt()
811  * nand_memory_bbt - [GENERIC] create a memory based bad block table
813  * @bd: descriptor for the good/bad block search pattern
829  * @bd: descriptor for the good/bad block search pattern
890 			/* Create the bad block table by scanning the device? */  in check_create()
936 		/* Write the bad block table to the device? */  in check_create()
943 		/* Write the mirror bad block table to the device? */  in check_create()
954  * mark_bbt_regions - [GENERIC] mark the bad block table regions
956  * @td: bad block table descriptor
958  * The bad block table regions are marked as "bad" to prevent accidental
964 	int i, j, chips, block, nrblocks, update;  in mark_bbt_region()  local
981 			block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);  in mark_bbt_region()
982 			oldval = bbt_get_entry(this, block);  in mark_bbt_region()
983 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);  in mark_bbt_region()
986 				nand_update_bbt(mtd, (loff_t)block <<  in mark_bbt_region()
992 			block = ((i + 1) * nrblocks) - td->maxblocks;  in mark_bbt_region()
994 			block = i * nrblocks;  in mark_bbt_region()
996 			oldval = bbt_get_entry(this, block);  in mark_bbt_region()
997 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);  in mark_bbt_region()
1000 			block++;  in mark_bbt_region()
1008 			nand_update_bbt(mtd, (loff_t)(block - 1) <<  in mark_bbt_region()
1014  * verify_bbt_descr - verify the bad block description
1018  * This functions performs a few sanity checks on the bad block description
1062  * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1064  * @bd: descriptor for the good/bad block search pattern
1066  * The function checks, if a bad block table(s) is/are already available. If
1068  * the bad block table(s) to the selected place.
1070  * The bad block table memory is allocated here. It must be freed by calling
1083 	 * Allocate memory (2bit per block) and clear the memory bad block  in nand_scan_bbt()
1092 	 * memory based bad block table.  in nand_scan_bbt()
1117 		/* Search the bad block table using a pattern in oob */  in nand_scan_bbt()
1140  * nand_update_bbt - update bad block table(s)
1142  * @offs: the offset of the newly marked block
1144  * The function updates the bad block table(s).
1178 	/* Write the bad block table to the device? */  in nand_update_bbt()
1184 	/* Write the mirror bad block table to the device? */  in nand_update_bbt()
1195  * Define some generic bad / good block scan pattern which are used
1258 		pr_warn("Bad block pattern already allocated; not replacing\n");  in nand_create_badblock_pattern()
1274  * nand_default_bbt - [NAND Interface] Select a default bad block table for the device
1277  * This function selects the default bad block table support for the device and
1285 	/* Is a flash based bad block table requested? */  in nand_default_bbt()
1312  * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
1319 	int block;  in nand_isreserved_bbt()  local
1321 	block = (int)(offs >> this->bbt_erase_shift);  in nand_isreserved_bbt()
1322 	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;  in nand_isreserved_bbt()
1326  * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1329  * @allowbbt: allow access to bad block table region
1334 	int block, res;  in nand_isbad_bbt()  local
1336 	block = (int)(offs >> this->bbt_erase_shift);  in nand_isbad_bbt()
1337 	res = bbt_get_entry(this, block);  in nand_isbad_bbt()
1339 	pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",  in nand_isbad_bbt()
1340 		 (unsigned int)offs, block, res);  in nand_isbad_bbt()
1354  * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1356  * @offs: offset of the bad block
1361 	int block, ret = 0;  in nand_markbad_bbt()  local
1363 	block = (int)(offs >> this->bbt_erase_shift);  in nand_markbad_bbt()
1365 	/* Mark bad block in memory */  in nand_markbad_bbt()
1366 	bbt_mark_entry(this, block, BBT_BLOCK_WORN);  in nand_markbad_bbt()
1368 	/* Update flash-based bad block table */  in nand_markbad_bbt()