4  *   Bad block table support for the NAND driver
10  * When nand_scan_bbt is called, then it tries to find the bad block table
14  * Once a new bad block is discovered then the "factory" information is updated
21  * If the tables are not versioned, then we "or" the bad block information.
24  * good / bad blocks and the bad block tables are created.
29  * The auto generated bad block table is located in the last good blocks
38  * The table uses 2 bits per block
39  * 11b:		block is good
40  * 00b:		block is factory marked bad
41  * 01b, 10b:	block is marked bad due to wear
43  * The memory bad block table uses the following scheme:
44  * 00b:		block is good
45  * 01b:		block is marked bad due to wear
46  * 10b:		block is reserved (to protect the bbt area)
47  * 11b:		block is factory marked bad
49  * Multichip devices like DOC store the bad block info per floor.
52  * - bbts start at a page boundary, if autolocated on a block boundary
53  * - the space necessary for a bbt in FLASH does not exceed a block boundary
76 static inline uint8_t bbt_get_entry(struct nand_chip *chip, int block)  in bbt_get_entry()  argument
78 	uint8_t entry = chip->bbt[block >> BBT_ENTRY_SHIFT];  in bbt_get_entry()
79 	entry >>= (block & BBT_ENTRY_MASK) * 2;  in bbt_get_entry()
83 static inline void bbt_mark_entry(struct nand_chip *chip, int block,  in bbt_mark_entry()  argument
86 	uint8_t msk = (mark & BBT_ENTRY_MASK) << ((block & BBT_ENTRY_MASK) * 2);  in bbt_mark_entry()
87 	chip->bbt[block >> BBT_ENTRY_SHIFT] |= msk;  in bbt_mark_entry()
104  * Check for a pattern at the given place. Used to search bad block tables and
105  * good / bad block identifiers.
124  * Check for a pattern at the given place. Used to search bad block tables and
125  * good / bad block identifiers. Same as check_pattern, but no optional empty
156  * read_bbt - [GENERIC] Read the bad block table starting from page
162  * @offs: block number offset in the table
164  * Read the bad block table starting from page.
217 					pr_info("nand_read_bbt: reserved block at 0x%012llx\n",  in read_bbt()
229 				pr_info("nand_read_bbt: bad block at 0x%012llx\n",  in read_bbt()
249  * read_abs_bbt - [GENERIC] Read the bad block table starting at a given page
252  * @td: descriptor for the bad block table
256  * Read the bad block table for all chips starting at a given page. We assume
380  * read_abs_bbts - [GENERIC] Read the bad block table(s) for all chips starting at a given page
383  * @td: descriptor for the bad block table
384  * @md:	descriptor for the bad block table mirror
386  * Read the bad block table(s) for all chips starting at a given page. We
399 		pr_info("Bad block table at page %d, version 0x%02X\n",  in read_abs_bbts()
408 		pr_info("Bad block table at page %d, version 0x%02X\n",  in read_abs_bbts()
413 /* Scan a given block partially */
450 /* Check if a potential BBT block is marked as bad */
457 	 * No need to check for a bad BBT block if the BBM area overlaps with  in bbt_block_checkbad()
458 	 * the bad block table marker area in OOB since writing a BBM here  in bbt_block_checkbad()
459 	 * invalidates the bad block table marker anyway.  in bbt_block_checkbad()
466 	 * There is no point in checking for a bad block marker if writing  in bbt_block_checkbad()
480  * create_bbt - [GENERIC] Create a bad block table by scanning the device
483  * @bd: descriptor for the good/bad block search pattern
487  * Create a bad block table by scanning the device for the given good/bad block
538  * search_bbt - [GENERIC] scan the device for a specific bad block table
541  * @td: descriptor for the bad block table
543  * Read the bad block table by searching for a given ident pattern. Search is
545  * downwards. The search starts always at the start of a block. If the option
547  * the bad block information of this chip. This is necessary to provide support
550  * The bbt ident pattern resides in the oob area of the first page in a block.
558 	int startblock, block, dir;  in search_bbt()  local
586 		for (block = 0; block < td->maxblocks; block++) {  in search_bbt()
588 			int actblock = startblock + dir * block;  in search_bbt()
591 			/* Check if block is marked bad */  in search_bbt()
611 			pr_warn("Bad block table not found for chip %d\n", i);  in search_bbt()
613 			pr_info("Bad block table found at page %d, version 0x%02X\n",  in search_bbt()
620  * search_read_bbts - [GENERIC] scan the device for bad block table(s)
623  * @td: descriptor for the bad block table
624  * @md: descriptor for the bad block table mirror
626  * Search and read the bad block table(s).
647  * This functions returns a positive block number pointing a valid eraseblock
650  * pointing to a valid block we re-use it, otherwise we search for the next
673 	 * Automatic placement of the bad block table. Search direction  in get_bbt_block()
685 		int block = startblock + dir * i;  in get_bbt_block()  local
687 		/* Check, if the block is bad */  in get_bbt_block()
688 		switch (bbt_get_entry(this, block)) {  in get_bbt_block()
694 		page = block << (this->bbt_erase_shift - this->page_shift);  in get_bbt_block()
696 		/* Check, if the block is used by the mirror table */  in get_bbt_block()
698 			return block;  in get_bbt_block()
705  * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
709  * @block: the BBT block to mark
713  * block as bad using a bad block marker and invalidating the associated
718 			       int chip, int block)  in mark_bbt_block_bad()  argument
723 	bbt_mark_entry(this, block, BBT_BLOCK_WORN);  in mark_bbt_block_bad()
725 	to = (loff_t)block << this->bbt_erase_shift;  in mark_bbt_block_bad()
728 		pr_warn("nand_bbt: error %d while marking block %d bad\n",  in mark_bbt_block_bad()
729 			res, block);  in mark_bbt_block_bad()
735  * write_bbt - [GENERIC] (Re)write the bad block table
738  * @td: descriptor for the bad block table
739  * @md: descriptor for the bad block table mirror
742  * (Re)write the bad block table.
767 	/* Write bad block table per chip rather than per device? */  in write_bbt()
784 		int block;  in write_bbt()  local
786 		block = get_bbt_block(this, td, md, chip);  in write_bbt()
787 		if (block < 0) {  in write_bbt()
788 			pr_err("No space left to write bad block table\n");  in write_bbt()
789 			res = block;  in write_bbt()
794 		 * get_bbt_block() returns a block number, shift the value to  in write_bbt()
797 		page = block << (this->bbt_erase_shift - this->page_shift);  in write_bbt()
820 		/* Must we save the block contents? */  in write_bbt()
822 			/* Make it block aligned */  in write_bbt()
828 					pr_info("nand_bbt: error reading block for writing the bad block table\n");  in write_bbt()
831 				pr_warn("nand_bbt: ECC error while reading block for writing bad block table\n");  in write_bbt()
893 			pr_warn("nand_bbt: error while erasing BBT block %d\n",  in write_bbt()
895 			mark_bbt_block_bad(this, td, chip, block);  in write_bbt()
903 			pr_warn("nand_bbt: error while writing BBT block %d\n",  in write_bbt()
905 			mark_bbt_block_bad(this, td, chip, block);  in write_bbt()
909 		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",  in write_bbt()
918 	pr_warn("nand_bbt: error while writing bad block table %d\n", res);  in write_bbt()
923  * nand_memory_bbt - [GENERIC] create a memory based bad block table
925  * @bd: descriptor for the good/bad block search pattern
942  * @bd: descriptor for the good/bad block search pattern
1003 			/* Create the bad block table by scanning the device? */  in check_create()
1049 		/* Write the bad block table to the device? */  in check_create()
1056 		/* Write the mirror bad block table to the device? */  in check_create()
1067  * nand_update_bbt - update bad block table(s)
1069  * @offs: the offset of the newly marked block
1071  * The function updates the bad block table(s).
1105 	/* Write the bad block table to the device? */  in nand_update_bbt()
1111 	/* Write the mirror bad block table to the device? */  in nand_update_bbt()
1122  * mark_bbt_region - [GENERIC] mark the bad block table regions
1124  * @td: bad block table descriptor
1126  * The bad block table regions are marked as "bad" to prevent accidental
1133 	int i, j, chips, block, nrblocks, update;  in mark_bbt_region()  local
1150 			block = td->pages[i] >> (this->bbt_erase_shift - this->page_shift);  in mark_bbt_region()
1151 			oldval = bbt_get_entry(this, block);  in mark_bbt_region()
1152 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);  in mark_bbt_region()
1155 				nand_update_bbt(this, (loff_t)block <<  in mark_bbt_region()
1161 			block = ((i + 1) * nrblocks) - td->maxblocks;  in mark_bbt_region()
1163 			block = i * nrblocks;  in mark_bbt_region()
1165 			oldval = bbt_get_entry(this, block);  in mark_bbt_region()
1166 			bbt_mark_entry(this, block, BBT_BLOCK_RESERVED);  in mark_bbt_region()
1169 			block++;  in mark_bbt_region()
1177 			nand_update_bbt(this, (loff_t)(block - 1) <<  in mark_bbt_region()
1183  * verify_bbt_descr - verify the bad block description
1187  * This functions performs a few sanity checks on the bad block description
1232  * nand_scan_bbt - [NAND Interface] scan, find, read and maybe create bad block table(s)
1234  * @bd: descriptor for the good/bad block search pattern
1236  * The function checks, if a bad block table(s) is/are already available. If
1238  * the bad block table(s) to the selected place.
1240  * The bad block table memory is allocated here. It must be freed by calling
1253 	 * Allocate memory (2bit per block) and clear the memory bad block  in nand_scan_bbt()
1262 	 * memory based bad block table.  in nand_scan_bbt()
1287 		/* Search the bad block table using a pattern in oob */  in nand_scan_bbt()
1312  * Define some generic bad / good block scan pattern which are used
1375 		pr_warn("Bad block pattern already allocated; not replacing\n");  in nand_create_badblock_pattern()
1391  * nand_create_bbt - [NAND Interface] Select a default bad block table for the device
1394  * This function selects the default bad block table support for the device and
1401 	/* Is a flash based bad block table requested? */  in nand_create_bbt()
1429  * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
1435 	int block;  in nand_isreserved_bbt()  local
1437 	block = (int)(offs >> this->bbt_erase_shift);  in nand_isreserved_bbt()
1438 	return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;  in nand_isreserved_bbt()
1442  * nand_isbad_bbt - [NAND Interface] Check if a block is bad
1445  * @allowbbt: allow access to bad block table region
1449 	int block, res;  in nand_isbad_bbt()  local
1451 	block = (int)(offs >> this->bbt_erase_shift);  in nand_isbad_bbt()
1452 	res = bbt_get_entry(this, block);  in nand_isbad_bbt()
1454 	pr_debug("nand_isbad_bbt(): bbt info for offs 0x%08x: (block %d) 0x%02x\n",  in nand_isbad_bbt()
1455 		 (unsigned int)offs, block, res);  in nand_isbad_bbt()
1472  * nand_markbad_bbt - [NAND Interface] Mark a block bad in the BBT
1474  * @offs: offset of the bad block
1478 	int block, ret = 0;  in nand_markbad_bbt()  local
1480 	block = (int)(offs >> this->bbt_erase_shift);  in nand_markbad_bbt()
1482 	/* Mark bad block in memory */  in nand_markbad_bbt()
1483 	bbt_mark_entry(this, block, BBT_BLOCK_WORN);  in nand_markbad_bbt()
1485 	/* Update flash-based bad block table */  in nand_markbad_bbt()