1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2017 Free Electrons 4 * 5 * Authors: 6 * Boris Brezillon <boris.brezillon@free-electrons.com> 7 * Peter Pan <peterpandong@micron.com> 8 */ 9 10 #define pr_fmt(fmt) "nand-bbt: " fmt 11 12 #include <linux/mtd/nand.h> 13 #include <linux/slab.h> 14 15 /** 16 * nanddev_bbt_init() - Initialize the BBT (Bad Block Table) 17 * @nand: NAND device 18 * 19 * Initialize the in-memory BBT. 20 * 21 * Return: 0 in case of success, a negative error code otherwise. 22 */ 23 int nanddev_bbt_init(struct nand_device *nand) 24 { 25 unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS); 26 unsigned int nblocks = nanddev_neraseblocks(nand); 27 unsigned int nwords = DIV_ROUND_UP(nblocks * bits_per_block, 28 BITS_PER_LONG); 29 30 nand->bbt.cache = kcalloc(nwords, sizeof(*nand->bbt.cache), 31 GFP_KERNEL); 32 if (!nand->bbt.cache) 33 return -ENOMEM; 34 35 return 0; 36 } 37 EXPORT_SYMBOL_GPL(nanddev_bbt_init); 38 39 /** 40 * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table) 41 * @nand: NAND device 42 * 43 * Undoes what has been done in nanddev_bbt_init() 44 */ 45 void nanddev_bbt_cleanup(struct nand_device *nand) 46 { 47 kfree(nand->bbt.cache); 48 } 49 EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup); 50 51 /** 52 * nanddev_bbt_update() - Update a BBT 53 * @nand: nand device 54 * 55 * Update the BBT. Currently a NOP function since on-flash bbt is not yet 56 * supported. 57 * 58 * Return: 0 in case of success, a negative error code otherwise. 59 */ 60 int nanddev_bbt_update(struct nand_device *nand) 61 { 62 return 0; 63 } 64 EXPORT_SYMBOL_GPL(nanddev_bbt_update); 65 66 /** 67 * nanddev_bbt_get_block_status() - Return the status of an eraseblock 68 * @nand: nand device 69 * @entry: the BBT entry 70 * 71 * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry 72 * is bigger than the BBT size. 73 */ 74 int nanddev_bbt_get_block_status(const struct nand_device *nand, 75 unsigned int entry) 76 { 77 unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS); 78 unsigned long *pos = nand->bbt.cache + 79 ((entry * bits_per_block) / BITS_PER_LONG); 80 unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG; 81 unsigned long status; 82 83 if (entry >= nanddev_neraseblocks(nand)) 84 return -ERANGE; 85 86 status = pos[0] >> offs; 87 if (bits_per_block + offs > BITS_PER_LONG) 88 status |= pos[1] << (BITS_PER_LONG - offs); 89 90 return status & GENMASK(bits_per_block - 1, 0); 91 } 92 EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status); 93 94 /** 95 * nanddev_bbt_set_block_status() - Update the status of an eraseblock in the 96 * in-memory BBT 97 * @nand: nand device 98 * @entry: the BBT entry to update 99 * @status: the new status 100 * 101 * Update an entry of the in-memory BBT. If you want to push the updated BBT 102 * the NAND you should call nanddev_bbt_update(). 103 * 104 * Return: 0 in case of success or -%ERANGE if @entry is bigger than the BBT 105 * size. 106 */ 107 int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry, 108 enum nand_bbt_block_status status) 109 { 110 unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS); 111 unsigned long *pos = nand->bbt.cache + 112 ((entry * bits_per_block) / BITS_PER_LONG); 113 unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG; 114 unsigned long val = status & GENMASK(bits_per_block - 1, 0); 115 116 if (entry >= nanddev_neraseblocks(nand)) 117 return -ERANGE; 118 119 pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs); 120 pos[0] |= val << offs; 121 122 if (bits_per_block + offs > BITS_PER_LONG) { 123 unsigned int rbits = bits_per_block + offs - BITS_PER_LONG; 124 125 pos[1] &= ~GENMASK(rbits - 1, 0); 126 pos[1] |= val >> (bits_per_block - rbits); 127 } 128 129 return 0; 130 } 131 EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status); 132