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 */
nanddev_bbt_init(struct nand_device * nand)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 */
nanddev_bbt_cleanup(struct nand_device * nand)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 */
nanddev_bbt_update(struct nand_device * nand)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 */
nanddev_bbt_get_block_status(const struct nand_device * nand,unsigned int entry)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 */
nanddev_bbt_set_block_status(struct nand_device * nand,unsigned int entry,enum nand_bbt_block_status status)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