xref: /kernel/linux/linux-5.10/drivers/mtd/nand/bbt.c (revision 8c2ecf20) 
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 */
23int 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}
37EXPORT_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 */
45void nanddev_bbt_cleanup(struct nand_device *nand)
46{
47	kfree(nand->bbt.cache);
48}
49EXPORT_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 */
60int nanddev_bbt_update(struct nand_device *nand)
61{
62	return 0;
63}
64EXPORT_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 */
74int 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}
92EXPORT_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 */
107int 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}
131EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status);
132