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 
28 	nand->bbt.cache = bitmap_zalloc(nblocks * bits_per_block, GFP_KERNEL);
29 	if (!nand->bbt.cache)
30 		return -ENOMEM;
31 
32 	return 0;
33 }
34 EXPORT_SYMBOL_GPL(nanddev_bbt_init);
35 
36 /**
37  * nanddev_bbt_cleanup() - Cleanup the BBT (Bad Block Table)
38  * @nand: NAND device
39  *
40  * Undoes what has been done in nanddev_bbt_init()
41  */
nanddev_bbt_cleanup(struct nand_device * nand)42 void nanddev_bbt_cleanup(struct nand_device *nand)
43 {
44 	bitmap_free(nand->bbt.cache);
45 }
46 EXPORT_SYMBOL_GPL(nanddev_bbt_cleanup);
47 
48 /**
49  * nanddev_bbt_update() - Update a BBT
50  * @nand: nand device
51  *
52  * Update the BBT. Currently a NOP function since on-flash bbt is not yet
53  * supported.
54  *
55  * Return: 0 in case of success, a negative error code otherwise.
56  */
nanddev_bbt_update(struct nand_device * nand)57 int nanddev_bbt_update(struct nand_device *nand)
58 {
59 	return 0;
60 }
61 EXPORT_SYMBOL_GPL(nanddev_bbt_update);
62 
63 /**
64  * nanddev_bbt_get_block_status() - Return the status of an eraseblock
65  * @nand: nand device
66  * @entry: the BBT entry
67  *
68  * Return: a positive number nand_bbt_block_status status or -%ERANGE if @entry
69  *	   is bigger than the BBT size.
70  */
nanddev_bbt_get_block_status(const struct nand_device * nand,unsigned int entry)71 int nanddev_bbt_get_block_status(const struct nand_device *nand,
72 				 unsigned int entry)
73 {
74 	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
75 	unsigned long *pos = nand->bbt.cache +
76 			     ((entry * bits_per_block) / BITS_PER_LONG);
77 	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
78 	unsigned long status;
79 
80 	if (entry >= nanddev_neraseblocks(nand))
81 		return -ERANGE;
82 
83 	status = pos[0] >> offs;
84 	if (bits_per_block + offs > BITS_PER_LONG)
85 		status |= pos[1] << (BITS_PER_LONG - offs);
86 
87 	return status & GENMASK(bits_per_block - 1, 0);
88 }
89 EXPORT_SYMBOL_GPL(nanddev_bbt_get_block_status);
90 
91 /**
92  * nanddev_bbt_set_block_status() - Update the status of an eraseblock in the
93  *				    in-memory BBT
94  * @nand: nand device
95  * @entry: the BBT entry to update
96  * @status: the new status
97  *
98  * Update an entry of the in-memory BBT. If you want to push the updated BBT
99  * the NAND you should call nanddev_bbt_update().
100  *
101  * Return: 0 in case of success or -%ERANGE if @entry is bigger than the BBT
102  *	   size.
103  */
nanddev_bbt_set_block_status(struct nand_device * nand,unsigned int entry,enum nand_bbt_block_status status)104 int nanddev_bbt_set_block_status(struct nand_device *nand, unsigned int entry,
105 				 enum nand_bbt_block_status status)
106 {
107 	unsigned int bits_per_block = fls(NAND_BBT_BLOCK_NUM_STATUS);
108 	unsigned long *pos = nand->bbt.cache +
109 			     ((entry * bits_per_block) / BITS_PER_LONG);
110 	unsigned int offs = (entry * bits_per_block) % BITS_PER_LONG;
111 	unsigned long val = status & GENMASK(bits_per_block - 1, 0);
112 
113 	if (entry >= nanddev_neraseblocks(nand))
114 		return -ERANGE;
115 
116 	pos[0] &= ~GENMASK(offs + bits_per_block - 1, offs);
117 	pos[0] |= val << offs;
118 
119 	if (bits_per_block + offs > BITS_PER_LONG) {
120 		unsigned int rbits = bits_per_block + offs - BITS_PER_LONG;
121 
122 		pos[1] &= ~GENMASK(rbits - 1, 0);
123 		pos[1] |= val >> (bits_per_block - rbits);
124 	}
125 
126 	return 0;
127 }
128 EXPORT_SYMBOL_GPL(nanddev_bbt_set_block_status);
129