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