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