1// SPDX-License-Identifier: GPL-2.0
2//
3// Register cache access API - flat caching support
4//
5// Copyright 2012 Wolfson Microelectronics plc
6//
7// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
8
9#include <linux/bitmap.h>
10#include <linux/bitops.h>
11#include <linux/device.h>
12#include <linux/limits.h>
13#include <linux/overflow.h>
14#include <linux/seq_file.h>
15#include <linux/slab.h>
16
17#include "internal.h"
18
19static inline unsigned int regcache_flat_get_index(const struct regmap *map,
20 unsigned int reg)
21{
22 return regcache_get_index_by_order(map, reg);
23}
24
25struct regcache_flat_data {
26 unsigned long *valid;
27 unsigned int data[];
28};
29
30static int regcache_flat_init(struct regmap *map)
31{
32 unsigned int cache_size;
33 struct regcache_flat_data *cache;
34
35 if (!map || map->reg_stride_order < 0 || !map->max_register_is_set)
36 return -EINVAL;
37
38 cache_size = regcache_flat_get_index(map, reg: map->max_register) + 1;
39 cache = kzalloc(struct_size(cache, data, cache_size), map->alloc_flags);
40 if (!cache)
41 return -ENOMEM;
42
43 cache->valid = bitmap_zalloc(nbits: cache_size, flags: map->alloc_flags);
44 if (!cache->valid)
45 goto err_free;
46
47 map->cache = cache;
48
49 return 0;
50
51err_free:
52 kfree(objp: cache);
53 return -ENOMEM;
54}
55
56static int regcache_flat_exit(struct regmap *map)
57{
58 struct regcache_flat_data *cache = map->cache;
59
60 if (cache)
61 bitmap_free(bitmap: cache->valid);
62
63 kfree(objp: cache);
64 map->cache = NULL;
65
66 return 0;
67}
68
69static int regcache_flat_populate(struct regmap *map)
70{
71 struct regcache_flat_data *cache = map->cache;
72 unsigned int i;
73
74 for (i = 0; i < map->num_reg_defaults; i++) {
75 unsigned int reg = map->reg_defaults[i].reg;
76 unsigned int index = regcache_flat_get_index(map, reg);
77
78 cache->data[index] = map->reg_defaults[i].def;
79 __set_bit(index, cache->valid);
80 }
81
82 return 0;
83}
84
85static int regcache_flat_read(struct regmap *map,
86 unsigned int reg, unsigned int *value)
87{
88 struct regcache_flat_data *cache = map->cache;
89 unsigned int index = regcache_flat_get_index(map, reg);
90
91 /* legacy behavior: ignore validity, but warn the user */
92 if (unlikely(!test_bit(index, cache->valid)))
93 dev_warn_once(map->dev,
94 "using zero-initialized flat cache, this may cause unexpected behavior");
95
96 *value = cache->data[index];
97
98 return 0;
99}
100
101static int regcache_flat_sparse_read(struct regmap *map,
102 unsigned int reg, unsigned int *value)
103{
104 struct regcache_flat_data *cache = map->cache;
105 unsigned int index = regcache_flat_get_index(map, reg);
106
107 if (unlikely(!test_bit(index, cache->valid)))
108 return -ENOENT;
109
110 *value = cache->data[index];
111
112 return 0;
113}
114
115static int regcache_flat_write(struct regmap *map, unsigned int reg,
116 unsigned int value)
117{
118 struct regcache_flat_data *cache = map->cache;
119 unsigned int index = regcache_flat_get_index(map, reg);
120
121 cache->data[index] = value;
122 __set_bit(index, cache->valid);
123
124 return 0;
125}
126
127static int regcache_flat_drop(struct regmap *map, unsigned int min,
128 unsigned int max)
129{
130 struct regcache_flat_data *cache = map->cache;
131 unsigned int bitmap_min = regcache_flat_get_index(map, reg: min);
132 unsigned int bitmap_max = regcache_flat_get_index(map, reg: max);
133
134 bitmap_clear(map: cache->valid, start: bitmap_min, nbits: bitmap_max + 1 - bitmap_min);
135
136 return 0;
137}
138
139struct regcache_ops regcache_flat_ops = {
140 .type = REGCACHE_FLAT,
141 .name = "flat",
142 .init = regcache_flat_init,
143 .exit = regcache_flat_exit,
144 .populate = regcache_flat_populate,
145 .read = regcache_flat_read,
146 .write = regcache_flat_write,
147};
148
149struct regcache_ops regcache_flat_sparse_ops = {
150 .type = REGCACHE_FLAT_S,
151 .name = "flat-sparse",
152 .init = regcache_flat_init,
153 .exit = regcache_flat_exit,
154 .populate = regcache_flat_populate,
155 .read = regcache_flat_sparse_read,
156 .write = regcache_flat_write,
157 .drop = regcache_flat_drop,
158};
159

source code of linux/drivers/base/regmap/regcache-flat.c