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 19 static 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 25 struct regcache_flat_data { 26 unsigned long *valid; 27 unsigned int data[]; 28 }; 29 30 static 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, 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(cache_size, map->alloc_flags); 44 if (!cache->valid) 45 goto err_free; 46 47 map->cache = cache; 48 49 return 0; 50 51 err_free: 52 kfree(cache); 53 return -ENOMEM; 54 } 55 56 static int regcache_flat_exit(struct regmap *map) 57 { 58 struct regcache_flat_data *cache = map->cache; 59 60 if (cache) 61 bitmap_free(cache->valid); 62 63 kfree(cache); 64 map->cache = NULL; 65 66 return 0; 67 } 68 69 static 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 85 static 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 } 100 101 static 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 } 114 115 static 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 } 126 127 static 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, min); 132 unsigned int bitmap_max = regcache_flat_get_index(map, max); 133 134 bitmap_clear(cache->valid, bitmap_min, bitmap_max + 1 - bitmap_min); 135 136 return 0; 137 } 138 139 struct 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 }; 148 149 struct 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