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1// SPDX-License-Identifier: GPL-2.0
2//
3// Register map access API - Memory region with raw access
4//
5// This is intended for testing only
6//
7// Copyright (c) 2023, Arm Ltd
8
9#include <linux/clk.h>
10#include <linux/err.h>
11#include <linux/io.h>
12#include <linux/module.h>
13#include <linux/regmap.h>
14#include <linux/slab.h>
15#include <linux/swab.h>
16
17#include "internal.h"
18
19static unsigned int decode_reg(enum regmap_endian endian, const void *reg)
20{
21 const u16 *r = reg;
22
23 if (endian == REGMAP_ENDIAN_BIG)
24 return be16_to_cpu(*r);
25 else
26 return le16_to_cpu(*r);
27}
28
29static int regmap_raw_ram_gather_write(void *context,
30 const void *reg, size_t reg_len,
31 const void *val, size_t val_len)
32{
33 struct regmap_ram_data *data = context;
34 unsigned int r;
35 u16 *our_buf = (u16 *)data->vals;
36 int i;
37
38 if (reg_len != 2)
39 return -EINVAL;
40 if (val_len % 2)
41 return -EINVAL;
42
43 r = decode_reg(data->reg_endian, reg);
44 if (data->noinc_reg && data->noinc_reg(data, r)) {
45 memcpy(&our_buf[r], val + val_len - 2, 2);
46 data->written[r] = true;
47 } else {
48 memcpy(&our_buf[r], val, val_len);
49
50 for (i = 0; i < val_len / 2; i++)
51 data->written[r + i] = true;
52 }
53
54 return 0;
55}
56
57static int regmap_raw_ram_write(void *context, const void *data, size_t count)
58{
59 return regmap_raw_ram_gather_write(context, data, 2,
60 data + 2, count - 2);
61}
62
63static int regmap_raw_ram_read(void *context,
64 const void *reg, size_t reg_len,
65 void *val, size_t val_len)
66{
67 struct regmap_ram_data *data = context;
68 unsigned int r;
69 u16 *our_buf = (u16 *)data->vals;
70 int i;
71
72 if (reg_len != 2)
73 return -EINVAL;
74 if (val_len % 2)
75 return -EINVAL;
76
77 r = decode_reg(data->reg_endian, reg);
78 if (data->noinc_reg && data->noinc_reg(data, r)) {
79 for (i = 0; i < val_len; i += 2)
80 memcpy(val + i, &our_buf[r], 2);
81 data->read[r] = true;
82 } else {
83 memcpy(val, &our_buf[r], val_len);
84
85 for (i = 0; i < val_len / 2; i++)
86 data->read[r + i] = true;
87 }
88
89 return 0;
90}
91
92static void regmap_raw_ram_free_context(void *context)
93{
94 struct regmap_ram_data *data = context;
95
96 kfree(data->vals);
97 kfree(data->read);
98 kfree(data->written);
99 kfree(data);
100}
101
102static const struct regmap_bus regmap_raw_ram = {
103 .fast_io = true,
104 .write = regmap_raw_ram_write,
105 .gather_write = regmap_raw_ram_gather_write,
106 .read = regmap_raw_ram_read,
107 .free_context = regmap_raw_ram_free_context,
108};
109
110struct regmap *__regmap_init_raw_ram(struct device *dev,
111 const struct regmap_config *config,
112 struct regmap_ram_data *data,
113 struct lock_class_key *lock_key,
114 const char *lock_name)
115{
116 struct regmap *map;
117
118 if (config->reg_bits != 16)
119 return ERR_PTR(-EINVAL);
120
121 if (!config->max_register) {
122 pr_crit("No max_register specified for RAM regmap\n");
123 return ERR_PTR(-EINVAL);
124 }
125
126 data->read = kzalloc_objs(bool, config->max_register + 1);
127 if (!data->read)
128 return ERR_PTR(-ENOMEM);
129
130 data->written = kzalloc_objs(bool, config->max_register + 1);
131 if (!data->written)
132 return ERR_PTR(-ENOMEM);
133
134 data->reg_endian = config->reg_format_endian;
135
136 map = __regmap_init(dev, &regmap_raw_ram, data, config,
137 lock_key, lock_name);
138
139 return map;
140}
141EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
142
143MODULE_DESCRIPTION("Register map access API - Memory region with raw access");
144MODULE_LICENSE("GPL v2");