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
decode_reg(enum regmap_endian endian,const void * reg)19 static 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
regmap_raw_ram_gather_write(void * context,const void * reg,size_t reg_len,const void * val,size_t val_len)29 static 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
regmap_raw_ram_write(void * context,const void * data,size_t count)57 static 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
regmap_raw_ram_read(void * context,const void * reg,size_t reg_len,void * val,size_t val_len)63 static 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
regmap_raw_ram_free_context(void * context)92 static 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
102 static 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
__regmap_init_raw_ram(struct device * dev,const struct regmap_config * config,struct regmap_ram_data * data,struct lock_class_key * lock_key,const char * lock_name)110 struct 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 = kcalloc(config->max_register + 1, sizeof(bool),
127 GFP_KERNEL);
128 if (!data->read)
129 return ERR_PTR(-ENOMEM);
130
131 data->written = kcalloc(config->max_register + 1, sizeof(bool),
132 GFP_KERNEL);
133 if (!data->written)
134 return ERR_PTR(-ENOMEM);
135
136 data->reg_endian = config->reg_format_endian;
137
138 map = __regmap_init(dev, ®map_raw_ram, data, config,
139 lock_key, lock_name);
140
141 return map;
142 }
143 EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
144
145 MODULE_DESCRIPTION("Register map access API - Memory region with raw access");
146 MODULE_LICENSE("GPL v2");
147