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 
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 
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 	memcpy(&our_buf[r], val, val_len);
45 
46 	for (i = 0; i < val_len / 2; i++)
47 		data->written[r + i] = true;
48 
49 	return 0;
50 }
51 
52 static int regmap_raw_ram_write(void *context, const void *data, size_t count)
53 {
54 	return regmap_raw_ram_gather_write(context, data, 2,
55 					   data + 2, count - 2);
56 }
57 
58 static int regmap_raw_ram_read(void *context,
59 			       const void *reg, size_t reg_len,
60 			       void *val, size_t val_len)
61 {
62 	struct regmap_ram_data *data = context;
63 	unsigned int r;
64 	u16 *our_buf = (u16 *)data->vals;
65 	int i;
66 
67 	if (reg_len != 2)
68 		return -EINVAL;
69 	if (val_len % 2)
70 		return -EINVAL;
71 
72 	r = decode_reg(data->reg_endian, reg);
73 	memcpy(val, &our_buf[r], val_len);
74 
75 	for (i = 0; i < val_len / 2; i++)
76 		data->read[r + i] = true;
77 
78 	return 0;
79 }
80 
81 static void regmap_raw_ram_free_context(void *context)
82 {
83 	struct regmap_ram_data *data = context;
84 
85 	kfree(data->vals);
86 	kfree(data->read);
87 	kfree(data->written);
88 	kfree(data);
89 }
90 
91 static const struct regmap_bus regmap_raw_ram = {
92 	.fast_io = true,
93 	.write = regmap_raw_ram_write,
94 	.gather_write = regmap_raw_ram_gather_write,
95 	.read = regmap_raw_ram_read,
96 	.free_context = regmap_raw_ram_free_context,
97 };
98 
99 struct regmap *__regmap_init_raw_ram(const struct regmap_config *config,
100 				     struct regmap_ram_data *data,
101 				     struct lock_class_key *lock_key,
102 				     const char *lock_name)
103 {
104 	struct regmap *map;
105 
106 	if (config->reg_bits != 16)
107 		return ERR_PTR(-EINVAL);
108 
109 	if (!config->max_register) {
110 		pr_crit("No max_register specified for RAM regmap\n");
111 		return ERR_PTR(-EINVAL);
112 	}
113 
114 	data->read = kcalloc(sizeof(bool), config->max_register + 1,
115 			     GFP_KERNEL);
116 	if (!data->read)
117 		return ERR_PTR(-ENOMEM);
118 
119 	data->written = kcalloc(sizeof(bool), config->max_register + 1,
120 				GFP_KERNEL);
121 	if (!data->written)
122 		return ERR_PTR(-ENOMEM);
123 
124 	data->reg_endian = config->reg_format_endian;
125 
126 	map = __regmap_init(NULL, &regmap_raw_ram, data, config,
127 			    lock_key, lock_name);
128 
129 	return map;
130 }
131 EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
132 
133 MODULE_LICENSE("GPL v2");
134