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	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
52static 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
58static 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
81static 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
91static 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
99struct 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}
131EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
132
133MODULE_LICENSE("GPL v2");
134