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(const struct regmap_config *config,
111				     struct regmap_ram_data *data,
112				     struct lock_class_key *lock_key,
113				     const char *lock_name)
114{
115	struct regmap *map;
116
117	if (config->reg_bits != 16)
118		return ERR_PTR(-EINVAL);
119
120	if (!config->max_register) {
121		pr_crit("No max_register specified for RAM regmap\n");
122		return ERR_PTR(-EINVAL);
123	}
124
125	data->read = kcalloc(config->max_register + 1, sizeof(bool),
126			     GFP_KERNEL);
127	if (!data->read)
128		return ERR_PTR(-ENOMEM);
129
130	data->written = kcalloc(config->max_register + 1, sizeof(bool),
131				GFP_KERNEL);
132	if (!data->written)
133		return ERR_PTR(-ENOMEM);
134
135	data->reg_endian = config->reg_format_endian;
136
137	map = __regmap_init(NULL, &regmap_raw_ram, data, config,
138			    lock_key, lock_name);
139
140	return map;
141}
142EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
143
144MODULE_LICENSE("GPL v2");
145