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");