1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
  4 */
  5
  6#include <linux/bcm47xx_nvram.h>
  7#include <linux/io.h>
  8#include <linux/mod_devicetable.h>
  9#include <linux/module.h>
 10#include <linux/nvmem-consumer.h>
 11#include <linux/nvmem-provider.h>
 12#include <linux/of.h>
 13#include <linux/platform_device.h>
 14#include <linux/slab.h>
 15
 16#define NVRAM_MAGIC			"FLSH"
 17
 18struct brcm_nvram {
 19	struct device *dev;
 20	void __iomem *base;
 21	struct nvmem_cell_info *cells;
 22	int ncells;
 23};
 24
 25struct brcm_nvram_header {
 26	char magic[4];
 27	__le32 len;
 28	__le32 crc_ver_init;	/* 0:7 crc, 8:15 ver, 16:31 sdram_init */
 29	__le32 config_refresh;	/* 0:15 sdram_config, 16:31 sdram_refresh */
 30	__le32 config_ncdl;	/* ncdl values for memc */
 31};
 32
 33static int brcm_nvram_read(void *context, unsigned int offset, void *val,
 34			   size_t bytes)
 35{
 36	struct brcm_nvram *priv = context;
 37	u8 *dst = val;
 38
 39	while (bytes--)
 40		*dst++ = readb(priv->base + offset++);
 41
 42	return 0;
 43}
 44
 45static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
 46				size_t len)
 47{
 48	struct device *dev = priv->dev;
 49	char *var, *value, *eq;
 50	int idx;
 51
 52	priv->ncells = 0;
 53	for (var = data + sizeof(struct brcm_nvram_header);
 54	     var < (char *)data + len && *var;
 55	     var += strlen(var) + 1) {
 56		priv->ncells++;
 57	}
 58
 59	priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
 60	if (!priv->cells)
 61		return -ENOMEM;
 62
 63	for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
 64	     var < (char *)data + len && *var;
 65	     var = value + strlen(value) + 1, idx++) {
 66		eq = strchr(var, '=');
 67		if (!eq)
 68			break;
 69		*eq = '\0';
 70		value = eq + 1;
 71
 72		priv->cells[idx].name = devm_kstrdup(dev, var, GFP_KERNEL);
 73		if (!priv->cells[idx].name)
 74			return -ENOMEM;
 75		priv->cells[idx].offset = value - (char *)data;
 76		priv->cells[idx].bytes = strlen(value);
 77		priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
 78	}
 79
 80	return 0;
 81}
 82
 83static int brcm_nvram_parse(struct brcm_nvram *priv)
 84{
 85	struct device *dev = priv->dev;
 86	struct brcm_nvram_header header;
 87	uint8_t *data;
 88	size_t len;
 89	int err;
 90
 91	memcpy_fromio(&header, priv->base, sizeof(header));
 92
 93	if (memcmp(header.magic, NVRAM_MAGIC, 4)) {
 94		dev_err(dev, "Invalid NVRAM magic\n");
 95		return -EINVAL;
 96	}
 97
 98	len = le32_to_cpu(header.len);
 99
100	data = kzalloc(len, GFP_KERNEL);
101	if (!data)
102		return -ENOMEM;
103
104	memcpy_fromio(data, priv->base, len);
105	data[len - 1] = '\0';
106
107	err = brcm_nvram_add_cells(priv, data, len);
108	if (err) {
109		dev_err(dev, "Failed to add cells: %d\n", err);
110		return err;
111	}
112
113	kfree(data);
114
115	return 0;
116}
117
118static int brcm_nvram_probe(struct platform_device *pdev)
119{
120	struct nvmem_config config = {
121		.name = "brcm-nvram",
122		.reg_read = brcm_nvram_read,
123	};
124	struct device *dev = &pdev->dev;
125	struct resource *res;
126	struct brcm_nvram *priv;
127	int err;
128
129	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
130	if (!priv)
131		return -ENOMEM;
132	priv->dev = dev;
133
134	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
135	priv->base = devm_ioremap_resource(dev, res);
136	if (IS_ERR(priv->base))
137		return PTR_ERR(priv->base);
138
139	err = brcm_nvram_parse(priv);
140	if (err)
141		return err;
142
143	bcm47xx_nvram_init_from_iomem(priv->base, resource_size(res));
144
145	config.dev = dev;
146	config.cells = priv->cells;
147	config.ncells = priv->ncells;
148	config.priv = priv;
149	config.size = resource_size(res);
150
151	return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
152}
153
154static const struct of_device_id brcm_nvram_of_match_table[] = {
155	{ .compatible = "brcm,nvram", },
156	{},
157};
158
159static struct platform_driver brcm_nvram_driver = {
160	.probe = brcm_nvram_probe,
161	.driver = {
162		.name = "brcm_nvram",
163		.of_match_table = brcm_nvram_of_match_table,
164	},
165};
166
167static int __init brcm_nvram_init(void)
168{
169	return platform_driver_register(&brcm_nvram_driver);
170}
171
172subsys_initcall_sync(brcm_nvram_init);
173
174MODULE_AUTHOR("Rafał Miłecki");
175MODULE_LICENSE("GPL");
176MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);