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/etherdevice.h>
8#include <linux/if_ether.h>
9#include <linux/io.h>
10#include <linux/mod_devicetable.h>
11#include <linux/module.h>
12#include <linux/nvmem-consumer.h>
13#include <linux/nvmem-provider.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/slab.h>
17
18#define NVRAM_MAGIC "FLSH"
19
20/**
21 * struct brcm_nvram - driver state internal struct
22 *
23 * @dev: NVMEM device pointer
24 * @nvmem_size: Size of the whole space available for NVRAM
25 * @data: NVRAM data copy stored to avoid poking underlaying flash controller
26 * @data_len: NVRAM data size
27 * @padding_byte: Padding value used to fill remaining space
28 * @cells: Array of discovered NVMEM cells
29 * @ncells: Number of elements in cells
30 */
31struct brcm_nvram {
32 struct device *dev;
33 size_t nvmem_size;
34 uint8_t *data;
35 size_t data_len;
36 uint8_t padding_byte;
37 struct nvmem_cell_info *cells;
38 int ncells;
39};
40
41struct brcm_nvram_header {
42 char magic[4];
43 __le32 len;
44 __le32 crc_ver_init; /* 0:7 crc, 8:15 ver, 16:31 sdram_init */
45 __le32 config_refresh; /* 0:15 sdram_config, 16:31 sdram_refresh */
46 __le32 config_ncdl; /* ncdl values for memc */
47};
48
49static int brcm_nvram_read(void *context, unsigned int offset, void *val,
50 size_t bytes)
51{
52 struct brcm_nvram *priv = context;
53 size_t to_copy;
54
55 if (offset + bytes > priv->data_len)
56 to_copy = max_t(ssize_t, (ssize_t)priv->data_len - offset, 0);
57 else
58 to_copy = bytes;
59
60 memcpy(val, priv->data + offset, to_copy);
61
62 memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
63
64 return 0;
65}
66
67static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
68{
69 struct resource *res;
70 void __iomem *base;
71
72 base = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &res);
73 if (IS_ERR(ptr: base))
74 return PTR_ERR(ptr: base);
75
76 priv->nvmem_size = resource_size(res);
77
78 priv->padding_byte = readb(addr: base + priv->nvmem_size - 1);
79 for (priv->data_len = priv->nvmem_size;
80 priv->data_len;
81 priv->data_len--) {
82 if (readb(addr: base + priv->data_len - 1) != priv->padding_byte)
83 break;
84 }
85 WARN(priv->data_len > SZ_128K, "Unexpected (big) NVRAM size: %zu B\n", priv->data_len);
86
87 priv->data = devm_kzalloc(dev: priv->dev, size: priv->data_len, GFP_KERNEL);
88 if (!priv->data)
89 return -ENOMEM;
90
91 memcpy_fromio(priv->data, base, priv->data_len);
92
93 bcm47xx_nvram_init_from_iomem(nvram_start: base, res_size: priv->data_len);
94
95 return 0;
96}
97
98static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index,
99 unsigned int offset, void *buf, size_t bytes)
100{
101 u8 mac[ETH_ALEN];
102
103 if (bytes != 3 * ETH_ALEN - 1)
104 return -EINVAL;
105
106 if (!mac_pton(s: buf, mac))
107 return -EINVAL;
108
109 if (index)
110 eth_addr_add(addr: mac, offset: index);
111
112 ether_addr_copy(dst: buf, src: mac);
113
114 return 0;
115}
116
117static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
118 size_t len)
119{
120 struct device *dev = priv->dev;
121 char *var, *value;
122 uint8_t tmp;
123 int idx;
124 int err = 0;
125
126 tmp = priv->data[len - 1];
127 priv->data[len - 1] = '\0';
128
129 priv->ncells = 0;
130 for (var = data + sizeof(struct brcm_nvram_header);
131 var < (char *)data + len && *var;
132 var += strlen(var) + 1) {
133 priv->ncells++;
134 }
135
136 priv->cells = devm_kcalloc(dev, n: priv->ncells, size: sizeof(*priv->cells), GFP_KERNEL);
137 if (!priv->cells) {
138 err = -ENOMEM;
139 goto out;
140 }
141
142 for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
143 var < (char *)data + len && *var;
144 var = value + strlen(value) + 1, idx++) {
145 char *eq, *name;
146
147 eq = strchr(var, '=');
148 if (!eq)
149 break;
150 *eq = '\0';
151 name = devm_kstrdup(dev, s: var, GFP_KERNEL);
152 *eq = '=';
153 if (!name) {
154 err = -ENOMEM;
155 goto out;
156 }
157 value = eq + 1;
158
159 priv->cells[idx].name = name;
160 priv->cells[idx].offset = value - (char *)data;
161 priv->cells[idx].bytes = strlen(value);
162 priv->cells[idx].np = of_get_child_by_name(node: dev->of_node, name: priv->cells[idx].name);
163 if (!strcmp(name, "et0macaddr") ||
164 !strcmp(name, "et1macaddr") ||
165 !strcmp(name, "et2macaddr")) {
166 priv->cells[idx].raw_len = strlen(value);
167 priv->cells[idx].bytes = ETH_ALEN;
168 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
169 }
170 }
171
172out:
173 priv->data[len - 1] = tmp;
174 return err;
175}
176
177static int brcm_nvram_parse(struct brcm_nvram *priv)
178{
179 struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
180 struct device *dev = priv->dev;
181 size_t len;
182 int err;
183
184 if (memcmp(p: header->magic, NVRAM_MAGIC, size: 4)) {
185 dev_err(dev, "Invalid NVRAM magic\n");
186 return -EINVAL;
187 }
188
189 len = le32_to_cpu(header->len);
190 if (len > priv->nvmem_size) {
191 dev_err(dev, "NVRAM length (%zd) exceeds mapped size (%zd)\n", len,
192 priv->nvmem_size);
193 return -EINVAL;
194 }
195
196 err = brcm_nvram_add_cells(priv, data: priv->data, len);
197 if (err)
198 dev_err(dev, "Failed to add cells: %d\n", err);
199
200 return 0;
201}
202
203static int brcm_nvram_probe(struct platform_device *pdev)
204{
205 struct nvmem_config config = {
206 .name = "brcm-nvram",
207 .reg_read = brcm_nvram_read,
208 };
209 struct device *dev = &pdev->dev;
210 struct brcm_nvram *priv;
211 int err;
212
213 priv = devm_kzalloc(dev, size: sizeof(*priv), GFP_KERNEL);
214 if (!priv)
215 return -ENOMEM;
216 priv->dev = dev;
217
218 err = brcm_nvram_copy_data(priv, pdev);
219 if (err)
220 return err;
221
222 err = brcm_nvram_parse(priv);
223 if (err)
224 return err;
225
226 config.dev = dev;
227 config.cells = priv->cells;
228 config.ncells = priv->ncells;
229 config.priv = priv;
230 config.size = priv->nvmem_size;
231
232 return PTR_ERR_OR_ZERO(ptr: devm_nvmem_register(dev, cfg: &config));
233}
234
235static const struct of_device_id brcm_nvram_of_match_table[] = {
236 { .compatible = "brcm,nvram", },
237 {},
238};
239
240static struct platform_driver brcm_nvram_driver = {
241 .probe = brcm_nvram_probe,
242 .driver = {
243 .name = "brcm_nvram",
244 .of_match_table = brcm_nvram_of_match_table,
245 },
246};
247
248static int __init brcm_nvram_init(void)
249{
250 return platform_driver_register(&brcm_nvram_driver);
251}
252
253subsys_initcall_sync(brcm_nvram_init);
254
255MODULE_AUTHOR("Rafał Miłecki");
256MODULE_LICENSE("GPL");
257MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);
258

source code of linux/drivers/nvmem/brcm_nvram.c