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/hex.h>
9 #include <linux/if_ether.h>
10 #include <linux/io.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 underlying 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 */
31 struct 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
41 struct 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
brcm_nvram_read(void * context,unsigned int offset,void * val,size_t bytes)49 static 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
brcm_nvram_copy_data(struct brcm_nvram * priv,struct platform_device * pdev)67 static 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, 0, &res);
73 if (IS_ERR(base))
74 return PTR_ERR(base);
75
76 priv->nvmem_size = resource_size(res);
77
78 priv->padding_byte = readb(base + priv->nvmem_size - 1);
79 for (priv->data_len = priv->nvmem_size;
80 priv->data_len;
81 priv->data_len--) {
82 if (readb(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 if (priv->data_len < sizeof(struct brcm_nvram_header)) {
88 dev_err(priv->dev, "NVRAM data too small (%zu)\n", priv->data_len);
89 return -EINVAL;
90 }
91
92 priv->data = devm_kzalloc(priv->dev, priv->data_len, GFP_KERNEL);
93 if (!priv->data)
94 return -ENOMEM;
95
96 memcpy_fromio(priv->data, base, priv->data_len);
97
98 bcm47xx_nvram_init_from_iomem(base, priv->data_len);
99
100 return 0;
101 }
102
brcm_nvram_read_post_process_macaddr(void * context,const char * id,int index,unsigned int offset,void * buf,size_t bytes)103 static int brcm_nvram_read_post_process_macaddr(void *context, const char *id, int index,
104 unsigned int offset, void *buf, size_t bytes)
105 {
106 u8 mac[ETH_ALEN];
107
108 if (bytes != MAC_ADDR_STR_LEN)
109 return -EINVAL;
110
111 if (!mac_pton(buf, mac))
112 return -EINVAL;
113
114 if (index)
115 eth_addr_add(mac, index);
116
117 ether_addr_copy(buf, mac);
118
119 return 0;
120 }
121
brcm_nvram_add_cells(struct brcm_nvram * priv,uint8_t * data,size_t len)122 static int brcm_nvram_add_cells(struct brcm_nvram *priv, uint8_t *data,
123 size_t len)
124 {
125 struct device *dev = priv->dev;
126 char *var, *value;
127 uint8_t tmp;
128 int idx;
129 int err = 0;
130
131 tmp = priv->data[len - 1];
132 priv->data[len - 1] = '\0';
133
134 priv->ncells = 0;
135 for (var = data + sizeof(struct brcm_nvram_header);
136 var < (char *)data + len && *var;
137 var += strlen(var) + 1) {
138 priv->ncells++;
139 }
140
141 priv->cells = devm_kcalloc(dev, priv->ncells, sizeof(*priv->cells), GFP_KERNEL);
142 if (!priv->cells) {
143 err = -ENOMEM;
144 goto out;
145 }
146
147 for (var = data + sizeof(struct brcm_nvram_header), idx = 0;
148 var < (char *)data + len && *var;
149 var = value + strlen(value) + 1, idx++) {
150 char *eq, *name;
151
152 eq = strchr(var, '=');
153 if (!eq)
154 break;
155 *eq = '\0';
156 name = devm_kstrdup(dev, var, GFP_KERNEL);
157 *eq = '=';
158 if (!name) {
159 err = -ENOMEM;
160 goto out;
161 }
162 value = eq + 1;
163
164 priv->cells[idx].name = name;
165 priv->cells[idx].offset = value - (char *)data;
166 priv->cells[idx].bytes = strlen(value);
167 priv->cells[idx].np = of_get_child_by_name(dev->of_node, priv->cells[idx].name);
168 if (!strcmp(name, "et0macaddr") ||
169 !strcmp(name, "et1macaddr") ||
170 !strcmp(name, "et2macaddr")) {
171 priv->cells[idx].raw_len = strlen(value);
172 priv->cells[idx].bytes = ETH_ALEN;
173 priv->cells[idx].read_post_process = brcm_nvram_read_post_process_macaddr;
174 }
175 }
176
177 out:
178 priv->data[len - 1] = tmp;
179 return err;
180 }
181
brcm_nvram_parse(struct brcm_nvram * priv)182 static int brcm_nvram_parse(struct brcm_nvram *priv)
183 {
184 struct brcm_nvram_header *header = (struct brcm_nvram_header *)priv->data;
185 struct device *dev = priv->dev;
186 size_t len;
187 int err;
188
189 if (memcmp(header->magic, NVRAM_MAGIC, 4)) {
190 dev_err(dev, "Invalid NVRAM magic\n");
191 return -EINVAL;
192 }
193
194 len = le32_to_cpu(header->len);
195 if (len < sizeof(*header)) {
196 dev_err(dev, "NVRAM length (%zd) too small\n", len);
197 return -EINVAL;
198 }
199 if (len > priv->data_len) {
200 dev_err(dev, "NVRAM length (%zd) exceeds data size (%zd)\n", len,
201 priv->data_len);
202 return -EINVAL;
203 }
204
205 err = brcm_nvram_add_cells(priv, priv->data, len);
206 if (err)
207 dev_err(dev, "Failed to add cells: %d\n", err);
208
209 return 0;
210 }
211
brcm_nvram_probe(struct platform_device * pdev)212 static int brcm_nvram_probe(struct platform_device *pdev)
213 {
214 struct nvmem_config config = {
215 .name = "brcm-nvram",
216 .reg_read = brcm_nvram_read,
217 };
218 struct device *dev = &pdev->dev;
219 struct brcm_nvram *priv;
220 int err;
221
222 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
223 if (!priv)
224 return -ENOMEM;
225 priv->dev = dev;
226
227 err = brcm_nvram_copy_data(priv, pdev);
228 if (err)
229 return err;
230
231 err = brcm_nvram_parse(priv);
232 if (err)
233 return err;
234
235 config.dev = dev;
236 config.cells = priv->cells;
237 config.ncells = priv->ncells;
238 config.priv = priv;
239 config.size = priv->nvmem_size;
240
241 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
242 }
243
244 static const struct of_device_id brcm_nvram_of_match_table[] = {
245 { .compatible = "brcm,nvram", },
246 {},
247 };
248
249 static struct platform_driver brcm_nvram_driver = {
250 .probe = brcm_nvram_probe,
251 .driver = {
252 .name = "brcm_nvram",
253 .of_match_table = brcm_nvram_of_match_table,
254 },
255 };
256
brcm_nvram_init(void)257 static int __init brcm_nvram_init(void)
258 {
259 return platform_driver_register(&brcm_nvram_driver);
260 }
261
262 subsys_initcall_sync(brcm_nvram_init);
263
264 MODULE_AUTHOR("Rafał Miłecki");
265 MODULE_DESCRIPTION("Broadcom I/O-mapped NVRAM support driver");
266 MODULE_LICENSE("GPL");
267 MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);
268