1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2021 Rafa�� Mi��ecki <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, 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	priv->data = devm_kzalloc(priv->dev, 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(base, 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(buf, mac))
107		return -EINVAL;
108
109	if (index)
110		eth_addr_add(mac, index);
111
112	ether_addr_copy(buf, 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, priv->ncells, 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, 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(dev->of_node, 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(header->magic, NVRAM_MAGIC, 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, 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, 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(devm_nvmem_register(dev, &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("Rafa�� Mi��ecki");
256MODULE_LICENSE("GPL");
257MODULE_DEVICE_TABLE(of, brcm_nvram_of_match_table);
258