1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * drivers/mtd/scpart.c: Sercomm Partition Parser |
4 | * |
5 | * Copyright (C) 2018 NOGUCHI Hiroshi |
6 | * Copyright (C) 2022 Mikhail Zhilkin |
7 | */ |
8 | |
9 | #include <linux/kernel.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/mtd/mtd.h> |
12 | #include <linux/mtd/partitions.h> |
13 | #include <linux/module.h> |
14 | |
15 | #define MOD_NAME "scpart" |
16 | |
17 | #ifdef pr_fmt |
18 | #undef pr_fmt |
19 | #endif |
20 | |
21 | #define pr_fmt(fmt) MOD_NAME ": " fmt |
22 | |
23 | #define ID_ALREADY_FOUND 0xffffffffUL |
24 | |
25 | #define MAP_OFFS_IN_BLK 0x800 |
26 | #define MAP_MIRROR_NUM 2 |
27 | |
28 | static const char sc_part_magic[] = { |
29 | 'S', 'C', 'F', 'L', 'M', 'A', 'P', 'O', 'K', '\0', |
30 | }; |
31 | #define PART_MAGIC_LEN sizeof(sc_part_magic) |
32 | |
33 | /* assumes that all fields are set by CPU native endian */ |
34 | struct sc_part_desc { |
35 | uint32_t part_id; |
36 | uint32_t part_offs; |
37 | uint32_t part_bytes; |
38 | }; |
39 | |
40 | static uint32_t scpart_desc_is_valid(struct sc_part_desc *pdesc) |
41 | { |
42 | return ((pdesc->part_id != 0xffffffffUL) && |
43 | (pdesc->part_offs != 0xffffffffUL) && |
44 | (pdesc->part_bytes != 0xffffffffUL)); |
45 | } |
46 | |
47 | static int scpart_scan_partmap(struct mtd_info *master, loff_t partmap_offs, |
48 | struct sc_part_desc **ppdesc) |
49 | { |
50 | int cnt = 0; |
51 | int res = 0; |
52 | int res2; |
53 | uint32_t offs; |
54 | size_t retlen; |
55 | struct sc_part_desc *pdesc = NULL; |
56 | struct sc_part_desc *tmpdesc; |
57 | uint8_t *buf; |
58 | |
59 | buf = kzalloc(size: master->erasesize, GFP_KERNEL); |
60 | if (!buf) { |
61 | res = -ENOMEM; |
62 | goto out; |
63 | } |
64 | |
65 | res2 = mtd_read(mtd: master, from: partmap_offs, len: master->erasesize, retlen: &retlen, buf); |
66 | if (res2 || retlen != master->erasesize) { |
67 | res = -EIO; |
68 | goto free; |
69 | } |
70 | |
71 | for (offs = MAP_OFFS_IN_BLK; |
72 | offs < master->erasesize - sizeof(*tmpdesc); |
73 | offs += sizeof(*tmpdesc)) { |
74 | tmpdesc = (struct sc_part_desc *)&buf[offs]; |
75 | if (!scpart_desc_is_valid(pdesc: tmpdesc)) |
76 | break; |
77 | cnt++; |
78 | } |
79 | |
80 | if (cnt > 0) { |
81 | int bytes = cnt * sizeof(*pdesc); |
82 | |
83 | pdesc = kcalloc(n: cnt, size: sizeof(*pdesc), GFP_KERNEL); |
84 | if (!pdesc) { |
85 | res = -ENOMEM; |
86 | goto free; |
87 | } |
88 | memcpy(pdesc, &(buf[MAP_OFFS_IN_BLK]), bytes); |
89 | |
90 | *ppdesc = pdesc; |
91 | res = cnt; |
92 | } |
93 | |
94 | free: |
95 | kfree(objp: buf); |
96 | |
97 | out: |
98 | return res; |
99 | } |
100 | |
101 | static int scpart_find_partmap(struct mtd_info *master, |
102 | struct sc_part_desc **ppdesc) |
103 | { |
104 | int magic_found = 0; |
105 | int res = 0; |
106 | int res2; |
107 | loff_t offs = 0; |
108 | size_t retlen; |
109 | uint8_t rdbuf[PART_MAGIC_LEN]; |
110 | |
111 | while ((magic_found < MAP_MIRROR_NUM) && |
112 | (offs < master->size) && |
113 | !mtd_block_isbad(mtd: master, ofs: offs)) { |
114 | res2 = mtd_read(mtd: master, from: offs, PART_MAGIC_LEN, retlen: &retlen, buf: rdbuf); |
115 | if (res2 || retlen != PART_MAGIC_LEN) { |
116 | res = -EIO; |
117 | goto out; |
118 | } |
119 | if (!memcmp(p: rdbuf, q: sc_part_magic, PART_MAGIC_LEN)) { |
120 | pr_debug("Signature found at 0x%llx\n" , offs); |
121 | magic_found++; |
122 | res = scpart_scan_partmap(master, partmap_offs: offs, ppdesc); |
123 | if (res > 0) |
124 | goto out; |
125 | } |
126 | offs += master->erasesize; |
127 | } |
128 | |
129 | out: |
130 | if (res > 0) |
131 | pr_info("Valid 'SC PART MAP' (%d partitions) found at 0x%llx\n" , res, offs); |
132 | else |
133 | pr_info("No valid 'SC PART MAP' was found\n" ); |
134 | |
135 | return res; |
136 | } |
137 | |
138 | static int scpart_parse(struct mtd_info *master, |
139 | const struct mtd_partition **pparts, |
140 | struct mtd_part_parser_data *data) |
141 | { |
142 | const char *partname; |
143 | int n; |
144 | int nr_scparts; |
145 | int nr_parts = 0; |
146 | int res = 0; |
147 | struct sc_part_desc *scpart_map = NULL; |
148 | struct mtd_partition *parts = NULL; |
149 | struct device_node *mtd_node; |
150 | struct device_node *ofpart_node; |
151 | struct device_node *pp; |
152 | |
153 | mtd_node = mtd_get_of_node(mtd: master); |
154 | if (!mtd_node) { |
155 | res = -ENOENT; |
156 | goto out; |
157 | } |
158 | |
159 | ofpart_node = of_get_child_by_name(node: mtd_node, name: "partitions" ); |
160 | if (!ofpart_node) { |
161 | pr_info("%s: 'partitions' subnode not found on %pOF.\n" , |
162 | master->name, mtd_node); |
163 | res = -ENOENT; |
164 | goto out; |
165 | } |
166 | |
167 | nr_scparts = scpart_find_partmap(master, ppdesc: &scpart_map); |
168 | if (nr_scparts <= 0) { |
169 | pr_info("No any partitions was found in 'SC PART MAP'.\n" ); |
170 | res = -ENOENT; |
171 | goto free; |
172 | } |
173 | |
174 | parts = kcalloc(n: of_get_child_count(np: ofpart_node), size: sizeof(*parts), |
175 | GFP_KERNEL); |
176 | if (!parts) { |
177 | res = -ENOMEM; |
178 | goto free; |
179 | } |
180 | |
181 | for_each_child_of_node(ofpart_node, pp) { |
182 | u32 scpart_id; |
183 | |
184 | if (of_property_read_u32(np: pp, propname: "sercomm,scpart-id" , out_value: &scpart_id)) |
185 | continue; |
186 | |
187 | for (n = 0 ; n < nr_scparts ; n++) |
188 | if ((scpart_map[n].part_id != ID_ALREADY_FOUND) && |
189 | (scpart_id == scpart_map[n].part_id)) |
190 | break; |
191 | if (n >= nr_scparts) |
192 | /* not match */ |
193 | continue; |
194 | |
195 | /* add the partition found in OF into MTD partition array */ |
196 | parts[nr_parts].offset = scpart_map[n].part_offs; |
197 | parts[nr_parts].size = scpart_map[n].part_bytes; |
198 | parts[nr_parts].of_node = pp; |
199 | |
200 | if (!of_property_read_string(np: pp, propname: "label" , out_string: &partname)) |
201 | parts[nr_parts].name = partname; |
202 | if (of_property_read_bool(np: pp, propname: "read-only" )) |
203 | parts[nr_parts].mask_flags |= MTD_WRITEABLE; |
204 | if (of_property_read_bool(np: pp, propname: "lock" )) |
205 | parts[nr_parts].mask_flags |= MTD_POWERUP_LOCK; |
206 | |
207 | /* mark as 'done' */ |
208 | scpart_map[n].part_id = ID_ALREADY_FOUND; |
209 | |
210 | nr_parts++; |
211 | } |
212 | |
213 | if (nr_parts > 0) { |
214 | *pparts = parts; |
215 | res = nr_parts; |
216 | } else |
217 | pr_info("No partition in OF matches partition ID with 'SC PART MAP'.\n" ); |
218 | |
219 | of_node_put(node: pp); |
220 | |
221 | free: |
222 | of_node_put(node: ofpart_node); |
223 | kfree(objp: scpart_map); |
224 | if (res <= 0) |
225 | kfree(objp: parts); |
226 | |
227 | out: |
228 | return res; |
229 | } |
230 | |
231 | static const struct of_device_id scpart_parser_of_match_table[] = { |
232 | { .compatible = "sercomm,sc-partitions" }, |
233 | {}, |
234 | }; |
235 | MODULE_DEVICE_TABLE(of, scpart_parser_of_match_table); |
236 | |
237 | static struct mtd_part_parser scpart_parser = { |
238 | .parse_fn = scpart_parse, |
239 | .name = "scpart" , |
240 | .of_match_table = scpart_parser_of_match_table, |
241 | }; |
242 | module_mtd_part_parser(scpart_parser); |
243 | |
244 | /* mtd parsers will request the module by parser name */ |
245 | MODULE_ALIAS("scpart" ); |
246 | MODULE_LICENSE("GPL" ); |
247 | MODULE_AUTHOR("NOGUCHI Hiroshi <drvlabo@gmail.com>" ); |
248 | MODULE_AUTHOR("Mikhail Zhilkin <csharper2005@gmail.com>" ); |
249 | MODULE_DESCRIPTION("Sercomm partition parser" ); |
250 | |