1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Flash partitions described by the OF (or flattened) device tree
4  *
5  * Copyright © 2006 MontaVista Software Inc.
6  * Author: Vitaly Wool <vwool@ru.mvista.com>
7  *
8  * Revised to handle newer style flash binding by:
9  *   Copyright © 2007 David Gibson, IBM Corporation.
10  */
11 
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/of.h>
15 #include <linux/mtd/mtd.h>
16 #include <linux/slab.h>
17 #include <linux/mtd/partitions.h>
18 
19 #include "ofpart_bcm4908.h"
20 #include "ofpart_linksys_ns.h"
21 
22 struct fixed_partitions_quirks {
23 	int (*post_parse)(struct mtd_info *mtd, struct mtd_partition *parts, int nr_parts);
24 };
25 
26 static struct fixed_partitions_quirks bcm4908_partitions_quirks = {
27 	.post_parse = bcm4908_partitions_post_parse,
28 };
29 
30 static struct fixed_partitions_quirks linksys_ns_partitions_quirks = {
31 	.post_parse = linksys_ns_partitions_post_parse,
32 };
33 
34 static const struct of_device_id parse_ofpart_match_table[];
35 
node_has_compatible(struct device_node * pp)36 static bool node_has_compatible(struct device_node *pp)
37 {
38 	return of_get_property(pp, "compatible", NULL);
39 }
40 
parse_fixed_partitions(struct mtd_info * master,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)41 static int parse_fixed_partitions(struct mtd_info *master,
42 				  const struct mtd_partition **pparts,
43 				  struct mtd_part_parser_data *data)
44 {
45 	const struct fixed_partitions_quirks *quirks;
46 	const struct of_device_id *of_id;
47 	struct mtd_partition *parts;
48 	struct device_node *mtd_node;
49 	struct device_node *ofpart_node;
50 	const char *partname;
51 	struct device_node *pp;
52 	int nr_parts, i, ret = 0;
53 	bool dedicated = true;
54 
55 	/* Pull of_node from the master device node */
56 	mtd_node = mtd_get_of_node(master);
57 	if (!mtd_node)
58 		return 0;
59 
60 	if (!master->parent) { /* Master */
61 		ofpart_node = of_get_child_by_name(mtd_node, "partitions");
62 		if (!ofpart_node) {
63 			/*
64 			 * We might get here even when ofpart isn't used at all (e.g.,
65 			 * when using another parser), so don't be louder than
66 			 * KERN_DEBUG
67 			 */
68 			pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
69 				master->name, mtd_node);
70 			ofpart_node = mtd_node;
71 			dedicated = false;
72 		}
73 	} else { /* Partition */
74 		ofpart_node = mtd_node;
75 	}
76 
77 	of_id = of_match_node(parse_ofpart_match_table, ofpart_node);
78 	if (dedicated && !of_id) {
79 		/* The 'partitions' subnode might be used by another parser */
80 		return 0;
81 	}
82 
83 	quirks = of_id ? of_id->data : NULL;
84 
85 	/* First count the subnodes */
86 	nr_parts = 0;
87 	for_each_child_of_node(ofpart_node,  pp) {
88 		if (!dedicated && node_has_compatible(pp))
89 			continue;
90 
91 		nr_parts++;
92 	}
93 
94 	if (nr_parts == 0)
95 		return 0;
96 
97 	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
98 	if (!parts)
99 		return -ENOMEM;
100 
101 	i = 0;
102 	for_each_child_of_node(ofpart_node,  pp) {
103 		const __be32 *reg;
104 		int len;
105 		int a_cells, s_cells;
106 
107 		if (!dedicated && node_has_compatible(pp))
108 			continue;
109 
110 		reg = of_get_property(pp, "reg", &len);
111 		if (!reg) {
112 			if (dedicated) {
113 				pr_debug("%s: ofpart partition %pOF (%pOF) missing reg property.\n",
114 					 master->name, pp,
115 					 mtd_node);
116 				goto ofpart_fail;
117 			} else {
118 				nr_parts--;
119 				continue;
120 			}
121 		}
122 
123 		a_cells = of_n_addr_cells(pp);
124 		s_cells = of_n_size_cells(pp);
125 		if (!dedicated && s_cells == 0) {
126 			/*
127 			 * This is a ugly workaround to not create
128 			 * regression on devices that are still creating
129 			 * partitions as direct children of the nand controller.
130 			 * This can happen in case the nand controller node has
131 			 * #size-cells equal to 0 and the firmware (e.g.
132 			 * U-Boot) just add the partitions there assuming
133 			 * 32-bit addressing.
134 			 *
135 			 * If you get this warning your firmware and/or DTS
136 			 * should be really fixed.
137 			 *
138 			 * This is working only for devices smaller than 4GiB.
139 			 */
140 			pr_warn("%s: ofpart partition %pOF (%pOF) #size-cells is wrongly set to <0>, assuming <1> for parsing partitions.\n",
141 				master->name, pp, mtd_node);
142 			s_cells = 1;
143 		}
144 		if (len / 4 != a_cells + s_cells) {
145 			pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
146 				 master->name, pp,
147 				 mtd_node);
148 			goto ofpart_fail;
149 		}
150 
151 		parts[i].offset = of_read_number(reg, a_cells);
152 		parts[i].size = of_read_number(reg + a_cells, s_cells);
153 		parts[i].of_node = pp;
154 
155 		partname = of_get_property(pp, "label", &len);
156 		if (!partname)
157 			partname = of_get_property(pp, "name", &len);
158 		parts[i].name = partname;
159 
160 		if (of_get_property(pp, "read-only", &len))
161 			parts[i].mask_flags |= MTD_WRITEABLE;
162 
163 		if (of_get_property(pp, "lock", &len))
164 			parts[i].mask_flags |= MTD_POWERUP_LOCK;
165 
166 		if (of_property_read_bool(pp, "slc-mode"))
167 			parts[i].add_flags |= MTD_SLC_ON_MLC_EMULATION;
168 
169 		i++;
170 	}
171 
172 	if (!nr_parts)
173 		goto ofpart_none;
174 
175 	if (quirks && quirks->post_parse)
176 		quirks->post_parse(master, parts, nr_parts);
177 
178 	*pparts = parts;
179 	return nr_parts;
180 
181 ofpart_fail:
182 	pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
183 	       master->name, pp, mtd_node);
184 	ret = -EINVAL;
185 ofpart_none:
186 	of_node_put(pp);
187 	kfree(parts);
188 	return ret;
189 }
190 
191 static const struct of_device_id parse_ofpart_match_table[] = {
192 	/* Generic */
193 	{ .compatible = "fixed-partitions" },
194 	/* Customized */
195 	{ .compatible = "brcm,bcm4908-partitions", .data = &bcm4908_partitions_quirks, },
196 	{ .compatible = "linksys,ns-partitions", .data = &linksys_ns_partitions_quirks, },
197 	{},
198 };
199 MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
200 
201 static struct mtd_part_parser ofpart_parser = {
202 	.parse_fn = parse_fixed_partitions,
203 	.name = "fixed-partitions",
204 	.of_match_table = parse_ofpart_match_table,
205 };
206 
parse_ofoldpart_partitions(struct mtd_info * master,const struct mtd_partition ** pparts,struct mtd_part_parser_data * data)207 static int parse_ofoldpart_partitions(struct mtd_info *master,
208 				      const struct mtd_partition **pparts,
209 				      struct mtd_part_parser_data *data)
210 {
211 	struct mtd_partition *parts;
212 	struct device_node *dp;
213 	int i, plen, nr_parts;
214 	const struct {
215 		__be32 offset, len;
216 	} *part;
217 	const char *names;
218 
219 	/* Pull of_node from the master device node */
220 	dp = mtd_get_of_node(master);
221 	if (!dp)
222 		return 0;
223 
224 	part = of_get_property(dp, "partitions", &plen);
225 	if (!part)
226 		return 0; /* No partitions found */
227 
228 	pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);
229 
230 	nr_parts = plen / sizeof(part[0]);
231 
232 	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
233 	if (!parts)
234 		return -ENOMEM;
235 
236 	names = of_get_property(dp, "partition-names", &plen);
237 
238 	for (i = 0; i < nr_parts; i++) {
239 		parts[i].offset = be32_to_cpu(part->offset);
240 		parts[i].size   = be32_to_cpu(part->len) & ~1;
241 		/* bit 0 set signifies read only partition */
242 		if (be32_to_cpu(part->len) & 1)
243 			parts[i].mask_flags = MTD_WRITEABLE;
244 
245 		if (names && (plen > 0)) {
246 			int len = strlen(names) + 1;
247 
248 			parts[i].name = names;
249 			plen -= len;
250 			names += len;
251 		} else {
252 			parts[i].name = "unnamed";
253 		}
254 
255 		part++;
256 	}
257 
258 	*pparts = parts;
259 	return nr_parts;
260 }
261 
262 static struct mtd_part_parser ofoldpart_parser = {
263 	.parse_fn = parse_ofoldpart_partitions,
264 	.name = "ofoldpart",
265 };
266 
ofpart_parser_init(void)267 static int __init ofpart_parser_init(void)
268 {
269 	register_mtd_parser(&ofpart_parser);
270 	register_mtd_parser(&ofoldpart_parser);
271 	return 0;
272 }
273 
ofpart_parser_exit(void)274 static void __exit ofpart_parser_exit(void)
275 {
276 	deregister_mtd_parser(&ofpart_parser);
277 	deregister_mtd_parser(&ofoldpart_parser);
278 }
279 
280 module_init(ofpart_parser_init);
281 module_exit(ofpart_parser_exit);
282 
283 MODULE_LICENSE("GPL");
284 MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
285 MODULE_AUTHOR("Vitaly Wool, David Gibson");
286 /*
287  * When MTD core cannot find the requested parser, it tries to load the module
288  * with the same name. Since we provide the ofoldpart parser, we should have
289  * the corresponding alias.
290  */
291 MODULE_ALIAS("fixed-partitions");
292 MODULE_ALIAS("ofoldpart");
293