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
 19static bool node_has_compatible(struct device_node *pp)
 20{
 21	return of_get_property(pp, "compatible", NULL);
 22}
 23
 24static int parse_fixed_partitions(struct mtd_info *master,
 25				  const struct mtd_partition **pparts,
 26				  struct mtd_part_parser_data *data)
 27{
 28	struct mtd_partition *parts;
 29	struct device_node *mtd_node;
 30	struct device_node *ofpart_node;
 31	const char *partname;
 32	struct device_node *pp;
 33	int nr_parts, i, ret = 0;
 34	bool dedicated = true;
 35
 36
 37	/* Pull of_node from the master device node */
 38	mtd_node = mtd_get_of_node(master);
 39	if (!mtd_node)
 40		return 0;
 41
 42	ofpart_node = of_get_child_by_name(mtd_node, "partitions");
 43	if (!ofpart_node) {
 44		/*
 45		 * We might get here even when ofpart isn't used at all (e.g.,
 46		 * when using another parser), so don't be louder than
 47		 * KERN_DEBUG
 48		 */
 49		pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
 50			 master->name, mtd_node);
 51		ofpart_node = mtd_node;
 52		dedicated = false;
 53	} else if (!of_device_is_compatible(ofpart_node, "fixed-partitions")) {
 54		/* The 'partitions' subnode might be used by another parser */
 55		return 0;
 56	}
 57
 58	/* First count the subnodes */
 59	nr_parts = 0;
 60	for_each_child_of_node(ofpart_node,  pp) {
 61		if (!dedicated && node_has_compatible(pp))
 62			continue;
 63
 64		nr_parts++;
 65	}
 66
 67	if (nr_parts == 0)
 68		return 0;
 69
 70	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
 71	if (!parts)
 72		return -ENOMEM;
 73
 74	i = 0;
 75	for_each_child_of_node(ofpart_node,  pp) {
 76		const __be32 *reg;
 77		int len;
 78		int a_cells, s_cells;
 79
 80		if (!dedicated && node_has_compatible(pp))
 81			continue;
 82
 83		reg = of_get_property(pp, "reg", &len);
 84		if (!reg) {
 85			if (dedicated) {
 86				pr_debug("%s: ofpart partition %pOF (%pOF) missing reg property.\n",
 87					 master->name, pp,
 88					 mtd_node);
 89				goto ofpart_fail;
 90			} else {
 91				nr_parts--;
 92				continue;
 93			}
 94		}
 95
 96		a_cells = of_n_addr_cells(pp);
 97		s_cells = of_n_size_cells(pp);
 98		if (len / 4 != a_cells + s_cells) {
 99			pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
100				 master->name, pp,
101				 mtd_node);
102			goto ofpart_fail;
103		}
104
105		parts[i].offset = of_read_number(reg, a_cells);
106		parts[i].size = of_read_number(reg + a_cells, s_cells);
107		parts[i].of_node = pp;
108
109		partname = of_get_property(pp, "label", &len);
110		if (!partname)
111			partname = of_get_property(pp, "name", &len);
112		parts[i].name = partname;
113
114		if (of_get_property(pp, "read-only", &len))
115			parts[i].mask_flags |= MTD_WRITEABLE;
116
117		if (of_get_property(pp, "lock", &len))
118			parts[i].mask_flags |= MTD_POWERUP_LOCK;
119
120		i++;
121	}
122
123	if (!nr_parts)
124		goto ofpart_none;
125
126	*pparts = parts;
127	return nr_parts;
128
129ofpart_fail:
130	pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
131	       master->name, pp, mtd_node);
132	ret = -EINVAL;
133ofpart_none:
134	of_node_put(pp);
135	kfree(parts);
136	return ret;
137}
138
139static const struct of_device_id parse_ofpart_match_table[] = {
140	{ .compatible = "fixed-partitions" },
141	{},
142};
143MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
144
145static struct mtd_part_parser ofpart_parser = {
146	.parse_fn = parse_fixed_partitions,
147	.name = "fixed-partitions",
148	.of_match_table = parse_ofpart_match_table,
149};
150
151static int parse_ofoldpart_partitions(struct mtd_info *master,
152				      const struct mtd_partition **pparts,
153				      struct mtd_part_parser_data *data)
154{
155	struct mtd_partition *parts;
156	struct device_node *dp;
157	int i, plen, nr_parts;
158	const struct {
159		__be32 offset, len;
160	} *part;
161	const char *names;
162
163	/* Pull of_node from the master device node */
164	dp = mtd_get_of_node(master);
165	if (!dp)
166		return 0;
167
168	part = of_get_property(dp, "partitions", &plen);
169	if (!part)
170		return 0; /* No partitions found */
171
172	pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);
173
174	nr_parts = plen / sizeof(part[0]);
175
176	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
177	if (!parts)
178		return -ENOMEM;
179
180	names = of_get_property(dp, "partition-names", &plen);
181
182	for (i = 0; i < nr_parts; i++) {
183		parts[i].offset = be32_to_cpu(part->offset);
184		parts[i].size   = be32_to_cpu(part->len) & ~1;
185		/* bit 0 set signifies read only partition */
186		if (be32_to_cpu(part->len) & 1)
187			parts[i].mask_flags = MTD_WRITEABLE;
188
189		if (names && (plen > 0)) {
190			int len = strlen(names) + 1;
191
192			parts[i].name = names;
193			plen -= len;
194			names += len;
195		} else {
196			parts[i].name = "unnamed";
197		}
198
199		part++;
200	}
201
202	*pparts = parts;
203	return nr_parts;
204}
205
206static struct mtd_part_parser ofoldpart_parser = {
207	.parse_fn = parse_ofoldpart_partitions,
208	.name = "ofoldpart",
209};
210
211static int __init ofpart_parser_init(void)
212{
213	register_mtd_parser(&ofpart_parser);
214	register_mtd_parser(&ofoldpart_parser);
215	return 0;
216}
217
218static void __exit ofpart_parser_exit(void)
219{
220	deregister_mtd_parser(&ofpart_parser);
221	deregister_mtd_parser(&ofoldpart_parser);
222}
223
224module_init(ofpart_parser_init);
225module_exit(ofpart_parser_exit);
226
227MODULE_LICENSE("GPL");
228MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
229MODULE_AUTHOR("Vitaly Wool, David Gibson");
230/*
231 * When MTD core cannot find the requested parser, it tries to load the module
232 * with the same name. Since we provide the ofoldpart parser, we should have
233 * the corresponding alias.
234 */
235MODULE_ALIAS("fixed-partitions");
236MODULE_ALIAS("ofoldpart");