ofpart_core.c

  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
 22struct fixed_partitions_quirks {
 23	int (*post_parse)(struct mtd_info *mtd, struct mtd_partition *parts, int nr_parts);
 24};
 25
 26static struct fixed_partitions_quirks bcm4908_partitions_quirks = {
 27	.post_parse = bcm4908_partitions_post_parse,
 28};
 29
 30static struct fixed_partitions_quirks linksys_ns_partitions_quirks = {
 31	.post_parse = linksys_ns_partitions_post_parse,
 32};
 33
 34static const struct of_device_id parse_ofpart_match_table[];
 35
 36static bool node_has_compatible(struct device_node *pp)
 37{
 38	return of_get_property(pp, "compatible", NULL);
 39}
 40
 41static 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		of_node_put(ofpart_node);
 81		return 0;
 82	}
 83
 84	quirks = of_id ? of_id->data : NULL;
 85
 86	/* First count the subnodes */
 87	nr_parts = 0;
 88	for_each_child_of_node(ofpart_node,  pp) {
 89		if (!dedicated && node_has_compatible(pp))
 90			continue;
 91
 92		nr_parts++;
 93	}
 94
 95	if (nr_parts == 0) {
 96		if (dedicated)
 97			of_node_put(ofpart_node);
 98		return 0;
 99	}
100
101	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
102	if (!parts) {
103		if (dedicated)
104			of_node_put(ofpart_node);
105		return -ENOMEM;
106	}
107
108	i = 0;
109	for_each_child_of_node(ofpart_node,  pp) {
110		const __be32 *reg;
111		int len;
112		int a_cells, s_cells;
113
114		if (!dedicated && node_has_compatible(pp))
115			continue;
116
117		reg = of_get_property(pp, "reg", &len);
118		if (!reg) {
119			if (dedicated) {
120				pr_debug("%s: ofpart partition %pOF (%pOF) missing reg property.\n",
121					 master->name, pp,
122					 mtd_node);
123				goto ofpart_fail;
124			} else {
125				nr_parts--;
126				continue;
127			}
128		}
129
130		a_cells = of_n_addr_cells(pp);
131		s_cells = of_n_size_cells(pp);
132		if (!dedicated && s_cells == 0) {
133			/*
134			 * This is a ugly workaround to not create
135			 * regression on devices that are still creating
136			 * partitions as direct children of the nand controller.
137			 * This can happen in case the nand controller node has
138			 * #size-cells equal to 0 and the firmware (e.g.
139			 * U-Boot) just add the partitions there assuming
140			 * 32-bit addressing.
141			 *
142			 * If you get this warning your firmware and/or DTS
143			 * should be really fixed.
144			 *
145			 * This is working only for devices smaller than 4GiB.
146			 */
147			pr_warn("%s: ofpart partition %pOF (%pOF) #size-cells is wrongly set to <0>, assuming <1> for parsing partitions.\n",
148				master->name, pp, mtd_node);
149			s_cells = 1;
150		}
151		if (len / 4 != a_cells + s_cells) {
152			pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
153				 master->name, pp,
154				 mtd_node);
155			goto ofpart_fail;
156		}
157
158		parts[i].offset = of_read_number(reg, a_cells);
159		parts[i].size = of_read_number(reg + a_cells, s_cells);
160		parts[i].of_node = pp;
161
162		partname = of_get_property(pp, "label", &len);
163		if (!partname)
164			partname = of_get_property(pp, "name", &len);
165		parts[i].name = partname;
166
167		if (of_property_read_bool(pp, "read-only"))
168			parts[i].mask_flags |= MTD_WRITEABLE;
169
170		if (of_property_read_bool(pp, "lock"))
171			parts[i].mask_flags |= MTD_POWERUP_LOCK;
172
173		if (of_property_read_bool(pp, "slc-mode"))
174			parts[i].add_flags |= MTD_SLC_ON_MLC_EMULATION;
175
176		i++;
177	}
178
179	if (!nr_parts)
180		goto ofpart_none;
181
182	if (quirks && quirks->post_parse)
183		quirks->post_parse(master, parts, nr_parts);
184
185	if (dedicated)
186		of_node_put(ofpart_node);
187
188	*pparts = parts;
189	return nr_parts;
190
191ofpart_fail:
192	pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
193	       master->name, pp, mtd_node);
194	ret = -EINVAL;
195ofpart_none:
196	if (dedicated)
197		of_node_put(ofpart_node);
198	of_node_put(pp);
199	kfree(parts);
200	return ret;
201}
202
203static const struct of_device_id parse_ofpart_match_table[] = {
204	/* Generic */
205	{ .compatible = "fixed-partitions" },
206	/* Customized */
207	{ .compatible = "brcm,bcm4908-partitions", .data = &bcm4908_partitions_quirks, },
208	{ .compatible = "linksys,ns-partitions", .data = &linksys_ns_partitions_quirks, },
209	{},
210};
211MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
212
213static struct mtd_part_parser ofpart_parser = {
214	.parse_fn = parse_fixed_partitions,
215	.name = "fixed-partitions",
216	.of_match_table = parse_ofpart_match_table,
217};
218
219static int parse_ofoldpart_partitions(struct mtd_info *master,
220				      const struct mtd_partition **pparts,
221				      struct mtd_part_parser_data *data)
222{
223	struct mtd_partition *parts;
224	struct device_node *dp;
225	int i, plen, nr_parts;
226	const struct {
227		__be32 offset, len;
228	} *part;
229	const char *names;
230
231	/* Pull of_node from the master device node */
232	dp = mtd_get_of_node(master);
233	if (!dp)
234		return 0;
235
236	part = of_get_property(dp, "partitions", &plen);
237	if (!part)
238		return 0; /* No partitions found */
239
240	pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);
241
242	nr_parts = plen / sizeof(part[0]);
243
244	parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
245	if (!parts)
246		return -ENOMEM;
247
248	names = of_get_property(dp, "partition-names", &plen);
249
250	for (i = 0; i < nr_parts; i++) {
251		parts[i].offset = be32_to_cpu(part->offset);
252		parts[i].size   = be32_to_cpu(part->len) & ~1;
253		/* bit 0 set signifies read only partition */
254		if (be32_to_cpu(part->len) & 1)
255			parts[i].mask_flags = MTD_WRITEABLE;
256
257		if (names && (plen > 0)) {
258			int len = strlen(names) + 1;
259
260			parts[i].name = names;
261			plen -= len;
262			names += len;
263		} else {
264			parts[i].name = "unnamed";
265		}
266
267		part++;
268	}
269
270	*pparts = parts;
271	return nr_parts;
272}
273
274static struct mtd_part_parser ofoldpart_parser = {
275	.parse_fn = parse_ofoldpart_partitions,
276	.name = "ofoldpart",
277};
278
279static int __init ofpart_parser_init(void)
280{
281	register_mtd_parser(&ofpart_parser);
282	register_mtd_parser(&ofoldpart_parser);
283	return 0;
284}
285
286static void __exit ofpart_parser_exit(void)
287{
288	deregister_mtd_parser(&ofpart_parser);
289	deregister_mtd_parser(&ofoldpart_parser);
290}
291
292module_init(ofpart_parser_init);
293module_exit(ofpart_parser_exit);
294
295MODULE_LICENSE("GPL");
296MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
297MODULE_AUTHOR("Vitaly Wool, David Gibson");
298/*
299 * When MTD core cannot find the requested parser, it tries to load the module
300 * with the same name. Since we provide the ofoldpart parser, we should have
301 * the corresponding alias.
302 */
303MODULE_ALIAS("fixed-partitions");
304MODULE_ALIAS("ofoldpart");