drivers/mtd/parsers/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
  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
  36 static bool node_has_compatible(struct device_node *pp)
  37 {
  38         return of_get_property(pp, "compatible", NULL);
  39 }
  40
  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_property_read_bool(pp, "read-only"))
 161                         parts[i].mask_flags |= MTD_WRITEABLE;
 162
 163                 if (of_property_read_bool(pp, "lock"))
 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
 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
 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
 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");