drivers/mtd/parsers/ofpart.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 static bool node_has_compatible(struct device_node *pp)
  20 {
  21         return of_get_property(pp, "compatible", NULL);
  22 }
  23
  24 static 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                 if (of_property_read_bool(pp, "slc-mode"))
 121                         parts[i].add_flags |= MTD_SLC_ON_MLC_EMULATION;
 122
 123                 i++;
 124         }
 125
 126         if (!nr_parts)
 127                 goto ofpart_none;
 128
 129         *pparts = parts;
 130         return nr_parts;
 131
 132 ofpart_fail:
 133         pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
 134                master->name, pp, mtd_node);
 135         ret = -EINVAL;
 136 ofpart_none:
 137         of_node_put(pp);
 138         kfree(parts);
 139         return ret;
 140 }
 141
 142 static const struct of_device_id parse_ofpart_match_table[] = {
 143         { .compatible = "fixed-partitions" },
 144         {},
 145 };
 146 MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
 147
 148 static struct mtd_part_parser ofpart_parser = {
 149         .parse_fn = parse_fixed_partitions,
 150         .name = "fixed-partitions",
 151         .of_match_table = parse_ofpart_match_table,
 152 };
 153
 154 static int parse_ofoldpart_partitions(struct mtd_info *master,
 155                                       const struct mtd_partition **pparts,
 156                                       struct mtd_part_parser_data *data)
 157 {
 158         struct mtd_partition *parts;
 159         struct device_node *dp;
 160         int i, plen, nr_parts;
 161         const struct {
 162                 __be32 offset, len;
 163         } *part;
 164         const char *names;
 165
 166         /* Pull of_node from the master device node */
 167         dp = mtd_get_of_node(master);
 168         if (!dp)
 169                 return 0;
 170
 171         part = of_get_property(dp, "partitions", &plen);
 172         if (!part)
 173                 return 0; /* No partitions found */
 174
 175         pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);
 176
 177         nr_parts = plen / sizeof(part[0]);
 178
 179         parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
 180         if (!parts)
 181                 return -ENOMEM;
 182
 183         names = of_get_property(dp, "partition-names", &plen);
 184
 185         for (i = 0; i < nr_parts; i++) {
 186                 parts[i].offset = be32_to_cpu(part->offset);
 187                 parts[i].size   = be32_to_cpu(part->len) & ~1;
 188                 /* bit 0 set signifies read only partition */
 189                 if (be32_to_cpu(part->len) & 1)
 190                         parts[i].mask_flags = MTD_WRITEABLE;
 191
 192                 if (names && (plen > 0)) {
 193                         int len = strlen(names) + 1;
 194
 195                         parts[i].name = names;
 196                         plen -= len;
 197                         names += len;
 198                 } else {
 199                         parts[i].name = "unnamed";
 200                 }
 201
 202                 part++;
 203         }
 204
 205         *pparts = parts;
 206         return nr_parts;
 207 }
 208
 209 static struct mtd_part_parser ofoldpart_parser = {
 210         .parse_fn = parse_ofoldpart_partitions,
 211         .name = "ofoldpart",
 212 };
 213
 214 static int __init ofpart_parser_init(void)
 215 {
 216         register_mtd_parser(&ofpart_parser);
 217         register_mtd_parser(&ofoldpart_parser);
 218         return 0;
 219 }
 220
 221 static void __exit ofpart_parser_exit(void)
 222 {
 223         deregister_mtd_parser(&ofpart_parser);
 224         deregister_mtd_parser(&ofoldpart_parser);
 225 }
 226
 227 module_init(ofpart_parser_init);
 228 module_exit(ofpart_parser_exit);
 229
 230 MODULE_LICENSE("GPL");
 231 MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
 232 MODULE_AUTHOR("Vitaly Wool, David Gibson");
 233 /*
 234  * When MTD core cannot find the requested parser, it tries to load the module
 235  * with the same name. Since we provide the ofoldpart parser, we should have
 236  * the corresponding alias.
 237  */
 238 MODULE_ALIAS("fixed-partitions");
 239 MODULE_ALIAS("ofoldpart");