drivers/mtd/ofpart.c

   1 /*
   2  * Flash partitions described by the OF (or flattened) device tree
   3  *
   4  * Copyright © 2006 MontaVista Software Inc.
   5  * Author: Vitaly Wool <vwool@ru.mvista.com>
   6  *
   7  * Revised to handle newer style flash binding by:
   8  *   Copyright © 2007 David Gibson, IBM Corporation.
   9  *
  10  * This program is free software; you can redistribute  it and/or modify it
  11  * under  the terms of  the GNU General  Public License as published by the
  12  * Free Software Foundation;  either version 2 of the  License, or (at your
  13  * option) any later version.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/of.h>
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/slab.h>
  21 #include <linux/mtd/partitions.h>
  22
  23 static bool node_has_compatible(struct device_node *pp)
  24 {
  25         return of_get_property(pp, "compatible", NULL);
  26 }
  27
  28 static int parse_fixed_partitions(struct mtd_info *master,
  29                                   const struct mtd_partition **pparts,
  30                                   struct mtd_part_parser_data *data)
  31 {
  32         struct mtd_partition *parts;
  33         struct device_node *mtd_node;
  34         struct device_node *ofpart_node;
  35         const char *partname;
  36         struct device_node *pp;
  37         int nr_parts, i, ret = 0;
  38         bool dedicated = true;
  39
  40
  41         /* Pull of_node from the master device node */
  42         mtd_node = mtd_get_of_node(master);
  43         if (!mtd_node)
  44                 return 0;
  45
  46         ofpart_node = of_get_child_by_name(mtd_node, "partitions");
  47         if (!ofpart_node) {
  48                 /*
  49                  * We might get here even when ofpart isn't used at all (e.g.,
  50                  * when using another parser), so don't be louder than
  51                  * KERN_DEBUG
  52                  */
  53                 pr_debug("%s: 'partitions' subnode not found on %pOF. Trying to parse direct subnodes as partitions.\n",
  54                          master->name, mtd_node);
  55                 ofpart_node = mtd_node;
  56                 dedicated = false;
  57         } else if (!of_device_is_compatible(ofpart_node, "fixed-partitions")) {
  58                 /* The 'partitions' subnode might be used by another parser */
  59                 return 0;
  60         }
  61
  62         /* First count the subnodes */
  63         nr_parts = 0;
  64         for_each_child_of_node(ofpart_node,  pp) {
  65                 if (!dedicated && node_has_compatible(pp))
  66                         continue;
  67
  68                 nr_parts++;
  69         }
  70
  71         if (nr_parts == 0)
  72                 return 0;
  73
  74         parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
  75         if (!parts)
  76                 return -ENOMEM;
  77
  78         i = 0;
  79         for_each_child_of_node(ofpart_node,  pp) {
  80                 const __be32 *reg;
  81                 int len;
  82                 int a_cells, s_cells;
  83
  84                 if (!dedicated && node_has_compatible(pp))
  85                         continue;
  86
  87                 reg = of_get_property(pp, "reg", &len);
  88                 if (!reg) {
  89                         if (dedicated) {
  90                                 pr_debug("%s: ofpart partition %pOF (%pOF) missing reg property.\n",
  91                                          master->name, pp,
  92                                          mtd_node);
  93                                 goto ofpart_fail;
  94                         } else {
  95                                 nr_parts--;
  96                                 continue;
  97                         }
  98                 }
  99
 100                 a_cells = of_n_addr_cells(pp);
 101                 s_cells = of_n_size_cells(pp);
 102                 if (len / 4 != a_cells + s_cells) {
 103                         pr_debug("%s: ofpart partition %pOF (%pOF) error parsing reg property.\n",
 104                                  master->name, pp,
 105                                  mtd_node);
 106                         goto ofpart_fail;
 107                 }
 108
 109                 parts[i].offset = of_read_number(reg, a_cells);
 110                 parts[i].size = of_read_number(reg + a_cells, s_cells);
 111                 parts[i].of_node = pp;
 112
 113                 partname = of_get_property(pp, "label", &len);
 114                 if (!partname)
 115                         partname = of_get_property(pp, "name", &len);
 116                 parts[i].name = partname;
 117
 118                 if (of_get_property(pp, "read-only", &len))
 119                         parts[i].mask_flags |= MTD_WRITEABLE;
 120
 121                 if (of_get_property(pp, "lock", &len))
 122                         parts[i].mask_flags |= MTD_POWERUP_LOCK;
 123
 124                 i++;
 125         }
 126
 127         if (!nr_parts)
 128                 goto ofpart_none;
 129
 130         *pparts = parts;
 131         return nr_parts;
 132
 133 ofpart_fail:
 134         pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
 135                master->name, pp, mtd_node);
 136         ret = -EINVAL;
 137 ofpart_none:
 138         of_node_put(pp);
 139         kfree(parts);
 140         return ret;
 141 }
 142
 143 static const struct of_device_id parse_ofpart_match_table[] = {
 144         { .compatible = "fixed-partitions" },
 145         {},
 146 };
 147 MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
 148
 149 static struct mtd_part_parser ofpart_parser = {
 150         .parse_fn = parse_fixed_partitions,
 151         .name = "fixed-partitions",
 152         .of_match_table = parse_ofpart_match_table,
 153 };
 154
 155 static int parse_ofoldpart_partitions(struct mtd_info *master,
 156                                       const struct mtd_partition **pparts,
 157                                       struct mtd_part_parser_data *data)
 158 {
 159         struct mtd_partition *parts;
 160         struct device_node *dp;
 161         int i, plen, nr_parts;
 162         const struct {
 163                 __be32 offset, len;
 164         } *part;
 165         const char *names;
 166
 167         /* Pull of_node from the master device node */
 168         dp = mtd_get_of_node(master);
 169         if (!dp)
 170                 return 0;
 171
 172         part = of_get_property(dp, "partitions", &plen);
 173         if (!part)
 174                 return 0; /* No partitions found */
 175
 176         pr_warn("Device tree uses obsolete partition map binding: %pOF\n", dp);
 177
 178         nr_parts = plen / sizeof(part[0]);
 179
 180         parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
 181         if (!parts)
 182                 return -ENOMEM;
 183
 184         names = of_get_property(dp, "partition-names", &plen);
 185
 186         for (i = 0; i < nr_parts; i++) {
 187                 parts[i].offset = be32_to_cpu(part->offset);
 188                 parts[i].size   = be32_to_cpu(part->len) & ~1;
 189                 /* bit 0 set signifies read only partition */
 190                 if (be32_to_cpu(part->len) & 1)
 191                         parts[i].mask_flags = MTD_WRITEABLE;
 192
 193                 if (names && (plen > 0)) {
 194                         int len = strlen(names) + 1;
 195
 196                         parts[i].name = names;
 197                         plen -= len;
 198                         names += len;
 199                 } else {
 200                         parts[i].name = "unnamed";
 201                 }
 202
 203                 part++;
 204         }
 205
 206         *pparts = parts;
 207         return nr_parts;
 208 }
 209
 210 static struct mtd_part_parser ofoldpart_parser = {
 211         .parse_fn = parse_ofoldpart_partitions,
 212         .name = "ofoldpart",
 213 };
 214
 215 static int __init ofpart_parser_init(void)
 216 {
 217         register_mtd_parser(&ofpart_parser);
 218         register_mtd_parser(&ofoldpart_parser);
 219         return 0;
 220 }
 221
 222 static void __exit ofpart_parser_exit(void)
 223 {
 224         deregister_mtd_parser(&ofpart_parser);
 225         deregister_mtd_parser(&ofoldpart_parser);
 226 }
 227
 228 module_init(ofpart_parser_init);
 229 module_exit(ofpart_parser_exit);
 230
 231 MODULE_LICENSE("GPL");
 232 MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
 233 MODULE_AUTHOR("Vitaly Wool, David Gibson");
 234 /*
 235  * When MTD core cannot find the requested parser, it tries to load the module
 236  * with the same name. Since we provide the ofoldpart parser, we should have
 237  * the corresponding alias.
 238  */
 239 MODULE_ALIAS("fixed-partitions");
 240 MODULE_ALIAS("ofoldpart");