drivers/mtd/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                 i++;
 121         }
 122
 123         if (!nr_parts)
 124                 goto ofpart_none;
 125
 126         *pparts = parts;
 127         return nr_parts;
 128
 129 ofpart_fail:
 130         pr_err("%s: error parsing ofpart partition %pOF (%pOF)\n",
 131                master->name, pp, mtd_node);
 132         ret = -EINVAL;
 133 ofpart_none:
 134         of_node_put(pp);
 135         kfree(parts);
 136         return ret;
 137 }
 138
 139 static const struct of_device_id parse_ofpart_match_table[] = {
 140         { .compatible = "fixed-partitions" },
 141         {},
 142 };
 143 MODULE_DEVICE_TABLE(of, parse_ofpart_match_table);
 144
 145 static 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
 151 static 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
 206 static struct mtd_part_parser ofoldpart_parser = {
 207         .parse_fn = parse_ofoldpart_partitions,
 208         .name = "ofoldpart",
 209 };
 210
 211 static int __init ofpart_parser_init(void)
 212 {
 213         register_mtd_parser(&ofpart_parser);
 214         register_mtd_parser(&ofoldpart_parser);
 215         return 0;
 216 }
 217
 218 static void __exit ofpart_parser_exit(void)
 219 {
 220         deregister_mtd_parser(&ofpart_parser);
 221         deregister_mtd_parser(&ofoldpart_parser);
 222 }
 223
 224 module_init(ofpart_parser_init);
 225 module_exit(ofpart_parser_exit);
 226
 227 MODULE_LICENSE("GPL");
 228 MODULE_DESCRIPTION("Parser for MTD partitioning information in device tree");
 229 MODULE_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  */
 235 MODULE_ALIAS("fixed-partitions");
 236 MODULE_ALIAS("ofoldpart");