drivers/mtd/maps/physmap_of.c

   1 /*
   2  * Flash mappings described by the OF (or flattened) device tree
   3  *
   4  * Copyright (C) 2006 MontaVista Software Inc.
   5  * Author: Vitaly Wool <vwool@ru.mvista.com>
   6  *
   7  * Revised to handle newer style flash binding by:
   8  *   Copyright (C) 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/types.h>
  18 #include <linux/init.h>
  19 #include <linux/device.h>
  20 #include <linux/mtd/mtd.h>
  21 #include <linux/mtd/map.h>
  22 #include <linux/mtd/partitions.h>
  23 #include <linux/of.h>
  24 #include <linux/of_platform.h>
  25
  26 struct of_flash {
  27         struct mtd_info         *mtd;
  28         struct map_info         map;
  29         struct resource         *res;
  30 #ifdef CONFIG_MTD_PARTITIONS
  31         struct mtd_partition    *parts;
  32 #endif
  33 };
  34
  35 #ifdef CONFIG_MTD_PARTITIONS
  36 #define OF_FLASH_PARTS(info)    ((info)->parts)
  37
  38 static int parse_obsolete_partitions(struct of_device *dev,
  39                                      struct of_flash *info,
  40                                      struct device_node *dp)
  41 {
  42         int i, plen, nr_parts;
  43         const struct {
  44                 u32 offset, len;
  45         } *part;
  46         const char *names;
  47
  48         part = of_get_property(dp, "partitions", &plen);
  49         if (!part)
  50                 return 0; /* No partitions found */
  51
  52         dev_warn(&dev->dev, "Device tree uses obsolete partition map binding\n");
  53
  54         nr_parts = plen / sizeof(part[0]);
  55
  56         info->parts = kzalloc(nr_parts * sizeof(*info->parts), GFP_KERNEL);
  57         if (!info->parts)
  58                 return -ENOMEM;
  59
  60         names = of_get_property(dp, "partition-names", &plen);
  61
  62         for (i = 0; i < nr_parts; i++) {
  63                 info->parts[i].offset = part->offset;
  64                 info->parts[i].size   = part->len & ~1;
  65                 if (part->len & 1) /* bit 0 set signifies read only partition */
  66                         info->parts[i].mask_flags = MTD_WRITEABLE;
  67
  68                 if (names && (plen > 0)) {
  69                         int len = strlen(names) + 1;
  70
  71                         info->parts[i].name = (char *)names;
  72                         plen -= len;
  73                         names += len;
  74                 } else {
  75                         info->parts[i].name = "unnamed";
  76                 }
  77
  78                 part++;
  79         }
  80
  81         return nr_parts;
  82 }
  83
  84 static int __devinit parse_partitions(struct of_flash *info,
  85                                       struct of_device *dev)
  86 {
  87         const char *partname;
  88         static const char *part_probe_types[]
  89                 = { "cmdlinepart", "RedBoot", NULL };
  90         struct device_node *dp = dev->node, *pp;
  91         int nr_parts, i;
  92
  93         /* First look for RedBoot table or partitions on the command
  94          * line, these take precedence over device tree information */
  95         nr_parts = parse_mtd_partitions(info->mtd, part_probe_types,
  96                                         &info->parts, 0);
  97         if (nr_parts > 0) {
  98                 add_mtd_partitions(info->mtd, info->parts, nr_parts);
  99                 return 0;
 100         }
 101
 102         /* First count the subnodes */
 103         nr_parts = 0;
 104         for (pp = dp->child; pp; pp = pp->sibling)
 105                 nr_parts++;
 106
 107         if (nr_parts == 0)
 108                 return parse_obsolete_partitions(dev, info, dp);
 109
 110         info->parts = kzalloc(nr_parts * sizeof(*info->parts),
 111                               GFP_KERNEL);
 112         if (!info->parts)
 113                 return -ENOMEM;
 114
 115         for (pp = dp->child, i = 0; pp; pp = pp->sibling, i++) {
 116                 const u32 *reg;
 117                 int len;
 118
 119                 reg = of_get_property(pp, "reg", &len);
 120                 if (!reg || (len != 2*sizeof(u32))) {
 121                         dev_err(&dev->dev, "Invalid 'reg' on %s\n",
 122                                 dp->full_name);
 123                         kfree(info->parts);
 124                         info->parts = NULL;
 125                         return -EINVAL;
 126                 }
 127                 info->parts[i].offset = reg[0];
 128                 info->parts[i].size = reg[1];
 129
 130                 partname = of_get_property(pp, "label", &len);
 131                 if (!partname)
 132                         partname = of_get_property(pp, "name", &len);
 133                 info->parts[i].name = (char *)partname;
 134
 135                 if (of_get_property(pp, "read-only", &len))
 136                         info->parts[i].mask_flags = MTD_WRITEABLE;
 137         }
 138
 139         return nr_parts;
 140 }
 141 #else /* MTD_PARTITIONS */
 142 #define OF_FLASH_PARTS(info)            (0)
 143 #define parse_partitions(info, dev)     (0)
 144 #endif /* MTD_PARTITIONS */
 145
 146 static int of_flash_remove(struct of_device *dev)
 147 {
 148         struct of_flash *info;
 149
 150         info = dev_get_drvdata(&dev->dev);
 151         if (!info)
 152                 return 0;
 153         dev_set_drvdata(&dev->dev, NULL);
 154
 155         if (info->mtd) {
 156                 if (OF_FLASH_PARTS(info)) {
 157                         del_mtd_partitions(info->mtd);
 158                         kfree(OF_FLASH_PARTS(info));
 159                 } else {
 160                         del_mtd_device(info->mtd);
 161                 }
 162                 map_destroy(info->mtd);
 163         }
 164
 165         if (info->map.virt)
 166                 iounmap(info->map.virt);
 167
 168         if (info->res) {
 169                 release_resource(info->res);
 170                 kfree(info->res);
 171         }
 172
 173         return 0;
 174 }
 175
 176 /* Helper function to handle probing of the obsolete "direct-mapped"
 177  * compatible binding, which has an extra "probe-type" property
 178  * describing the type of flash probe necessary. */
 179 static struct mtd_info * __devinit obsolete_probe(struct of_device *dev,
 180                                                   struct map_info *map)
 181 {
 182         struct device_node *dp = dev->node;
 183         const char *of_probe;
 184         struct mtd_info *mtd;
 185         static const char *rom_probe_types[]
 186                 = { "cfi_probe", "jedec_probe", "map_rom"};
 187         int i;
 188
 189         dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "
 190                  "flash binding\n");
 191
 192         of_probe = of_get_property(dp, "probe-type", NULL);
 193         if (!of_probe) {
 194                 for (i = 0; i < ARRAY_SIZE(rom_probe_types); i++) {
 195                         mtd = do_map_probe(rom_probe_types[i], map);
 196                         if (mtd)
 197                                 return mtd;
 198                 }
 199                 return NULL;
 200         } else if (strcmp(of_probe, "CFI") == 0) {
 201                 return do_map_probe("cfi_probe", map);
 202         } else if (strcmp(of_probe, "JEDEC") == 0) {
 203                 return do_map_probe("jedec_probe", map);
 204         } else {
 205                 if (strcmp(of_probe, "ROM") != 0)
 206                         dev_warn(&dev->dev, "obsolete_probe: don't know probe "
 207                                  "type '%s', mapping as rom\n", of_probe);
 208                 return do_map_probe("mtd_rom", map);
 209         }
 210 }
 211
 212 static int __devinit of_flash_probe(struct of_device *dev,
 213                                     const struct of_device_id *match)
 214 {
 215         struct device_node *dp = dev->node;
 216         struct resource res;
 217         struct of_flash *info;
 218         const char *probe_type = match->data;
 219         const u32 *width;
 220         int err;
 221
 222         err = -ENXIO;
 223         if (of_address_to_resource(dp, 0, &res)) {
 224                 dev_err(&dev->dev, "Can't get IO address from device tree\n");
 225                 goto err_out;
 226         }
 227
 228         dev_dbg(&dev->dev, "of_flash device: %.8llx-%.8llx\n",
 229                 (unsigned long long)res.start, (unsigned long long)res.end);
 230
 231         err = -ENOMEM;
 232         info = kzalloc(sizeof(*info), GFP_KERNEL);
 233         if (!info)
 234                 goto err_out;
 235         memset(info, 0, sizeof(*info));
 236
 237         dev_set_drvdata(&dev->dev, info);
 238
 239         err = -EBUSY;
 240         info->res = request_mem_region(res.start, res.end - res.start + 1,
 241                                        dev->dev.bus_id);
 242         if (!info->res)
 243                 goto err_out;
 244
 245         err = -ENXIO;
 246         width = of_get_property(dp, "bank-width", NULL);
 247         if (!width) {
 248                 dev_err(&dev->dev, "Can't get bank width from device tree\n");
 249                 goto err_out;
 250         }
 251
 252         info->map.name = dev->dev.bus_id;
 253         info->map.phys = res.start;
 254         info->map.size = res.end - res.start + 1;
 255         info->map.bankwidth = *width;
 256
 257         err = -ENOMEM;
 258         info->map.virt = ioremap(info->map.phys, info->map.size);
 259         if (!info->map.virt) {
 260                 dev_err(&dev->dev, "Failed to ioremap() flash region\n");
 261                 goto err_out;
 262         }
 263
 264         simple_map_init(&info->map);
 265
 266         if (probe_type)
 267                 info->mtd = do_map_probe(probe_type, &info->map);
 268         else
 269                 info->mtd = obsolete_probe(dev, &info->map);
 270
 271         err = -ENXIO;
 272         if (!info->mtd) {
 273                 dev_err(&dev->dev, "do_map_probe() failed\n");
 274                 goto err_out;
 275         }
 276         info->mtd->owner = THIS_MODULE;
 277
 278         err = parse_partitions(info, dev);
 279         if (err < 0)
 280                 goto err_out;
 281
 282         if (err > 0)
 283                 add_mtd_partitions(info->mtd, OF_FLASH_PARTS(info), err);
 284         else
 285                 add_mtd_device(info->mtd);
 286
 287         return 0;
 288
 289 err_out:
 290         of_flash_remove(dev);
 291         return err;
 292 }
 293
 294 static struct of_device_id of_flash_match[] = {
 295         {
 296                 .compatible     = "cfi-flash",
 297                 .data           = (void *)"cfi_probe",
 298         },
 299         {
 300                 /* FIXME: JEDEC chips can't be safely and reliably
 301                  * probed, although the mtd code gets it right in
 302                  * practice most of the time.  We should use the
 303                  * vendor and device ids specified by the binding to
 304                  * bypass the heuristic probe code, but the mtd layer
 305                  * provides, at present, no interface for doing so
 306                  * :(. */
 307                 .compatible     = "jedec-flash",
 308                 .data           = (void *)"jedec_probe",
 309         },
 310         {
 311                 .type           = "rom",
 312                 .compatible     = "direct-mapped"
 313         },
 314         { },
 315 };
 316 MODULE_DEVICE_TABLE(of, of_flash_match);
 317
 318 static struct of_platform_driver of_flash_driver = {
 319         .name           = "of-flash",
 320         .match_table    = of_flash_match,
 321         .probe          = of_flash_probe,
 322         .remove         = of_flash_remove,
 323 };
 324
 325 static int __init of_flash_init(void)
 326 {
 327         return of_register_platform_driver(&of_flash_driver);
 328 }
 329
 330 static void __exit of_flash_exit(void)
 331 {
 332         of_unregister_platform_driver(&of_flash_driver);
 333 }
 334
 335 module_init(of_flash_init);
 336 module_exit(of_flash_exit);
 337
 338 MODULE_LICENSE("GPL");
 339 MODULE_AUTHOR("Vitaly Wool <vwool@ru.mvista.com>");
 340 MODULE_DESCRIPTION("Device tree based MTD map driver");