kernel/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/device.h>
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/mtd/map.h>
  21 #include <linux/mtd/partitions.h>
  22 #include <linux/mtd/concat.h>
  23 #include <linux/of.h>
  24 #include <linux/of_address.h>
  25 #include <linux/of_platform.h>
  26 #include <linux/slab.h>
  27
  28 struct of_flash_list {
  29         struct mtd_info *mtd;
  30         struct map_info map;
  31         struct resource *res;
  32 };
  33
  34 struct of_flash {
  35         struct mtd_info         *cmtd;
  36         int list_size; /* number of elements in of_flash_list */
  37         struct of_flash_list    list[0];
  38 };
  39
  40 static int of_flash_remove(struct platform_device *dev)
  41 {
  42         struct of_flash *info;
  43         int i;
  44
  45         info = dev_get_drvdata(&dev->dev);
  46         if (!info)
  47                 return 0;
  48         dev_set_drvdata(&dev->dev, NULL);
  49
  50         if (info->cmtd) {
  51                 mtd_device_unregister(info->cmtd);
  52                 if (info->cmtd != info->list[0].mtd)
  53                         mtd_concat_destroy(info->cmtd);
  54         }
  55
  56         for (i = 0; i < info->list_size; i++) {
  57                 if (info->list[i].mtd)
  58                         map_destroy(info->list[i].mtd);
  59
  60                 if (info->list[i].map.virt)
  61                         iounmap(info->list[i].map.virt);
  62
  63                 if (info->list[i].res) {
  64                         release_resource(info->list[i].res);
  65                         kfree(info->list[i].res);
  66                 }
  67         }
  68         return 0;
  69 }
  70
  71 static const char * const rom_probe_types[] = {
  72         "cfi_probe", "jedec_probe", "map_rom" };
  73
  74 /* Helper function to handle probing of the obsolete "direct-mapped"
  75  * compatible binding, which has an extra "probe-type" property
  76  * describing the type of flash probe necessary. */
  77 static struct mtd_info *obsolete_probe(struct platform_device *dev,
  78                                        struct map_info *map)
  79 {
  80         struct device_node *dp = dev->dev.of_node;
  81         const char *of_probe;
  82         struct mtd_info *mtd;
  83         int i;
  84
  85         dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "
  86                  "flash binding\n");
  87
  88         of_probe = of_get_property(dp, "probe-type", NULL);
  89         if (!of_probe) {
  90                 for (i = 0; i < ARRAY_SIZE(rom_probe_types); i++) {
  91                         mtd = do_map_probe(rom_probe_types[i], map);
  92                         if (mtd)
  93                                 return mtd;
  94                 }
  95                 return NULL;
  96         } else if (strcmp(of_probe, "CFI") == 0) {
  97                 return do_map_probe("cfi_probe", map);
  98         } else if (strcmp(of_probe, "JEDEC") == 0) {
  99                 return do_map_probe("jedec_probe", map);
 100         } else {
 101                 if (strcmp(of_probe, "ROM") != 0)
 102                         dev_warn(&dev->dev, "obsolete_probe: don't know probe "
 103                                  "type '%s', mapping as rom\n", of_probe);
 104                 return do_map_probe("map_rom", map);
 105         }
 106 }
 107
 108 /* When partitions are set we look for a linux,part-probe property which
 109    specifies the list of partition probers to use. If none is given then the
 110    default is use. These take precedence over other device tree
 111    information. */
 112 static const char * const part_probe_types_def[] = {
 113         "cmdlinepart", "RedBoot", "ofpart", "ofoldpart", NULL };
 114
 115 static const char * const *of_get_probes(struct device_node *dp)
 116 {
 117         const char *cp;
 118         int cplen;
 119         unsigned int l;
 120         unsigned int count;
 121         const char **res;
 122
 123         cp = of_get_property(dp, "linux,part-probe", &cplen);
 124         if (cp == NULL)
 125                 return part_probe_types_def;
 126
 127         count = 0;
 128         for (l = 0; l != cplen; l++)
 129                 if (cp[l] == 0)
 130                         count++;
 131
 132         res = kzalloc((count + 1)*sizeof(*res), GFP_KERNEL);
 133         if (!res)
 134                 return NULL;
 135         count = 0;
 136         while (cplen > 0) {
 137                 res[count] = cp;
 138                 l = strlen(cp) + 1;
 139                 cp += l;
 140                 cplen -= l;
 141                 count++;
 142         }
 143         return res;
 144 }
 145
 146 static void of_free_probes(const char * const *probes)
 147 {
 148         if (probes != part_probe_types_def)
 149                 kfree(probes);
 150 }
 151
 152 static const struct of_device_id of_flash_match[];
 153 static int of_flash_probe(struct platform_device *dev)
 154 {
 155         const char * const *part_probe_types;
 156         const struct of_device_id *match;
 157         struct device_node *dp = dev->dev.of_node;
 158         struct resource res;
 159         struct of_flash *info;
 160         const char *probe_type;
 161         const __be32 *width;
 162         int err;
 163         int i;
 164         int count;
 165         const __be32 *p;
 166         int reg_tuple_size;
 167         struct mtd_info **mtd_list = NULL;
 168         resource_size_t res_size;
 169         struct mtd_part_parser_data ppdata;
 170         bool map_indirect;
 171         const char *mtd_name = NULL;
 172
 173         match = of_match_device(of_flash_match, &dev->dev);
 174         if (!match)
 175                 return -EINVAL;
 176         probe_type = match->data;
 177
 178         reg_tuple_size = (of_n_addr_cells(dp) + of_n_size_cells(dp)) * sizeof(u32);
 179
 180         of_property_read_string(dp, "linux,mtd-name", &mtd_name);
 181
 182         /*
 183          * Get number of "reg" tuples. Scan for MTD devices on area's
 184          * described by each "reg" region. This makes it possible (including
 185          * the concat support) to support the Intel P30 48F4400 chips which
 186          * consists internally of 2 non-identical NOR chips on one die.
 187          */
 188         p = of_get_property(dp, "reg", &count);
 189         if (count % reg_tuple_size != 0) {
 190                 dev_err(&dev->dev, "Malformed reg property on %s\n",
 191                                 dev->dev.of_node->full_name);
 192                 err = -EINVAL;
 193                 goto err_flash_remove;
 194         }
 195         count /= reg_tuple_size;
 196
 197         map_indirect = of_property_read_bool(dp, "no-unaligned-direct-access");
 198
 199         err = -ENOMEM;
 200         info = devm_kzalloc(&dev->dev,
 201                             sizeof(struct of_flash) +
 202                             sizeof(struct of_flash_list) * count, GFP_KERNEL);
 203         if (!info)
 204                 goto err_flash_remove;
 205
 206         dev_set_drvdata(&dev->dev, info);
 207
 208         mtd_list = kzalloc(sizeof(*mtd_list) * count, GFP_KERNEL);
 209         if (!mtd_list)
 210                 goto err_flash_remove;
 211
 212         for (i = 0; i < count; i++) {
 213                 err = -ENXIO;
 214                 if (of_address_to_resource(dp, i, &res)) {
 215                         /*
 216                          * Continue with next register tuple if this
 217                          * one is not mappable
 218                          */
 219                         continue;
 220                 }
 221
 222                 dev_dbg(&dev->dev, "of_flash device: %pR\n", &res);
 223
 224                 err = -EBUSY;
 225                 res_size = resource_size(&res);
 226                 info->list[i].res = request_mem_region(res.start, res_size,
 227                                                        dev_name(&dev->dev));
 228                 if (!info->list[i].res)
 229                         goto err_out;
 230
 231                 err = -ENXIO;
 232                 width = of_get_property(dp, "bank-width", NULL);
 233                 if (!width) {
 234                         dev_err(&dev->dev, "Can't get bank width from device"
 235                                 " tree\n");
 236                         goto err_out;
 237                 }
 238
 239                 info->list[i].map.name = mtd_name ?: dev_name(&dev->dev);
 240                 info->list[i].map.phys = res.start;
 241                 info->list[i].map.size = res_size;
 242                 info->list[i].map.bankwidth = be32_to_cpup(width);
 243                 info->list[i].map.device_node = dp;
 244
 245                 err = -ENOMEM;
 246                 info->list[i].map.virt = ioremap(info->list[i].map.phys,
 247                                                  info->list[i].map.size);
 248                 if (!info->list[i].map.virt) {
 249                         dev_err(&dev->dev, "Failed to ioremap() flash"
 250                                 " region\n");
 251                         goto err_out;
 252                 }
 253
 254                 simple_map_init(&info->list[i].map);
 255
 256                 /*
 257                  * On some platforms (e.g. MPC5200) a direct 1:1 mapping
 258                  * may cause problems with JFFS2 usage, as the local bus (LPB)
 259                  * doesn't support unaligned accesses as implemented in the
 260                  * JFFS2 code via memcpy(). By setting NO_XIP, the
 261                  * flash will not be exposed directly to the MTD users
 262                  * (e.g. JFFS2) any more.
 263                  */
 264                 if (map_indirect)
 265                         info->list[i].map.phys = NO_XIP;
 266
 267                 if (probe_type) {
 268                         info->list[i].mtd = do_map_probe(probe_type,
 269                                                          &info->list[i].map);
 270                 } else {
 271                         info->list[i].mtd = obsolete_probe(dev,
 272                                                            &info->list[i].map);
 273                 }
 274
 275                 /* Fall back to mapping region as ROM */
 276                 if (!info->list[i].mtd) {
 277                         dev_warn(&dev->dev,
 278                                 "do_map_probe() failed for type %s\n",
 279                                  probe_type);
 280
 281                         info->list[i].mtd = do_map_probe("map_rom",
 282                                                          &info->list[i].map);
 283                 }
 284                 mtd_list[i] = info->list[i].mtd;
 285
 286                 err = -ENXIO;
 287                 if (!info->list[i].mtd) {
 288                         dev_err(&dev->dev, "do_map_probe() failed\n");
 289                         goto err_out;
 290                 } else {
 291                         info->list_size++;
 292                 }
 293                 info->list[i].mtd->dev.parent = &dev->dev;
 294         }
 295
 296         err = 0;
 297         info->cmtd = NULL;
 298         if (info->list_size == 1) {
 299                 info->cmtd = info->list[0].mtd;
 300         } else if (info->list_size > 1) {
 301                 /*
 302                  * We detected multiple devices. Concatenate them together.
 303                  */
 304                 info->cmtd = mtd_concat_create(mtd_list, info->list_size,
 305                                                dev_name(&dev->dev));
 306         }
 307         if (info->cmtd == NULL)
 308                 err = -ENXIO;
 309
 310         if (err)
 311                 goto err_out;
 312
 313         ppdata.of_node = dp;
 314         part_probe_types = of_get_probes(dp);
 315         if (!part_probe_types) {
 316                 err = -ENOMEM;
 317                 goto err_out;
 318         }
 319         mtd_device_parse_register(info->cmtd, part_probe_types, &ppdata,
 320                         NULL, 0);
 321         of_free_probes(part_probe_types);
 322
 323         kfree(mtd_list);
 324
 325         return 0;
 326
 327 err_out:
 328         kfree(mtd_list);
 329 err_flash_remove:
 330         of_flash_remove(dev);
 331
 332         return err;
 333 }
 334
 335 static const struct of_device_id of_flash_match[] = {
 336         {
 337                 .compatible     = "cfi-flash",
 338                 .data           = (void *)"cfi_probe",
 339         },
 340         {
 341                 /* FIXME: JEDEC chips can't be safely and reliably
 342                  * probed, although the mtd code gets it right in
 343                  * practice most of the time.  We should use the
 344                  * vendor and device ids specified by the binding to
 345                  * bypass the heuristic probe code, but the mtd layer
 346                  * provides, at present, no interface for doing so
 347                  * :(. */
 348                 .compatible     = "jedec-flash",
 349                 .data           = (void *)"jedec_probe",
 350         },
 351         {
 352                 .compatible     = "mtd-ram",
 353                 .data           = (void *)"map_ram",
 354         },
 355         {
 356                 .compatible     = "mtd-rom",
 357                 .data           = (void *)"map_rom",
 358         },
 359         {
 360                 .type           = "rom",
 361                 .compatible     = "direct-mapped"
 362         },
 363         { },
 364 };
 365 MODULE_DEVICE_TABLE(of, of_flash_match);
 366
 367 static struct platform_driver of_flash_driver = {
 368         .driver = {
 369                 .name = "of-flash",
 370                 .of_match_table = of_flash_match,
 371         },
 372         .probe          = of_flash_probe,
 373         .remove         = of_flash_remove,
 374 };
 375
 376 module_platform_driver(of_flash_driver);
 377
 378 MODULE_LICENSE("GPL");
 379 MODULE_AUTHOR("Vitaly Wool <vwool@ru.mvista.com>");
 380 MODULE_DESCRIPTION("Device tree based MTD map driver");