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 #else /* MTD_PARTITIONS */
  84 #define OF_FLASH_PARTS(info)            (0)
  85 #define parse_partitions(info, dev)     (0)
  86 #endif /* MTD_PARTITIONS */
  87
  88 static int of_flash_remove(struct of_device *dev)
  89 {
  90         struct of_flash *info;
  91
  92         info = dev_get_drvdata(&dev->dev);
  93         if (!info)
  94                 return 0;
  95         dev_set_drvdata(&dev->dev, NULL);
  96
  97         if (info->mtd) {
  98                 if (OF_FLASH_PARTS(info)) {
  99                         del_mtd_partitions(info->mtd);
 100                         kfree(OF_FLASH_PARTS(info));
 101                 } else {
 102                         del_mtd_device(info->mtd);
 103                 }
 104                 map_destroy(info->mtd);
 105         }
 106
 107         if (info->map.virt)
 108                 iounmap(info->map.virt);
 109
 110         if (info->res) {
 111                 release_resource(info->res);
 112                 kfree(info->res);
 113         }
 114
 115         return 0;
 116 }
 117
 118 /* Helper function to handle probing of the obsolete "direct-mapped"
 119  * compatible binding, which has an extra "probe-type" property
 120  * describing the type of flash probe necessary. */
 121 static struct mtd_info * __devinit obsolete_probe(struct of_device *dev,
 122                                                   struct map_info *map)
 123 {
 124         struct device_node *dp = dev->node;
 125         const char *of_probe;
 126         struct mtd_info *mtd;
 127         static const char *rom_probe_types[]
 128                 = { "cfi_probe", "jedec_probe", "map_rom"};
 129         int i;
 130
 131         dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "
 132                  "flash binding\n");
 133
 134         of_probe = of_get_property(dp, "probe-type", NULL);
 135         if (!of_probe) {
 136                 for (i = 0; i < ARRAY_SIZE(rom_probe_types); i++) {
 137                         mtd = do_map_probe(rom_probe_types[i], map);
 138                         if (mtd)
 139                                 return mtd;
 140                 }
 141                 return NULL;
 142         } else if (strcmp(of_probe, "CFI") == 0) {
 143                 return do_map_probe("cfi_probe", map);
 144         } else if (strcmp(of_probe, "JEDEC") == 0) {
 145                 return do_map_probe("jedec_probe", map);
 146         } else {
 147                 if (strcmp(of_probe, "ROM") != 0)
 148                         dev_warn(&dev->dev, "obsolete_probe: don't know probe "
 149                                  "type '%s', mapping as rom\n", of_probe);
 150                 return do_map_probe("mtd_rom", map);
 151         }
 152 }
 153
 154 static int __devinit of_flash_probe(struct of_device *dev,
 155                                     const struct of_device_id *match)
 156 {
 157 #ifdef CONFIG_MTD_PARTITIONS
 158         static const char *part_probe_types[]
 159                 = { "cmdlinepart", "RedBoot", NULL };
 160 #endif
 161         struct device_node *dp = dev->node;
 162         struct resource res;
 163         struct of_flash *info;
 164         const char *probe_type = match->data;
 165         const u32 *width;
 166         int err;
 167
 168         err = -ENXIO;
 169         if (of_address_to_resource(dp, 0, &res)) {
 170                 dev_err(&dev->dev, "Can't get IO address from device tree\n");
 171                 goto err_out;
 172         }
 173
 174         dev_dbg(&dev->dev, "of_flash device: %.8llx-%.8llx\n",
 175                 (unsigned long long)res.start, (unsigned long long)res.end);
 176
 177         err = -ENOMEM;
 178         info = kzalloc(sizeof(*info), GFP_KERNEL);
 179         if (!info)
 180                 goto err_out;
 181
 182         dev_set_drvdata(&dev->dev, info);
 183
 184         err = -EBUSY;
 185         info->res = request_mem_region(res.start, res.end - res.start + 1,
 186                                        dev->dev.bus_id);
 187         if (!info->res)
 188                 goto err_out;
 189
 190         err = -ENXIO;
 191         width = of_get_property(dp, "bank-width", NULL);
 192         if (!width) {
 193                 dev_err(&dev->dev, "Can't get bank width from device tree\n");
 194                 goto err_out;
 195         }
 196
 197         info->map.name = dev->dev.bus_id;
 198         info->map.phys = res.start;
 199         info->map.size = res.end - res.start + 1;
 200         info->map.bankwidth = *width;
 201
 202         err = -ENOMEM;
 203         info->map.virt = ioremap(info->map.phys, info->map.size);
 204         if (!info->map.virt) {
 205                 dev_err(&dev->dev, "Failed to ioremap() flash region\n");
 206                 goto err_out;
 207         }
 208
 209         simple_map_init(&info->map);
 210
 211         if (probe_type)
 212                 info->mtd = do_map_probe(probe_type, &info->map);
 213         else
 214                 info->mtd = obsolete_probe(dev, &info->map);
 215
 216         err = -ENXIO;
 217         if (!info->mtd) {
 218                 dev_err(&dev->dev, "do_map_probe() failed\n");
 219                 goto err_out;
 220         }
 221         info->mtd->owner = THIS_MODULE;
 222
 223 #ifdef CONFIG_MTD_PARTITIONS
 224         /* First look for RedBoot table or partitions on the command
 225          * line, these take precedence over device tree information */
 226         err = parse_mtd_partitions(info->mtd, part_probe_types,
 227                                    &info->parts, 0);
 228         if (err < 0)
 229                 return err;
 230
 231 #ifdef CONFIG_MTD_OF_PARTS
 232         if (err == 0) {
 233                 err = of_mtd_parse_partitions(&dev->dev, info->mtd,
 234                                               dp, &info->parts);
 235                 if (err < 0)
 236                         return err;
 237         }
 238 #endif
 239
 240         if (err == 0) {
 241                 err = parse_obsolete_partitions(dev, info, dp);
 242                 if (err < 0)
 243                         return err;
 244         }
 245
 246         if (err > 0)
 247                 add_mtd_partitions(info->mtd, info->parts, err);
 248         else
 249 #endif
 250                 add_mtd_device(info->mtd);
 251
 252         return 0;
 253
 254 err_out:
 255         of_flash_remove(dev);
 256         return err;
 257 }
 258
 259 static struct of_device_id of_flash_match[] = {
 260         {
 261                 .compatible     = "cfi-flash",
 262                 .data           = (void *)"cfi_probe",
 263         },
 264         {
 265                 /* FIXME: JEDEC chips can't be safely and reliably
 266                  * probed, although the mtd code gets it right in
 267                  * practice most of the time.  We should use the
 268                  * vendor and device ids specified by the binding to
 269                  * bypass the heuristic probe code, but the mtd layer
 270                  * provides, at present, no interface for doing so
 271                  * :(. */
 272                 .compatible     = "jedec-flash",
 273                 .data           = (void *)"jedec_probe",
 274         },
 275         {
 276                 .type           = "rom",
 277                 .compatible     = "direct-mapped"
 278         },
 279         { },
 280 };
 281 MODULE_DEVICE_TABLE(of, of_flash_match);
 282
 283 static struct of_platform_driver of_flash_driver = {
 284         .name           = "of-flash",
 285         .match_table    = of_flash_match,
 286         .probe          = of_flash_probe,
 287         .remove         = of_flash_remove,
 288 };
 289
 290 static int __init of_flash_init(void)
 291 {
 292         return of_register_platform_driver(&of_flash_driver);
 293 }
 294
 295 static void __exit of_flash_exit(void)
 296 {
 297         of_unregister_platform_driver(&of_flash_driver);
 298 }
 299
 300 module_init(of_flash_init);
 301 module_exit(of_flash_exit);
 302
 303 MODULE_LICENSE("GPL");
 304 MODULE_AUTHOR("Vitaly Wool <vwool@ru.mvista.com>");
 305 MODULE_DESCRIPTION("Device tree based MTD map driver");