drivers/mtd/maps/plat-ram.c

   1 /* drivers/mtd/maps/plat-ram.c
   2  *
   3  * (c) 2004-2005 Simtec Electronics
   4  *      http://www.simtec.co.uk/products/SWLINUX/
   5  *      Ben Dooks <ben@simtec.co.uk>
   6  *
   7  * Generic platform device based RAM map
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22 */
  23
  24 #include <linux/module.h>
  25 #include <linux/types.h>
  26 #include <linux/init.h>
  27 #include <linux/kernel.h>
  28 #include <linux/string.h>
  29 #include <linux/ioport.h>
  30 #include <linux/device.h>
  31 #include <linux/slab.h>
  32 #include <linux/platform_device.h>
  33
  34 #include <linux/mtd/mtd.h>
  35 #include <linux/mtd/map.h>
  36 #include <linux/mtd/partitions.h>
  37 #include <linux/mtd/plat-ram.h>
  38
  39 #include <asm/io.h>
  40
  41 /* private structure for each mtd platform ram device created */
  42
  43 struct platram_info {
  44         struct device           *dev;
  45         struct mtd_info         *mtd;
  46         struct map_info          map;
  47         struct mtd_partition    *partitions;
  48         bool                    free_partitions;
  49         struct resource         *area;
  50         struct platdata_mtd_ram *pdata;
  51 };
  52
  53 /* to_platram_info()
  54  *
  55  * device private data to struct platram_info conversion
  56 */
  57
  58 static inline struct platram_info *to_platram_info(struct platform_device *dev)
  59 {
  60         return (struct platram_info *)platform_get_drvdata(dev);
  61 }
  62
  63 /* platram_setrw
  64  *
  65  * call the platform device's set rw/ro control
  66  *
  67  * to = 0 => read-only
  68  *    = 1 => read-write
  69 */
  70
  71 static inline void platram_setrw(struct platram_info *info, int to)
  72 {
  73         if (info->pdata == NULL)
  74                 return;
  75
  76         if (info->pdata->set_rw != NULL)
  77                 (info->pdata->set_rw)(info->dev, to);
  78 }
  79
  80 /* platram_remove
  81  *
  82  * called to remove the device from the driver's control
  83 */
  84
  85 static int platram_remove(struct platform_device *pdev)
  86 {
  87         struct platram_info *info = to_platram_info(pdev);
  88
  89         platform_set_drvdata(pdev, NULL);
  90
  91         dev_dbg(&pdev->dev, "removing device\n");
  92
  93         if (info == NULL)
  94                 return 0;
  95
  96         if (info->mtd) {
  97                 mtd_device_unregister(info->mtd);
  98                 if (info->partitions) {
  99                         if (info->free_partitions)
 100                                 kfree(info->partitions);
 101                 }
 102                 map_destroy(info->mtd);
 103         }
 104
 105         /* ensure ram is left read-only */
 106
 107         platram_setrw(info, PLATRAM_RO);
 108
 109         /* release resources */
 110
 111         if (info->area) {
 112                 release_resource(info->area);
 113                 kfree(info->area);
 114         }
 115
 116         if (info->map.virt != NULL)
 117                 iounmap(info->map.virt);
 118
 119         kfree(info);
 120
 121         return 0;
 122 }
 123
 124 /* platram_probe
 125  *
 126  * called from device drive system when a device matching our
 127  * driver is found.
 128 */
 129
 130 static int platram_probe(struct platform_device *pdev)
 131 {
 132         struct platdata_mtd_ram *pdata;
 133         struct platram_info *info;
 134         struct resource *res;
 135         int err = 0;
 136
 137         dev_dbg(&pdev->dev, "probe entered\n");
 138
 139         if (pdev->dev.platform_data == NULL) {
 140                 dev_err(&pdev->dev, "no platform data supplied\n");
 141                 err = -ENOENT;
 142                 goto exit_error;
 143         }
 144
 145         pdata = pdev->dev.platform_data;
 146
 147         info = kzalloc(sizeof(*info), GFP_KERNEL);
 148         if (info == NULL) {
 149                 dev_err(&pdev->dev, "no memory for flash info\n");
 150                 err = -ENOMEM;
 151                 goto exit_error;
 152         }
 153
 154         platform_set_drvdata(pdev, info);
 155
 156         info->dev = &pdev->dev;
 157         info->pdata = pdata;
 158
 159         /* get the resource for the memory mapping */
 160
 161         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 162
 163         if (res == NULL) {
 164                 dev_err(&pdev->dev, "no memory resource specified\n");
 165                 err = -ENOENT;
 166                 goto exit_free;
 167         }
 168
 169         dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
 170                 (unsigned long long)res->start);
 171
 172         /* setup map parameters */
 173
 174         info->map.phys = res->start;
 175         info->map.size = resource_size(res);
 176         info->map.name = pdata->mapname != NULL ?
 177                         (char *)pdata->mapname : (char *)pdev->name;
 178         info->map.bankwidth = pdata->bankwidth;
 179
 180         /* register our usage of the memory area */
 181
 182         info->area = request_mem_region(res->start, info->map.size, pdev->name);
 183         if (info->area == NULL) {
 184                 dev_err(&pdev->dev, "failed to request memory region\n");
 185                 err = -EIO;
 186                 goto exit_free;
 187         }
 188
 189         /* remap the memory area */
 190
 191         info->map.virt = ioremap(res->start, info->map.size);
 192         dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 193
 194         if (info->map.virt == NULL) {
 195                 dev_err(&pdev->dev, "failed to ioremap() region\n");
 196                 err = -EIO;
 197                 goto exit_free;
 198         }
 199
 200         simple_map_init(&info->map);
 201
 202         dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
 203
 204         /* probe for the right mtd map driver
 205          * supplied by the platform_data struct */
 206
 207         if (pdata->map_probes) {
 208                 const char **map_probes = pdata->map_probes;
 209
 210                 for ( ; !info->mtd && *map_probes; map_probes++)
 211                         info->mtd = do_map_probe(*map_probes , &info->map);
 212         }
 213         /* fallback to map_ram */
 214         else
 215                 info->mtd = do_map_probe("map_ram", &info->map);
 216
 217         if (info->mtd == NULL) {
 218                 dev_err(&pdev->dev, "failed to probe for map_ram\n");
 219                 err = -ENOMEM;
 220                 goto exit_free;
 221         }
 222
 223         info->mtd->owner = THIS_MODULE;
 224         info->mtd->dev.parent = &pdev->dev;
 225
 226         platram_setrw(info, PLATRAM_RW);
 227
 228         /* check to see if there are any available partitions, or wether
 229          * to add this device whole */
 230
 231         if (!pdata->nr_partitions) {
 232                 /* try to probe using the supplied probe type */
 233                 if (pdata->probes) {
 234                         err = parse_mtd_partitions(info->mtd, pdata->probes,
 235                                            &info->partitions, 0);
 236                         info->free_partitions = 1;
 237                         if (err > 0)
 238                                 err = mtd_device_register(info->mtd,
 239                                         info->partitions, err);
 240                 }
 241         }
 242         /* use the static mapping */
 243         else
 244                 err = mtd_device_register(info->mtd, pdata->partitions,
 245                                           pdata->nr_partitions);
 246         if (!err)
 247                 dev_info(&pdev->dev, "registered mtd device\n");
 248
 249         /* add the whole device. */
 250         err = mtd_device_register(info->mtd, NULL, 0);
 251         if (err)
 252                 dev_err(&pdev->dev, "failed to register the entire device\n");
 253
 254         return err;
 255
 256  exit_free:
 257         platram_remove(pdev);
 258  exit_error:
 259         return err;
 260 }
 261
 262 /* device driver info */
 263
 264 /* work with hotplug and coldplug */
 265 MODULE_ALIAS("platform:mtd-ram");
 266
 267 static struct platform_driver platram_driver = {
 268         .probe          = platram_probe,
 269         .remove         = platram_remove,
 270         .driver         = {
 271                 .name   = "mtd-ram",
 272                 .owner  = THIS_MODULE,
 273         },
 274 };
 275
 276 /* module init/exit */
 277
 278 static int __init platram_init(void)
 279 {
 280         printk("Generic platform RAM MTD, (c) 2004 Simtec Electronics\n");
 281         return platform_driver_register(&platram_driver);
 282 }
 283
 284 static void __exit platram_exit(void)
 285 {
 286         platform_driver_unregister(&platram_driver);
 287 }
 288
 289 module_init(platram_init);
 290 module_exit(platram_exit);
 291
 292 MODULE_LICENSE("GPL");
 293 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 294 MODULE_DESCRIPTION("MTD platform RAM map driver");