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 resource         *area;
  48         struct platdata_mtd_ram *pdata;
  49 };
  50
  51 /* to_platram_info()
  52  *
  53  * device private data to struct platram_info conversion
  54 */
  55
  56 static inline struct platram_info *to_platram_info(struct platform_device *dev)
  57 {
  58         return (struct platram_info *)platform_get_drvdata(dev);
  59 }
  60
  61 /* platram_setrw
  62  *
  63  * call the platform device's set rw/ro control
  64  *
  65  * to = 0 => read-only
  66  *    = 1 => read-write
  67 */
  68
  69 static inline void platram_setrw(struct platram_info *info, int to)
  70 {
  71         if (info->pdata == NULL)
  72                 return;
  73
  74         if (info->pdata->set_rw != NULL)
  75                 (info->pdata->set_rw)(info->dev, to);
  76 }
  77
  78 /* platram_remove
  79  *
  80  * called to remove the device from the driver's control
  81 */
  82
  83 static int platram_remove(struct platform_device *pdev)
  84 {
  85         struct platram_info *info = to_platram_info(pdev);
  86
  87         platform_set_drvdata(pdev, NULL);
  88
  89         dev_dbg(&pdev->dev, "removing device\n");
  90
  91         if (info == NULL)
  92                 return 0;
  93
  94         if (info->mtd) {
  95                 mtd_device_unregister(info->mtd);
  96                 map_destroy(info->mtd);
  97         }
  98
  99         /* ensure ram is left read-only */
 100
 101         platram_setrw(info, PLATRAM_RO);
 102
 103         /* release resources */
 104
 105         if (info->area) {
 106                 release_resource(info->area);
 107                 kfree(info->area);
 108         }
 109
 110         if (info->map.virt != NULL)
 111                 iounmap(info->map.virt);
 112
 113         kfree(info);
 114
 115         return 0;
 116 }
 117
 118 /* platram_probe
 119  *
 120  * called from device drive system when a device matching our
 121  * driver is found.
 122 */
 123
 124 static int platram_probe(struct platform_device *pdev)
 125 {
 126         struct platdata_mtd_ram *pdata;
 127         struct platram_info *info;
 128         struct resource *res;
 129         int err = 0;
 130
 131         dev_dbg(&pdev->dev, "probe entered\n");
 132
 133         if (pdev->dev.platform_data == NULL) {
 134                 dev_err(&pdev->dev, "no platform data supplied\n");
 135                 err = -ENOENT;
 136                 goto exit_error;
 137         }
 138
 139         pdata = pdev->dev.platform_data;
 140
 141         info = kzalloc(sizeof(*info), GFP_KERNEL);
 142         if (info == NULL) {
 143                 dev_err(&pdev->dev, "no memory for flash info\n");
 144                 err = -ENOMEM;
 145                 goto exit_error;
 146         }
 147
 148         platform_set_drvdata(pdev, info);
 149
 150         info->dev = &pdev->dev;
 151         info->pdata = pdata;
 152
 153         /* get the resource for the memory mapping */
 154
 155         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 156
 157         if (res == NULL) {
 158                 dev_err(&pdev->dev, "no memory resource specified\n");
 159                 err = -ENOENT;
 160                 goto exit_free;
 161         }
 162
 163         dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
 164                 (unsigned long long)res->start);
 165
 166         /* setup map parameters */
 167
 168         info->map.phys = res->start;
 169         info->map.size = resource_size(res);
 170         info->map.name = pdata->mapname != NULL ?
 171                         (char *)pdata->mapname : (char *)pdev->name;
 172         info->map.bankwidth = pdata->bankwidth;
 173
 174         /* register our usage of the memory area */
 175
 176         info->area = request_mem_region(res->start, info->map.size, pdev->name);
 177         if (info->area == NULL) {
 178                 dev_err(&pdev->dev, "failed to request memory region\n");
 179                 err = -EIO;
 180                 goto exit_free;
 181         }
 182
 183         /* remap the memory area */
 184
 185         info->map.virt = ioremap(res->start, info->map.size);
 186         dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 187
 188         if (info->map.virt == NULL) {
 189                 dev_err(&pdev->dev, "failed to ioremap() region\n");
 190                 err = -EIO;
 191                 goto exit_free;
 192         }
 193
 194         simple_map_init(&info->map);
 195
 196         dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
 197
 198         /* probe for the right mtd map driver
 199          * supplied by the platform_data struct */
 200
 201         if (pdata->map_probes) {
 202                 const char **map_probes = pdata->map_probes;
 203
 204                 for ( ; !info->mtd && *map_probes; map_probes++)
 205                         info->mtd = do_map_probe(*map_probes , &info->map);
 206         }
 207         /* fallback to map_ram */
 208         else
 209                 info->mtd = do_map_probe("map_ram", &info->map);
 210
 211         if (info->mtd == NULL) {
 212                 dev_err(&pdev->dev, "failed to probe for map_ram\n");
 213                 err = -ENOMEM;
 214                 goto exit_free;
 215         }
 216
 217         info->mtd->owner = THIS_MODULE;
 218         info->mtd->dev.parent = &pdev->dev;
 219
 220         platram_setrw(info, PLATRAM_RW);
 221
 222         /* check to see if there are any available partitions, or wether
 223          * to add this device whole */
 224
 225         err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
 226                                         pdata->partitions,
 227                                         pdata->nr_partitions);
 228         if (!err)
 229                 dev_info(&pdev->dev, "registered mtd device\n");
 230
 231         if (pdata->nr_partitions) {
 232                 /* add the whole device. */
 233                 err = mtd_device_register(info->mtd, NULL, 0);
 234                 if (err) {
 235                         dev_err(&pdev->dev,
 236                                 "failed to register the entire device\n");
 237                 }
 238         }
 239
 240         return err;
 241
 242  exit_free:
 243         platram_remove(pdev);
 244  exit_error:
 245         return err;
 246 }
 247
 248 /* device driver info */
 249
 250 /* work with hotplug and coldplug */
 251 MODULE_ALIAS("platform:mtd-ram");
 252
 253 static struct platform_driver platram_driver = {
 254         .probe          = platram_probe,
 255         .remove         = platram_remove,
 256         .driver         = {
 257                 .name   = "mtd-ram",
 258                 .owner  = THIS_MODULE,
 259         },
 260 };
 261
 262 /* module init/exit */
 263
 264 static int __init platram_init(void)
 265 {
 266         printk("Generic platform RAM MTD, (c) 2004 Simtec Electronics\n");
 267         return platform_driver_register(&platram_driver);
 268 }
 269
 270 static void __exit platram_exit(void)
 271 {
 272         platform_driver_unregister(&platram_driver);
 273 }
 274
 275 module_init(platram_init);
 276 module_exit(platram_exit);
 277
 278 MODULE_LICENSE("GPL");
 279 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 280 MODULE_DESCRIPTION("MTD platform RAM map driver");