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 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         dev_dbg(&pdev->dev, "removing device\n");
  88
  89         if (info == NULL)
  90                 return 0;
  91
  92         if (info->mtd) {
  93                 mtd_device_unregister(info->mtd);
  94                 map_destroy(info->mtd);
  95         }
  96
  97         /* ensure ram is left read-only */
  98
  99         platram_setrw(info, PLATRAM_RO);
 100
 101         /* release resources */
 102
 103         if (info->area) {
 104                 release_resource(info->area);
 105                 kfree(info->area);
 106         }
 107
 108         if (info->map.virt != NULL)
 109                 iounmap(info->map.virt);
 110
 111         kfree(info);
 112
 113         return 0;
 114 }
 115
 116 /* platram_probe
 117  *
 118  * called from device drive system when a device matching our
 119  * driver is found.
 120 */
 121
 122 static int platram_probe(struct platform_device *pdev)
 123 {
 124         struct platdata_mtd_ram *pdata;
 125         struct platram_info *info;
 126         struct resource *res;
 127         int err = 0;
 128
 129         dev_dbg(&pdev->dev, "probe entered\n");
 130
 131         if (dev_get_platdata(&pdev->dev) == NULL) {
 132                 dev_err(&pdev->dev, "no platform data supplied\n");
 133                 err = -ENOENT;
 134                 goto exit_error;
 135         }
 136
 137         pdata = dev_get_platdata(&pdev->dev);
 138
 139         info = kzalloc(sizeof(*info), GFP_KERNEL);
 140         if (info == NULL) {
 141                 dev_err(&pdev->dev, "no memory for flash info\n");
 142                 err = -ENOMEM;
 143                 goto exit_error;
 144         }
 145
 146         platform_set_drvdata(pdev, info);
 147
 148         info->dev = &pdev->dev;
 149         info->pdata = pdata;
 150
 151         /* get the resource for the memory mapping */
 152
 153         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 154
 155         if (res == NULL) {
 156                 dev_err(&pdev->dev, "no memory resource specified\n");
 157                 err = -ENOENT;
 158                 goto exit_free;
 159         }
 160
 161         dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
 162                 (unsigned long long)res->start);
 163
 164         /* setup map parameters */
 165
 166         info->map.phys = res->start;
 167         info->map.size = resource_size(res);
 168         info->map.name = pdata->mapname != NULL ?
 169                         (char *)pdata->mapname : (char *)pdev->name;
 170         info->map.bankwidth = pdata->bankwidth;
 171
 172         /* register our usage of the memory area */
 173
 174         info->area = request_mem_region(res->start, info->map.size, pdev->name);
 175         if (info->area == NULL) {
 176                 dev_err(&pdev->dev, "failed to request memory region\n");
 177                 err = -EIO;
 178                 goto exit_free;
 179         }
 180
 181         /* remap the memory area */
 182
 183         info->map.virt = ioremap(res->start, info->map.size);
 184         dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 185
 186         if (info->map.virt == NULL) {
 187                 dev_err(&pdev->dev, "failed to ioremap() region\n");
 188                 err = -EIO;
 189                 goto exit_free;
 190         }
 191
 192         simple_map_init(&info->map);
 193
 194         dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
 195
 196         /* probe for the right mtd map driver
 197          * supplied by the platform_data struct */
 198
 199         if (pdata->map_probes) {
 200                 const char * const *map_probes = pdata->map_probes;
 201
 202                 for ( ; !info->mtd && *map_probes; map_probes++)
 203                         info->mtd = do_map_probe(*map_probes , &info->map);
 204         }
 205         /* fallback to map_ram */
 206         else
 207                 info->mtd = do_map_probe("map_ram", &info->map);
 208
 209         if (info->mtd == NULL) {
 210                 dev_err(&pdev->dev, "failed to probe for map_ram\n");
 211                 err = -ENOMEM;
 212                 goto exit_free;
 213         }
 214
 215         info->mtd->owner = THIS_MODULE;
 216         info->mtd->dev.parent = &pdev->dev;
 217
 218         platram_setrw(info, PLATRAM_RW);
 219
 220         /* check to see if there are any available partitions, or whether
 221          * to add this device whole */
 222
 223         err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
 224                                         pdata->partitions,
 225                                         pdata->nr_partitions);
 226         if (!err)
 227                 dev_info(&pdev->dev, "registered mtd device\n");
 228
 229         if (pdata->nr_partitions) {
 230                 /* add the whole device. */
 231                 err = mtd_device_register(info->mtd, NULL, 0);
 232                 if (err) {
 233                         dev_err(&pdev->dev,
 234                                 "failed to register the entire device\n");
 235                 }
 236         }
 237
 238         return err;
 239
 240  exit_free:
 241         platram_remove(pdev);
 242  exit_error:
 243         return err;
 244 }
 245
 246 /* device driver info */
 247
 248 /* work with hotplug and coldplug */
 249 MODULE_ALIAS("platform:mtd-ram");
 250
 251 static struct platform_driver platram_driver = {
 252         .probe          = platram_probe,
 253         .remove         = platram_remove,
 254         .driver         = {
 255                 .name   = "mtd-ram",
 256                 .owner  = THIS_MODULE,
 257         },
 258 };
 259
 260 module_platform_driver(platram_driver);
 261
 262 MODULE_LICENSE("GPL");
 263 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 264 MODULE_DESCRIPTION("MTD platform RAM map driver");