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/kernel.h>
  27 #include <linux/string.h>
  28 #include <linux/ioport.h>
  29 #include <linux/device.h>
  30 #include <linux/slab.h>
  31 #include <linux/platform_device.h>
  32
  33 #include <linux/mtd/mtd.h>
  34 #include <linux/mtd/map.h>
  35 #include <linux/mtd/partitions.h>
  36 #include <linux/mtd/plat-ram.h>
  37
  38 #include <asm/io.h>
  39
  40 /* private structure for each mtd platform ram device created */
  41
  42 struct platram_info {
  43         struct device           *dev;
  44         struct mtd_info         *mtd;
  45         struct map_info          map;
  46         struct resource         *area;
  47         struct platdata_mtd_ram *pdata;
  48 };
  49
  50 /* to_platram_info()
  51  *
  52  * device private data to struct platram_info conversion
  53 */
  54
  55 static inline struct platram_info *to_platram_info(struct platform_device *dev)
  56 {
  57         return platform_get_drvdata(dev);
  58 }
  59
  60 /* platram_setrw
  61  *
  62  * call the platform device's set rw/ro control
  63  *
  64  * to = 0 => read-only
  65  *    = 1 => read-write
  66 */
  67
  68 static inline void platram_setrw(struct platram_info *info, int to)
  69 {
  70         if (info->pdata == NULL)
  71                 return;
  72
  73         if (info->pdata->set_rw != NULL)
  74                 (info->pdata->set_rw)(info->dev, to);
  75 }
  76
  77 /* platram_remove
  78  *
  79  * called to remove the device from the driver's control
  80 */
  81
  82 static int platram_remove(struct platform_device *pdev)
  83 {
  84         struct platram_info *info = to_platram_info(pdev);
  85
  86         dev_dbg(&pdev->dev, "removing device\n");
  87
  88         if (info == NULL)
  89                 return 0;
  90
  91         if (info->mtd) {
  92                 mtd_device_unregister(info->mtd);
  93                 map_destroy(info->mtd);
  94         }
  95
  96         /* ensure ram is left read-only */
  97
  98         platram_setrw(info, PLATRAM_RO);
  99
 100         /* release resources */
 101
 102         if (info->area) {
 103                 release_resource(info->area);
 104                 kfree(info->area);
 105         }
 106
 107         if (info->map.virt != NULL)
 108                 iounmap(info->map.virt);
 109
 110         kfree(info);
 111
 112         return 0;
 113 }
 114
 115 /* platram_probe
 116  *
 117  * called from device drive system when a device matching our
 118  * driver is found.
 119 */
 120
 121 static int platram_probe(struct platform_device *pdev)
 122 {
 123         struct platdata_mtd_ram *pdata;
 124         struct platram_info *info;
 125         struct resource *res;
 126         int err = 0;
 127
 128         dev_dbg(&pdev->dev, "probe entered\n");
 129
 130         if (dev_get_platdata(&pdev->dev) == NULL) {
 131                 dev_err(&pdev->dev, "no platform data supplied\n");
 132                 err = -ENOENT;
 133                 goto exit_error;
 134         }
 135
 136         pdata = dev_get_platdata(&pdev->dev);
 137
 138         info = kzalloc(sizeof(*info), GFP_KERNEL);
 139         if (info == NULL) {
 140                 err = -ENOMEM;
 141                 goto exit_error;
 142         }
 143
 144         platform_set_drvdata(pdev, info);
 145
 146         info->dev = &pdev->dev;
 147         info->pdata = pdata;
 148
 149         /* get the resource for the memory mapping */
 150
 151         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 152
 153         if (res == NULL) {
 154                 dev_err(&pdev->dev, "no memory resource specified\n");
 155                 err = -ENOENT;
 156                 goto exit_free;
 157         }
 158
 159         dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
 160                 (unsigned long long)res->start);
 161
 162         /* setup map parameters */
 163
 164         info->map.phys = res->start;
 165         info->map.size = resource_size(res);
 166         info->map.name = pdata->mapname != NULL ?
 167                         (char *)pdata->mapname : (char *)pdev->name;
 168         info->map.bankwidth = pdata->bankwidth;
 169
 170         /* register our usage of the memory area */
 171
 172         info->area = request_mem_region(res->start, info->map.size, pdev->name);
 173         if (info->area == NULL) {
 174                 dev_err(&pdev->dev, "failed to request memory region\n");
 175                 err = -EIO;
 176                 goto exit_free;
 177         }
 178
 179         /* remap the memory area */
 180
 181         info->map.virt = ioremap(res->start, info->map.size);
 182         dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 183
 184         if (info->map.virt == NULL) {
 185                 dev_err(&pdev->dev, "failed to ioremap() region\n");
 186                 err = -EIO;
 187                 goto exit_free;
 188         }
 189
 190         simple_map_init(&info->map);
 191
 192         dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
 193
 194         /* probe for the right mtd map driver
 195          * supplied by the platform_data struct */
 196
 197         if (pdata->map_probes) {
 198                 const char * const *map_probes = pdata->map_probes;
 199
 200                 for ( ; !info->mtd && *map_probes; map_probes++)
 201                         info->mtd = do_map_probe(*map_probes , &info->map);
 202         }
 203         /* fallback to map_ram */
 204         else
 205                 info->mtd = do_map_probe("map_ram", &info->map);
 206
 207         if (info->mtd == NULL) {
 208                 dev_err(&pdev->dev, "failed to probe for map_ram\n");
 209                 err = -ENOMEM;
 210                 goto exit_free;
 211         }
 212
 213         info->mtd->owner = THIS_MODULE;
 214         info->mtd->dev.parent = &pdev->dev;
 215
 216         platram_setrw(info, PLATRAM_RW);
 217
 218         /* check to see if there are any available partitions, or whether
 219          * to add this device whole */
 220
 221         err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
 222                                         pdata->partitions,
 223                                         pdata->nr_partitions);
 224         if (!err)
 225                 dev_info(&pdev->dev, "registered mtd device\n");
 226
 227         if (pdata->nr_partitions) {
 228                 /* add the whole device. */
 229                 err = mtd_device_register(info->mtd, NULL, 0);
 230                 if (err) {
 231                         dev_err(&pdev->dev,
 232                                 "failed to register the entire device\n");
 233                 }
 234         }
 235
 236         return err;
 237
 238  exit_free:
 239         platram_remove(pdev);
 240  exit_error:
 241         return err;
 242 }
 243
 244 /* device driver info */
 245
 246 /* work with hotplug and coldplug */
 247 MODULE_ALIAS("platform:mtd-ram");
 248
 249 static struct platform_driver platram_driver = {
 250         .probe          = platram_probe,
 251         .remove         = platram_remove,
 252         .driver         = {
 253                 .name   = "mtd-ram",
 254                 .owner  = THIS_MODULE,
 255         },
 256 };
 257
 258 module_platform_driver(platram_driver);
 259
 260 MODULE_LICENSE("GPL");
 261 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 262 MODULE_DESCRIPTION("MTD platform RAM map driver");