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