drivers/mtd/maps/plat-ram.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* drivers/mtd/maps/plat-ram.c
   3  *
   4  * (c) 2004-2005 Simtec Electronics
   5  *      http://www.simtec.co.uk/products/SWLINUX/
   6  *      Ben Dooks <ben@simtec.co.uk>
   7  *
   8  * Generic platform device based RAM map
   9 */
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/ioport.h>
  16 #include <linux/device.h>
  17 #include <linux/slab.h>
  18 #include <linux/platform_device.h>
  19
  20 #include <linux/mtd/mtd.h>
  21 #include <linux/mtd/map.h>
  22 #include <linux/mtd/partitions.h>
  23 #include <linux/mtd/plat-ram.h>
  24
  25 #include <asm/io.h>
  26
  27 /* private structure for each mtd platform ram device created */
  28
  29 struct platram_info {
  30         struct device           *dev;
  31         struct mtd_info         *mtd;
  32         struct map_info          map;
  33         struct platdata_mtd_ram *pdata;
  34 };
  35
  36 /* to_platram_info()
  37  *
  38  * device private data to struct platram_info conversion
  39 */
  40
  41 static inline struct platram_info *to_platram_info(struct platform_device *dev)
  42 {
  43         return platform_get_drvdata(dev);
  44 }
  45
  46 /* platram_setrw
  47  *
  48  * call the platform device's set rw/ro control
  49  *
  50  * to = 0 => read-only
  51  *    = 1 => read-write
  52 */
  53
  54 static inline void platram_setrw(struct platram_info *info, int to)
  55 {
  56         if (info->pdata == NULL)
  57                 return;
  58
  59         if (info->pdata->set_rw != NULL)
  60                 (info->pdata->set_rw)(info->dev, to);
  61 }
  62
  63 /* platram_remove
  64  *
  65  * called to remove the device from the driver's control
  66 */
  67
  68 static void platram_remove(struct platform_device *pdev)
  69 {
  70         struct platram_info *info = to_platram_info(pdev);
  71
  72         dev_dbg(&pdev->dev, "removing device\n");
  73
  74         if (info == NULL)
  75                 return;
  76
  77         if (info->mtd) {
  78                 mtd_device_unregister(info->mtd);
  79                 map_destroy(info->mtd);
  80         }
  81
  82         /* ensure ram is left read-only */
  83
  84         platram_setrw(info, PLATRAM_RO);
  85
  86         kfree(info);
  87 }
  88
  89 /* platram_probe
  90  *
  91  * called from device drive system when a device matching our
  92  * driver is found.
  93 */
  94
  95 static int platram_probe(struct platform_device *pdev)
  96 {
  97         struct platdata_mtd_ram *pdata;
  98         struct platram_info *info;
  99         struct resource *res;
 100         int err = 0;
 101
 102         dev_dbg(&pdev->dev, "probe entered\n");
 103
 104         if (dev_get_platdata(&pdev->dev) == NULL) {
 105                 dev_err(&pdev->dev, "no platform data supplied\n");
 106                 err = -ENOENT;
 107                 goto exit_error;
 108         }
 109
 110         pdata = dev_get_platdata(&pdev->dev);
 111
 112         info = kzalloc(sizeof(*info), GFP_KERNEL);
 113         if (info == NULL) {
 114                 err = -ENOMEM;
 115                 goto exit_error;
 116         }
 117
 118         platform_set_drvdata(pdev, info);
 119
 120         info->dev = &pdev->dev;
 121         info->pdata = pdata;
 122
 123         /* get the resource for the memory mapping */
 124         info->map.virt = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 125         if (IS_ERR(info->map.virt)) {
 126                 err = PTR_ERR(info->map.virt);
 127                 goto exit_free;
 128         }
 129
 130         dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
 131                 (unsigned long long)res->start);
 132
 133         /* setup map parameters */
 134
 135         info->map.phys = res->start;
 136         info->map.size = resource_size(res);
 137         info->map.name = pdata->mapname != NULL ?
 138                         (char *)pdata->mapname : (char *)pdev->name;
 139         info->map.bankwidth = pdata->bankwidth;
 140
 141         dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
 142
 143         simple_map_init(&info->map);
 144
 145         dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");
 146
 147         /* probe for the right mtd map driver
 148          * supplied by the platform_data struct */
 149
 150         if (pdata->map_probes) {
 151                 const char * const *map_probes = pdata->map_probes;
 152
 153                 for ( ; !info->mtd && *map_probes; map_probes++)
 154                         info->mtd = do_map_probe(*map_probes , &info->map);
 155         }
 156         /* fallback to map_ram */
 157         else
 158                 info->mtd = do_map_probe("map_ram", &info->map);
 159
 160         if (info->mtd == NULL) {
 161                 dev_err(&pdev->dev, "failed to probe for map_ram\n");
 162                 err = -ENOMEM;
 163                 goto exit_free;
 164         }
 165
 166         info->mtd->dev.parent = &pdev->dev;
 167
 168         platram_setrw(info, PLATRAM_RW);
 169
 170         /* check to see if there are any available partitions, or whether
 171          * to add this device whole */
 172
 173         err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
 174                                         pdata->partitions,
 175                                         pdata->nr_partitions);
 176         if (err) {
 177                 dev_err(&pdev->dev, "failed to register mtd device\n");
 178                 goto exit_free;
 179         }
 180
 181         dev_info(&pdev->dev, "registered mtd device\n");
 182
 183         if (pdata->nr_partitions) {
 184                 /* add the whole device. */
 185                 err = mtd_device_register(info->mtd, NULL, 0);
 186                 if (err) {
 187                         dev_err(&pdev->dev,
 188                                 "failed to register the entire device\n");
 189                         goto exit_free;
 190                 }
 191         }
 192
 193         return 0;
 194
 195  exit_free:
 196         platram_remove(pdev);
 197  exit_error:
 198         return err;
 199 }
 200
 201 /* device driver info */
 202
 203 /* work with hotplug and coldplug */
 204 MODULE_ALIAS("platform:mtd-ram");
 205
 206 static struct platform_driver platram_driver = {
 207         .probe          = platram_probe,
 208         .remove         = platram_remove,
 209         .driver         = {
 210                 .name   = "mtd-ram",
 211         },
 212 };
 213
 214 module_platform_driver(platram_driver);
 215
 216 MODULE_LICENSE("GPL");
 217 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 218 MODULE_DESCRIPTION("MTD platform RAM map driver");