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