drivers/mtd/maps/pismo.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * PISMO memory driver - http://www.pismoworld.org/
   4  *
   5  * For ARM Realview and Versatile platforms
   6  */
   7 #include <linux/init.h>
   8 #include <linux/module.h>
   9 #include <linux/i2c.h>
  10 #include <linux/slab.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/mutex.h>
  14 #include <linux/mtd/physmap.h>
  15 #include <linux/mtd/plat-ram.h>
  16 #include <linux/mtd/pismo.h>
  17
  18 #define PISMO_NUM_CS    5
  19
  20 struct pismo_cs_block {
  21         u8      type;
  22         u8      width;
  23         __le16  access;
  24         __le32  size;
  25         u32     reserved[2];
  26         char    device[32];
  27 } __packed;
  28
  29 struct pismo_eeprom {
  30         struct pismo_cs_block cs[PISMO_NUM_CS];
  31         char    board[15];
  32         u8      sum;
  33 } __packed;
  34
  35 struct pismo_mem {
  36         phys_addr_t base;
  37         u32     size;
  38         u16     access;
  39         u8      width;
  40         u8      type;
  41 };
  42
  43 struct pismo_data {
  44         struct i2c_client       *client;
  45         void                    (*vpp)(void *, int);
  46         void                    *vpp_data;
  47         struct platform_device  *dev[PISMO_NUM_CS];
  48 };
  49
  50 static void pismo_set_vpp(struct platform_device *pdev, int on)
  51 {
  52         struct i2c_client *client = to_i2c_client(pdev->dev.parent);
  53         struct pismo_data *pismo = i2c_get_clientdata(client);
  54
  55         pismo->vpp(pismo->vpp_data, on);
  56 }
  57
  58 static unsigned int pismo_width_to_bytes(unsigned int width)
  59 {
  60         width &= 15;
  61         if (width > 2)
  62                 return 0;
  63         return 1 << width;
  64 }
  65
  66 static int pismo_eeprom_read(struct i2c_client *client, void *buf, u8 addr,
  67                              size_t size)
  68 {
  69         int ret;
  70         struct i2c_msg msg[] = {
  71                 {
  72                         .addr = client->addr,
  73                         .len = sizeof(addr),
  74                         .buf = &addr,
  75                 }, {
  76                         .addr = client->addr,
  77                         .flags = I2C_M_RD,
  78                         .len = size,
  79                         .buf = buf,
  80                 },
  81         };
  82
  83         ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
  84
  85         return ret == ARRAY_SIZE(msg) ? size : -EIO;
  86 }
  87
  88 static int pismo_add_device(struct pismo_data *pismo, int i,
  89                             struct pismo_mem *region, const char *name,
  90                             void *pdata, size_t psize)
  91 {
  92         struct platform_device *dev;
  93         struct resource res = { };
  94         phys_addr_t base = region->base;
  95         int ret;
  96
  97         if (base == ~0)
  98                 return -ENXIO;
  99
 100         res.start = base;
 101         res.end = base + region->size - 1;
 102         res.flags = IORESOURCE_MEM;
 103
 104         dev = platform_device_alloc(name, i);
 105         if (!dev)
 106                 return -ENOMEM;
 107         dev->dev.parent = &pismo->client->dev;
 108
 109         do {
 110                 ret = platform_device_add_resources(dev, &res, 1);
 111                 if (ret)
 112                         break;
 113
 114                 ret = platform_device_add_data(dev, pdata, psize);
 115                 if (ret)
 116                         break;
 117
 118                 ret = platform_device_add(dev);
 119                 if (ret)
 120                         break;
 121
 122                 pismo->dev[i] = dev;
 123                 return 0;
 124         } while (0);
 125
 126         platform_device_put(dev);
 127         return ret;
 128 }
 129
 130 static int pismo_add_nor(struct pismo_data *pismo, int i,
 131                          struct pismo_mem *region)
 132 {
 133         struct physmap_flash_data data = {
 134                 .width = region->width,
 135         };
 136
 137         if (pismo->vpp)
 138                 data.set_vpp = pismo_set_vpp;
 139
 140         return pismo_add_device(pismo, i, region, "physmap-flash",
 141                 &data, sizeof(data));
 142 }
 143
 144 static int pismo_add_sram(struct pismo_data *pismo, int i,
 145                           struct pismo_mem *region)
 146 {
 147         struct platdata_mtd_ram data = {
 148                 .bankwidth = region->width,
 149         };
 150
 151         return pismo_add_device(pismo, i, region, "mtd-ram",
 152                 &data, sizeof(data));
 153 }
 154
 155 static void pismo_add_one(struct pismo_data *pismo, int i,
 156                           const struct pismo_cs_block *cs, phys_addr_t base)
 157 {
 158         struct device *dev = &pismo->client->dev;
 159         struct pismo_mem region;
 160
 161         region.base = base;
 162         region.type = cs->type;
 163         region.width = pismo_width_to_bytes(cs->width);
 164         region.access = le16_to_cpu(cs->access);
 165         region.size = le32_to_cpu(cs->size);
 166
 167         if (region.width == 0) {
 168                 dev_err(dev, "cs%u: bad width: %02x, ignoring\n", i, cs->width);
 169                 return;
 170         }
 171
 172         /*
 173          * FIXME: may need to the platforms memory controller here, but at
 174          * the moment we assume that it has already been correctly setup.
 175          * The memory controller can also tell us the base address as well.
 176          */
 177
 178         dev_info(dev, "cs%u: %.32s: type %02x access %u00ps size %uK\n",
 179                 i, cs->device, region.type, region.access, region.size / 1024);
 180
 181         switch (region.type) {
 182         case 0:
 183                 break;
 184         case 1:
 185                 /* static DOC */
 186                 break;
 187         case 2:
 188                 /* static NOR */
 189                 pismo_add_nor(pismo, i, &region);
 190                 break;
 191         case 3:
 192                 /* static RAM */
 193                 pismo_add_sram(pismo, i, &region);
 194                 break;
 195         }
 196 }
 197
 198 static void pismo_remove(struct i2c_client *client)
 199 {
 200         struct pismo_data *pismo = i2c_get_clientdata(client);
 201         int i;
 202
 203         for (i = 0; i < ARRAY_SIZE(pismo->dev); i++)
 204                 platform_device_unregister(pismo->dev[i]);
 205
 206         kfree(pismo);
 207 }
 208
 209 static int pismo_probe(struct i2c_client *client)
 210 {
 211         struct pismo_pdata *pdata = client->dev.platform_data;
 212         struct pismo_eeprom eeprom;
 213         struct pismo_data *pismo;
 214         int ret, i;
 215
 216         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 217                 dev_err(&client->dev, "functionality mismatch\n");
 218                 return -EIO;
 219         }
 220
 221         pismo = kzalloc(sizeof(*pismo), GFP_KERNEL);
 222         if (!pismo)
 223                 return -ENOMEM;
 224
 225         pismo->client = client;
 226         if (pdata) {
 227                 pismo->vpp = pdata->set_vpp;
 228                 pismo->vpp_data = pdata->vpp_data;
 229         }
 230         i2c_set_clientdata(client, pismo);
 231
 232         ret = pismo_eeprom_read(client, &eeprom, 0, sizeof(eeprom));
 233         if (ret < 0) {
 234                 dev_err(&client->dev, "error reading EEPROM: %d\n", ret);
 235                 goto exit_free;
 236         }
 237
 238         dev_info(&client->dev, "%.15s board found\n", eeprom.board);
 239
 240         for (i = 0; i < ARRAY_SIZE(eeprom.cs); i++)
 241                 if (eeprom.cs[i].type != 0xff)
 242                         pismo_add_one(pismo, i, &eeprom.cs[i],
 243                                       pdata->cs_addrs[i]);
 244
 245         return 0;
 246
 247  exit_free:
 248         kfree(pismo);
 249         return ret;
 250 }
 251
 252 static const struct i2c_device_id pismo_id[] = {
 253         { "pismo" },
 254         { },
 255 };
 256 MODULE_DEVICE_TABLE(i2c, pismo_id);
 257
 258 static struct i2c_driver pismo_driver = {
 259         .driver = {
 260                 .name   = "pismo",
 261         },
 262         .probe          = pismo_probe,
 263         .remove         = pismo_remove,
 264         .id_table       = pismo_id,
 265 };
 266
 267 static int __init pismo_init(void)
 268 {
 269         BUILD_BUG_ON(sizeof(struct pismo_cs_block) != 48);
 270         BUILD_BUG_ON(sizeof(struct pismo_eeprom) != 256);
 271
 272         return i2c_add_driver(&pismo_driver);
 273 }
 274 module_init(pismo_init);
 275
 276 static void __exit pismo_exit(void)
 277 {
 278         i2c_del_driver(&pismo_driver);
 279 }
 280 module_exit(pismo_exit);
 281
 282 MODULE_AUTHOR("Russell King <linux@arm.linux.org.uk>");
 283 MODULE_DESCRIPTION("PISMO memory driver");
 284 MODULE_LICENSE("GPL");