release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/mtd/devices/slram.c

   1
   2
   3
   4 #include <linux/module.h>
   5 #include <asm/uaccess.h>
   6 #include <linux/types.h>
   7 #include <linux/kernel.h>
   8 #include <linux/ptrace.h>
   9 #include <linux/slab.h>
  10 #include <linux/string.h>
  11 #include <linux/timer.h>
  12 #include <linux/major.h>
  13 #include <linux/fs.h>
  14 #include <linux/ioctl.h>
  15 #include <linux/init.h>
  16 #include <asm/io.h>
  17 #include <asm/system.h>
  18
  19 #include <linux/mtd/mtd.h>
  20
  21 #define SLRAM_MAX_DEVICES_PARAMS 6              /* 3 parameters / device */
  22 #define SLRAM_BLK_SZ 0x4000
  23
  24 #define T(fmt, args...) printk(KERN_DEBUG fmt, ## args)
  25 #define E(fmt, args...) printk(KERN_NOTICE fmt, ## args)
  26
  27 typedef struct slram_priv {
  28         u_char *start;
  29         u_char *end;
  30 } slram_priv_t;
  31
  32 typedef struct slram_mtd_list {
  33         struct mtd_info *mtdinfo;
  34         struct slram_mtd_list *next;
  35 } slram_mtd_list_t;
  36
  37 #ifdef MODULE
  38 static char *map[SLRAM_MAX_DEVICES_PARAMS];
  39
  40 module_param_array(map, charp, NULL, 0);
  41 MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\"");
  42 #else
  43 static char *map;
  44 #endif
  45
  46 static slram_mtd_list_t *slram_mtdlist = NULL;
  47
  48 static int slram_erase(struct mtd_info *, struct erase_info *);
  49 static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, void **,
  50                 resource_size_t *);
  51 static void slram_unpoint(struct mtd_info *, loff_t, size_t);
  52 static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *);
  53 static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *);
  54
  55 static int slram_erase(struct mtd_info *mtd, struct erase_info *instr)
  56 {
  57         slram_priv_t *priv = mtd->priv;
  58
  59         if (instr->addr + instr->len > mtd->size) {
  60                 return(-EINVAL);
  61         }
  62
  63         memset(priv->start + instr->addr, 0xff, instr->len);
  64
  65         /* This'll catch a few races. Free the thing before returning :)
  66          * I don't feel at all ashamed. This kind of thing is possible anyway
  67          * with flash, but unlikely.
  68          */
  69
  70         instr->state = MTD_ERASE_DONE;
  71
  72         mtd_erase_callback(instr);
  73
  74         return(0);
  75 }
  76
  77 static int slram_point(struct mtd_info *mtd, loff_t from, size_t len,
  78                 size_t *retlen, void **virt, resource_size_t *phys)
  79 {
  80         slram_priv_t *priv = mtd->priv;
  81
  82         /* can we return a physical address with this driver? */
  83         if (phys)
  84                 return -EINVAL;
  85
  86         if (from + len > mtd->size)
  87                 return -EINVAL;
  88
  89         *virt = priv->start + from;
  90         *retlen = len;
  91         return(0);
  92 }
  93
  94 static void slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
  95 {
  96 }
  97
  98 static int slram_read(struct mtd_info *mtd, loff_t from, size_t len,
  99                 size_t *retlen, u_char *buf)
 100 {
 101         slram_priv_t *priv = mtd->priv;
 102
 103         if (from > mtd->size)
 104                 return -EINVAL;
 105
 106         if (from + len > mtd->size)
 107                 len = mtd->size - from;
 108
 109         memcpy(buf, priv->start + from, len);
 110
 111         *retlen = len;
 112         return(0);
 113 }
 114
 115 static int slram_write(struct mtd_info *mtd, loff_t to, size_t len,
 116                 size_t *retlen, const u_char *buf)
 117 {
 118         slram_priv_t *priv = mtd->priv;
 119
 120         if (to + len > mtd->size)
 121                 return -EINVAL;
 122
 123         memcpy(priv->start + to, buf, len);
 124
 125         *retlen = len;
 126         return(0);
 127 }
 128
 129 /*====================================================================*/
 130
 131 static int register_device(char *name, unsigned long start, unsigned long length)
 132 {
 133         slram_mtd_list_t **curmtd;
 134
 135         curmtd = &slram_mtdlist;
 136         while (*curmtd) {
 137                 curmtd = &(*curmtd)->next;
 138         }
 139
 140         *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL);
 141         if (!(*curmtd)) {
 142                 E("slram: Cannot allocate new MTD device.\n");
 143                 return(-ENOMEM);
 144         }
 145         (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
 146         (*curmtd)->next = NULL;
 147
 148         if ((*curmtd)->mtdinfo) {
 149                 (*curmtd)->mtdinfo->priv =
 150                         kzalloc(sizeof(slram_priv_t), GFP_KERNEL);
 151
 152                 if (!(*curmtd)->mtdinfo->priv) {
 153                         kfree((*curmtd)->mtdinfo);
 154                         (*curmtd)->mtdinfo = NULL;
 155                 }
 156         }
 157
 158         if (!(*curmtd)->mtdinfo) {
 159                 E("slram: Cannot allocate new MTD device.\n");
 160                 return(-ENOMEM);
 161         }
 162
 163         if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start =
 164                                 ioremap(start, length))) {
 165                 E("slram: ioremap failed\n");
 166                 return -EIO;
 167         }
 168         ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end =
 169                 ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length;
 170
 171
 172         (*curmtd)->mtdinfo->name = name;
 173         (*curmtd)->mtdinfo->size = length;
 174         (*curmtd)->mtdinfo->flags = MTD_CAP_RAM;
 175         (*curmtd)->mtdinfo->erase = slram_erase;
 176         (*curmtd)->mtdinfo->point = slram_point;
 177         (*curmtd)->mtdinfo->unpoint = slram_unpoint;
 178         (*curmtd)->mtdinfo->read = slram_read;
 179         (*curmtd)->mtdinfo->write = slram_write;
 180         (*curmtd)->mtdinfo->owner = THIS_MODULE;
 181         (*curmtd)->mtdinfo->type = MTD_RAM;
 182         (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ;
 183         (*curmtd)->mtdinfo->writesize = 1;
 184
 185         if (add_mtd_device((*curmtd)->mtdinfo)) {
 186                 E("slram: Failed to register new device\n");
 187                 iounmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start);
 188                 kfree((*curmtd)->mtdinfo->priv);
 189                 kfree((*curmtd)->mtdinfo);
 190                 return(-EAGAIN);
 191         }
 192         T("slram: Registered device %s from %luKiB to %luKiB\n", name,
 193                         (start / 1024), ((start + length) / 1024));
 194         T("slram: Mapped from 0x%p to 0x%p\n",
 195                         ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start,
 196                         ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end);
 197         return(0);
 198 }
 199
 200 static void unregister_devices(void)
 201 {
 202         slram_mtd_list_t *nextitem;
 203
 204         while (slram_mtdlist) {
 205                 nextitem = slram_mtdlist->next;
 206                 del_mtd_device(slram_mtdlist->mtdinfo);
 207                 iounmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start);
 208                 kfree(slram_mtdlist->mtdinfo->priv);
 209                 kfree(slram_mtdlist->mtdinfo);
 210                 kfree(slram_mtdlist);
 211                 slram_mtdlist = nextitem;
 212         }
 213 }
 214
 215 static unsigned long handle_unit(unsigned long value, char *unit)
 216 {
 217         if ((*unit == 'M') || (*unit == 'm')) {
 218                 return(value * 1024 * 1024);
 219         } else if ((*unit == 'K') || (*unit == 'k')) {
 220                 return(value * 1024);
 221         }
 222         return(value);
 223 }
 224
 225 static int parse_cmdline(char *devname, char *szstart, char *szlength)
 226 {
 227         char *buffer;
 228         unsigned long devstart;
 229         unsigned long devlength;
 230
 231         if ((!devname) || (!szstart) || (!szlength)) {
 232                 unregister_devices();
 233                 return(-EINVAL);
 234         }
 235
 236         devstart = simple_strtoul(szstart, &buffer, 0);
 237         devstart = handle_unit(devstart, buffer);
 238
 239         if (*(szlength) != '+') {
 240                 devlength = simple_strtoul(szlength, &buffer, 0);
 241                 devlength = handle_unit(devlength, buffer) - devstart;
 242                 if (devlength < devstart)
 243                         goto err_out;
 244
 245                 devlength -= devstart;
 246         } else {
 247                 devlength = simple_strtoul(szlength + 1, &buffer, 0);
 248                 devlength = handle_unit(devlength, buffer);
 249         }
 250         T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n",
 251                         devname, devstart, devlength);
 252         if (devlength % SLRAM_BLK_SZ != 0)
 253                 goto err_out;
 254
 255         if ((devstart = register_device(devname, devstart, devlength))){
 256                 unregister_devices();
 257                 return((int)devstart);
 258         }
 259         return(0);
 260
 261 err_out:
 262         E("slram: Illegal length parameter.\n");
 263         return(-EINVAL);
 264 }
 265
 266 #ifndef MODULE
 267
 268 static int __init mtd_slram_setup(char *str)
 269 {
 270         map = str;
 271         return(1);
 272 }
 273
 274 __setup("slram=", mtd_slram_setup);
 275
 276 #endif
 277
 278 static int __init init_slram(void)
 279 {
 280         char *devname;
 281         int i;
 282
 283 #ifndef MODULE
 284         char *devstart;
 285         char *devlength;
 286
 287         i = 0;
 288
 289         if (!map) {
 290                 E("slram: not enough parameters.\n");
 291                 return(-EINVAL);
 292         }
 293         while (map) {
 294                 devname = devstart = devlength = NULL;
 295
 296                 if (!(devname = strsep(&map, ","))) {
 297                         E("slram: No devicename specified.\n");
 298                         break;
 299                 }
 300                 T("slram: devname = %s\n", devname);
 301                 if ((!map) || (!(devstart = strsep(&map, ",")))) {
 302                         E("slram: No devicestart specified.\n");
 303                 }
 304                 T("slram: devstart = %s\n", devstart);
 305                 if ((!map) || (!(devlength = strsep(&map, ",")))) {
 306                         E("slram: No devicelength / -end specified.\n");
 307                 }
 308                 T("slram: devlength = %s\n", devlength);
 309                 if (parse_cmdline(devname, devstart, devlength) != 0) {
 310                         return(-EINVAL);
 311                 }
 312         }
 313 #else
 314         int count;
 315
 316         for (count = 0; count < SLRAM_MAX_DEVICES_PARAMS && map[count];
 317                         count++) {
 318         }
 319
 320         if ((count % 3 != 0) || (count == 0)) {
 321                 E("slram: not enough parameters.\n");
 322                 return(-EINVAL);
 323         }
 324         for (i = 0; i < (count / 3); i++) {
 325                 devname = map[i * 3];
 326
 327                 if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) {
 328                         return(-EINVAL);
 329                 }
 330
 331         }
 332 #endif /* !MODULE */
 333
 334         return(0);
 335 }
 336
 337 static void __exit cleanup_slram(void)
 338 {
 339         unregister_devices();
 340 }
 341
 342 module_init(init_slram);
 343 module_exit(cleanup_slram);
 344
 345 MODULE_LICENSE("GPL");
 346 MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>");
 347 MODULE_DESCRIPTION("MTD driver for uncached system RAM");