drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  drivers/s390/cio/ccwgroup.c
   3  *  bus driver for ccwgroup
   4  *
   5  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   6  *                       IBM Corporation
   7  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10 #include <linux/module.h>
  11 #include <linux/errno.h>
  12 #include <linux/slab.h>
  13 #include <linux/list.h>
  14 #include <linux/device.h>
  15 #include <linux/init.h>
  16 #include <linux/ctype.h>
  17 #include <linux/dcache.h>
  18
  19 #include <asm/semaphore.h>
  20 #include <asm/ccwdev.h>
  21 #include <asm/ccwgroup.h>
  22
  23 /* In Linux 2.4, we had a channel device layer called "chandev"
  24  * that did all sorts of obscure stuff for networking devices.
  25  * This is another driver that serves as a replacement for just
  26  * one of its functions, namely the translation of single subchannels
  27  * to devices that use multiple subchannels.
  28  */
  29
  30 /* a device matches a driver if all its slave devices match the same
  31  * entry of the driver */
  32 static int
  33 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
  34 {
  35         struct ccwgroup_device *gdev;
  36         struct ccwgroup_driver *gdrv;
  37
  38         gdev = container_of(dev, struct ccwgroup_device, dev);
  39         gdrv = container_of(drv, struct ccwgroup_driver, driver);
  40
  41         if (gdev->creator_id == gdrv->driver_id)
  42                 return 1;
  43
  44         return 0;
  45 }
  46 static int
  47 ccwgroup_uevent (struct device *dev, char **envp, int num_envp, char *buffer,
  48                   int buffer_size)
  49 {
  50         /* TODO */
  51         return 0;
  52 }
  53
  54 static struct bus_type ccwgroup_bus_type;
  55
  56 static void
  57 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  58 {
  59         int i;
  60         char str[8];
  61
  62         for (i = 0; i < gdev->count; i++) {
  63                 sprintf(str, "cdev%d", i);
  64                 sysfs_remove_link(&gdev->dev.kobj, str);
  65                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  66         }
  67
  68 }
  69
  70 /*
  71  * Provide an 'ungroup' attribute so the user can remove group devices no
  72  * longer needed or accidentially created. Saves memory :)
  73  */
  74 static ssize_t
  75 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  76 {
  77         struct ccwgroup_device *gdev;
  78
  79         gdev = to_ccwgroupdev(dev);
  80
  81         if (gdev->state != CCWGROUP_OFFLINE)
  82                 return -EINVAL;
  83
  84         __ccwgroup_remove_symlinks(gdev);
  85         device_unregister(dev);
  86
  87         return count;
  88 }
  89
  90 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
  91
  92 static void
  93 ccwgroup_release (struct device *dev)
  94 {
  95         struct ccwgroup_device *gdev;
  96         int i;
  97
  98         gdev = to_ccwgroupdev(dev);
  99
 100         for (i = 0; i < gdev->count; i++) {
 101                 gdev->cdev[i]->dev.driver_data = NULL;
 102                 put_device(&gdev->cdev[i]->dev);
 103         }
 104         kfree(gdev);
 105 }
 106
 107 static int
 108 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 109 {
 110         char str[8];
 111         int i, rc;
 112
 113         for (i = 0; i < gdev->count; i++) {
 114                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 115                                        "group_device");
 116                 if (rc) {
 117                         for (--i; i >= 0; i--)
 118                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 119                                                   "group_device");
 120                         return rc;
 121                 }
 122         }
 123         for (i = 0; i < gdev->count; i++) {
 124                 sprintf(str, "cdev%d", i);
 125                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 126                                        str);
 127                 if (rc) {
 128                         for (--i; i >= 0; i--) {
 129                                 sprintf(str, "cdev%d", i);
 130                                 sysfs_remove_link(&gdev->dev.kobj, str);
 131                         }
 132                         for (i = 0; i < gdev->count; i++)
 133                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 134                                                   "group_device");
 135                         return rc;
 136                 }
 137         }
 138         return 0;
 139 }
 140
 141 /*
 142  * try to add a new ccwgroup device for one driver
 143  * argc and argv[] are a list of bus_id's of devices
 144  * belonging to the driver.
 145  */
 146 int
 147 ccwgroup_create(struct device *root,
 148                 unsigned int creator_id,
 149                 struct ccw_driver *cdrv,
 150                 int argc, char *argv[])
 151 {
 152         struct ccwgroup_device *gdev;
 153         int i;
 154         int rc;
 155
 156         if (argc > 256) /* disallow dumb users */
 157                 return -EINVAL;
 158
 159         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 160         if (!gdev)
 161                 return -ENOMEM;
 162
 163         atomic_set(&gdev->onoff, 0);
 164
 165         for (i = 0; i < argc; i++) {
 166                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 167
 168                 /* all devices have to be of the same type in
 169                  * order to be grouped */
 170                 if (!gdev->cdev[i]
 171                     || gdev->cdev[i]->id.driver_info !=
 172                     gdev->cdev[0]->id.driver_info) {
 173                         rc = -EINVAL;
 174                         goto free_dev;
 175                 }
 176                 /* Don't allow a device to belong to more than one group. */
 177                 if (gdev->cdev[i]->dev.driver_data) {
 178                         rc = -EINVAL;
 179                         goto free_dev;
 180                 }
 181                 gdev->cdev[i]->dev.driver_data = gdev;
 182         }
 183
 184         gdev->creator_id = creator_id;
 185         gdev->count = argc;
 186         gdev->dev.bus = &ccwgroup_bus_type;
 187         gdev->dev.parent = root;
 188         gdev->dev.release = ccwgroup_release;
 189
 190         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 191                         gdev->cdev[0]->dev.bus_id);
 192
 193         rc = device_register(&gdev->dev);
 194
 195         if (rc)
 196                 goto free_dev;
 197         get_device(&gdev->dev);
 198         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 199
 200         if (rc) {
 201                 device_unregister(&gdev->dev);
 202                 goto error;
 203         }
 204
 205         rc = __ccwgroup_create_symlinks(gdev);
 206         if (!rc) {
 207                 put_device(&gdev->dev);
 208                 return 0;
 209         }
 210         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 211         device_unregister(&gdev->dev);
 212 error:
 213         for (i = 0; i < argc; i++)
 214                 if (gdev->cdev[i]) {
 215                         put_device(&gdev->cdev[i]->dev);
 216                         gdev->cdev[i]->dev.driver_data = NULL;
 217                 }
 218         put_device(&gdev->dev);
 219         return rc;
 220 free_dev:
 221         for (i = 0; i < argc; i++)
 222                 if (gdev->cdev[i]) {
 223                         if (gdev->cdev[i]->dev.driver_data == gdev)
 224                                 gdev->cdev[i]->dev.driver_data = NULL;
 225                         put_device(&gdev->cdev[i]->dev);
 226                 }
 227         kfree(gdev);
 228         return rc;
 229 }
 230
 231 static int __init
 232 init_ccwgroup (void)
 233 {
 234         return bus_register (&ccwgroup_bus_type);
 235 }
 236
 237 static void __exit
 238 cleanup_ccwgroup (void)
 239 {
 240         bus_unregister (&ccwgroup_bus_type);
 241 }
 242
 243 module_init(init_ccwgroup);
 244 module_exit(cleanup_ccwgroup);
 245
 246 /************************** driver stuff ******************************/
 247
 248 static int
 249 ccwgroup_set_online(struct ccwgroup_device *gdev)
 250 {
 251         struct ccwgroup_driver *gdrv;
 252         int ret;
 253
 254         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 255                 return -EAGAIN;
 256         if (gdev->state == CCWGROUP_ONLINE) {
 257                 ret = 0;
 258                 goto out;
 259         }
 260         if (!gdev->dev.driver) {
 261                 ret = -EINVAL;
 262                 goto out;
 263         }
 264         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 265         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 266                 goto out;
 267
 268         gdev->state = CCWGROUP_ONLINE;
 269  out:
 270         atomic_set(&gdev->onoff, 0);
 271         return ret;
 272 }
 273
 274 static int
 275 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 276 {
 277         struct ccwgroup_driver *gdrv;
 278         int ret;
 279
 280         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 281                 return -EAGAIN;
 282         if (gdev->state == CCWGROUP_OFFLINE) {
 283                 ret = 0;
 284                 goto out;
 285         }
 286         if (!gdev->dev.driver) {
 287                 ret = -EINVAL;
 288                 goto out;
 289         }
 290         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 291         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 292                 goto out;
 293
 294         gdev->state = CCWGROUP_OFFLINE;
 295  out:
 296         atomic_set(&gdev->onoff, 0);
 297         return ret;
 298 }
 299
 300 static ssize_t
 301 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 302 {
 303         struct ccwgroup_device *gdev;
 304         struct ccwgroup_driver *gdrv;
 305         unsigned int value;
 306         int ret;
 307
 308         gdev = to_ccwgroupdev(dev);
 309         if (!dev->driver)
 310                 return count;
 311
 312         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 313         if (!try_module_get(gdrv->owner))
 314                 return -EINVAL;
 315
 316         value = simple_strtoul(buf, NULL, 0);
 317         ret = count;
 318         if (value == 1)
 319                 ccwgroup_set_online(gdev);
 320         else if (value == 0)
 321                 ccwgroup_set_offline(gdev);
 322         else
 323                 ret = -EINVAL;
 324         module_put(gdrv->owner);
 325         return ret;
 326 }
 327
 328 static ssize_t
 329 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 330 {
 331         int online;
 332
 333         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 334
 335         return sprintf(buf, online ? "1\n" : "0\n");
 336 }
 337
 338 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 339
 340 static int
 341 ccwgroup_probe (struct device *dev)
 342 {
 343         struct ccwgroup_device *gdev;
 344         struct ccwgroup_driver *gdrv;
 345
 346         int ret;
 347
 348         gdev = to_ccwgroupdev(dev);
 349         gdrv = to_ccwgroupdrv(dev->driver);
 350
 351         if ((ret = device_create_file(dev, &dev_attr_online)))
 352                 return ret;
 353
 354         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 355         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 356         if (ret)
 357                 device_remove_file(dev, &dev_attr_online);
 358
 359         return ret;
 360 }
 361
 362 static int
 363 ccwgroup_remove (struct device *dev)
 364 {
 365         struct ccwgroup_device *gdev;
 366         struct ccwgroup_driver *gdrv;
 367
 368         gdev = to_ccwgroupdev(dev);
 369         gdrv = to_ccwgroupdrv(dev->driver);
 370
 371         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 372
 373         device_remove_file(dev, &dev_attr_online);
 374
 375         if (gdrv && gdrv->remove)
 376                 gdrv->remove(gdev);
 377         return 0;
 378 }
 379
 380 static struct bus_type ccwgroup_bus_type = {
 381         .name   = "ccwgroup",
 382         .match  = ccwgroup_bus_match,
 383         .uevent = ccwgroup_uevent,
 384         .probe  = ccwgroup_probe,
 385         .remove = ccwgroup_remove,
 386 };
 387
 388 int
 389 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 390 {
 391         /* register our new driver with the core */
 392         cdriver->driver.bus = &ccwgroup_bus_type;
 393         cdriver->driver.name = cdriver->name;
 394
 395         return driver_register(&cdriver->driver);
 396 }
 397
 398 static int
 399 __ccwgroup_match_all(struct device *dev, void *data)
 400 {
 401         return 1;
 402 }
 403
 404 void
 405 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 406 {
 407         struct device *dev;
 408
 409         /* We don't want ccwgroup devices to live longer than their driver. */
 410         get_driver(&cdriver->driver);
 411         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 412                                          __ccwgroup_match_all))) {
 413                 __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
 414                 device_unregister(dev);
 415                 put_device(dev);
 416         }
 417         put_driver(&cdriver->driver);
 418         driver_unregister(&cdriver->driver);
 419 }
 420
 421 int
 422 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 423 {
 424         return 0;
 425 }
 426
 427 static struct ccwgroup_device *
 428 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 429 {
 430         struct ccwgroup_device *gdev;
 431
 432         if (cdev->dev.driver_data) {
 433                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 434                 if (get_device(&gdev->dev)) {
 435                         if (device_is_registered(&gdev->dev))
 436                                 return gdev;
 437                         put_device(&gdev->dev);
 438                 }
 439                 return NULL;
 440         }
 441         return NULL;
 442 }
 443
 444 void
 445 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 446 {
 447         struct ccwgroup_device *gdev;
 448
 449         /* Ignore offlining errors, device is gone anyway. */
 450         ccw_device_set_offline(cdev);
 451         /* If one of its devices is gone, the whole group is done for. */
 452         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 453         if (gdev) {
 454                 __ccwgroup_remove_symlinks(gdev);
 455                 device_unregister(&gdev->dev);
 456                 put_device(&gdev->dev);
 457         }
 458 }
 459
 460 MODULE_LICENSE("GPL");
 461 EXPORT_SYMBOL(ccwgroup_driver_register);
 462 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 463 EXPORT_SYMBOL(ccwgroup_create);
 464 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 465 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);