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 void ccwgroup_ungroup_callback(struct device *dev)
  75 {
  76         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
  77
  78         mutex_lock(&gdev->reg_mutex);
  79         __ccwgroup_remove_symlinks(gdev);
  80         device_unregister(dev);
  81         mutex_unlock(&gdev->reg_mutex);
  82 }
  83
  84 static ssize_t
  85 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  86 {
  87         struct ccwgroup_device *gdev;
  88         int rc;
  89
  90         gdev = to_ccwgroupdev(dev);
  91
  92         if (gdev->state != CCWGROUP_OFFLINE)
  93                 return -EINVAL;
  94
  95         /* Note that we cannot unregister the device from one of its
  96          * attribute methods, so we have to use this roundabout approach.
  97          */
  98         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
  99         if (rc)
 100                 count = rc;
 101         return count;
 102 }
 103
 104 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 105
 106 static void
 107 ccwgroup_release (struct device *dev)
 108 {
 109         struct ccwgroup_device *gdev;
 110         int i;
 111
 112         gdev = to_ccwgroupdev(dev);
 113
 114         for (i = 0; i < gdev->count; i++) {
 115                 gdev->cdev[i]->dev.driver_data = NULL;
 116                 put_device(&gdev->cdev[i]->dev);
 117         }
 118         kfree(gdev);
 119 }
 120
 121 static int
 122 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 123 {
 124         char str[8];
 125         int i, rc;
 126
 127         for (i = 0; i < gdev->count; i++) {
 128                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 129                                        "group_device");
 130                 if (rc) {
 131                         for (--i; i >= 0; i--)
 132                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 133                                                   "group_device");
 134                         return rc;
 135                 }
 136         }
 137         for (i = 0; i < gdev->count; i++) {
 138                 sprintf(str, "cdev%d", i);
 139                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 140                                        str);
 141                 if (rc) {
 142                         for (--i; i >= 0; i--) {
 143                                 sprintf(str, "cdev%d", i);
 144                                 sysfs_remove_link(&gdev->dev.kobj, str);
 145                         }
 146                         for (i = 0; i < gdev->count; i++)
 147                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 148                                                   "group_device");
 149                         return rc;
 150                 }
 151         }
 152         return 0;
 153 }
 154
 155 /*
 156  * try to add a new ccwgroup device for one driver
 157  * argc and argv[] are a list of bus_id's of devices
 158  * belonging to the driver.
 159  */
 160 int
 161 ccwgroup_create(struct device *root,
 162                 unsigned int creator_id,
 163                 struct ccw_driver *cdrv,
 164                 int argc, char *argv[])
 165 {
 166         struct ccwgroup_device *gdev;
 167         int i;
 168         int rc;
 169
 170         if (argc > 256) /* disallow dumb users */
 171                 return -EINVAL;
 172
 173         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 174         if (!gdev)
 175                 return -ENOMEM;
 176
 177         atomic_set(&gdev->onoff, 0);
 178         mutex_init(&gdev->reg_mutex);
 179         mutex_lock(&gdev->reg_mutex);
 180         for (i = 0; i < argc; i++) {
 181                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 182
 183                 /* all devices have to be of the same type in
 184                  * order to be grouped */
 185                 if (!gdev->cdev[i]
 186                     || gdev->cdev[i]->id.driver_info !=
 187                     gdev->cdev[0]->id.driver_info) {
 188                         rc = -EINVAL;
 189                         goto error;
 190                 }
 191                 /* Don't allow a device to belong to more than one group. */
 192                 if (gdev->cdev[i]->dev.driver_data) {
 193                         rc = -EINVAL;
 194                         goto error;
 195                 }
 196                 gdev->cdev[i]->dev.driver_data = gdev;
 197         }
 198
 199         gdev->creator_id = creator_id;
 200         gdev->count = argc;
 201         gdev->dev.bus = &ccwgroup_bus_type;
 202         gdev->dev.parent = root;
 203         gdev->dev.release = ccwgroup_release;
 204
 205         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 206                         gdev->cdev[0]->dev.bus_id);
 207
 208         rc = device_register(&gdev->dev);
 209         if (rc)
 210                 goto error;
 211         get_device(&gdev->dev);
 212         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 213
 214         if (rc) {
 215                 device_unregister(&gdev->dev);
 216                 goto error;
 217         }
 218
 219         rc = __ccwgroup_create_symlinks(gdev);
 220         if (!rc) {
 221                 mutex_unlock(&gdev->reg_mutex);
 222                 put_device(&gdev->dev);
 223                 return 0;
 224         }
 225         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 226         device_unregister(&gdev->dev);
 227 error:
 228         for (i = 0; i < argc; i++)
 229                 if (gdev->cdev[i]) {
 230                         if (gdev->cdev[i]->dev.driver_data == gdev)
 231                                 gdev->cdev[i]->dev.driver_data = NULL;
 232                         put_device(&gdev->cdev[i]->dev);
 233                 }
 234         mutex_unlock(&gdev->reg_mutex);
 235         put_device(&gdev->dev);
 236         return rc;
 237 }
 238
 239 static int __init
 240 init_ccwgroup (void)
 241 {
 242         return bus_register (&ccwgroup_bus_type);
 243 }
 244
 245 static void __exit
 246 cleanup_ccwgroup (void)
 247 {
 248         bus_unregister (&ccwgroup_bus_type);
 249 }
 250
 251 module_init(init_ccwgroup);
 252 module_exit(cleanup_ccwgroup);
 253
 254 /************************** driver stuff ******************************/
 255
 256 static int
 257 ccwgroup_set_online(struct ccwgroup_device *gdev)
 258 {
 259         struct ccwgroup_driver *gdrv;
 260         int ret;
 261
 262         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 263                 return -EAGAIN;
 264         if (gdev->state == CCWGROUP_ONLINE) {
 265                 ret = 0;
 266                 goto out;
 267         }
 268         if (!gdev->dev.driver) {
 269                 ret = -EINVAL;
 270                 goto out;
 271         }
 272         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 273         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 274                 goto out;
 275
 276         gdev->state = CCWGROUP_ONLINE;
 277  out:
 278         atomic_set(&gdev->onoff, 0);
 279         return ret;
 280 }
 281
 282 static int
 283 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 284 {
 285         struct ccwgroup_driver *gdrv;
 286         int ret;
 287
 288         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 289                 return -EAGAIN;
 290         if (gdev->state == CCWGROUP_OFFLINE) {
 291                 ret = 0;
 292                 goto out;
 293         }
 294         if (!gdev->dev.driver) {
 295                 ret = -EINVAL;
 296                 goto out;
 297         }
 298         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 299         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 300                 goto out;
 301
 302         gdev->state = CCWGROUP_OFFLINE;
 303  out:
 304         atomic_set(&gdev->onoff, 0);
 305         return ret;
 306 }
 307
 308 static ssize_t
 309 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 310 {
 311         struct ccwgroup_device *gdev;
 312         struct ccwgroup_driver *gdrv;
 313         unsigned int value;
 314         int ret;
 315
 316         gdev = to_ccwgroupdev(dev);
 317         if (!dev->driver)
 318                 return count;
 319
 320         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 321         if (!try_module_get(gdrv->owner))
 322                 return -EINVAL;
 323
 324         value = simple_strtoul(buf, NULL, 0);
 325         ret = count;
 326         if (value == 1)
 327                 ccwgroup_set_online(gdev);
 328         else if (value == 0)
 329                 ccwgroup_set_offline(gdev);
 330         else
 331                 ret = -EINVAL;
 332         module_put(gdrv->owner);
 333         return ret;
 334 }
 335
 336 static ssize_t
 337 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 338 {
 339         int online;
 340
 341         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 342
 343         return sprintf(buf, online ? "1\n" : "0\n");
 344 }
 345
 346 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 347
 348 static int
 349 ccwgroup_probe (struct device *dev)
 350 {
 351         struct ccwgroup_device *gdev;
 352         struct ccwgroup_driver *gdrv;
 353
 354         int ret;
 355
 356         gdev = to_ccwgroupdev(dev);
 357         gdrv = to_ccwgroupdrv(dev->driver);
 358
 359         if ((ret = device_create_file(dev, &dev_attr_online)))
 360                 return ret;
 361
 362         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 363         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 364         if (ret)
 365                 device_remove_file(dev, &dev_attr_online);
 366
 367         return ret;
 368 }
 369
 370 static int
 371 ccwgroup_remove (struct device *dev)
 372 {
 373         struct ccwgroup_device *gdev;
 374         struct ccwgroup_driver *gdrv;
 375
 376         gdev = to_ccwgroupdev(dev);
 377         gdrv = to_ccwgroupdrv(dev->driver);
 378
 379         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 380
 381         device_remove_file(dev, &dev_attr_online);
 382
 383         if (gdrv && gdrv->remove)
 384                 gdrv->remove(gdev);
 385         return 0;
 386 }
 387
 388 static struct bus_type ccwgroup_bus_type = {
 389         .name   = "ccwgroup",
 390         .match  = ccwgroup_bus_match,
 391         .uevent = ccwgroup_uevent,
 392         .probe  = ccwgroup_probe,
 393         .remove = ccwgroup_remove,
 394 };
 395
 396 int
 397 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 398 {
 399         /* register our new driver with the core */
 400         cdriver->driver.bus = &ccwgroup_bus_type;
 401         cdriver->driver.name = cdriver->name;
 402
 403         return driver_register(&cdriver->driver);
 404 }
 405
 406 static int
 407 __ccwgroup_match_all(struct device *dev, void *data)
 408 {
 409         return 1;
 410 }
 411
 412 void
 413 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 414 {
 415         struct device *dev;
 416
 417         /* We don't want ccwgroup devices to live longer than their driver. */
 418         get_driver(&cdriver->driver);
 419         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 420                                          __ccwgroup_match_all))) {
 421                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 422
 423                 mutex_lock(&gdev->reg_mutex);
 424                 __ccwgroup_remove_symlinks(gdev);
 425                 device_unregister(dev);
 426                 mutex_unlock(&gdev->reg_mutex);
 427                 put_device(dev);
 428         }
 429         put_driver(&cdriver->driver);
 430         driver_unregister(&cdriver->driver);
 431 }
 432
 433 int
 434 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 435 {
 436         return 0;
 437 }
 438
 439 static struct ccwgroup_device *
 440 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 441 {
 442         struct ccwgroup_device *gdev;
 443
 444         if (cdev->dev.driver_data) {
 445                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 446                 if (get_device(&gdev->dev)) {
 447                         mutex_lock(&gdev->reg_mutex);
 448                         if (device_is_registered(&gdev->dev))
 449                                 return gdev;
 450                         mutex_unlock(&gdev->reg_mutex);
 451                         put_device(&gdev->dev);
 452                 }
 453                 return NULL;
 454         }
 455         return NULL;
 456 }
 457
 458 void
 459 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 460 {
 461         struct ccwgroup_device *gdev;
 462
 463         /* Ignore offlining errors, device is gone anyway. */
 464         ccw_device_set_offline(cdev);
 465         /* If one of its devices is gone, the whole group is done for. */
 466         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 467         if (gdev) {
 468                 __ccwgroup_remove_symlinks(gdev);
 469                 device_unregister(&gdev->dev);
 470                 mutex_unlock(&gdev->reg_mutex);
 471                 put_device(&gdev->dev);
 472         }
 473 }
 474
 475 MODULE_LICENSE("GPL");
 476 EXPORT_SYMBOL(ccwgroup_driver_register);
 477 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 478 EXPORT_SYMBOL(ccwgroup_create);
 479 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 480 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);