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