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 inline 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 inline 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         int del_drvdata;
 156
 157         if (argc > 256) /* disallow dumb users */
 158                 return -EINVAL;
 159
 160         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 161         if (!gdev)
 162                 return -ENOMEM;
 163
 164         atomic_set(&gdev->onoff, 0);
 165
 166         del_drvdata = 0;
 167         for (i = 0; i < argc; i++) {
 168                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 169
 170                 /* all devices have to be of the same type in
 171                  * order to be grouped */
 172                 if (!gdev->cdev[i]
 173                     || gdev->cdev[i]->id.driver_info !=
 174                     gdev->cdev[0]->id.driver_info) {
 175                         rc = -EINVAL;
 176                         goto free_dev;
 177                 }
 178                 /* Don't allow a device to belong to more than one group. */
 179                 if (gdev->cdev[i]->dev.driver_data) {
 180                         rc = -EINVAL;
 181                         goto free_dev;
 182                 }
 183         }
 184         for (i = 0; i < argc; i++)
 185                 gdev->cdev[i]->dev.driver_data = gdev;
 186         del_drvdata = 1;
 187
 188         gdev->creator_id = creator_id;
 189         gdev->count = argc;
 190         gdev->dev = (struct device ) {
 191                 .bus = &ccwgroup_bus_type,
 192                 .parent = root,
 193                 .release = ccwgroup_release,
 194         };
 195
 196         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 197                         gdev->cdev[0]->dev.bus_id);
 198
 199         rc = device_register(&gdev->dev);
 200
 201         if (rc)
 202                 goto free_dev;
 203         get_device(&gdev->dev);
 204         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 205
 206         if (rc) {
 207                 device_unregister(&gdev->dev);
 208                 goto error;
 209         }
 210
 211         rc = __ccwgroup_create_symlinks(gdev);
 212         if (!rc) {
 213                 put_device(&gdev->dev);
 214                 return 0;
 215         }
 216         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 217         device_unregister(&gdev->dev);
 218 error:
 219         for (i = 0; i < argc; i++)
 220                 if (gdev->cdev[i]) {
 221                         put_device(&gdev->cdev[i]->dev);
 222                         gdev->cdev[i]->dev.driver_data = NULL;
 223                 }
 224         put_device(&gdev->dev);
 225         return rc;
 226 free_dev:
 227         for (i = 0; i < argc; i++)
 228                 if (gdev->cdev[i]) {
 229                         put_device(&gdev->cdev[i]->dev);
 230                         if (del_drvdata)
 231                                 gdev->cdev[i]->dev.driver_data = NULL;
 232                 }
 233         kfree(gdev);
 234         return rc;
 235 }
 236
 237 static int __init
 238 init_ccwgroup (void)
 239 {
 240         return bus_register (&ccwgroup_bus_type);
 241 }
 242
 243 static void __exit
 244 cleanup_ccwgroup (void)
 245 {
 246         bus_unregister (&ccwgroup_bus_type);
 247 }
 248
 249 module_init(init_ccwgroup);
 250 module_exit(cleanup_ccwgroup);
 251
 252 /************************** driver stuff ******************************/
 253
 254 static int
 255 ccwgroup_set_online(struct ccwgroup_device *gdev)
 256 {
 257         struct ccwgroup_driver *gdrv;
 258         int ret;
 259
 260         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 261                 return -EAGAIN;
 262         if (gdev->state == CCWGROUP_ONLINE) {
 263                 ret = 0;
 264                 goto out;
 265         }
 266         if (!gdev->dev.driver) {
 267                 ret = -EINVAL;
 268                 goto out;
 269         }
 270         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 271         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 272                 goto out;
 273
 274         gdev->state = CCWGROUP_ONLINE;
 275  out:
 276         atomic_set(&gdev->onoff, 0);
 277         return ret;
 278 }
 279
 280 static int
 281 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 282 {
 283         struct ccwgroup_driver *gdrv;
 284         int ret;
 285
 286         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 287                 return -EAGAIN;
 288         if (gdev->state == CCWGROUP_OFFLINE) {
 289                 ret = 0;
 290                 goto out;
 291         }
 292         if (!gdev->dev.driver) {
 293                 ret = -EINVAL;
 294                 goto out;
 295         }
 296         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 297         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 298                 goto out;
 299
 300         gdev->state = CCWGROUP_OFFLINE;
 301  out:
 302         atomic_set(&gdev->onoff, 0);
 303         return ret;
 304 }
 305
 306 static ssize_t
 307 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 308 {
 309         struct ccwgroup_device *gdev;
 310         struct ccwgroup_driver *gdrv;
 311         unsigned int value;
 312         int ret;
 313
 314         gdev = to_ccwgroupdev(dev);
 315         if (!dev->driver)
 316                 return count;
 317
 318         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 319         if (!try_module_get(gdrv->owner))
 320                 return -EINVAL;
 321
 322         value = simple_strtoul(buf, 0, 0);
 323         ret = count;
 324         if (value == 1)
 325                 ccwgroup_set_online(gdev);
 326         else if (value == 0)
 327                 ccwgroup_set_offline(gdev);
 328         else
 329                 ret = -EINVAL;
 330         module_put(gdrv->owner);
 331         return ret;
 332 }
 333
 334 static ssize_t
 335 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 336 {
 337         int online;
 338
 339         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 340
 341         return sprintf(buf, online ? "1\n" : "0\n");
 342 }
 343
 344 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 345
 346 static int
 347 ccwgroup_probe (struct device *dev)
 348 {
 349         struct ccwgroup_device *gdev;
 350         struct ccwgroup_driver *gdrv;
 351
 352         int ret;
 353
 354         gdev = to_ccwgroupdev(dev);
 355         gdrv = to_ccwgroupdrv(dev->driver);
 356
 357         if ((ret = device_create_file(dev, &dev_attr_online)))
 358                 return ret;
 359
 360         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 361         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 362         if (ret)
 363                 device_remove_file(dev, &dev_attr_online);
 364
 365         return ret;
 366 }
 367
 368 static int
 369 ccwgroup_remove (struct device *dev)
 370 {
 371         struct ccwgroup_device *gdev;
 372         struct ccwgroup_driver *gdrv;
 373
 374         gdev = to_ccwgroupdev(dev);
 375         gdrv = to_ccwgroupdrv(dev->driver);
 376
 377         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 378
 379         device_remove_file(dev, &dev_attr_online);
 380
 381         if (gdrv && gdrv->remove)
 382                 gdrv->remove(gdev);
 383         return 0;
 384 }
 385
 386 static struct bus_type ccwgroup_bus_type = {
 387         .name   = "ccwgroup",
 388         .match  = ccwgroup_bus_match,
 389         .uevent = ccwgroup_uevent,
 390         .probe  = ccwgroup_probe,
 391         .remove = ccwgroup_remove,
 392 };
 393
 394 int
 395 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 396 {
 397         /* register our new driver with the core */
 398         cdriver->driver = (struct device_driver) {
 399                 .bus = &ccwgroup_bus_type,
 400                 .name = cdriver->name,
 401         };
 402
 403         return driver_register(&cdriver->driver);
 404 }
 405
 406 static int
 407 __ccwgroup_driver_unregister_device(struct device *dev, void *data)
 408 {
 409         __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
 410         device_unregister(dev);
 411         put_device(dev);
 412         return 0;
 413 }
 414
 415 void
 416 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 417 {
 418         /* We don't want ccwgroup devices to live longer than their driver. */
 419         get_driver(&cdriver->driver);
 420         driver_for_each_device(&cdriver->driver, NULL, NULL,
 421                                __ccwgroup_driver_unregister_device);
 422         put_driver(&cdriver->driver);
 423         driver_unregister(&cdriver->driver);
 424 }
 425
 426 int
 427 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 428 {
 429         return 0;
 430 }
 431
 432 static inline struct ccwgroup_device *
 433 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 434 {
 435         struct ccwgroup_device *gdev;
 436
 437         if (cdev->dev.driver_data) {
 438                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 439                 if (get_device(&gdev->dev)) {
 440                         if (device_is_registered(&gdev->dev))
 441                                 return gdev;
 442                         put_device(&gdev->dev);
 443                 }
 444                 return NULL;
 445         }
 446         return NULL;
 447 }
 448
 449 void
 450 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 451 {
 452         struct ccwgroup_device *gdev;
 453
 454         /* Ignore offlining errors, device is gone anyway. */
 455         ccw_device_set_offline(cdev);
 456         /* If one of its devices is gone, the whole group is done for. */
 457         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 458         if (gdev) {
 459                 __ccwgroup_remove_symlinks(gdev);
 460                 device_unregister(&gdev->dev);
 461                 put_device(&gdev->dev);
 462         }
 463 }
 464
 465 MODULE_LICENSE("GPL");
 466 EXPORT_SYMBOL(ccwgroup_driver_register);
 467 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 468 EXPORT_SYMBOL(ccwgroup_create);
 469 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 470 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);