drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  drivers/s390/cio/ccwgroup.c
   3  *  bus driver for ccwgroup
   4  *   $Revision: 1.35 $
   5  *
   6  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   7  *                       IBM Corporation
   8  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   9  *               Cornelia Huck (cornelia.huck@de.ibm.com)
  10  */
  11 #include <linux/module.h>
  12 #include <linux/errno.h>
  13 #include <linux/slab.h>
  14 #include <linux/list.h>
  15 #include <linux/device.h>
  16 #include <linux/init.h>
  17 #include <linux/ctype.h>
  18 #include <linux/dcache.h>
  19
  20 #include <asm/semaphore.h>
  21 #include <asm/ccwdev.h>
  22 #include <asm/ccwgroup.h>
  23
  24 /* In Linux 2.4, we had a channel device layer called "chandev"
  25  * that did all sorts of obscure stuff for networking devices.
  26  * This is another driver that serves as a replacement for just
  27  * one of its functions, namely the translation of single subchannels
  28  * to devices that use multiple subchannels.
  29  */
  30
  31 /* a device matches a driver if all its slave devices match the same
  32  * entry of the driver */
  33 static int
  34 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
  35 {
  36         struct ccwgroup_device *gdev;
  37         struct ccwgroup_driver *gdrv;
  38
  39         gdev = container_of(dev, struct ccwgroup_device, dev);
  40         gdrv = container_of(drv, struct ccwgroup_driver, driver);
  41
  42         if (gdev->creator_id == gdrv->driver_id)
  43                 return 1;
  44
  45         return 0;
  46 }
  47 static int
  48 ccwgroup_uevent (struct device *dev, char **envp, int num_envp, char *buffer,
  49                   int buffer_size)
  50 {
  51         /* TODO */
  52         return 0;
  53 }
  54
  55 static struct bus_type ccwgroup_bus_type;
  56
  57 static inline void
  58 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  59 {
  60         int i;
  61         char str[8];
  62
  63         for (i = 0; i < gdev->count; i++) {
  64                 sprintf(str, "cdev%d", i);
  65                 sysfs_remove_link(&gdev->dev.kobj, str);
  66                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  67         }
  68
  69 }
  70
  71 /*
  72  * Provide an 'ungroup' attribute so the user can remove group devices no
  73  * longer needed or accidentially created. Saves memory :)
  74  */
  75 static ssize_t
  76 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  77 {
  78         struct ccwgroup_device *gdev;
  79
  80         gdev = to_ccwgroupdev(dev);
  81
  82         if (gdev->state != CCWGROUP_OFFLINE)
  83                 return -EINVAL;
  84
  85         __ccwgroup_remove_symlinks(gdev);
  86         device_unregister(dev);
  87
  88         return count;
  89 }
  90
  91 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
  92
  93 static void
  94 ccwgroup_release (struct device *dev)
  95 {
  96         struct ccwgroup_device *gdev;
  97         int i;
  98
  99         gdev = to_ccwgroupdev(dev);
 100
 101         for (i = 0; i < gdev->count; i++) {
 102                 gdev->cdev[i]->dev.driver_data = NULL;
 103                 put_device(&gdev->cdev[i]->dev);
 104         }
 105         kfree(gdev);
 106 }
 107
 108 static inline int
 109 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 110 {
 111         char str[8];
 112         int i, rc;
 113
 114         for (i = 0; i < gdev->count; i++) {
 115                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 116                                        "group_device");
 117                 if (rc) {
 118                         for (--i; i >= 0; i--)
 119                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 120                                                   "group_device");
 121                         return rc;
 122                 }
 123         }
 124         for (i = 0; i < gdev->count; i++) {
 125                 sprintf(str, "cdev%d", i);
 126                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 127                                        str);
 128                 if (rc) {
 129                         for (--i; i >= 0; i--) {
 130                                 sprintf(str, "cdev%d", i);
 131                                 sysfs_remove_link(&gdev->dev.kobj, str);
 132                         }
 133                         for (i = 0; i < gdev->count; i++)
 134                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 135                                                   "group_device");
 136                         return rc;
 137                 }
 138         }
 139         return 0;
 140 }
 141
 142 /*
 143  * try to add a new ccwgroup device for one driver
 144  * argc and argv[] are a list of bus_id's of devices
 145  * belonging to the driver.
 146  */
 147 int
 148 ccwgroup_create(struct device *root,
 149                 unsigned int creator_id,
 150                 struct ccw_driver *cdrv,
 151                 int argc, char *argv[])
 152 {
 153         struct ccwgroup_device *gdev;
 154         int i;
 155         int rc;
 156         int del_drvdata;
 157
 158         if (argc > 256) /* disallow dumb users */
 159                 return -EINVAL;
 160
 161         gdev = kmalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 162         if (!gdev)
 163                 return -ENOMEM;
 164
 165         memset(gdev, 0, sizeof(*gdev) + argc*sizeof(gdev->cdev[0]));
 166         atomic_set(&gdev->onoff, 0);
 167
 168         del_drvdata = 0;
 169         for (i = 0; i < argc; i++) {
 170                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 171
 172                 /* all devices have to be of the same type in
 173                  * order to be grouped */
 174                 if (!gdev->cdev[i]
 175                     || gdev->cdev[i]->id.driver_info !=
 176                     gdev->cdev[0]->id.driver_info) {
 177                         rc = -EINVAL;
 178                         goto free_dev;
 179                 }
 180                 /* Don't allow a device to belong to more than one group. */
 181                 if (gdev->cdev[i]->dev.driver_data) {
 182                         rc = -EINVAL;
 183                         goto free_dev;
 184                 }
 185         }
 186         for (i = 0; i < argc; i++)
 187                 gdev->cdev[i]->dev.driver_data = gdev;
 188         del_drvdata = 1;
 189
 190         gdev->creator_id = creator_id;
 191         gdev->count = argc;
 192         gdev->dev = (struct device ) {
 193                 .bus = &ccwgroup_bus_type,
 194                 .parent = root,
 195                 .release = ccwgroup_release,
 196         };
 197
 198         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 199                         gdev->cdev[0]->dev.bus_id);
 200
 201         rc = device_register(&gdev->dev);
 202
 203         if (rc)
 204                 goto free_dev;
 205         get_device(&gdev->dev);
 206         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 207
 208         if (rc) {
 209                 device_unregister(&gdev->dev);
 210                 goto error;
 211         }
 212
 213         rc = __ccwgroup_create_symlinks(gdev);
 214         if (!rc) {
 215                 put_device(&gdev->dev);
 216                 return 0;
 217         }
 218         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 219         device_unregister(&gdev->dev);
 220 error:
 221         for (i = 0; i < argc; i++)
 222                 if (gdev->cdev[i]) {
 223                         put_device(&gdev->cdev[i]->dev);
 224                         gdev->cdev[i]->dev.driver_data = NULL;
 225                 }
 226         put_device(&gdev->dev);
 227         return rc;
 228 free_dev:
 229         for (i = 0; i < argc; i++)
 230                 if (gdev->cdev[i]) {
 231                         put_device(&gdev->cdev[i]->dev);
 232                         if (del_drvdata)
 233                                 gdev->cdev[i]->dev.driver_data = NULL;
 234                 }
 235         kfree(gdev);
 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, 0, 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 = (struct device_driver) {
 401                 .bus = &ccwgroup_bus_type,
 402                 .name = cdriver->name,
 403         };
 404
 405         return driver_register(&cdriver->driver);
 406 }
 407
 408 static int
 409 __ccwgroup_driver_unregister_device(struct device *dev, void *data)
 410 {
 411         __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
 412         device_unregister(dev);
 413         put_device(dev);
 414         return 0;
 415 }
 416
 417 void
 418 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 419 {
 420         /* We don't want ccwgroup devices to live longer than their driver. */
 421         get_driver(&cdriver->driver);
 422         driver_for_each_device(&cdriver->driver, NULL, NULL,
 423                                __ccwgroup_driver_unregister_device);
 424         put_driver(&cdriver->driver);
 425         driver_unregister(&cdriver->driver);
 426 }
 427
 428 int
 429 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 430 {
 431         return 0;
 432 }
 433
 434 static inline struct ccwgroup_device *
 435 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 436 {
 437         struct ccwgroup_device *gdev;
 438
 439         if (cdev->dev.driver_data) {
 440                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 441                 if (get_device(&gdev->dev)) {
 442                         if (device_is_registered(&gdev->dev))
 443                                 return gdev;
 444                         put_device(&gdev->dev);
 445                 }
 446                 return NULL;
 447         }
 448         return NULL;
 449 }
 450
 451 void
 452 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 453 {
 454         struct ccwgroup_device *gdev;
 455
 456         /* Ignore offlining errors, device is gone anyway. */
 457         ccw_device_set_offline(cdev);
 458         /* If one of its devices is gone, the whole group is done for. */
 459         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 460         if (gdev) {
 461                 __ccwgroup_remove_symlinks(gdev);
 462                 device_unregister(&gdev->dev);
 463                 put_device(&gdev->dev);
 464         }
 465 }
 466
 467 MODULE_LICENSE("GPL");
 468 EXPORT_SYMBOL(ccwgroup_driver_register);
 469 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 470 EXPORT_SYMBOL(ccwgroup_create);
 471 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 472 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);