drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  drivers/s390/cio/ccwgroup.c
   3  *  bus driver for ccwgroup
   4  *   $Revision: 1.29 $
   5  *
   6  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   7  *                       IBM Corporation
   8  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   9  *               Cornelia Huck (cohuck@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_hotplug (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         .name    = "ccwgroup",
  57         .match   = ccwgroup_bus_match,
  58         .hotplug = ccwgroup_hotplug,
  59 };
  60
  61 static inline void
  62 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  63 {
  64         int i;
  65         char str[8];
  66
  67         for (i = 0; i < gdev->count; i++) {
  68                 sprintf(str, "cdev%d", i);
  69                 sysfs_remove_link(&gdev->dev.kobj, str);
  70                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  71         }
  72
  73 }
  74
  75 /*
  76  * Provide an 'ungroup' attribute so the user can remove group devices no
  77  * longer needed or accidentially created. Saves memory :)
  78  */
  79 static ssize_t
  80 ccwgroup_ungroup_store(struct device *dev, const char *buf, size_t count)
  81 {
  82         struct ccwgroup_device *gdev;
  83
  84         gdev = to_ccwgroupdev(dev);
  85
  86         if (gdev->state != CCWGROUP_OFFLINE)
  87                 return -EINVAL;
  88
  89         __ccwgroup_remove_symlinks(gdev);
  90         device_unregister(dev);
  91
  92         return count;
  93 }
  94
  95 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
  96
  97 static void
  98 ccwgroup_release (struct device *dev)
  99 {
 100         struct ccwgroup_device *gdev;
 101         int i;
 102
 103         gdev = to_ccwgroupdev(dev);
 104
 105         for (i = 0; i < gdev->count; i++) {
 106                 gdev->cdev[i]->dev.driver_data = NULL;
 107                 put_device(&gdev->cdev[i]->dev);
 108         }
 109         kfree(gdev);
 110 }
 111
 112 static inline int
 113 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 114 {
 115         char str[8];
 116         int i, rc;
 117
 118         for (i = 0; i < gdev->count; i++) {
 119                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 120                                        "group_device");
 121                 if (rc) {
 122                         for (--i; i >= 0; i--)
 123                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 124                                                   "group_device");
 125                         return rc;
 126                 }
 127         }
 128         for (i = 0; i < gdev->count; i++) {
 129                 sprintf(str, "cdev%d", i);
 130                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 131                                        str);
 132                 if (rc) {
 133                         for (--i; i >= 0; i--) {
 134                                 sprintf(str, "cdev%d", i);
 135                                 sysfs_remove_link(&gdev->dev.kobj, str);
 136                         }
 137                         for (i = 0; i < gdev->count; i++)
 138                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 139                                                   "group_device");
 140                         return rc;
 141                 }
 142         }
 143         return 0;
 144 }
 145
 146 /*
 147  * try to add a new ccwgroup device for one driver
 148  * argc and argv[] are a list of bus_id's of devices
 149  * belonging to the driver.
 150  */
 151 int
 152 ccwgroup_create(struct device *root,
 153                 unsigned int creator_id,
 154                 struct ccw_driver *cdrv,
 155                 int argc, char *argv[])
 156 {
 157         struct ccwgroup_device *gdev;
 158         int i;
 159         int rc;
 160         int del_drvdata;
 161
 162         if (argc > 256) /* disallow dumb users */
 163                 return -EINVAL;
 164
 165         gdev = kmalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 166         if (!gdev)
 167                 return -ENOMEM;
 168
 169         memset(gdev, 0, sizeof(*gdev) + argc*sizeof(gdev->cdev[0]));
 170         atomic_set(&gdev->onoff, 0);
 171
 172         del_drvdata = 0;
 173         for (i = 0; i < argc; i++) {
 174                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 175
 176                 /* all devices have to be of the same type in
 177                  * order to be grouped */
 178                 if (!gdev->cdev[i]
 179                     || gdev->cdev[i]->id.driver_info !=
 180                     gdev->cdev[0]->id.driver_info) {
 181                         rc = -EINVAL;
 182                         goto free_dev;
 183                 }
 184                 /* Don't allow a device to belong to more than one group. */
 185                 if (gdev->cdev[i]->dev.driver_data) {
 186                         rc = -EINVAL;
 187                         goto free_dev;
 188                 }
 189         }
 190         for (i = 0; i < argc; i++)
 191                 gdev->cdev[i]->dev.driver_data = gdev;
 192         del_drvdata = 1;
 193
 194         gdev->creator_id = creator_id;
 195         gdev->count = argc;
 196         gdev->dev = (struct device ) {
 197                 .bus = &ccwgroup_bus_type,
 198                 .parent = root,
 199                 .release = ccwgroup_release,
 200         };
 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                         put_device(&gdev->cdev[i]->dev);
 236                         if (del_drvdata)
 237                                 gdev->cdev[i]->dev.driver_data = NULL;
 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_compare_and_swap(0, 1, &gdev->onoff))
 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(gdev)))
 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_compare_and_swap(0, 1, &gdev->onoff))
 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(gdev)))
 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, 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, 0, 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, 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 int
 393 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 394 {
 395         /* register our new driver with the core */
 396         cdriver->driver = (struct device_driver) {
 397                 .bus = &ccwgroup_bus_type,
 398                 .name = cdriver->name,
 399                 .probe = ccwgroup_probe,
 400                 .remove = ccwgroup_remove,
 401         };
 402
 403         return driver_register(&cdriver->driver);
 404 }
 405
 406 static inline struct device *
 407 __get_next_ccwgroup_device(struct device_driver *drv)
 408 {
 409         struct device *dev, *d;
 410
 411         down_read(&drv->bus->subsys.rwsem);
 412         dev = NULL;
 413         list_for_each_entry(d, &drv->devices, driver_list) {
 414                 dev = get_device(d);
 415                 if (dev)
 416                         break;
 417         }
 418         up_read(&drv->bus->subsys.rwsem);
 419         return dev;
 420 }
 421
 422 void
 423 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 424 {
 425         struct device *dev;
 426
 427         /* We don't want ccwgroup devices to live longer than their driver. */
 428         get_driver(&cdriver->driver);
 429         while ((dev = __get_next_ccwgroup_device(&cdriver->driver))) {
 430                 __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
 431                 device_unregister(dev);
 432                 put_device(dev);
 433         };
 434         put_driver(&cdriver->driver);
 435         driver_unregister(&cdriver->driver);
 436 }
 437
 438 int
 439 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 440 {
 441         return 0;
 442 }
 443
 444 static inline struct ccwgroup_device *
 445 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 446 {
 447         struct ccwgroup_device *gdev;
 448
 449         if (cdev->dev.driver_data) {
 450                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 451                 if (get_device(&gdev->dev)) {
 452                         if (!list_empty(&gdev->dev.node))
 453                                 return gdev;
 454                         put_device(&gdev->dev);
 455                 }
 456                 return NULL;
 457         }
 458         return NULL;
 459 }
 460
 461 void
 462 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 463 {
 464         struct ccwgroup_device *gdev;
 465
 466         /* Ignore offlining errors, device is gone anyway. */
 467         ccw_device_set_offline(cdev);
 468         /* If one of its devices is gone, the whole group is done for. */
 469         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 470         if (gdev) {
 471                 __ccwgroup_remove_symlinks(gdev);
 472                 device_unregister(&gdev->dev);
 473                 put_device(&gdev->dev);
 474         }
 475 }
 476
 477 MODULE_LICENSE("GPL");
 478 EXPORT_SYMBOL(ccwgroup_driver_register);
 479 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 480 EXPORT_SYMBOL(ccwgroup_create);
 481 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 482 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);