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