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; 155 156 if (argc > 256) /* disallow dumb users */ 157 return -EINVAL; 158 159 gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL); 160 if (!gdev) 161 return -ENOMEM; 162 163 atomic_set(&gdev->onoff, 0); 164 165 for (i = 0; i < argc; i++) { 166 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]); 167 168 /* all devices have to be of the same type in 169 * order to be grouped */ 170 if (!gdev->cdev[i] 171 || gdev->cdev[i]->id.driver_info != 172 gdev->cdev[0]->id.driver_info) { 173 rc = -EINVAL; 174 goto free_dev; 175 } 176 /* Don't allow a device to belong to more than one group. */ 177 if (gdev->cdev[i]->dev.driver_data) { 178 rc = -EINVAL; 179 goto free_dev; 180 } 181 gdev->cdev[i]->dev.driver_data = gdev; 182 } 183 184 gdev->creator_id = creator_id; 185 gdev->count = argc; 186 gdev->dev = (struct device ) { 187 .bus = &ccwgroup_bus_type, 188 .parent = root, 189 .release = ccwgroup_release, 190 }; 191 192 snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s", 193 gdev->cdev[0]->dev.bus_id); 194 195 rc = device_register(&gdev->dev); 196 197 if (rc) 198 goto free_dev; 199 get_device(&gdev->dev); 200 rc = device_create_file(&gdev->dev, &dev_attr_ungroup); 201 202 if (rc) { 203 device_unregister(&gdev->dev); 204 goto error; 205 } 206 207 rc = __ccwgroup_create_symlinks(gdev); 208 if (!rc) { 209 put_device(&gdev->dev); 210 return 0; 211 } 212 device_remove_file(&gdev->dev, &dev_attr_ungroup); 213 device_unregister(&gdev->dev); 214 error: 215 for (i = 0; i < argc; i++) 216 if (gdev->cdev[i]) { 217 put_device(&gdev->cdev[i]->dev); 218 gdev->cdev[i]->dev.driver_data = NULL; 219 } 220 put_device(&gdev->dev); 221 return rc; 222 free_dev: 223 for (i = 0; i < argc; i++) 224 if (gdev->cdev[i]) { 225 if (gdev->cdev[i]->dev.driver_data == gdev) 226 gdev->cdev[i]->dev.driver_data = NULL; 227 put_device(&gdev->cdev[i]->dev); 228 } 229 kfree(gdev); 230 return rc; 231 } 232 233 static int __init 234 init_ccwgroup (void) 235 { 236 return bus_register (&ccwgroup_bus_type); 237 } 238 239 static void __exit 240 cleanup_ccwgroup (void) 241 { 242 bus_unregister (&ccwgroup_bus_type); 243 } 244 245 module_init(init_ccwgroup); 246 module_exit(cleanup_ccwgroup); 247 248 /************************** driver stuff ******************************/ 249 250 static int 251 ccwgroup_set_online(struct ccwgroup_device *gdev) 252 { 253 struct ccwgroup_driver *gdrv; 254 int ret; 255 256 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) 257 return -EAGAIN; 258 if (gdev->state == CCWGROUP_ONLINE) { 259 ret = 0; 260 goto out; 261 } 262 if (!gdev->dev.driver) { 263 ret = -EINVAL; 264 goto out; 265 } 266 gdrv = to_ccwgroupdrv (gdev->dev.driver); 267 if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0)) 268 goto out; 269 270 gdev->state = CCWGROUP_ONLINE; 271 out: 272 atomic_set(&gdev->onoff, 0); 273 return ret; 274 } 275 276 static int 277 ccwgroup_set_offline(struct ccwgroup_device *gdev) 278 { 279 struct ccwgroup_driver *gdrv; 280 int ret; 281 282 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) 283 return -EAGAIN; 284 if (gdev->state == CCWGROUP_OFFLINE) { 285 ret = 0; 286 goto out; 287 } 288 if (!gdev->dev.driver) { 289 ret = -EINVAL; 290 goto out; 291 } 292 gdrv = to_ccwgroupdrv (gdev->dev.driver); 293 if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0)) 294 goto out; 295 296 gdev->state = CCWGROUP_OFFLINE; 297 out: 298 atomic_set(&gdev->onoff, 0); 299 return ret; 300 } 301 302 static ssize_t 303 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count) 304 { 305 struct ccwgroup_device *gdev; 306 struct ccwgroup_driver *gdrv; 307 unsigned int value; 308 int ret; 309 310 gdev = to_ccwgroupdev(dev); 311 if (!dev->driver) 312 return count; 313 314 gdrv = to_ccwgroupdrv (gdev->dev.driver); 315 if (!try_module_get(gdrv->owner)) 316 return -EINVAL; 317 318 value = simple_strtoul(buf, NULL, 0); 319 ret = count; 320 if (value == 1) 321 ccwgroup_set_online(gdev); 322 else if (value == 0) 323 ccwgroup_set_offline(gdev); 324 else 325 ret = -EINVAL; 326 module_put(gdrv->owner); 327 return ret; 328 } 329 330 static ssize_t 331 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf) 332 { 333 int online; 334 335 online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE); 336 337 return sprintf(buf, online ? "1\n" : "0\n"); 338 } 339 340 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store); 341 342 static int 343 ccwgroup_probe (struct device *dev) 344 { 345 struct ccwgroup_device *gdev; 346 struct ccwgroup_driver *gdrv; 347 348 int ret; 349 350 gdev = to_ccwgroupdev(dev); 351 gdrv = to_ccwgroupdrv(dev->driver); 352 353 if ((ret = device_create_file(dev, &dev_attr_online))) 354 return ret; 355 356 pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id); 357 ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV; 358 if (ret) 359 device_remove_file(dev, &dev_attr_online); 360 361 return ret; 362 } 363 364 static int 365 ccwgroup_remove (struct device *dev) 366 { 367 struct ccwgroup_device *gdev; 368 struct ccwgroup_driver *gdrv; 369 370 gdev = to_ccwgroupdev(dev); 371 gdrv = to_ccwgroupdrv(dev->driver); 372 373 pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id); 374 375 device_remove_file(dev, &dev_attr_online); 376 377 if (gdrv && gdrv->remove) 378 gdrv->remove(gdev); 379 return 0; 380 } 381 382 static struct bus_type ccwgroup_bus_type = { 383 .name = "ccwgroup", 384 .match = ccwgroup_bus_match, 385 .uevent = ccwgroup_uevent, 386 .probe = ccwgroup_probe, 387 .remove = ccwgroup_remove, 388 }; 389 390 int 391 ccwgroup_driver_register (struct ccwgroup_driver *cdriver) 392 { 393 /* register our new driver with the core */ 394 cdriver->driver = (struct device_driver) { 395 .bus = &ccwgroup_bus_type, 396 .name = cdriver->name, 397 }; 398 399 return driver_register(&cdriver->driver); 400 } 401 402 static int 403 __ccwgroup_match_all(struct device *dev, void *data) 404 { 405 return 1; 406 } 407 408 void 409 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver) 410 { 411 struct device *dev; 412 413 /* We don't want ccwgroup devices to live longer than their driver. */ 414 get_driver(&cdriver->driver); 415 while ((dev = driver_find_device(&cdriver->driver, NULL, NULL, 416 __ccwgroup_match_all))) { 417 __ccwgroup_remove_symlinks(to_ccwgroupdev(dev)); 418 device_unregister(dev); 419 put_device(dev); 420 } 421 put_driver(&cdriver->driver); 422 driver_unregister(&cdriver->driver); 423 } 424 425 int 426 ccwgroup_probe_ccwdev(struct ccw_device *cdev) 427 { 428 return 0; 429 } 430 431 static inline struct ccwgroup_device * 432 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev) 433 { 434 struct ccwgroup_device *gdev; 435 436 if (cdev->dev.driver_data) { 437 gdev = (struct ccwgroup_device *)cdev->dev.driver_data; 438 if (get_device(&gdev->dev)) { 439 if (device_is_registered(&gdev->dev)) 440 return gdev; 441 put_device(&gdev->dev); 442 } 443 return NULL; 444 } 445 return NULL; 446 } 447 448 void 449 ccwgroup_remove_ccwdev(struct ccw_device *cdev) 450 { 451 struct ccwgroup_device *gdev; 452 453 /* Ignore offlining errors, device is gone anyway. */ 454 ccw_device_set_offline(cdev); 455 /* If one of its devices is gone, the whole group is done for. */ 456 gdev = __ccwgroup_get_gdev_by_cdev(cdev); 457 if (gdev) { 458 __ccwgroup_remove_symlinks(gdev); 459 device_unregister(&gdev->dev); 460 put_device(&gdev->dev); 461 } 462 } 463 464 MODULE_LICENSE("GPL"); 465 EXPORT_SYMBOL(ccwgroup_driver_register); 466 EXPORT_SYMBOL(ccwgroup_driver_unregister); 467 EXPORT_SYMBOL(ccwgroup_create); 468 EXPORT_SYMBOL(ccwgroup_probe_ccwdev); 469 EXPORT_SYMBOL(ccwgroup_remove_ccwdev); 470