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