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); 483