1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * bus driver for ccwgroup 4 * 5 * Copyright IBM Corp. 2002, 2012 6 * 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/cio.h> 20 #include <asm/ccwdev.h> 21 #include <asm/ccwgroup.h> 22 23 #include "device.h" 24 25 #define CCW_BUS_ID_SIZE 10 26 27 /* In Linux 2.4, we had a channel device layer called "chandev" 28 * that did all sorts of obscure stuff for networking devices. 29 * This is another driver that serves as a replacement for just 30 * one of its functions, namely the translation of single subchannels 31 * to devices that use multiple subchannels. 32 */ 33 34 static struct bus_type ccwgroup_bus_type; 35 36 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev) 37 { 38 int i; 39 char str[16]; 40 41 for (i = 0; i < gdev->count; i++) { 42 sprintf(str, "cdev%d", i); 43 sysfs_remove_link(&gdev->dev.kobj, str); 44 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device"); 45 } 46 } 47 48 /* 49 * Remove references from ccw devices to ccw group device and from 50 * ccw group device to ccw devices. 51 */ 52 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev) 53 { 54 struct ccw_device *cdev; 55 int i; 56 57 for (i = 0; i < gdev->count; i++) { 58 cdev = gdev->cdev[i]; 59 if (!cdev) 60 continue; 61 spin_lock_irq(cdev->ccwlock); 62 dev_set_drvdata(&cdev->dev, NULL); 63 spin_unlock_irq(cdev->ccwlock); 64 gdev->cdev[i] = NULL; 65 put_device(&cdev->dev); 66 } 67 } 68 69 /** 70 * ccwgroup_set_online() - enable a ccwgroup device 71 * @gdev: target ccwgroup device 72 * 73 * This function attempts to put the ccwgroup device into the online state. 74 * Returns: 75 * %0 on success and a negative error value on failure. 76 */ 77 int ccwgroup_set_online(struct ccwgroup_device *gdev) 78 { 79 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 80 int ret = -EINVAL; 81 82 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) 83 return -EAGAIN; 84 if (gdev->state == CCWGROUP_ONLINE) 85 goto out; 86 if (gdrv->set_online) 87 ret = gdrv->set_online(gdev); 88 if (ret) 89 goto out; 90 91 gdev->state = CCWGROUP_ONLINE; 92 out: 93 atomic_set(&gdev->onoff, 0); 94 return ret; 95 } 96 EXPORT_SYMBOL(ccwgroup_set_online); 97 98 /** 99 * ccwgroup_set_offline() - disable a ccwgroup device 100 * @gdev: target ccwgroup device 101 * 102 * This function attempts to put the ccwgroup device into the offline state. 103 * Returns: 104 * %0 on success and a negative error value on failure. 105 */ 106 int ccwgroup_set_offline(struct ccwgroup_device *gdev) 107 { 108 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 109 int ret = -EINVAL; 110 111 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) 112 return -EAGAIN; 113 if (gdev->state == CCWGROUP_OFFLINE) 114 goto out; 115 if (gdrv->set_offline) 116 ret = gdrv->set_offline(gdev); 117 if (ret) 118 goto out; 119 120 gdev->state = CCWGROUP_OFFLINE; 121 out: 122 atomic_set(&gdev->onoff, 0); 123 return ret; 124 } 125 EXPORT_SYMBOL(ccwgroup_set_offline); 126 127 static ssize_t ccwgroup_online_store(struct device *dev, 128 struct device_attribute *attr, 129 const char *buf, size_t count) 130 { 131 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 132 unsigned long value; 133 int ret; 134 135 device_lock(dev); 136 if (!dev->driver) { 137 ret = -EINVAL; 138 goto out; 139 } 140 141 ret = kstrtoul(buf, 0, &value); 142 if (ret) 143 goto out; 144 145 if (value == 1) 146 ret = ccwgroup_set_online(gdev); 147 else if (value == 0) 148 ret = ccwgroup_set_offline(gdev); 149 else 150 ret = -EINVAL; 151 out: 152 device_unlock(dev); 153 return (ret == 0) ? count : ret; 154 } 155 156 static ssize_t ccwgroup_online_show(struct device *dev, 157 struct device_attribute *attr, 158 char *buf) 159 { 160 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 161 int online; 162 163 online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0; 164 165 return scnprintf(buf, PAGE_SIZE, "%d\n", online); 166 } 167 168 /* 169 * Provide an 'ungroup' attribute so the user can remove group devices no 170 * longer needed or accidentially created. Saves memory :) 171 */ 172 static void ccwgroup_ungroup(struct ccwgroup_device *gdev) 173 { 174 mutex_lock(&gdev->reg_mutex); 175 if (device_is_registered(&gdev->dev)) { 176 __ccwgroup_remove_symlinks(gdev); 177 device_unregister(&gdev->dev); 178 __ccwgroup_remove_cdev_refs(gdev); 179 } 180 mutex_unlock(&gdev->reg_mutex); 181 } 182 183 static ssize_t ccwgroup_ungroup_store(struct device *dev, 184 struct device_attribute *attr, 185 const char *buf, size_t count) 186 { 187 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 188 int rc = 0; 189 190 /* Prevent concurrent online/offline processing and ungrouping. */ 191 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0) 192 return -EAGAIN; 193 if (gdev->state != CCWGROUP_OFFLINE) { 194 rc = -EINVAL; 195 goto out; 196 } 197 198 if (device_remove_file_self(dev, attr)) 199 ccwgroup_ungroup(gdev); 200 else 201 rc = -ENODEV; 202 out: 203 if (rc) { 204 /* Release onoff "lock" when ungrouping failed. */ 205 atomic_set(&gdev->onoff, 0); 206 return rc; 207 } 208 return count; 209 } 210 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store); 211 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store); 212 213 static struct attribute *ccwgroup_attrs[] = { 214 &dev_attr_online.attr, 215 &dev_attr_ungroup.attr, 216 NULL, 217 }; 218 static struct attribute_group ccwgroup_attr_group = { 219 .attrs = ccwgroup_attrs, 220 }; 221 static const struct attribute_group *ccwgroup_attr_groups[] = { 222 &ccwgroup_attr_group, 223 NULL, 224 }; 225 226 static void ccwgroup_ungroup_workfn(struct work_struct *work) 227 { 228 struct ccwgroup_device *gdev = 229 container_of(work, struct ccwgroup_device, ungroup_work); 230 231 ccwgroup_ungroup(gdev); 232 put_device(&gdev->dev); 233 } 234 235 static void ccwgroup_release(struct device *dev) 236 { 237 kfree(to_ccwgroupdev(dev)); 238 } 239 240 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev) 241 { 242 char str[16]; 243 int i, rc; 244 245 for (i = 0; i < gdev->count; i++) { 246 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, 247 &gdev->dev.kobj, "group_device"); 248 if (rc) { 249 for (--i; i >= 0; i--) 250 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, 251 "group_device"); 252 return rc; 253 } 254 } 255 for (i = 0; i < gdev->count; i++) { 256 sprintf(str, "cdev%d", i); 257 rc = sysfs_create_link(&gdev->dev.kobj, 258 &gdev->cdev[i]->dev.kobj, str); 259 if (rc) { 260 for (--i; i >= 0; i--) { 261 sprintf(str, "cdev%d", i); 262 sysfs_remove_link(&gdev->dev.kobj, str); 263 } 264 for (i = 0; i < gdev->count; i++) 265 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, 266 "group_device"); 267 return rc; 268 } 269 } 270 return 0; 271 } 272 273 static int __get_next_id(const char **buf, struct ccw_dev_id *id) 274 { 275 unsigned int cssid, ssid, devno; 276 int ret = 0, len; 277 char *start, *end; 278 279 start = (char *)*buf; 280 end = strchr(start, ','); 281 if (!end) { 282 /* Last entry. Strip trailing newline, if applicable. */ 283 end = strchr(start, '\n'); 284 if (end) 285 *end = '\0'; 286 len = strlen(start) + 1; 287 } else { 288 len = end - start + 1; 289 end++; 290 } 291 if (len <= CCW_BUS_ID_SIZE) { 292 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3) 293 ret = -EINVAL; 294 } else 295 ret = -EINVAL; 296 297 if (!ret) { 298 id->ssid = ssid; 299 id->devno = devno; 300 } 301 *buf = end; 302 return ret; 303 } 304 305 /** 306 * ccwgroup_create_dev() - create and register a ccw group device 307 * @parent: parent device for the new device 308 * @gdrv: driver for the new group device 309 * @num_devices: number of slave devices 310 * @buf: buffer containing comma separated bus ids of slave devices 311 * 312 * Create and register a new ccw group device as a child of @parent. Slave 313 * devices are obtained from the list of bus ids given in @buf. 314 * Returns: 315 * %0 on success and an error code on failure. 316 * Context: 317 * non-atomic 318 */ 319 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv, 320 int num_devices, const char *buf) 321 { 322 struct ccwgroup_device *gdev; 323 struct ccw_dev_id dev_id; 324 int rc, i; 325 326 if (num_devices < 1) 327 return -EINVAL; 328 329 gdev = kzalloc(struct_size(gdev, cdev, num_devices), GFP_KERNEL); 330 if (!gdev) 331 return -ENOMEM; 332 333 atomic_set(&gdev->onoff, 0); 334 mutex_init(&gdev->reg_mutex); 335 mutex_lock(&gdev->reg_mutex); 336 INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn); 337 gdev->count = num_devices; 338 gdev->dev.bus = &ccwgroup_bus_type; 339 gdev->dev.parent = parent; 340 gdev->dev.release = ccwgroup_release; 341 device_initialize(&gdev->dev); 342 343 for (i = 0; i < num_devices && buf; i++) { 344 rc = __get_next_id(&buf, &dev_id); 345 if (rc != 0) 346 goto error; 347 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id); 348 /* 349 * All devices have to be of the same type in 350 * order to be grouped. 351 */ 352 if (!gdev->cdev[i] || !gdev->cdev[i]->drv || 353 gdev->cdev[i]->drv != gdev->cdev[0]->drv || 354 gdev->cdev[i]->id.driver_info != 355 gdev->cdev[0]->id.driver_info) { 356 rc = -EINVAL; 357 goto error; 358 } 359 /* Don't allow a device to belong to more than one group. */ 360 spin_lock_irq(gdev->cdev[i]->ccwlock); 361 if (dev_get_drvdata(&gdev->cdev[i]->dev)) { 362 spin_unlock_irq(gdev->cdev[i]->ccwlock); 363 rc = -EINVAL; 364 goto error; 365 } 366 dev_set_drvdata(&gdev->cdev[i]->dev, gdev); 367 spin_unlock_irq(gdev->cdev[i]->ccwlock); 368 } 369 /* Check for sufficient number of bus ids. */ 370 if (i < num_devices) { 371 rc = -EINVAL; 372 goto error; 373 } 374 /* Check for trailing stuff. */ 375 if (i == num_devices && strlen(buf) > 0) { 376 rc = -EINVAL; 377 goto error; 378 } 379 /* Check if the devices are bound to the required ccw driver. */ 380 if (gdrv && gdrv->ccw_driver && 381 gdev->cdev[0]->drv != gdrv->ccw_driver) { 382 rc = -EINVAL; 383 goto error; 384 } 385 386 dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev)); 387 gdev->dev.groups = ccwgroup_attr_groups; 388 389 if (gdrv) { 390 gdev->dev.driver = &gdrv->driver; 391 rc = gdrv->setup ? gdrv->setup(gdev) : 0; 392 if (rc) 393 goto error; 394 } 395 rc = device_add(&gdev->dev); 396 if (rc) 397 goto error; 398 rc = __ccwgroup_create_symlinks(gdev); 399 if (rc) { 400 device_del(&gdev->dev); 401 goto error; 402 } 403 mutex_unlock(&gdev->reg_mutex); 404 return 0; 405 error: 406 for (i = 0; i < num_devices; i++) 407 if (gdev->cdev[i]) { 408 spin_lock_irq(gdev->cdev[i]->ccwlock); 409 if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev) 410 dev_set_drvdata(&gdev->cdev[i]->dev, NULL); 411 spin_unlock_irq(gdev->cdev[i]->ccwlock); 412 put_device(&gdev->cdev[i]->dev); 413 gdev->cdev[i] = NULL; 414 } 415 mutex_unlock(&gdev->reg_mutex); 416 put_device(&gdev->dev); 417 return rc; 418 } 419 EXPORT_SYMBOL(ccwgroup_create_dev); 420 421 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action, 422 void *data) 423 { 424 struct ccwgroup_device *gdev = to_ccwgroupdev(data); 425 426 if (action == BUS_NOTIFY_UNBIND_DRIVER) { 427 get_device(&gdev->dev); 428 schedule_work(&gdev->ungroup_work); 429 } 430 431 return NOTIFY_OK; 432 } 433 434 static struct notifier_block ccwgroup_nb = { 435 .notifier_call = ccwgroup_notifier 436 }; 437 438 static int __init init_ccwgroup(void) 439 { 440 int ret; 441 442 ret = bus_register(&ccwgroup_bus_type); 443 if (ret) 444 return ret; 445 446 ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb); 447 if (ret) 448 bus_unregister(&ccwgroup_bus_type); 449 450 return ret; 451 } 452 453 static void __exit cleanup_ccwgroup(void) 454 { 455 bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb); 456 bus_unregister(&ccwgroup_bus_type); 457 } 458 459 module_init(init_ccwgroup); 460 module_exit(cleanup_ccwgroup); 461 462 /************************** driver stuff ******************************/ 463 464 static int ccwgroup_remove(struct device *dev) 465 { 466 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 467 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); 468 469 if (!dev->driver) 470 return 0; 471 if (gdrv->remove) 472 gdrv->remove(gdev); 473 474 return 0; 475 } 476 477 static void ccwgroup_shutdown(struct device *dev) 478 { 479 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 480 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); 481 482 if (!dev->driver) 483 return; 484 if (gdrv->shutdown) 485 gdrv->shutdown(gdev); 486 } 487 488 static int ccwgroup_pm_prepare(struct device *dev) 489 { 490 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 491 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 492 493 /* Fail while device is being set online/offline. */ 494 if (atomic_read(&gdev->onoff)) 495 return -EAGAIN; 496 497 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE) 498 return 0; 499 500 return gdrv->prepare ? gdrv->prepare(gdev) : 0; 501 } 502 503 static void ccwgroup_pm_complete(struct device *dev) 504 { 505 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 506 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver); 507 508 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE) 509 return; 510 511 if (gdrv->complete) 512 gdrv->complete(gdev); 513 } 514 515 static int ccwgroup_pm_freeze(struct device *dev) 516 { 517 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 518 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 519 520 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE) 521 return 0; 522 523 return gdrv->freeze ? gdrv->freeze(gdev) : 0; 524 } 525 526 static int ccwgroup_pm_thaw(struct device *dev) 527 { 528 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 529 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 530 531 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE) 532 return 0; 533 534 return gdrv->thaw ? gdrv->thaw(gdev) : 0; 535 } 536 537 static int ccwgroup_pm_restore(struct device *dev) 538 { 539 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 540 struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver); 541 542 if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE) 543 return 0; 544 545 return gdrv->restore ? gdrv->restore(gdev) : 0; 546 } 547 548 static const struct dev_pm_ops ccwgroup_pm_ops = { 549 .prepare = ccwgroup_pm_prepare, 550 .complete = ccwgroup_pm_complete, 551 .freeze = ccwgroup_pm_freeze, 552 .thaw = ccwgroup_pm_thaw, 553 .restore = ccwgroup_pm_restore, 554 }; 555 556 static struct bus_type ccwgroup_bus_type = { 557 .name = "ccwgroup", 558 .remove = ccwgroup_remove, 559 .shutdown = ccwgroup_shutdown, 560 .pm = &ccwgroup_pm_ops, 561 }; 562 563 bool dev_is_ccwgroup(struct device *dev) 564 { 565 return dev->bus == &ccwgroup_bus_type; 566 } 567 EXPORT_SYMBOL(dev_is_ccwgroup); 568 569 /** 570 * ccwgroup_driver_register() - register a ccw group driver 571 * @cdriver: driver to be registered 572 * 573 * This function is mainly a wrapper around driver_register(). 574 */ 575 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver) 576 { 577 /* register our new driver with the core */ 578 cdriver->driver.bus = &ccwgroup_bus_type; 579 580 return driver_register(&cdriver->driver); 581 } 582 EXPORT_SYMBOL(ccwgroup_driver_register); 583 584 static int __ccwgroup_match_all(struct device *dev, const void *data) 585 { 586 return 1; 587 } 588 589 /** 590 * ccwgroup_driver_unregister() - deregister a ccw group driver 591 * @cdriver: driver to be deregistered 592 * 593 * This function is mainly a wrapper around driver_unregister(). 594 */ 595 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver) 596 { 597 struct device *dev; 598 599 /* We don't want ccwgroup devices to live longer than their driver. */ 600 while ((dev = driver_find_device(&cdriver->driver, NULL, NULL, 601 __ccwgroup_match_all))) { 602 struct ccwgroup_device *gdev = to_ccwgroupdev(dev); 603 604 ccwgroup_ungroup(gdev); 605 put_device(dev); 606 } 607 driver_unregister(&cdriver->driver); 608 } 609 EXPORT_SYMBOL(ccwgroup_driver_unregister); 610 611 static int __ccwgroupdev_check_busid(struct device *dev, const void *id) 612 { 613 const char *bus_id = id; 614 615 return (strcmp(bus_id, dev_name(dev)) == 0); 616 } 617 618 /** 619 * get_ccwgroupdev_by_busid() - obtain device from a bus id 620 * @gdrv: driver the device is owned by 621 * @bus_id: bus id of the device to be searched 622 * 623 * This function searches all devices owned by @gdrv for a device with a bus 624 * id matching @bus_id. 625 * Returns: 626 * If a match is found, its reference count of the found device is increased 627 * and it is returned; else %NULL is returned. 628 */ 629 struct ccwgroup_device *get_ccwgroupdev_by_busid(struct ccwgroup_driver *gdrv, 630 char *bus_id) 631 { 632 struct device *dev; 633 634 dev = driver_find_device(&gdrv->driver, NULL, bus_id, 635 __ccwgroupdev_check_busid); 636 637 return dev ? to_ccwgroupdev(dev) : NULL; 638 } 639 EXPORT_SYMBOL_GPL(get_ccwgroupdev_by_busid); 640 641 /** 642 * ccwgroup_probe_ccwdev() - probe function for slave devices 643 * @cdev: ccw device to be probed 644 * 645 * This is a dummy probe function for ccw devices that are slave devices in 646 * a ccw group device. 647 * Returns: 648 * always %0 649 */ 650 int ccwgroup_probe_ccwdev(struct ccw_device *cdev) 651 { 652 return 0; 653 } 654 EXPORT_SYMBOL(ccwgroup_probe_ccwdev); 655 656 /** 657 * ccwgroup_remove_ccwdev() - remove function for slave devices 658 * @cdev: ccw device to be removed 659 * 660 * This is a remove function for ccw devices that are slave devices in a ccw 661 * group device. It sets the ccw device offline and also deregisters the 662 * embedding ccw group device. 663 */ 664 void ccwgroup_remove_ccwdev(struct ccw_device *cdev) 665 { 666 struct ccwgroup_device *gdev; 667 668 /* Ignore offlining errors, device is gone anyway. */ 669 ccw_device_set_offline(cdev); 670 /* If one of its devices is gone, the whole group is done for. */ 671 spin_lock_irq(cdev->ccwlock); 672 gdev = dev_get_drvdata(&cdev->dev); 673 if (!gdev) { 674 spin_unlock_irq(cdev->ccwlock); 675 return; 676 } 677 /* Get ccwgroup device reference for local processing. */ 678 get_device(&gdev->dev); 679 spin_unlock_irq(cdev->ccwlock); 680 /* Unregister group device. */ 681 ccwgroup_ungroup(gdev); 682 /* Release ccwgroup device reference for local processing. */ 683 put_device(&gdev->dev); 684 } 685 EXPORT_SYMBOL(ccwgroup_remove_ccwdev); 686 MODULE_LICENSE("GPL"); 687