1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2021, Linaro Ltd <loic.poulain@linaro.org> */ 3 4 #include <linux/bitmap.h> 5 #include <linux/err.h> 6 #include <linux/errno.h> 7 #include <linux/debugfs.h> 8 #include <linux/fs.h> 9 #include <linux/init.h> 10 #include <linux/idr.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/poll.h> 14 #include <linux/skbuff.h> 15 #include <linux/slab.h> 16 #include <linux/types.h> 17 #include <linux/uaccess.h> 18 #include <linux/termios.h> 19 #include <linux/wwan.h> 20 #include <net/rtnetlink.h> 21 #include <uapi/linux/wwan.h> 22 23 /* Maximum number of minors in use */ 24 #define WWAN_MAX_MINORS (1 << MINORBITS) 25 26 static DEFINE_MUTEX(wwan_register_lock); /* WWAN device create|remove lock */ 27 static DEFINE_IDA(minors); /* minors for WWAN port chardevs */ 28 static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */ 29 static struct class *wwan_class; 30 static int wwan_major; 31 static struct dentry *wwan_debugfs_dir; 32 33 #define to_wwan_dev(d) container_of(d, struct wwan_device, dev) 34 #define to_wwan_port(d) container_of(d, struct wwan_port, dev) 35 36 /* WWAN port flags */ 37 #define WWAN_PORT_TX_OFF 0 38 39 /** 40 * struct wwan_device - The structure that defines a WWAN device 41 * 42 * @id: WWAN device unique ID. 43 * @dev: Underlying device. 44 * @port_id: Current available port ID to pick. 45 * @ops: wwan device ops 46 * @ops_ctxt: context to pass to ops 47 * @debugfs_dir: WWAN device debugfs dir 48 */ 49 struct wwan_device { 50 unsigned int id; 51 struct device dev; 52 atomic_t port_id; 53 const struct wwan_ops *ops; 54 void *ops_ctxt; 55 #ifdef CONFIG_WWAN_DEBUGFS 56 struct dentry *debugfs_dir; 57 #endif 58 }; 59 60 /** 61 * struct wwan_port - The structure that defines a WWAN port 62 * @type: Port type 63 * @start_count: Port start counter 64 * @flags: Store port state and capabilities 65 * @ops: Pointer to WWAN port operations 66 * @ops_lock: Protect port ops 67 * @dev: Underlying device 68 * @rxq: Buffer inbound queue 69 * @waitqueue: The waitqueue for port fops (read/write/poll) 70 * @data_lock: Port specific data access serialization 71 * @headroom_len: SKB reserved headroom size 72 * @frag_len: Length to fragment packet 73 * @at_data: AT port specific data 74 */ 75 struct wwan_port { 76 enum wwan_port_type type; 77 unsigned int start_count; 78 unsigned long flags; 79 const struct wwan_port_ops *ops; 80 struct mutex ops_lock; /* Serialize ops + protect against removal */ 81 struct device dev; 82 struct sk_buff_head rxq; 83 wait_queue_head_t waitqueue; 84 struct mutex data_lock; /* Port specific data access serialization */ 85 size_t headroom_len; 86 size_t frag_len; 87 union { 88 struct { 89 struct ktermios termios; 90 int mdmbits; 91 } at_data; 92 }; 93 }; 94 95 static ssize_t index_show(struct device *dev, struct device_attribute *attr, char *buf) 96 { 97 struct wwan_device *wwan = to_wwan_dev(dev); 98 99 return sprintf(buf, "%d\n", wwan->id); 100 } 101 static DEVICE_ATTR_RO(index); 102 103 static struct attribute *wwan_dev_attrs[] = { 104 &dev_attr_index.attr, 105 NULL, 106 }; 107 ATTRIBUTE_GROUPS(wwan_dev); 108 109 static void wwan_dev_destroy(struct device *dev) 110 { 111 struct wwan_device *wwandev = to_wwan_dev(dev); 112 113 ida_free(&wwan_dev_ids, wwandev->id); 114 kfree(wwandev); 115 } 116 117 static const struct device_type wwan_dev_type = { 118 .name = "wwan_dev", 119 .release = wwan_dev_destroy, 120 .groups = wwan_dev_groups, 121 }; 122 123 static int wwan_dev_parent_match(struct device *dev, const void *parent) 124 { 125 return (dev->type == &wwan_dev_type && 126 (dev->parent == parent || dev == parent)); 127 } 128 129 static struct wwan_device *wwan_dev_get_by_parent(struct device *parent) 130 { 131 struct device *dev; 132 133 dev = class_find_device(wwan_class, NULL, parent, wwan_dev_parent_match); 134 if (!dev) 135 return ERR_PTR(-ENODEV); 136 137 return to_wwan_dev(dev); 138 } 139 140 static int wwan_dev_name_match(struct device *dev, const void *name) 141 { 142 return dev->type == &wwan_dev_type && 143 strcmp(dev_name(dev), name) == 0; 144 } 145 146 static struct wwan_device *wwan_dev_get_by_name(const char *name) 147 { 148 struct device *dev; 149 150 dev = class_find_device(wwan_class, NULL, name, wwan_dev_name_match); 151 if (!dev) 152 return ERR_PTR(-ENODEV); 153 154 return to_wwan_dev(dev); 155 } 156 157 #ifdef CONFIG_WWAN_DEBUGFS 158 struct dentry *wwan_get_debugfs_dir(struct device *parent) 159 { 160 struct wwan_device *wwandev; 161 162 wwandev = wwan_dev_get_by_parent(parent); 163 if (IS_ERR(wwandev)) 164 return ERR_CAST(wwandev); 165 166 return wwandev->debugfs_dir; 167 } 168 EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir); 169 170 static int wwan_dev_debugfs_match(struct device *dev, const void *dir) 171 { 172 struct wwan_device *wwandev; 173 174 if (dev->type != &wwan_dev_type) 175 return 0; 176 177 wwandev = to_wwan_dev(dev); 178 179 return wwandev->debugfs_dir == dir; 180 } 181 182 static struct wwan_device *wwan_dev_get_by_debugfs(struct dentry *dir) 183 { 184 struct device *dev; 185 186 dev = class_find_device(wwan_class, NULL, dir, wwan_dev_debugfs_match); 187 if (!dev) 188 return ERR_PTR(-ENODEV); 189 190 return to_wwan_dev(dev); 191 } 192 193 void wwan_put_debugfs_dir(struct dentry *dir) 194 { 195 struct wwan_device *wwandev = wwan_dev_get_by_debugfs(dir); 196 197 if (WARN_ON(IS_ERR(wwandev))) 198 return; 199 200 /* wwan_dev_get_by_debugfs() also got a reference */ 201 put_device(&wwandev->dev); 202 put_device(&wwandev->dev); 203 } 204 EXPORT_SYMBOL_GPL(wwan_put_debugfs_dir); 205 #endif 206 207 /* This function allocates and registers a new WWAN device OR if a WWAN device 208 * already exist for the given parent, it gets a reference and return it. 209 * This function is not exported (for now), it is called indirectly via 210 * wwan_create_port(). 211 */ 212 static struct wwan_device *wwan_create_dev(struct device *parent) 213 { 214 struct wwan_device *wwandev; 215 int err, id; 216 217 /* The 'find-alloc-register' operation must be protected against 218 * concurrent execution, a WWAN device is possibly shared between 219 * multiple callers or concurrently unregistered from wwan_remove_dev(). 220 */ 221 mutex_lock(&wwan_register_lock); 222 223 /* If wwandev already exists, return it */ 224 wwandev = wwan_dev_get_by_parent(parent); 225 if (!IS_ERR(wwandev)) 226 goto done_unlock; 227 228 id = ida_alloc(&wwan_dev_ids, GFP_KERNEL); 229 if (id < 0) { 230 wwandev = ERR_PTR(id); 231 goto done_unlock; 232 } 233 234 wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL); 235 if (!wwandev) { 236 wwandev = ERR_PTR(-ENOMEM); 237 ida_free(&wwan_dev_ids, id); 238 goto done_unlock; 239 } 240 241 wwandev->dev.parent = parent; 242 wwandev->dev.class = wwan_class; 243 wwandev->dev.type = &wwan_dev_type; 244 wwandev->id = id; 245 dev_set_name(&wwandev->dev, "wwan%d", wwandev->id); 246 247 err = device_register(&wwandev->dev); 248 if (err) { 249 put_device(&wwandev->dev); 250 wwandev = ERR_PTR(err); 251 goto done_unlock; 252 } 253 254 #ifdef CONFIG_WWAN_DEBUGFS 255 wwandev->debugfs_dir = 256 debugfs_create_dir(kobject_name(&wwandev->dev.kobj), 257 wwan_debugfs_dir); 258 #endif 259 260 done_unlock: 261 mutex_unlock(&wwan_register_lock); 262 263 return wwandev; 264 } 265 266 static int is_wwan_child(struct device *dev, void *data) 267 { 268 return dev->class == wwan_class; 269 } 270 271 static void wwan_remove_dev(struct wwan_device *wwandev) 272 { 273 int ret; 274 275 /* Prevent concurrent picking from wwan_create_dev */ 276 mutex_lock(&wwan_register_lock); 277 278 /* WWAN device is created and registered (get+add) along with its first 279 * child port, and subsequent port registrations only grab a reference 280 * (get). The WWAN device must then be unregistered (del+put) along with 281 * its last port, and reference simply dropped (put) otherwise. In the 282 * same fashion, we must not unregister it when the ops are still there. 283 */ 284 if (wwandev->ops) 285 ret = 1; 286 else 287 ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); 288 289 if (!ret) { 290 #ifdef CONFIG_WWAN_DEBUGFS 291 debugfs_remove_recursive(wwandev->debugfs_dir); 292 #endif 293 device_unregister(&wwandev->dev); 294 } else { 295 put_device(&wwandev->dev); 296 } 297 298 mutex_unlock(&wwan_register_lock); 299 } 300 301 /* ------- WWAN port management ------- */ 302 303 static const struct { 304 const char * const name; /* Port type name */ 305 const char * const devsuf; /* Port device name suffix */ 306 } wwan_port_types[WWAN_PORT_MAX + 1] = { 307 [WWAN_PORT_AT] = { 308 .name = "AT", 309 .devsuf = "at", 310 }, 311 [WWAN_PORT_MBIM] = { 312 .name = "MBIM", 313 .devsuf = "mbim", 314 }, 315 [WWAN_PORT_QMI] = { 316 .name = "QMI", 317 .devsuf = "qmi", 318 }, 319 [WWAN_PORT_QCDM] = { 320 .name = "QCDM", 321 .devsuf = "qcdm", 322 }, 323 [WWAN_PORT_FIREHOSE] = { 324 .name = "FIREHOSE", 325 .devsuf = "firehose", 326 }, 327 [WWAN_PORT_XMMRPC] = { 328 .name = "XMMRPC", 329 .devsuf = "xmmrpc", 330 }, 331 }; 332 333 static ssize_t type_show(struct device *dev, struct device_attribute *attr, 334 char *buf) 335 { 336 struct wwan_port *port = to_wwan_port(dev); 337 338 return sprintf(buf, "%s\n", wwan_port_types[port->type].name); 339 } 340 static DEVICE_ATTR_RO(type); 341 342 static struct attribute *wwan_port_attrs[] = { 343 &dev_attr_type.attr, 344 NULL, 345 }; 346 ATTRIBUTE_GROUPS(wwan_port); 347 348 static void wwan_port_destroy(struct device *dev) 349 { 350 struct wwan_port *port = to_wwan_port(dev); 351 352 ida_free(&minors, MINOR(port->dev.devt)); 353 mutex_destroy(&port->data_lock); 354 mutex_destroy(&port->ops_lock); 355 kfree(port); 356 } 357 358 static const struct device_type wwan_port_dev_type = { 359 .name = "wwan_port", 360 .release = wwan_port_destroy, 361 .groups = wwan_port_groups, 362 }; 363 364 static int wwan_port_minor_match(struct device *dev, const void *minor) 365 { 366 return (dev->type == &wwan_port_dev_type && 367 MINOR(dev->devt) == *(unsigned int *)minor); 368 } 369 370 static struct wwan_port *wwan_port_get_by_minor(unsigned int minor) 371 { 372 struct device *dev; 373 374 dev = class_find_device(wwan_class, NULL, &minor, wwan_port_minor_match); 375 if (!dev) 376 return ERR_PTR(-ENODEV); 377 378 return to_wwan_port(dev); 379 } 380 381 /* Allocate and set unique name based on passed format 382 * 383 * Name allocation approach is highly inspired by the __dev_alloc_name() 384 * function. 385 * 386 * To avoid names collision, the caller must prevent the new port device 387 * registration as well as concurrent invocation of this function. 388 */ 389 static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt) 390 { 391 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent); 392 const unsigned int max_ports = PAGE_SIZE * 8; 393 struct class_dev_iter iter; 394 unsigned long *idmap; 395 struct device *dev; 396 char buf[0x20]; 397 int id; 398 399 idmap = bitmap_zalloc(max_ports, GFP_KERNEL); 400 if (!idmap) 401 return -ENOMEM; 402 403 /* Collect ids of same name format ports */ 404 class_dev_iter_init(&iter, wwan_class, NULL, &wwan_port_dev_type); 405 while ((dev = class_dev_iter_next(&iter))) { 406 if (dev->parent != &wwandev->dev) 407 continue; 408 if (sscanf(dev_name(dev), fmt, &id) != 1) 409 continue; 410 if (id < 0 || id >= max_ports) 411 continue; 412 set_bit(id, idmap); 413 } 414 class_dev_iter_exit(&iter); 415 416 /* Allocate unique id */ 417 id = find_first_zero_bit(idmap, max_ports); 418 bitmap_free(idmap); 419 420 snprintf(buf, sizeof(buf), fmt, id); /* Name generation */ 421 422 dev = device_find_child_by_name(&wwandev->dev, buf); 423 if (dev) { 424 put_device(dev); 425 return -ENFILE; 426 } 427 428 return dev_set_name(&port->dev, buf); 429 } 430 431 struct wwan_port *wwan_create_port(struct device *parent, 432 enum wwan_port_type type, 433 const struct wwan_port_ops *ops, 434 struct wwan_port_caps *caps, 435 void *drvdata) 436 { 437 struct wwan_device *wwandev; 438 struct wwan_port *port; 439 char namefmt[0x20]; 440 int minor, err; 441 442 if (type > WWAN_PORT_MAX || !ops) 443 return ERR_PTR(-EINVAL); 444 445 /* A port is always a child of a WWAN device, retrieve (allocate or 446 * pick) the WWAN device based on the provided parent device. 447 */ 448 wwandev = wwan_create_dev(parent); 449 if (IS_ERR(wwandev)) 450 return ERR_CAST(wwandev); 451 452 /* A port is exposed as character device, get a minor */ 453 minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS - 1, GFP_KERNEL); 454 if (minor < 0) { 455 err = minor; 456 goto error_wwandev_remove; 457 } 458 459 port = kzalloc(sizeof(*port), GFP_KERNEL); 460 if (!port) { 461 err = -ENOMEM; 462 ida_free(&minors, minor); 463 goto error_wwandev_remove; 464 } 465 466 port->type = type; 467 port->ops = ops; 468 port->frag_len = caps ? caps->frag_len : SIZE_MAX; 469 port->headroom_len = caps ? caps->headroom_len : 0; 470 mutex_init(&port->ops_lock); 471 skb_queue_head_init(&port->rxq); 472 init_waitqueue_head(&port->waitqueue); 473 mutex_init(&port->data_lock); 474 475 port->dev.parent = &wwandev->dev; 476 port->dev.class = wwan_class; 477 port->dev.type = &wwan_port_dev_type; 478 port->dev.devt = MKDEV(wwan_major, minor); 479 dev_set_drvdata(&port->dev, drvdata); 480 481 /* allocate unique name based on wwan device id, port type and number */ 482 snprintf(namefmt, sizeof(namefmt), "wwan%u%s%%d", wwandev->id, 483 wwan_port_types[port->type].devsuf); 484 485 /* Serialize ports registration */ 486 mutex_lock(&wwan_register_lock); 487 488 __wwan_port_dev_assign_name(port, namefmt); 489 err = device_register(&port->dev); 490 491 mutex_unlock(&wwan_register_lock); 492 493 if (err) 494 goto error_put_device; 495 496 dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev)); 497 return port; 498 499 error_put_device: 500 put_device(&port->dev); 501 error_wwandev_remove: 502 wwan_remove_dev(wwandev); 503 504 return ERR_PTR(err); 505 } 506 EXPORT_SYMBOL_GPL(wwan_create_port); 507 508 void wwan_remove_port(struct wwan_port *port) 509 { 510 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent); 511 512 mutex_lock(&port->ops_lock); 513 if (port->start_count) 514 port->ops->stop(port); 515 port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */ 516 mutex_unlock(&port->ops_lock); 517 518 wake_up_interruptible(&port->waitqueue); 519 520 skb_queue_purge(&port->rxq); 521 dev_set_drvdata(&port->dev, NULL); 522 523 dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev)); 524 device_unregister(&port->dev); 525 526 /* Release related wwan device */ 527 wwan_remove_dev(wwandev); 528 } 529 EXPORT_SYMBOL_GPL(wwan_remove_port); 530 531 void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb) 532 { 533 skb_queue_tail(&port->rxq, skb); 534 wake_up_interruptible(&port->waitqueue); 535 } 536 EXPORT_SYMBOL_GPL(wwan_port_rx); 537 538 void wwan_port_txon(struct wwan_port *port) 539 { 540 clear_bit(WWAN_PORT_TX_OFF, &port->flags); 541 wake_up_interruptible(&port->waitqueue); 542 } 543 EXPORT_SYMBOL_GPL(wwan_port_txon); 544 545 void wwan_port_txoff(struct wwan_port *port) 546 { 547 set_bit(WWAN_PORT_TX_OFF, &port->flags); 548 } 549 EXPORT_SYMBOL_GPL(wwan_port_txoff); 550 551 void *wwan_port_get_drvdata(struct wwan_port *port) 552 { 553 return dev_get_drvdata(&port->dev); 554 } 555 EXPORT_SYMBOL_GPL(wwan_port_get_drvdata); 556 557 static int wwan_port_op_start(struct wwan_port *port) 558 { 559 int ret = 0; 560 561 mutex_lock(&port->ops_lock); 562 if (!port->ops) { /* Port got unplugged */ 563 ret = -ENODEV; 564 goto out_unlock; 565 } 566 567 /* If port is already started, don't start again */ 568 if (!port->start_count) 569 ret = port->ops->start(port); 570 571 if (!ret) 572 port->start_count++; 573 574 out_unlock: 575 mutex_unlock(&port->ops_lock); 576 577 return ret; 578 } 579 580 static void wwan_port_op_stop(struct wwan_port *port) 581 { 582 mutex_lock(&port->ops_lock); 583 port->start_count--; 584 if (!port->start_count) { 585 if (port->ops) 586 port->ops->stop(port); 587 skb_queue_purge(&port->rxq); 588 } 589 mutex_unlock(&port->ops_lock); 590 } 591 592 static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb, 593 bool nonblock) 594 { 595 int ret; 596 597 mutex_lock(&port->ops_lock); 598 if (!port->ops) { /* Port got unplugged */ 599 ret = -ENODEV; 600 goto out_unlock; 601 } 602 603 if (nonblock || !port->ops->tx_blocking) 604 ret = port->ops->tx(port, skb); 605 else 606 ret = port->ops->tx_blocking(port, skb); 607 608 out_unlock: 609 mutex_unlock(&port->ops_lock); 610 611 return ret; 612 } 613 614 static bool is_read_blocked(struct wwan_port *port) 615 { 616 return skb_queue_empty(&port->rxq) && port->ops; 617 } 618 619 static bool is_write_blocked(struct wwan_port *port) 620 { 621 return test_bit(WWAN_PORT_TX_OFF, &port->flags) && port->ops; 622 } 623 624 static int wwan_wait_rx(struct wwan_port *port, bool nonblock) 625 { 626 if (!is_read_blocked(port)) 627 return 0; 628 629 if (nonblock) 630 return -EAGAIN; 631 632 if (wait_event_interruptible(port->waitqueue, !is_read_blocked(port))) 633 return -ERESTARTSYS; 634 635 return 0; 636 } 637 638 static int wwan_wait_tx(struct wwan_port *port, bool nonblock) 639 { 640 if (!is_write_blocked(port)) 641 return 0; 642 643 if (nonblock) 644 return -EAGAIN; 645 646 if (wait_event_interruptible(port->waitqueue, !is_write_blocked(port))) 647 return -ERESTARTSYS; 648 649 return 0; 650 } 651 652 static int wwan_port_fops_open(struct inode *inode, struct file *file) 653 { 654 struct wwan_port *port; 655 int err = 0; 656 657 port = wwan_port_get_by_minor(iminor(inode)); 658 if (IS_ERR(port)) 659 return PTR_ERR(port); 660 661 file->private_data = port; 662 stream_open(inode, file); 663 664 err = wwan_port_op_start(port); 665 if (err) 666 put_device(&port->dev); 667 668 return err; 669 } 670 671 static int wwan_port_fops_release(struct inode *inode, struct file *filp) 672 { 673 struct wwan_port *port = filp->private_data; 674 675 wwan_port_op_stop(port); 676 put_device(&port->dev); 677 678 return 0; 679 } 680 681 static ssize_t wwan_port_fops_read(struct file *filp, char __user *buf, 682 size_t count, loff_t *ppos) 683 { 684 struct wwan_port *port = filp->private_data; 685 struct sk_buff *skb; 686 size_t copied; 687 int ret; 688 689 ret = wwan_wait_rx(port, !!(filp->f_flags & O_NONBLOCK)); 690 if (ret) 691 return ret; 692 693 skb = skb_dequeue(&port->rxq); 694 if (!skb) 695 return -EIO; 696 697 copied = min_t(size_t, count, skb->len); 698 if (copy_to_user(buf, skb->data, copied)) { 699 kfree_skb(skb); 700 return -EFAULT; 701 } 702 skb_pull(skb, copied); 703 704 /* skb is not fully consumed, keep it in the queue */ 705 if (skb->len) 706 skb_queue_head(&port->rxq, skb); 707 else 708 consume_skb(skb); 709 710 return copied; 711 } 712 713 static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf, 714 size_t count, loff_t *offp) 715 { 716 struct sk_buff *skb, *head = NULL, *tail = NULL; 717 struct wwan_port *port = filp->private_data; 718 size_t frag_len, remain = count; 719 int ret; 720 721 ret = wwan_wait_tx(port, !!(filp->f_flags & O_NONBLOCK)); 722 if (ret) 723 return ret; 724 725 do { 726 frag_len = min(remain, port->frag_len); 727 skb = alloc_skb(frag_len + port->headroom_len, GFP_KERNEL); 728 if (!skb) { 729 ret = -ENOMEM; 730 goto freeskb; 731 } 732 skb_reserve(skb, port->headroom_len); 733 734 if (!head) { 735 head = skb; 736 } else if (!tail) { 737 skb_shinfo(head)->frag_list = skb; 738 tail = skb; 739 } else { 740 tail->next = skb; 741 tail = skb; 742 } 743 744 if (copy_from_user(skb_put(skb, frag_len), buf + count - remain, frag_len)) { 745 ret = -EFAULT; 746 goto freeskb; 747 } 748 749 if (skb != head) { 750 head->data_len += skb->len; 751 head->len += skb->len; 752 head->truesize += skb->truesize; 753 } 754 } while (remain -= frag_len); 755 756 ret = wwan_port_op_tx(port, head, !!(filp->f_flags & O_NONBLOCK)); 757 if (!ret) 758 return count; 759 760 freeskb: 761 kfree_skb(head); 762 return ret; 763 } 764 765 static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait) 766 { 767 struct wwan_port *port = filp->private_data; 768 __poll_t mask = 0; 769 770 poll_wait(filp, &port->waitqueue, wait); 771 772 mutex_lock(&port->ops_lock); 773 if (port->ops && port->ops->tx_poll) 774 mask |= port->ops->tx_poll(port, filp, wait); 775 else if (!is_write_blocked(port)) 776 mask |= EPOLLOUT | EPOLLWRNORM; 777 if (!is_read_blocked(port)) 778 mask |= EPOLLIN | EPOLLRDNORM; 779 if (!port->ops) 780 mask |= EPOLLHUP | EPOLLERR; 781 mutex_unlock(&port->ops_lock); 782 783 return mask; 784 } 785 786 /* Implements minimalistic stub terminal IOCTLs support */ 787 static long wwan_port_fops_at_ioctl(struct wwan_port *port, unsigned int cmd, 788 unsigned long arg) 789 { 790 int ret = 0; 791 792 mutex_lock(&port->data_lock); 793 794 switch (cmd) { 795 case TCFLSH: 796 break; 797 798 case TCGETS: 799 if (copy_to_user((void __user *)arg, &port->at_data.termios, 800 sizeof(struct termios))) 801 ret = -EFAULT; 802 break; 803 804 case TCSETS: 805 case TCSETSW: 806 case TCSETSF: 807 if (copy_from_user(&port->at_data.termios, (void __user *)arg, 808 sizeof(struct termios))) 809 ret = -EFAULT; 810 break; 811 812 #ifdef TCGETS2 813 case TCGETS2: 814 if (copy_to_user((void __user *)arg, &port->at_data.termios, 815 sizeof(struct termios2))) 816 ret = -EFAULT; 817 break; 818 819 case TCSETS2: 820 case TCSETSW2: 821 case TCSETSF2: 822 if (copy_from_user(&port->at_data.termios, (void __user *)arg, 823 sizeof(struct termios2))) 824 ret = -EFAULT; 825 break; 826 #endif 827 828 case TIOCMGET: 829 ret = put_user(port->at_data.mdmbits, (int __user *)arg); 830 break; 831 832 case TIOCMSET: 833 case TIOCMBIC: 834 case TIOCMBIS: { 835 int mdmbits; 836 837 if (copy_from_user(&mdmbits, (int __user *)arg, sizeof(int))) { 838 ret = -EFAULT; 839 break; 840 } 841 if (cmd == TIOCMBIC) 842 port->at_data.mdmbits &= ~mdmbits; 843 else if (cmd == TIOCMBIS) 844 port->at_data.mdmbits |= mdmbits; 845 else 846 port->at_data.mdmbits = mdmbits; 847 break; 848 } 849 850 default: 851 ret = -ENOIOCTLCMD; 852 } 853 854 mutex_unlock(&port->data_lock); 855 856 return ret; 857 } 858 859 static long wwan_port_fops_ioctl(struct file *filp, unsigned int cmd, 860 unsigned long arg) 861 { 862 struct wwan_port *port = filp->private_data; 863 int res; 864 865 if (port->type == WWAN_PORT_AT) { /* AT port specific IOCTLs */ 866 res = wwan_port_fops_at_ioctl(port, cmd, arg); 867 if (res != -ENOIOCTLCMD) 868 return res; 869 } 870 871 switch (cmd) { 872 case TIOCINQ: { /* aka SIOCINQ aka FIONREAD */ 873 unsigned long flags; 874 struct sk_buff *skb; 875 int amount = 0; 876 877 spin_lock_irqsave(&port->rxq.lock, flags); 878 skb_queue_walk(&port->rxq, skb) 879 amount += skb->len; 880 spin_unlock_irqrestore(&port->rxq.lock, flags); 881 882 return put_user(amount, (int __user *)arg); 883 } 884 885 default: 886 return -ENOIOCTLCMD; 887 } 888 } 889 890 static const struct file_operations wwan_port_fops = { 891 .owner = THIS_MODULE, 892 .open = wwan_port_fops_open, 893 .release = wwan_port_fops_release, 894 .read = wwan_port_fops_read, 895 .write = wwan_port_fops_write, 896 .poll = wwan_port_fops_poll, 897 .unlocked_ioctl = wwan_port_fops_ioctl, 898 #ifdef CONFIG_COMPAT 899 .compat_ioctl = compat_ptr_ioctl, 900 #endif 901 .llseek = noop_llseek, 902 }; 903 904 static int wwan_rtnl_validate(struct nlattr *tb[], struct nlattr *data[], 905 struct netlink_ext_ack *extack) 906 { 907 if (!data) 908 return -EINVAL; 909 910 if (!tb[IFLA_PARENT_DEV_NAME]) 911 return -EINVAL; 912 913 if (!data[IFLA_WWAN_LINK_ID]) 914 return -EINVAL; 915 916 return 0; 917 } 918 919 static struct device_type wwan_type = { .name = "wwan" }; 920 921 static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[], 922 const char *ifname, 923 unsigned char name_assign_type, 924 unsigned int num_tx_queues, 925 unsigned int num_rx_queues) 926 { 927 const char *devname = nla_data(tb[IFLA_PARENT_DEV_NAME]); 928 struct wwan_device *wwandev = wwan_dev_get_by_name(devname); 929 struct net_device *dev; 930 unsigned int priv_size; 931 932 if (IS_ERR(wwandev)) 933 return ERR_CAST(wwandev); 934 935 /* only supported if ops were registered (not just ports) */ 936 if (!wwandev->ops) { 937 dev = ERR_PTR(-EOPNOTSUPP); 938 goto out; 939 } 940 941 priv_size = sizeof(struct wwan_netdev_priv) + wwandev->ops->priv_size; 942 dev = alloc_netdev_mqs(priv_size, ifname, name_assign_type, 943 wwandev->ops->setup, num_tx_queues, num_rx_queues); 944 945 if (dev) { 946 SET_NETDEV_DEV(dev, &wwandev->dev); 947 SET_NETDEV_DEVTYPE(dev, &wwan_type); 948 } 949 950 out: 951 /* release the reference */ 952 put_device(&wwandev->dev); 953 return dev; 954 } 955 956 static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev, 957 struct nlattr *tb[], struct nlattr *data[], 958 struct netlink_ext_ack *extack) 959 { 960 struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); 961 u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]); 962 struct wwan_netdev_priv *priv = netdev_priv(dev); 963 int ret; 964 965 if (IS_ERR(wwandev)) 966 return PTR_ERR(wwandev); 967 968 /* shouldn't have a netdev (left) with us as parent so WARN */ 969 if (WARN_ON(!wwandev->ops)) { 970 ret = -EOPNOTSUPP; 971 goto out; 972 } 973 974 priv->link_id = link_id; 975 if (wwandev->ops->newlink) 976 ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev, 977 link_id, extack); 978 else 979 ret = register_netdevice(dev); 980 981 out: 982 /* release the reference */ 983 put_device(&wwandev->dev); 984 return ret; 985 } 986 987 static void wwan_rtnl_dellink(struct net_device *dev, struct list_head *head) 988 { 989 struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); 990 991 if (IS_ERR(wwandev)) 992 return; 993 994 /* shouldn't have a netdev (left) with us as parent so WARN */ 995 if (WARN_ON(!wwandev->ops)) 996 goto out; 997 998 if (wwandev->ops->dellink) 999 wwandev->ops->dellink(wwandev->ops_ctxt, dev, head); 1000 else 1001 unregister_netdevice_queue(dev, head); 1002 1003 out: 1004 /* release the reference */ 1005 put_device(&wwandev->dev); 1006 } 1007 1008 static size_t wwan_rtnl_get_size(const struct net_device *dev) 1009 { 1010 return 1011 nla_total_size(4) + /* IFLA_WWAN_LINK_ID */ 1012 0; 1013 } 1014 1015 static int wwan_rtnl_fill_info(struct sk_buff *skb, 1016 const struct net_device *dev) 1017 { 1018 struct wwan_netdev_priv *priv = netdev_priv(dev); 1019 1020 if (nla_put_u32(skb, IFLA_WWAN_LINK_ID, priv->link_id)) 1021 goto nla_put_failure; 1022 1023 return 0; 1024 1025 nla_put_failure: 1026 return -EMSGSIZE; 1027 } 1028 1029 static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = { 1030 [IFLA_WWAN_LINK_ID] = { .type = NLA_U32 }, 1031 }; 1032 1033 static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = { 1034 .kind = "wwan", 1035 .maxtype = __IFLA_WWAN_MAX, 1036 .alloc = wwan_rtnl_alloc, 1037 .validate = wwan_rtnl_validate, 1038 .newlink = wwan_rtnl_newlink, 1039 .dellink = wwan_rtnl_dellink, 1040 .get_size = wwan_rtnl_get_size, 1041 .fill_info = wwan_rtnl_fill_info, 1042 .policy = wwan_rtnl_policy, 1043 }; 1044 1045 static void wwan_create_default_link(struct wwan_device *wwandev, 1046 u32 def_link_id) 1047 { 1048 struct nlattr *tb[IFLA_MAX + 1], *linkinfo[IFLA_INFO_MAX + 1]; 1049 struct nlattr *data[IFLA_WWAN_MAX + 1]; 1050 struct net_device *dev; 1051 struct nlmsghdr *nlh; 1052 struct sk_buff *msg; 1053 1054 /* Forge attributes required to create a WWAN netdev. We first 1055 * build a netlink message and then parse it. This looks 1056 * odd, but such approach is less error prone. 1057 */ 1058 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1059 if (WARN_ON(!msg)) 1060 return; 1061 nlh = nlmsg_put(msg, 0, 0, RTM_NEWLINK, 0, 0); 1062 if (WARN_ON(!nlh)) 1063 goto free_attrs; 1064 1065 if (nla_put_string(msg, IFLA_PARENT_DEV_NAME, dev_name(&wwandev->dev))) 1066 goto free_attrs; 1067 tb[IFLA_LINKINFO] = nla_nest_start(msg, IFLA_LINKINFO); 1068 if (!tb[IFLA_LINKINFO]) 1069 goto free_attrs; 1070 linkinfo[IFLA_INFO_DATA] = nla_nest_start(msg, IFLA_INFO_DATA); 1071 if (!linkinfo[IFLA_INFO_DATA]) 1072 goto free_attrs; 1073 if (nla_put_u32(msg, IFLA_WWAN_LINK_ID, def_link_id)) 1074 goto free_attrs; 1075 nla_nest_end(msg, linkinfo[IFLA_INFO_DATA]); 1076 nla_nest_end(msg, tb[IFLA_LINKINFO]); 1077 1078 nlmsg_end(msg, nlh); 1079 1080 /* The next three parsing calls can not fail */ 1081 nlmsg_parse_deprecated(nlh, 0, tb, IFLA_MAX, NULL, NULL); 1082 nla_parse_nested_deprecated(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO], 1083 NULL, NULL); 1084 nla_parse_nested_deprecated(data, IFLA_WWAN_MAX, 1085 linkinfo[IFLA_INFO_DATA], NULL, NULL); 1086 1087 rtnl_lock(); 1088 1089 dev = rtnl_create_link(&init_net, "wwan%d", NET_NAME_ENUM, 1090 &wwan_rtnl_link_ops, tb, NULL); 1091 if (WARN_ON(IS_ERR(dev))) 1092 goto unlock; 1093 1094 if (WARN_ON(wwan_rtnl_newlink(&init_net, dev, tb, data, NULL))) { 1095 free_netdev(dev); 1096 goto unlock; 1097 } 1098 1099 rtnl_configure_link(dev, NULL, 0, NULL); /* Link initialized, notify new link */ 1100 1101 unlock: 1102 rtnl_unlock(); 1103 1104 free_attrs: 1105 nlmsg_free(msg); 1106 } 1107 1108 /** 1109 * wwan_register_ops - register WWAN device ops 1110 * @parent: Device to use as parent and shared by all WWAN ports and 1111 * created netdevs 1112 * @ops: operations to register 1113 * @ctxt: context to pass to operations 1114 * @def_link_id: id of the default link that will be automatically created by 1115 * the WWAN core for the WWAN device. The default link will not be created 1116 * if the passed value is WWAN_NO_DEFAULT_LINK. 1117 * 1118 * Returns: 0 on success, a negative error code on failure 1119 */ 1120 int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, 1121 void *ctxt, u32 def_link_id) 1122 { 1123 struct wwan_device *wwandev; 1124 1125 if (WARN_ON(!parent || !ops || !ops->setup)) 1126 return -EINVAL; 1127 1128 wwandev = wwan_create_dev(parent); 1129 if (IS_ERR(wwandev)) 1130 return PTR_ERR(wwandev); 1131 1132 if (WARN_ON(wwandev->ops)) { 1133 wwan_remove_dev(wwandev); 1134 return -EBUSY; 1135 } 1136 1137 wwandev->ops = ops; 1138 wwandev->ops_ctxt = ctxt; 1139 1140 /* NB: we do not abort ops registration in case of default link 1141 * creation failure. Link ops is the management interface, while the 1142 * default link creation is a service option. And we should not prevent 1143 * a user from manually creating a link latter if service option failed 1144 * now. 1145 */ 1146 if (def_link_id != WWAN_NO_DEFAULT_LINK) 1147 wwan_create_default_link(wwandev, def_link_id); 1148 1149 return 0; 1150 } 1151 EXPORT_SYMBOL_GPL(wwan_register_ops); 1152 1153 /* Enqueue child netdev deletion */ 1154 static int wwan_child_dellink(struct device *dev, void *data) 1155 { 1156 struct list_head *kill_list = data; 1157 1158 if (dev->type == &wwan_type) 1159 wwan_rtnl_dellink(to_net_dev(dev), kill_list); 1160 1161 return 0; 1162 } 1163 1164 /** 1165 * wwan_unregister_ops - remove WWAN device ops 1166 * @parent: Device to use as parent and shared by all WWAN ports and 1167 * created netdevs 1168 */ 1169 void wwan_unregister_ops(struct device *parent) 1170 { 1171 struct wwan_device *wwandev = wwan_dev_get_by_parent(parent); 1172 LIST_HEAD(kill_list); 1173 1174 if (WARN_ON(IS_ERR(wwandev))) 1175 return; 1176 if (WARN_ON(!wwandev->ops)) { 1177 put_device(&wwandev->dev); 1178 return; 1179 } 1180 1181 /* put the reference obtained by wwan_dev_get_by_parent(), 1182 * we should still have one (that the owner is giving back 1183 * now) due to the ops being assigned. 1184 */ 1185 put_device(&wwandev->dev); 1186 1187 rtnl_lock(); /* Prevent concurrent netdev(s) creation/destroying */ 1188 1189 /* Remove all child netdev(s), using batch removing */ 1190 device_for_each_child(&wwandev->dev, &kill_list, 1191 wwan_child_dellink); 1192 unregister_netdevice_many(&kill_list); 1193 1194 wwandev->ops = NULL; /* Finally remove ops */ 1195 1196 rtnl_unlock(); 1197 1198 wwandev->ops_ctxt = NULL; 1199 wwan_remove_dev(wwandev); 1200 } 1201 EXPORT_SYMBOL_GPL(wwan_unregister_ops); 1202 1203 static int __init wwan_init(void) 1204 { 1205 int err; 1206 1207 err = rtnl_link_register(&wwan_rtnl_link_ops); 1208 if (err) 1209 return err; 1210 1211 wwan_class = class_create("wwan"); 1212 if (IS_ERR(wwan_class)) { 1213 err = PTR_ERR(wwan_class); 1214 goto unregister; 1215 } 1216 1217 /* chrdev used for wwan ports */ 1218 wwan_major = __register_chrdev(0, 0, WWAN_MAX_MINORS, "wwan_port", 1219 &wwan_port_fops); 1220 if (wwan_major < 0) { 1221 err = wwan_major; 1222 goto destroy; 1223 } 1224 1225 #ifdef CONFIG_WWAN_DEBUGFS 1226 wwan_debugfs_dir = debugfs_create_dir("wwan", NULL); 1227 #endif 1228 1229 return 0; 1230 1231 destroy: 1232 class_destroy(wwan_class); 1233 unregister: 1234 rtnl_link_unregister(&wwan_rtnl_link_ops); 1235 return err; 1236 } 1237 1238 static void __exit wwan_exit(void) 1239 { 1240 debugfs_remove_recursive(wwan_debugfs_dir); 1241 __unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port"); 1242 rtnl_link_unregister(&wwan_rtnl_link_ops); 1243 class_destroy(wwan_class); 1244 } 1245 1246 module_init(wwan_init); 1247 module_exit(wwan_exit); 1248 1249 MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>"); 1250 MODULE_DESCRIPTION("WWAN core"); 1251 MODULE_LICENSE("GPL v2"); 1252