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 const struct class wwan_class = { 30 .name = "wwan", 31 }; 32 static int wwan_major; 33 static struct dentry *wwan_debugfs_dir; 34 35 #define to_wwan_dev(d) container_of(d, struct wwan_device, dev) 36 #define to_wwan_port(d) container_of(d, struct wwan_port, dev) 37 38 /* WWAN port flags */ 39 #define WWAN_PORT_TX_OFF 0 40 41 /** 42 * struct wwan_device - The structure that defines a WWAN device 43 * 44 * @id: WWAN device unique ID. 45 * @dev: Underlying device. 46 * @port_id: Current available port ID to pick. 47 * @ops: wwan device ops 48 * @ops_ctxt: context to pass to ops 49 * @debugfs_dir: WWAN device debugfs dir 50 */ 51 struct wwan_device { 52 unsigned int id; 53 struct device dev; 54 atomic_t port_id; 55 const struct wwan_ops *ops; 56 void *ops_ctxt; 57 #ifdef CONFIG_WWAN_DEBUGFS 58 struct dentry *debugfs_dir; 59 #endif 60 }; 61 62 /** 63 * struct wwan_port - The structure that defines a WWAN port 64 * @type: Port type 65 * @start_count: Port start counter 66 * @flags: Store port state and capabilities 67 * @ops: Pointer to WWAN port operations 68 * @ops_lock: Protect port ops 69 * @dev: Underlying device 70 * @rxq: Buffer inbound queue 71 * @waitqueue: The waitqueue for port fops (read/write/poll) 72 * @data_lock: Port specific data access serialization 73 * @headroom_len: SKB reserved headroom size 74 * @frag_len: Length to fragment packet 75 * @at_data: AT port specific data 76 */ 77 struct wwan_port { 78 enum wwan_port_type type; 79 unsigned int start_count; 80 unsigned long flags; 81 const struct wwan_port_ops *ops; 82 struct mutex ops_lock; /* Serialize ops + protect against removal */ 83 struct device dev; 84 struct sk_buff_head rxq; 85 wait_queue_head_t waitqueue; 86 struct mutex data_lock; /* Port specific data access serialization */ 87 size_t headroom_len; 88 size_t frag_len; 89 union { 90 struct { 91 struct ktermios termios; 92 int mdmbits; 93 } at_data; 94 }; 95 }; 96 97 static ssize_t index_show(struct device *dev, struct device_attribute *attr, char *buf) 98 { 99 struct wwan_device *wwan = to_wwan_dev(dev); 100 101 return sprintf(buf, "%d\n", wwan->id); 102 } 103 static DEVICE_ATTR_RO(index); 104 105 static struct attribute *wwan_dev_attrs[] = { 106 &dev_attr_index.attr, 107 NULL, 108 }; 109 ATTRIBUTE_GROUPS(wwan_dev); 110 111 static void wwan_dev_destroy(struct device *dev) 112 { 113 struct wwan_device *wwandev = to_wwan_dev(dev); 114 115 ida_free(&wwan_dev_ids, wwandev->id); 116 kfree(wwandev); 117 } 118 119 static const struct device_type wwan_dev_type = { 120 .name = "wwan_dev", 121 .release = wwan_dev_destroy, 122 .groups = wwan_dev_groups, 123 }; 124 125 static int wwan_dev_parent_match(struct device *dev, const void *parent) 126 { 127 return (dev->type == &wwan_dev_type && 128 (dev->parent == parent || dev == parent)); 129 } 130 131 static struct wwan_device *wwan_dev_get_by_parent(struct device *parent) 132 { 133 struct device *dev; 134 135 dev = class_find_device(&wwan_class, NULL, parent, wwan_dev_parent_match); 136 if (!dev) 137 return ERR_PTR(-ENODEV); 138 139 return to_wwan_dev(dev); 140 } 141 142 static int wwan_dev_name_match(struct device *dev, const void *name) 143 { 144 return dev->type == &wwan_dev_type && 145 strcmp(dev_name(dev), name) == 0; 146 } 147 148 static struct wwan_device *wwan_dev_get_by_name(const char *name) 149 { 150 struct device *dev; 151 152 dev = class_find_device(&wwan_class, NULL, name, wwan_dev_name_match); 153 if (!dev) 154 return ERR_PTR(-ENODEV); 155 156 return to_wwan_dev(dev); 157 } 158 159 #ifdef CONFIG_WWAN_DEBUGFS 160 struct dentry *wwan_get_debugfs_dir(struct device *parent) 161 { 162 struct wwan_device *wwandev; 163 164 wwandev = wwan_dev_get_by_parent(parent); 165 if (IS_ERR(wwandev)) 166 return ERR_CAST(wwandev); 167 168 return wwandev->debugfs_dir; 169 } 170 EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir); 171 172 static int wwan_dev_debugfs_match(struct device *dev, const void *dir) 173 { 174 struct wwan_device *wwandev; 175 176 if (dev->type != &wwan_dev_type) 177 return 0; 178 179 wwandev = to_wwan_dev(dev); 180 181 return wwandev->debugfs_dir == dir; 182 } 183 184 static struct wwan_device *wwan_dev_get_by_debugfs(struct dentry *dir) 185 { 186 struct device *dev; 187 188 dev = class_find_device(&wwan_class, NULL, dir, wwan_dev_debugfs_match); 189 if (!dev) 190 return ERR_PTR(-ENODEV); 191 192 return to_wwan_dev(dev); 193 } 194 195 void wwan_put_debugfs_dir(struct dentry *dir) 196 { 197 struct wwan_device *wwandev = wwan_dev_get_by_debugfs(dir); 198 199 if (WARN_ON(IS_ERR(wwandev))) 200 return; 201 202 /* wwan_dev_get_by_debugfs() also got a reference */ 203 put_device(&wwandev->dev); 204 put_device(&wwandev->dev); 205 } 206 EXPORT_SYMBOL_GPL(wwan_put_debugfs_dir); 207 #endif 208 209 /* This function allocates and registers a new WWAN device OR if a WWAN device 210 * already exist for the given parent, it gets a reference and return it. 211 * This function is not exported (for now), it is called indirectly via 212 * wwan_create_port(). 213 */ 214 static struct wwan_device *wwan_create_dev(struct device *parent) 215 { 216 struct wwan_device *wwandev; 217 int err, id; 218 219 /* The 'find-alloc-register' operation must be protected against 220 * concurrent execution, a WWAN device is possibly shared between 221 * multiple callers or concurrently unregistered from wwan_remove_dev(). 222 */ 223 mutex_lock(&wwan_register_lock); 224 225 /* If wwandev already exists, return it */ 226 wwandev = wwan_dev_get_by_parent(parent); 227 if (!IS_ERR(wwandev)) 228 goto done_unlock; 229 230 id = ida_alloc(&wwan_dev_ids, GFP_KERNEL); 231 if (id < 0) { 232 wwandev = ERR_PTR(id); 233 goto done_unlock; 234 } 235 236 wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL); 237 if (!wwandev) { 238 wwandev = ERR_PTR(-ENOMEM); 239 ida_free(&wwan_dev_ids, id); 240 goto done_unlock; 241 } 242 243 wwandev->dev.parent = parent; 244 wwandev->dev.class = &wwan_class; 245 wwandev->dev.type = &wwan_dev_type; 246 wwandev->id = id; 247 dev_set_name(&wwandev->dev, "wwan%d", wwandev->id); 248 249 err = device_register(&wwandev->dev); 250 if (err) { 251 put_device(&wwandev->dev); 252 wwandev = ERR_PTR(err); 253 goto done_unlock; 254 } 255 256 #ifdef CONFIG_WWAN_DEBUGFS 257 wwandev->debugfs_dir = 258 debugfs_create_dir(kobject_name(&wwandev->dev.kobj), 259 wwan_debugfs_dir); 260 #endif 261 262 done_unlock: 263 mutex_unlock(&wwan_register_lock); 264 265 return wwandev; 266 } 267 268 static int is_wwan_child(struct device *dev, void *data) 269 { 270 return dev->class == &wwan_class; 271 } 272 273 static void wwan_remove_dev(struct wwan_device *wwandev) 274 { 275 int ret; 276 277 /* Prevent concurrent picking from wwan_create_dev */ 278 mutex_lock(&wwan_register_lock); 279 280 /* WWAN device is created and registered (get+add) along with its first 281 * child port, and subsequent port registrations only grab a reference 282 * (get). The WWAN device must then be unregistered (del+put) along with 283 * its last port, and reference simply dropped (put) otherwise. In the 284 * same fashion, we must not unregister it when the ops are still there. 285 */ 286 if (wwandev->ops) 287 ret = 1; 288 else 289 ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child); 290 291 if (!ret) { 292 #ifdef CONFIG_WWAN_DEBUGFS 293 debugfs_remove_recursive(wwandev->debugfs_dir); 294 #endif 295 device_unregister(&wwandev->dev); 296 } else { 297 put_device(&wwandev->dev); 298 } 299 300 mutex_unlock(&wwan_register_lock); 301 } 302 303 /* ------- WWAN port management ------- */ 304 305 static const struct { 306 const char * const name; /* Port type name */ 307 const char * const devsuf; /* Port device name suffix */ 308 } wwan_port_types[WWAN_PORT_MAX + 1] = { 309 [WWAN_PORT_AT] = { 310 .name = "AT", 311 .devsuf = "at", 312 }, 313 [WWAN_PORT_MBIM] = { 314 .name = "MBIM", 315 .devsuf = "mbim", 316 }, 317 [WWAN_PORT_QMI] = { 318 .name = "QMI", 319 .devsuf = "qmi", 320 }, 321 [WWAN_PORT_QCDM] = { 322 .name = "QCDM", 323 .devsuf = "qcdm", 324 }, 325 [WWAN_PORT_FIREHOSE] = { 326 .name = "FIREHOSE", 327 .devsuf = "firehose", 328 }, 329 [WWAN_PORT_XMMRPC] = { 330 .name = "XMMRPC", 331 .devsuf = "xmmrpc", 332 }, 333 [WWAN_PORT_FASTBOOT] = { 334 .name = "FASTBOOT", 335 .devsuf = "fastboot", 336 }, 337 }; 338 339 static ssize_t type_show(struct device *dev, struct device_attribute *attr, 340 char *buf) 341 { 342 struct wwan_port *port = to_wwan_port(dev); 343 344 return sprintf(buf, "%s\n", wwan_port_types[port->type].name); 345 } 346 static DEVICE_ATTR_RO(type); 347 348 static struct attribute *wwan_port_attrs[] = { 349 &dev_attr_type.attr, 350 NULL, 351 }; 352 ATTRIBUTE_GROUPS(wwan_port); 353 354 static void wwan_port_destroy(struct device *dev) 355 { 356 struct wwan_port *port = to_wwan_port(dev); 357 358 ida_free(&minors, MINOR(port->dev.devt)); 359 mutex_destroy(&port->data_lock); 360 mutex_destroy(&port->ops_lock); 361 kfree(port); 362 } 363 364 static const struct device_type wwan_port_dev_type = { 365 .name = "wwan_port", 366 .release = wwan_port_destroy, 367 .groups = wwan_port_groups, 368 }; 369 370 static int wwan_port_minor_match(struct device *dev, const void *minor) 371 { 372 return (dev->type == &wwan_port_dev_type && 373 MINOR(dev->devt) == *(unsigned int *)minor); 374 } 375 376 static struct wwan_port *wwan_port_get_by_minor(unsigned int minor) 377 { 378 struct device *dev; 379 380 dev = class_find_device(&wwan_class, NULL, &minor, wwan_port_minor_match); 381 if (!dev) 382 return ERR_PTR(-ENODEV); 383 384 return to_wwan_port(dev); 385 } 386 387 /* Allocate and set unique name based on passed format 388 * 389 * Name allocation approach is highly inspired by the __dev_alloc_name() 390 * function. 391 * 392 * To avoid names collision, the caller must prevent the new port device 393 * registration as well as concurrent invocation of this function. 394 */ 395 static int __wwan_port_dev_assign_name(struct wwan_port *port, const char *fmt) 396 { 397 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent); 398 const unsigned int max_ports = PAGE_SIZE * 8; 399 struct class_dev_iter iter; 400 unsigned long *idmap; 401 struct device *dev; 402 char buf[0x20]; 403 int id; 404 405 idmap = bitmap_zalloc(max_ports, GFP_KERNEL); 406 if (!idmap) 407 return -ENOMEM; 408 409 /* Collect ids of same name format ports */ 410 class_dev_iter_init(&iter, &wwan_class, NULL, &wwan_port_dev_type); 411 while ((dev = class_dev_iter_next(&iter))) { 412 if (dev->parent != &wwandev->dev) 413 continue; 414 if (sscanf(dev_name(dev), fmt, &id) != 1) 415 continue; 416 if (id < 0 || id >= max_ports) 417 continue; 418 set_bit(id, idmap); 419 } 420 class_dev_iter_exit(&iter); 421 422 /* Allocate unique id */ 423 id = find_first_zero_bit(idmap, max_ports); 424 bitmap_free(idmap); 425 426 snprintf(buf, sizeof(buf), fmt, id); /* Name generation */ 427 428 dev = device_find_child_by_name(&wwandev->dev, buf); 429 if (dev) { 430 put_device(dev); 431 return -ENFILE; 432 } 433 434 return dev_set_name(&port->dev, buf); 435 } 436 437 struct wwan_port *wwan_create_port(struct device *parent, 438 enum wwan_port_type type, 439 const struct wwan_port_ops *ops, 440 struct wwan_port_caps *caps, 441 void *drvdata) 442 { 443 struct wwan_device *wwandev; 444 struct wwan_port *port; 445 char namefmt[0x20]; 446 int minor, err; 447 448 if (type > WWAN_PORT_MAX || !ops) 449 return ERR_PTR(-EINVAL); 450 451 /* A port is always a child of a WWAN device, retrieve (allocate or 452 * pick) the WWAN device based on the provided parent device. 453 */ 454 wwandev = wwan_create_dev(parent); 455 if (IS_ERR(wwandev)) 456 return ERR_CAST(wwandev); 457 458 /* A port is exposed as character device, get a minor */ 459 minor = ida_alloc_range(&minors, 0, WWAN_MAX_MINORS - 1, GFP_KERNEL); 460 if (minor < 0) { 461 err = minor; 462 goto error_wwandev_remove; 463 } 464 465 port = kzalloc(sizeof(*port), GFP_KERNEL); 466 if (!port) { 467 err = -ENOMEM; 468 ida_free(&minors, minor); 469 goto error_wwandev_remove; 470 } 471 472 port->type = type; 473 port->ops = ops; 474 port->frag_len = caps ? caps->frag_len : SIZE_MAX; 475 port->headroom_len = caps ? caps->headroom_len : 0; 476 mutex_init(&port->ops_lock); 477 skb_queue_head_init(&port->rxq); 478 init_waitqueue_head(&port->waitqueue); 479 mutex_init(&port->data_lock); 480 481 port->dev.parent = &wwandev->dev; 482 port->dev.class = &wwan_class; 483 port->dev.type = &wwan_port_dev_type; 484 port->dev.devt = MKDEV(wwan_major, minor); 485 dev_set_drvdata(&port->dev, drvdata); 486 487 /* allocate unique name based on wwan device id, port type and number */ 488 snprintf(namefmt, sizeof(namefmt), "wwan%u%s%%d", wwandev->id, 489 wwan_port_types[port->type].devsuf); 490 491 /* Serialize ports registration */ 492 mutex_lock(&wwan_register_lock); 493 494 __wwan_port_dev_assign_name(port, namefmt); 495 err = device_register(&port->dev); 496 497 mutex_unlock(&wwan_register_lock); 498 499 if (err) 500 goto error_put_device; 501 502 dev_info(&wwandev->dev, "port %s attached\n", dev_name(&port->dev)); 503 return port; 504 505 error_put_device: 506 put_device(&port->dev); 507 error_wwandev_remove: 508 wwan_remove_dev(wwandev); 509 510 return ERR_PTR(err); 511 } 512 EXPORT_SYMBOL_GPL(wwan_create_port); 513 514 void wwan_remove_port(struct wwan_port *port) 515 { 516 struct wwan_device *wwandev = to_wwan_dev(port->dev.parent); 517 518 mutex_lock(&port->ops_lock); 519 if (port->start_count) 520 port->ops->stop(port); 521 port->ops = NULL; /* Prevent any new port operations (e.g. from fops) */ 522 mutex_unlock(&port->ops_lock); 523 524 wake_up_interruptible(&port->waitqueue); 525 526 skb_queue_purge(&port->rxq); 527 dev_set_drvdata(&port->dev, NULL); 528 529 dev_info(&wwandev->dev, "port %s disconnected\n", dev_name(&port->dev)); 530 device_unregister(&port->dev); 531 532 /* Release related wwan device */ 533 wwan_remove_dev(wwandev); 534 } 535 EXPORT_SYMBOL_GPL(wwan_remove_port); 536 537 void wwan_port_rx(struct wwan_port *port, struct sk_buff *skb) 538 { 539 skb_queue_tail(&port->rxq, skb); 540 wake_up_interruptible(&port->waitqueue); 541 } 542 EXPORT_SYMBOL_GPL(wwan_port_rx); 543 544 void wwan_port_txon(struct wwan_port *port) 545 { 546 clear_bit(WWAN_PORT_TX_OFF, &port->flags); 547 wake_up_interruptible(&port->waitqueue); 548 } 549 EXPORT_SYMBOL_GPL(wwan_port_txon); 550 551 void wwan_port_txoff(struct wwan_port *port) 552 { 553 set_bit(WWAN_PORT_TX_OFF, &port->flags); 554 } 555 EXPORT_SYMBOL_GPL(wwan_port_txoff); 556 557 void *wwan_port_get_drvdata(struct wwan_port *port) 558 { 559 return dev_get_drvdata(&port->dev); 560 } 561 EXPORT_SYMBOL_GPL(wwan_port_get_drvdata); 562 563 static int wwan_port_op_start(struct wwan_port *port) 564 { 565 int ret = 0; 566 567 mutex_lock(&port->ops_lock); 568 if (!port->ops) { /* Port got unplugged */ 569 ret = -ENODEV; 570 goto out_unlock; 571 } 572 573 /* If port is already started, don't start again */ 574 if (!port->start_count) 575 ret = port->ops->start(port); 576 577 if (!ret) 578 port->start_count++; 579 580 out_unlock: 581 mutex_unlock(&port->ops_lock); 582 583 return ret; 584 } 585 586 static void wwan_port_op_stop(struct wwan_port *port) 587 { 588 mutex_lock(&port->ops_lock); 589 port->start_count--; 590 if (!port->start_count) { 591 if (port->ops) 592 port->ops->stop(port); 593 skb_queue_purge(&port->rxq); 594 } 595 mutex_unlock(&port->ops_lock); 596 } 597 598 static int wwan_port_op_tx(struct wwan_port *port, struct sk_buff *skb, 599 bool nonblock) 600 { 601 int ret; 602 603 mutex_lock(&port->ops_lock); 604 if (!port->ops) { /* Port got unplugged */ 605 ret = -ENODEV; 606 goto out_unlock; 607 } 608 609 if (nonblock || !port->ops->tx_blocking) 610 ret = port->ops->tx(port, skb); 611 else 612 ret = port->ops->tx_blocking(port, skb); 613 614 out_unlock: 615 mutex_unlock(&port->ops_lock); 616 617 return ret; 618 } 619 620 static bool is_read_blocked(struct wwan_port *port) 621 { 622 return skb_queue_empty(&port->rxq) && port->ops; 623 } 624 625 static bool is_write_blocked(struct wwan_port *port) 626 { 627 return test_bit(WWAN_PORT_TX_OFF, &port->flags) && port->ops; 628 } 629 630 static int wwan_wait_rx(struct wwan_port *port, bool nonblock) 631 { 632 if (!is_read_blocked(port)) 633 return 0; 634 635 if (nonblock) 636 return -EAGAIN; 637 638 if (wait_event_interruptible(port->waitqueue, !is_read_blocked(port))) 639 return -ERESTARTSYS; 640 641 return 0; 642 } 643 644 static int wwan_wait_tx(struct wwan_port *port, bool nonblock) 645 { 646 if (!is_write_blocked(port)) 647 return 0; 648 649 if (nonblock) 650 return -EAGAIN; 651 652 if (wait_event_interruptible(port->waitqueue, !is_write_blocked(port))) 653 return -ERESTARTSYS; 654 655 return 0; 656 } 657 658 static int wwan_port_fops_open(struct inode *inode, struct file *file) 659 { 660 struct wwan_port *port; 661 int err = 0; 662 663 port = wwan_port_get_by_minor(iminor(inode)); 664 if (IS_ERR(port)) 665 return PTR_ERR(port); 666 667 file->private_data = port; 668 stream_open(inode, file); 669 670 err = wwan_port_op_start(port); 671 if (err) 672 put_device(&port->dev); 673 674 return err; 675 } 676 677 static int wwan_port_fops_release(struct inode *inode, struct file *filp) 678 { 679 struct wwan_port *port = filp->private_data; 680 681 wwan_port_op_stop(port); 682 put_device(&port->dev); 683 684 return 0; 685 } 686 687 static ssize_t wwan_port_fops_read(struct file *filp, char __user *buf, 688 size_t count, loff_t *ppos) 689 { 690 struct wwan_port *port = filp->private_data; 691 struct sk_buff *skb; 692 size_t copied; 693 int ret; 694 695 ret = wwan_wait_rx(port, !!(filp->f_flags & O_NONBLOCK)); 696 if (ret) 697 return ret; 698 699 skb = skb_dequeue(&port->rxq); 700 if (!skb) 701 return -EIO; 702 703 copied = min_t(size_t, count, skb->len); 704 if (copy_to_user(buf, skb->data, copied)) { 705 kfree_skb(skb); 706 return -EFAULT; 707 } 708 skb_pull(skb, copied); 709 710 /* skb is not fully consumed, keep it in the queue */ 711 if (skb->len) 712 skb_queue_head(&port->rxq, skb); 713 else 714 consume_skb(skb); 715 716 return copied; 717 } 718 719 static ssize_t wwan_port_fops_write(struct file *filp, const char __user *buf, 720 size_t count, loff_t *offp) 721 { 722 struct sk_buff *skb, *head = NULL, *tail = NULL; 723 struct wwan_port *port = filp->private_data; 724 size_t frag_len, remain = count; 725 int ret; 726 727 ret = wwan_wait_tx(port, !!(filp->f_flags & O_NONBLOCK)); 728 if (ret) 729 return ret; 730 731 do { 732 frag_len = min(remain, port->frag_len); 733 skb = alloc_skb(frag_len + port->headroom_len, GFP_KERNEL); 734 if (!skb) { 735 ret = -ENOMEM; 736 goto freeskb; 737 } 738 skb_reserve(skb, port->headroom_len); 739 740 if (!head) { 741 head = skb; 742 } else if (!tail) { 743 skb_shinfo(head)->frag_list = skb; 744 tail = skb; 745 } else { 746 tail->next = skb; 747 tail = skb; 748 } 749 750 if (copy_from_user(skb_put(skb, frag_len), buf + count - remain, frag_len)) { 751 ret = -EFAULT; 752 goto freeskb; 753 } 754 755 if (skb != head) { 756 head->data_len += skb->len; 757 head->len += skb->len; 758 head->truesize += skb->truesize; 759 } 760 } while (remain -= frag_len); 761 762 ret = wwan_port_op_tx(port, head, !!(filp->f_flags & O_NONBLOCK)); 763 if (!ret) 764 return count; 765 766 freeskb: 767 kfree_skb(head); 768 return ret; 769 } 770 771 static __poll_t wwan_port_fops_poll(struct file *filp, poll_table *wait) 772 { 773 struct wwan_port *port = filp->private_data; 774 __poll_t mask = 0; 775 776 poll_wait(filp, &port->waitqueue, wait); 777 778 mutex_lock(&port->ops_lock); 779 if (port->ops && port->ops->tx_poll) 780 mask |= port->ops->tx_poll(port, filp, wait); 781 else if (!is_write_blocked(port)) 782 mask |= EPOLLOUT | EPOLLWRNORM; 783 if (!is_read_blocked(port)) 784 mask |= EPOLLIN | EPOLLRDNORM; 785 if (!port->ops) 786 mask |= EPOLLHUP | EPOLLERR; 787 mutex_unlock(&port->ops_lock); 788 789 return mask; 790 } 791 792 /* Implements minimalistic stub terminal IOCTLs support */ 793 static long wwan_port_fops_at_ioctl(struct wwan_port *port, unsigned int cmd, 794 unsigned long arg) 795 { 796 int ret = 0; 797 798 mutex_lock(&port->data_lock); 799 800 switch (cmd) { 801 case TCFLSH: 802 break; 803 804 case TCGETS: 805 if (copy_to_user((void __user *)arg, &port->at_data.termios, 806 sizeof(struct termios))) 807 ret = -EFAULT; 808 break; 809 810 case TCSETS: 811 case TCSETSW: 812 case TCSETSF: 813 if (copy_from_user(&port->at_data.termios, (void __user *)arg, 814 sizeof(struct termios))) 815 ret = -EFAULT; 816 break; 817 818 #ifdef TCGETS2 819 case TCGETS2: 820 if (copy_to_user((void __user *)arg, &port->at_data.termios, 821 sizeof(struct termios2))) 822 ret = -EFAULT; 823 break; 824 825 case TCSETS2: 826 case TCSETSW2: 827 case TCSETSF2: 828 if (copy_from_user(&port->at_data.termios, (void __user *)arg, 829 sizeof(struct termios2))) 830 ret = -EFAULT; 831 break; 832 #endif 833 834 case TIOCMGET: 835 ret = put_user(port->at_data.mdmbits, (int __user *)arg); 836 break; 837 838 case TIOCMSET: 839 case TIOCMBIC: 840 case TIOCMBIS: { 841 int mdmbits; 842 843 if (copy_from_user(&mdmbits, (int __user *)arg, sizeof(int))) { 844 ret = -EFAULT; 845 break; 846 } 847 if (cmd == TIOCMBIC) 848 port->at_data.mdmbits &= ~mdmbits; 849 else if (cmd == TIOCMBIS) 850 port->at_data.mdmbits |= mdmbits; 851 else 852 port->at_data.mdmbits = mdmbits; 853 break; 854 } 855 856 default: 857 ret = -ENOIOCTLCMD; 858 } 859 860 mutex_unlock(&port->data_lock); 861 862 return ret; 863 } 864 865 static long wwan_port_fops_ioctl(struct file *filp, unsigned int cmd, 866 unsigned long arg) 867 { 868 struct wwan_port *port = filp->private_data; 869 int res; 870 871 if (port->type == WWAN_PORT_AT) { /* AT port specific IOCTLs */ 872 res = wwan_port_fops_at_ioctl(port, cmd, arg); 873 if (res != -ENOIOCTLCMD) 874 return res; 875 } 876 877 switch (cmd) { 878 case TIOCINQ: { /* aka SIOCINQ aka FIONREAD */ 879 unsigned long flags; 880 struct sk_buff *skb; 881 int amount = 0; 882 883 spin_lock_irqsave(&port->rxq.lock, flags); 884 skb_queue_walk(&port->rxq, skb) 885 amount += skb->len; 886 spin_unlock_irqrestore(&port->rxq.lock, flags); 887 888 return put_user(amount, (int __user *)arg); 889 } 890 891 default: 892 return -ENOIOCTLCMD; 893 } 894 } 895 896 static const struct file_operations wwan_port_fops = { 897 .owner = THIS_MODULE, 898 .open = wwan_port_fops_open, 899 .release = wwan_port_fops_release, 900 .read = wwan_port_fops_read, 901 .write = wwan_port_fops_write, 902 .poll = wwan_port_fops_poll, 903 .unlocked_ioctl = wwan_port_fops_ioctl, 904 #ifdef CONFIG_COMPAT 905 .compat_ioctl = compat_ptr_ioctl, 906 #endif 907 .llseek = noop_llseek, 908 }; 909 910 static int wwan_rtnl_validate(struct nlattr *tb[], struct nlattr *data[], 911 struct netlink_ext_ack *extack) 912 { 913 if (!data) 914 return -EINVAL; 915 916 if (!tb[IFLA_PARENT_DEV_NAME]) 917 return -EINVAL; 918 919 if (!data[IFLA_WWAN_LINK_ID]) 920 return -EINVAL; 921 922 return 0; 923 } 924 925 static const struct device_type wwan_type = { .name = "wwan" }; 926 927 static struct net_device *wwan_rtnl_alloc(struct nlattr *tb[], 928 const char *ifname, 929 unsigned char name_assign_type, 930 unsigned int num_tx_queues, 931 unsigned int num_rx_queues) 932 { 933 const char *devname = nla_data(tb[IFLA_PARENT_DEV_NAME]); 934 struct wwan_device *wwandev = wwan_dev_get_by_name(devname); 935 struct net_device *dev; 936 unsigned int priv_size; 937 938 if (IS_ERR(wwandev)) 939 return ERR_CAST(wwandev); 940 941 /* only supported if ops were registered (not just ports) */ 942 if (!wwandev->ops) { 943 dev = ERR_PTR(-EOPNOTSUPP); 944 goto out; 945 } 946 947 priv_size = sizeof(struct wwan_netdev_priv) + wwandev->ops->priv_size; 948 dev = alloc_netdev_mqs(priv_size, ifname, name_assign_type, 949 wwandev->ops->setup, num_tx_queues, num_rx_queues); 950 951 if (dev) { 952 SET_NETDEV_DEV(dev, &wwandev->dev); 953 SET_NETDEV_DEVTYPE(dev, &wwan_type); 954 } 955 956 out: 957 /* release the reference */ 958 put_device(&wwandev->dev); 959 return dev; 960 } 961 962 static int wwan_rtnl_newlink(struct net *src_net, struct net_device *dev, 963 struct nlattr *tb[], struct nlattr *data[], 964 struct netlink_ext_ack *extack) 965 { 966 struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); 967 u32 link_id = nla_get_u32(data[IFLA_WWAN_LINK_ID]); 968 struct wwan_netdev_priv *priv = netdev_priv(dev); 969 int ret; 970 971 if (IS_ERR(wwandev)) 972 return PTR_ERR(wwandev); 973 974 /* shouldn't have a netdev (left) with us as parent so WARN */ 975 if (WARN_ON(!wwandev->ops)) { 976 ret = -EOPNOTSUPP; 977 goto out; 978 } 979 980 priv->link_id = link_id; 981 if (wwandev->ops->newlink) 982 ret = wwandev->ops->newlink(wwandev->ops_ctxt, dev, 983 link_id, extack); 984 else 985 ret = register_netdevice(dev); 986 987 out: 988 /* release the reference */ 989 put_device(&wwandev->dev); 990 return ret; 991 } 992 993 static void wwan_rtnl_dellink(struct net_device *dev, struct list_head *head) 994 { 995 struct wwan_device *wwandev = wwan_dev_get_by_parent(dev->dev.parent); 996 997 if (IS_ERR(wwandev)) 998 return; 999 1000 /* shouldn't have a netdev (left) with us as parent so WARN */ 1001 if (WARN_ON(!wwandev->ops)) 1002 goto out; 1003 1004 if (wwandev->ops->dellink) 1005 wwandev->ops->dellink(wwandev->ops_ctxt, dev, head); 1006 else 1007 unregister_netdevice_queue(dev, head); 1008 1009 out: 1010 /* release the reference */ 1011 put_device(&wwandev->dev); 1012 } 1013 1014 static size_t wwan_rtnl_get_size(const struct net_device *dev) 1015 { 1016 return 1017 nla_total_size(4) + /* IFLA_WWAN_LINK_ID */ 1018 0; 1019 } 1020 1021 static int wwan_rtnl_fill_info(struct sk_buff *skb, 1022 const struct net_device *dev) 1023 { 1024 struct wwan_netdev_priv *priv = netdev_priv(dev); 1025 1026 if (nla_put_u32(skb, IFLA_WWAN_LINK_ID, priv->link_id)) 1027 goto nla_put_failure; 1028 1029 return 0; 1030 1031 nla_put_failure: 1032 return -EMSGSIZE; 1033 } 1034 1035 static const struct nla_policy wwan_rtnl_policy[IFLA_WWAN_MAX + 1] = { 1036 [IFLA_WWAN_LINK_ID] = { .type = NLA_U32 }, 1037 }; 1038 1039 static struct rtnl_link_ops wwan_rtnl_link_ops __read_mostly = { 1040 .kind = "wwan", 1041 .maxtype = __IFLA_WWAN_MAX, 1042 .alloc = wwan_rtnl_alloc, 1043 .validate = wwan_rtnl_validate, 1044 .newlink = wwan_rtnl_newlink, 1045 .dellink = wwan_rtnl_dellink, 1046 .get_size = wwan_rtnl_get_size, 1047 .fill_info = wwan_rtnl_fill_info, 1048 .policy = wwan_rtnl_policy, 1049 }; 1050 1051 static void wwan_create_default_link(struct wwan_device *wwandev, 1052 u32 def_link_id) 1053 { 1054 struct nlattr *tb[IFLA_MAX + 1], *linkinfo[IFLA_INFO_MAX + 1]; 1055 struct nlattr *data[IFLA_WWAN_MAX + 1]; 1056 struct net_device *dev; 1057 struct nlmsghdr *nlh; 1058 struct sk_buff *msg; 1059 1060 /* Forge attributes required to create a WWAN netdev. We first 1061 * build a netlink message and then parse it. This looks 1062 * odd, but such approach is less error prone. 1063 */ 1064 msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); 1065 if (WARN_ON(!msg)) 1066 return; 1067 nlh = nlmsg_put(msg, 0, 0, RTM_NEWLINK, 0, 0); 1068 if (WARN_ON(!nlh)) 1069 goto free_attrs; 1070 1071 if (nla_put_string(msg, IFLA_PARENT_DEV_NAME, dev_name(&wwandev->dev))) 1072 goto free_attrs; 1073 tb[IFLA_LINKINFO] = nla_nest_start(msg, IFLA_LINKINFO); 1074 if (!tb[IFLA_LINKINFO]) 1075 goto free_attrs; 1076 linkinfo[IFLA_INFO_DATA] = nla_nest_start(msg, IFLA_INFO_DATA); 1077 if (!linkinfo[IFLA_INFO_DATA]) 1078 goto free_attrs; 1079 if (nla_put_u32(msg, IFLA_WWAN_LINK_ID, def_link_id)) 1080 goto free_attrs; 1081 nla_nest_end(msg, linkinfo[IFLA_INFO_DATA]); 1082 nla_nest_end(msg, tb[IFLA_LINKINFO]); 1083 1084 nlmsg_end(msg, nlh); 1085 1086 /* The next three parsing calls can not fail */ 1087 nlmsg_parse_deprecated(nlh, 0, tb, IFLA_MAX, NULL, NULL); 1088 nla_parse_nested_deprecated(linkinfo, IFLA_INFO_MAX, tb[IFLA_LINKINFO], 1089 NULL, NULL); 1090 nla_parse_nested_deprecated(data, IFLA_WWAN_MAX, 1091 linkinfo[IFLA_INFO_DATA], NULL, NULL); 1092 1093 rtnl_lock(); 1094 1095 dev = rtnl_create_link(&init_net, "wwan%d", NET_NAME_ENUM, 1096 &wwan_rtnl_link_ops, tb, NULL); 1097 if (WARN_ON(IS_ERR(dev))) 1098 goto unlock; 1099 1100 if (WARN_ON(wwan_rtnl_newlink(&init_net, dev, tb, data, NULL))) { 1101 free_netdev(dev); 1102 goto unlock; 1103 } 1104 1105 rtnl_configure_link(dev, NULL, 0, NULL); /* Link initialized, notify new link */ 1106 1107 unlock: 1108 rtnl_unlock(); 1109 1110 free_attrs: 1111 nlmsg_free(msg); 1112 } 1113 1114 /** 1115 * wwan_register_ops - register WWAN device ops 1116 * @parent: Device to use as parent and shared by all WWAN ports and 1117 * created netdevs 1118 * @ops: operations to register 1119 * @ctxt: context to pass to operations 1120 * @def_link_id: id of the default link that will be automatically created by 1121 * the WWAN core for the WWAN device. The default link will not be created 1122 * if the passed value is WWAN_NO_DEFAULT_LINK. 1123 * 1124 * Returns: 0 on success, a negative error code on failure 1125 */ 1126 int wwan_register_ops(struct device *parent, const struct wwan_ops *ops, 1127 void *ctxt, u32 def_link_id) 1128 { 1129 struct wwan_device *wwandev; 1130 1131 if (WARN_ON(!parent || !ops || !ops->setup)) 1132 return -EINVAL; 1133 1134 wwandev = wwan_create_dev(parent); 1135 if (IS_ERR(wwandev)) 1136 return PTR_ERR(wwandev); 1137 1138 if (WARN_ON(wwandev->ops)) { 1139 wwan_remove_dev(wwandev); 1140 return -EBUSY; 1141 } 1142 1143 wwandev->ops = ops; 1144 wwandev->ops_ctxt = ctxt; 1145 1146 /* NB: we do not abort ops registration in case of default link 1147 * creation failure. Link ops is the management interface, while the 1148 * default link creation is a service option. And we should not prevent 1149 * a user from manually creating a link latter if service option failed 1150 * now. 1151 */ 1152 if (def_link_id != WWAN_NO_DEFAULT_LINK) 1153 wwan_create_default_link(wwandev, def_link_id); 1154 1155 return 0; 1156 } 1157 EXPORT_SYMBOL_GPL(wwan_register_ops); 1158 1159 /* Enqueue child netdev deletion */ 1160 static int wwan_child_dellink(struct device *dev, void *data) 1161 { 1162 struct list_head *kill_list = data; 1163 1164 if (dev->type == &wwan_type) 1165 wwan_rtnl_dellink(to_net_dev(dev), kill_list); 1166 1167 return 0; 1168 } 1169 1170 /** 1171 * wwan_unregister_ops - remove WWAN device ops 1172 * @parent: Device to use as parent and shared by all WWAN ports and 1173 * created netdevs 1174 */ 1175 void wwan_unregister_ops(struct device *parent) 1176 { 1177 struct wwan_device *wwandev = wwan_dev_get_by_parent(parent); 1178 LIST_HEAD(kill_list); 1179 1180 if (WARN_ON(IS_ERR(wwandev))) 1181 return; 1182 if (WARN_ON(!wwandev->ops)) { 1183 put_device(&wwandev->dev); 1184 return; 1185 } 1186 1187 /* put the reference obtained by wwan_dev_get_by_parent(), 1188 * we should still have one (that the owner is giving back 1189 * now) due to the ops being assigned. 1190 */ 1191 put_device(&wwandev->dev); 1192 1193 rtnl_lock(); /* Prevent concurrent netdev(s) creation/destroying */ 1194 1195 /* Remove all child netdev(s), using batch removing */ 1196 device_for_each_child(&wwandev->dev, &kill_list, 1197 wwan_child_dellink); 1198 unregister_netdevice_many(&kill_list); 1199 1200 wwandev->ops = NULL; /* Finally remove ops */ 1201 1202 rtnl_unlock(); 1203 1204 wwandev->ops_ctxt = NULL; 1205 wwan_remove_dev(wwandev); 1206 } 1207 EXPORT_SYMBOL_GPL(wwan_unregister_ops); 1208 1209 static int __init wwan_init(void) 1210 { 1211 int err; 1212 1213 err = rtnl_link_register(&wwan_rtnl_link_ops); 1214 if (err) 1215 return err; 1216 1217 err = class_register(&wwan_class); 1218 if (err) 1219 goto unregister; 1220 1221 /* chrdev used for wwan ports */ 1222 wwan_major = __register_chrdev(0, 0, WWAN_MAX_MINORS, "wwan_port", 1223 &wwan_port_fops); 1224 if (wwan_major < 0) { 1225 err = wwan_major; 1226 goto destroy; 1227 } 1228 1229 #ifdef CONFIG_WWAN_DEBUGFS 1230 wwan_debugfs_dir = debugfs_create_dir("wwan", NULL); 1231 #endif 1232 1233 return 0; 1234 1235 destroy: 1236 class_unregister(&wwan_class); 1237 unregister: 1238 rtnl_link_unregister(&wwan_rtnl_link_ops); 1239 return err; 1240 } 1241 1242 static void __exit wwan_exit(void) 1243 { 1244 debugfs_remove_recursive(wwan_debugfs_dir); 1245 __unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port"); 1246 rtnl_link_unregister(&wwan_rtnl_link_ops); 1247 class_unregister(&wwan_class); 1248 } 1249 1250 module_init(wwan_init); 1251 module_exit(wwan_exit); 1252 1253 MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>"); 1254 MODULE_DESCRIPTION("WWAN core"); 1255 MODULE_LICENSE("GPL v2"); 1256