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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * USB Serial Converter Generic functions
4 *
5 * Copyright (C) 2010 - 2013 Johan Hovold ([email protected])
6 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman ([email protected])
7 */
8
9#include <linux/kernel.h>
10#include <linux/sched/signal.h>
11#include <linux/errno.h>
12#include <linux/slab.h>
13#include <linux/sysrq.h>
14#include <linux/tty.h>
15#include <linux/tty_flip.h>
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/usb.h>
19#include <linux/usb/serial.h>
20#include <linux/kfifo.h>
21#include <linux/serial.h>
22
23#ifdef CONFIG_USB_SERIAL_GENERIC
24
25static __u16 vendor = 0x05f9;
26static __u16 product = 0xffff;
27
28module_param(vendor, ushort, 0);
29MODULE_PARM_DESC(vendor, "User specified USB idVendor");
30
31module_param(product, ushort, 0);
32MODULE_PARM_DESC(product, "User specified USB idProduct");
33
34static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
35
36static int usb_serial_generic_probe(struct usb_serial *serial,
37 const struct usb_device_id *id)
38{
39 struct device *dev = &serial->interface->dev;
40
41 dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
42 dev_info(dev, "Tell [email protected] to add your device to a proper driver.\n");
43
44 return 0;
45}
46
47static int usb_serial_generic_calc_num_ports(struct usb_serial *serial,
48 struct usb_serial_endpoints *epds)
49{
50 struct device *dev = &serial->interface->dev;
51 int num_ports;
52
53 num_ports = max(epds->num_bulk_in, epds->num_bulk_out);
54
55 if (num_ports == 0) {
56 dev_err(dev, "device has no bulk endpoints\n");
57 return -ENODEV;
58 }
59
60 return num_ports;
61}
62
63static struct usb_serial_driver usb_serial_generic_device = {
64 .driver = {
65 .name = "generic",
66 },
67 .id_table = generic_device_ids,
68 .probe = usb_serial_generic_probe,
69 .calc_num_ports = usb_serial_generic_calc_num_ports,
70 .throttle = usb_serial_generic_throttle,
71 .unthrottle = usb_serial_generic_unthrottle,
72 .resume = usb_serial_generic_resume,
73};
74
75static struct usb_serial_driver * const serial_drivers[] = {
76 &usb_serial_generic_device, NULL
77};
78
79#endif
80
81int usb_serial_generic_register(void)
82{
83 int retval = 0;
84
85#ifdef CONFIG_USB_SERIAL_GENERIC
86 generic_device_ids[0].idVendor = vendor;
87 generic_device_ids[0].idProduct = product;
88 generic_device_ids[0].match_flags =
89 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
90
91 retval = usb_serial_register_drivers(serial_drivers,
92 "usbserial_generic", generic_device_ids);
93#endif
94 return retval;
95}
96
97void usb_serial_generic_deregister(void)
98{
99#ifdef CONFIG_USB_SERIAL_GENERIC
100 usb_serial_deregister_drivers(serial_drivers);
101#endif
102}
103
104int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
105{
106 int result = 0;
107
108 clear_bit(USB_SERIAL_THROTTLED, &port->flags);
109
110 if (port->bulk_in_size)
111 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
112
113 return result;
114}
115EXPORT_SYMBOL_GPL(usb_serial_generic_open);
116
117void usb_serial_generic_close(struct usb_serial_port *port)
118{
119 unsigned long flags;
120 int i;
121
122 if (port->bulk_out_size) {
123 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
124 usb_kill_urb(port->write_urbs[i]);
125
126 spin_lock_irqsave(&port->lock, flags);
127 kfifo_reset_out(&port->write_fifo);
128 spin_unlock_irqrestore(&port->lock, flags);
129 }
130 if (port->bulk_in_size) {
131 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
132 usb_kill_urb(port->read_urbs[i]);
133 }
134}
135EXPORT_SYMBOL_GPL(usb_serial_generic_close);
136
137int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
138 void *dest, size_t size)
139{
140 return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
141}
142
143/**
144 * usb_serial_generic_write_start - start writing buffered data
145 * @port: usb-serial port
146 * @mem_flags: flags to use for memory allocations
147 *
148 * Serialised using USB_SERIAL_WRITE_BUSY flag.
149 *
150 * Return: Zero on success or if busy, otherwise a negative errno value.
151 */
152int usb_serial_generic_write_start(struct usb_serial_port *port,
153 gfp_t mem_flags)
154{
155 struct urb *urb;
156 int count, result;
157 unsigned long flags;
158 int i;
159
160 if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
161 return 0;
162retry:
163 spin_lock_irqsave(&port->lock, flags);
164 if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
165 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
166 spin_unlock_irqrestore(&port->lock, flags);
167 return 0;
168 }
169 i = (int)find_first_bit(&port->write_urbs_free,
170 ARRAY_SIZE(port->write_urbs));
171 spin_unlock_irqrestore(&port->lock, flags);
172
173 urb = port->write_urbs[i];
174 count = port->serial->type->prepare_write_buffer(port,
175 urb->transfer_buffer,
176 port->bulk_out_size);
177 urb->transfer_buffer_length = count;
178 usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
179 spin_lock_irqsave(&port->lock, flags);
180 port->tx_bytes += count;
181 spin_unlock_irqrestore(&port->lock, flags);
182
183 clear_bit(i, &port->write_urbs_free);
184 result = usb_submit_urb(urb, mem_flags);
185 if (result) {
186 dev_err_console(port, "%s - error submitting urb: %d\n",
187 __func__, result);
188 set_bit(i, &port->write_urbs_free);
189 spin_lock_irqsave(&port->lock, flags);
190 port->tx_bytes -= count;
191 spin_unlock_irqrestore(&port->lock, flags);
192
193 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
194 return result;
195 }
196
197 goto retry; /* try sending off another urb */
198}
199EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
200
201/**
202 * usb_serial_generic_write - generic write function
203 * @tty: tty for the port
204 * @port: usb-serial port
205 * @buf: data to write
206 * @count: number of bytes to write
207 *
208 * Return: The number of characters buffered, which may be anything from
209 * zero to @count, or a negative errno value.
210 */
211int usb_serial_generic_write(struct tty_struct *tty,
212 struct usb_serial_port *port, const unsigned char *buf, int count)
213{
214 int result;
215
216 if (!port->bulk_out_size)
217 return -ENODEV;
218
219 if (!count)
220 return 0;
221
222 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
223 result = usb_serial_generic_write_start(port, GFP_ATOMIC);
224 if (result)
225 return result;
226
227 return count;
228}
229EXPORT_SYMBOL_GPL(usb_serial_generic_write);
230
231unsigned int usb_serial_generic_write_room(struct tty_struct *tty)
232{
233 struct usb_serial_port *port = tty->driver_data;
234 unsigned long flags;
235 unsigned int room;
236
237 if (!port->bulk_out_size)
238 return 0;
239
240 spin_lock_irqsave(&port->lock, flags);
241 room = kfifo_avail(&port->write_fifo);
242 spin_unlock_irqrestore(&port->lock, flags);
243
244 dev_dbg(&port->dev, "%s - returns %u\n", __func__, room);
245 return room;
246}
247
248unsigned int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
249{
250 struct usb_serial_port *port = tty->driver_data;
251 unsigned long flags;
252 unsigned int chars;
253
254 if (!port->bulk_out_size)
255 return 0;
256
257 spin_lock_irqsave(&port->lock, flags);
258 chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
259 spin_unlock_irqrestore(&port->lock, flags);
260
261 dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars);
262 return chars;
263}
264EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
265
266void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
267{
268 struct usb_serial_port *port = tty->driver_data;
269 struct tty_port *tport = &port->port;
270 unsigned int bps;
271 unsigned long period;
272 unsigned long expire;
273
274 bps = tty_get_baud_rate(tty);
275 if (!bps)
276 bps = 9600; /* B0 */
277 /*
278 * Use a poll-period of roughly the time it takes to send one
279 * character or at least one jiffy.
280 */
281 period = max_t(unsigned long, (10 * HZ / bps), 1);
282 if (timeout)
283 period = min_t(unsigned long, period, timeout);
284
285 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
286 __func__, jiffies_to_msecs(timeout),
287 jiffies_to_msecs(period));
288 expire = jiffies + timeout;
289 for (;;) {
290 mutex_lock(&tport->mutex);
291 if (tty_io_error(tty) || port->serial->type->tx_empty(port)) {
292 mutex_unlock(&tport->mutex);
293 break;
294 }
295 mutex_unlock(&tport->mutex);
296
297 schedule_timeout_interruptible(period);
298 if (signal_pending(current))
299 break;
300 if (timeout && time_after(jiffies, expire))
301 break;
302 }
303}
304EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
305
306static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
307 int index, gfp_t mem_flags)
308{
309 int res;
310
311 if (!test_and_clear_bit(index, &port->read_urbs_free))
312 return 0;
313
314 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
315
316 res = usb_submit_urb(port->read_urbs[index], mem_flags);
317 if (res) {
318 if (res != -EPERM && res != -ENODEV) {
319 dev_err(&port->dev,
320 "%s - usb_submit_urb failed: %d\n",
321 __func__, res);
322 }
323 set_bit(index, &port->read_urbs_free);
324 return res;
325 }
326
327 return 0;
328}
329
330int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
331 gfp_t mem_flags)
332{
333 int res;
334 int i;
335
336 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
337 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
338 if (res)
339 goto err;
340 }
341
342 return 0;
343err:
344 for (; i >= 0; --i)
345 usb_kill_urb(port->read_urbs[i]);
346
347 return res;
348}
349EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
350
351void usb_serial_generic_process_read_urb(struct urb *urb)
352{
353 struct usb_serial_port *port = urb->context;
354 char *ch = urb->transfer_buffer;
355 int i;
356
357 if (!urb->actual_length)
358 return;
359 /*
360 * The per character mucking around with sysrq path it too slow for
361 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
362 * cases where the USB serial is not a console anyway.
363 */
364 if (port->sysrq) {
365 for (i = 0; i < urb->actual_length; i++, ch++) {
366 if (!usb_serial_handle_sysrq_char(port, *ch))
367 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
368 }
369 } else {
370 tty_insert_flip_string(&port->port, ch, urb->actual_length);
371 }
372 tty_flip_buffer_push(&port->port);
373}
374EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
375
376void usb_serial_generic_read_bulk_callback(struct urb *urb)
377{
378 struct usb_serial_port *port = urb->context;
379 unsigned char *data = urb->transfer_buffer;
380 bool stopped = false;
381 int status = urb->status;
382 int i;
383
384 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
385 if (urb == port->read_urbs[i])
386 break;
387 }
388
389 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
390 urb->actual_length);
391 switch (status) {
392 case 0:
393 usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
394 data);
395 port->serial->type->process_read_urb(urb);
396 break;
397 case -ENOENT:
398 case -ECONNRESET:
399 case -ESHUTDOWN:
400 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
401 __func__, status);
402 stopped = true;
403 break;
404 case -EPIPE:
405 dev_err(&port->dev, "%s - urb stopped: %d\n",
406 __func__, status);
407 stopped = true;
408 break;
409 default:
410 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
411 __func__, status);
412 break;
413 }
414
415 /*
416 * Make sure URB processing is done before marking as free to avoid
417 * racing with unthrottle() on another CPU. Matches the barriers
418 * implied by the test_and_clear_bit() in
419 * usb_serial_generic_submit_read_urb().
420 */
421 smp_mb__before_atomic();
422 set_bit(i, &port->read_urbs_free);
423 /*
424 * Make sure URB is marked as free before checking the throttled flag
425 * to avoid racing with unthrottle() on another CPU. Matches the
426 * smp_mb__after_atomic() in unthrottle().
427 */
428 smp_mb__after_atomic();
429
430 if (stopped)
431 return;
432
433 if (test_bit(USB_SERIAL_THROTTLED, &port->flags))
434 return;
435
436 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
437}
438EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
439
440void usb_serial_generic_write_bulk_callback(struct urb *urb)
441{
442 unsigned long flags;
443 struct usb_serial_port *port = urb->context;
444 int status = urb->status;
445 int i;
446
447 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
448 if (port->write_urbs[i] == urb)
449 break;
450 }
451 spin_lock_irqsave(&port->lock, flags);
452 port->tx_bytes -= urb->transfer_buffer_length;
453 set_bit(i, &port->write_urbs_free);
454 spin_unlock_irqrestore(&port->lock, flags);
455
456 switch (status) {
457 case 0:
458 break;
459 case -ENOENT:
460 case -ECONNRESET:
461 case -ESHUTDOWN:
462 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
463 __func__, status);
464 return;
465 case -EPIPE:
466 dev_err_console(port, "%s - urb stopped: %d\n",
467 __func__, status);
468 return;
469 default:
470 dev_err_console(port, "%s - nonzero urb status: %d\n",
471 __func__, status);
472 break;
473 }
474
475 usb_serial_generic_write_start(port, GFP_ATOMIC);
476 usb_serial_port_softint(port);
477}
478EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
479
480void usb_serial_generic_throttle(struct tty_struct *tty)
481{
482 struct usb_serial_port *port = tty->driver_data;
483
484 set_bit(USB_SERIAL_THROTTLED, &port->flags);
485}
486EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
487
488void usb_serial_generic_unthrottle(struct tty_struct *tty)
489{
490 struct usb_serial_port *port = tty->driver_data;
491
492 clear_bit(USB_SERIAL_THROTTLED, &port->flags);
493
494 /*
495 * Matches the smp_mb__after_atomic() in
496 * usb_serial_generic_read_bulk_callback().
497 */
498 smp_mb__after_atomic();
499
500 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
501}
502EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
503
504static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
505 unsigned long arg, struct async_icount *cprev)
506{
507 struct usb_serial_port *port = tty->driver_data;
508 struct async_icount cnow;
509 unsigned long flags;
510 bool ret;
511
512 /*
513 * Use tty-port initialised flag to detect all hangups including the
514 * one generated at USB-device disconnect.
515 */
516 if (!tty_port_initialized(&port->port))
517 return true;
518
519 spin_lock_irqsave(&port->lock, flags);
520 cnow = port->icount; /* atomic copy*/
521 spin_unlock_irqrestore(&port->lock, flags);
522
523 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
524 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
525 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) ||
526 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
527
528 *cprev = cnow;
529
530 return ret;
531}
532
533int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
534{
535 struct usb_serial_port *port = tty->driver_data;
536 struct async_icount cnow;
537 unsigned long flags;
538 int ret;
539
540 spin_lock_irqsave(&port->lock, flags);
541 cnow = port->icount; /* atomic copy */
542 spin_unlock_irqrestore(&port->lock, flags);
543
544 ret = wait_event_interruptible(port->port.delta_msr_wait,
545 usb_serial_generic_msr_changed(tty, arg, &cnow));
546 if (!ret && !tty_port_initialized(&port->port))
547 ret = -EIO;
548
549 return ret;
550}
551EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
552
553int usb_serial_generic_get_icount(struct tty_struct *tty,
554 struct serial_icounter_struct *icount)
555{
556 struct usb_serial_port *port = tty->driver_data;
557 struct async_icount cnow;
558 unsigned long flags;
559
560 spin_lock_irqsave(&port->lock, flags);
561 cnow = port->icount; /* atomic copy */
562 spin_unlock_irqrestore(&port->lock, flags);
563
564 icount->cts = cnow.cts;
565 icount->dsr = cnow.dsr;
566 icount->rng = cnow.rng;
567 icount->dcd = cnow.dcd;
568 icount->tx = cnow.tx;
569 icount->rx = cnow.rx;
570 icount->frame = cnow.frame;
571 icount->parity = cnow.parity;
572 icount->overrun = cnow.overrun;
573 icount->brk = cnow.brk;
574 icount->buf_overrun = cnow.buf_overrun;
575
576 return 0;
577}
578EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
579
580#if defined(CONFIG_USB_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
581int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
582{
583 if (port->sysrq) {
584 if (ch && time_before(jiffies, port->sysrq)) {
585 handle_sysrq(ch);
586 port->sysrq = 0;
587 return 1;
588 }
589 port->sysrq = 0;
590 }
591 return 0;
592}
593EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
594
595int usb_serial_handle_break(struct usb_serial_port *port)
596{
597 if (!port->port.console)
598 return 0;
599
600 if (!port->sysrq) {
601 port->sysrq = jiffies + HZ*5;
602 return 1;
603 }
604 port->sysrq = 0;
605 return 0;
606}
607EXPORT_SYMBOL_GPL(usb_serial_handle_break);
608#endif
609
610/**
611 * usb_serial_handle_dcd_change - handle a change of carrier detect state
612 * @port: usb-serial port
613 * @tty: tty for the port
614 * @status: new carrier detect status, nonzero if active
615 */
616void usb_serial_handle_dcd_change(struct usb_serial_port *port,
617 struct tty_struct *tty, unsigned int status)
618{
619 dev_dbg(&port->dev, "%s - status %d\n", __func__, status);
620
621 if (tty) {
622 struct tty_ldisc *ld = tty_ldisc_ref(tty);
623
624 if (ld) {
625 if (ld->ops->dcd_change)
626 ld->ops->dcd_change(tty, status);
627 tty_ldisc_deref(ld);
628 }
629 }
630
631 if (status)
632 wake_up_interruptible(&port->port.open_wait);
633 else if (tty && !C_CLOCAL(tty))
634 tty_hangup(tty);
635}
636EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
637
638int usb_serial_generic_resume(struct usb_serial *serial)
639{
640 struct usb_serial_port *port;
641 int i, c = 0, r;
642
643 for (i = 0; i < serial->num_ports; i++) {
644 port = serial->port[i];
645 if (!tty_port_initialized(&port->port))
646 continue;
647
648 if (port->bulk_in_size) {
649 r = usb_serial_generic_submit_read_urbs(port,
650 GFP_NOIO);
651 if (r < 0)
652 c++;
653 }
654
655 if (port->bulk_out_size) {
656 r = usb_serial_generic_write_start(port, GFP_NOIO);
657 if (r < 0)
658 c++;
659 }
660 }
661
662 return c ? -EIO : 0;
663}
664EXPORT_SYMBOL_GPL(usb_serial_generic_resume);