1 // SPDX-License-Identifier: GPL-2.0+
3 * u_serial.c - utilities for USB gadget "serial port"/TTY support
5 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
6 * Copyright (C) 2008 David Brownell
7 * Copyright (C) 2008 by Nokia Corporation
9 * This code also borrows from usbserial.c, which is
10 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
11 * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
12 * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
15 /* #define VERBOSE_DEBUG */
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/device.h>
20 #include <linux/delay.h>
21 #include <linux/tty.h>
22 #include <linux/tty_flip.h>
23 #include <linux/slab.h>
24 #include <linux/export.h>
25 #include <linux/module.h>
26 #include <linux/console.h>
27 #include <linux/kstrtox.h>
28 #include <linux/kthread.h>
29 #include <linux/workqueue.h>
30 #include <linux/kfifo.h>
36 * This component encapsulates the TTY layer glue needed to provide basic
37 * "serial port" functionality through the USB gadget stack. Each such
38 * port is exposed through a /dev/ttyGS* node.
40 * After this module has been loaded, the individual TTY port can be requested
41 * (gserial_alloc_line()) and it will stay available until they are removed
42 * (gserial_free_line()). Each one may be connected to a USB function
43 * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
44 * host issues a config change event. Data can only flow when the port is
45 * connected to the host.
47 * A given TTY port can be made available in multiple configurations.
48 * For example, each one might expose a ttyGS0 node which provides a
49 * login application. In one case that might use CDC ACM interface 0,
50 * while another configuration might use interface 3 for that. The
51 * work to handle that (including descriptor management) is not part
54 * Configurations may expose more than one TTY port. For example, if
55 * ttyGS0 provides login service, then ttyGS1 might provide dialer access
56 * for a telephone or fax link. And ttyGS2 might be something that just
57 * needs a simple byte stream interface for some messaging protocol that
58 * is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
61 * gserial is the lifecycle interface, used by USB functions
62 * gs_port is the I/O nexus, used by the tty driver
63 * tty_struct links to the tty/filesystem framework
65 * gserial <---> gs_port ... links will be null when the USB link is
66 * inactive; managed by gserial_{connect,disconnect}(). each gserial
67 * instance can wrap its own USB control protocol.
68 * gserial->ioport == usb_ep->driver_data ... gs_port
69 * gs_port->port_usb ... gserial
71 * gs_port <---> tty_struct ... links will be null when the TTY file
72 * isn't opened; managed by gs_open()/gs_close()
73 * gserial->port_tty ... tty_struct
74 * tty_struct->driver_data ... gserial
77 /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
78 * next layer of buffering. For TX that's a circular buffer; for RX
79 * consider it a NOP. A third layer is provided by the TTY code.
82 #define WRITE_BUF_SIZE 8192 /* TX only */
83 #define GS_CONSOLE_BUF_SIZE 8192
85 /* Prevents race conditions while accessing gser->ioport */
86 static DEFINE_SPINLOCK(serial_port_lock);
90 struct console console;
91 struct work_struct work;
93 struct usb_request *req;
99 * The port structure holds info for each port, one for each minor number
100 * (and thus for each /dev/ node).
103 struct tty_port port;
104 spinlock_t port_lock; /* guard port_* access */
106 struct gserial *port_usb;
107 #ifdef CONFIG_U_SERIAL_CONSOLE
108 struct gs_console *console;
113 struct list_head read_pool;
116 struct list_head read_queue;
118 struct delayed_work push;
120 struct list_head write_pool;
123 struct kfifo port_write_buf;
124 wait_queue_head_t drain_wait; /* wait while writes drain */
126 wait_queue_head_t close_wait;
127 bool suspended; /* port suspended */
128 bool start_delayed; /* delay start when suspended */
130 /* REVISIT this state ... */
131 struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
134 static struct portmaster {
135 struct mutex lock; /* protect open/close */
136 struct gs_port *port;
137 } ports[MAX_U_SERIAL_PORTS];
139 #define GS_CLOSE_TIMEOUT 15 /* seconds */
145 #define pr_vdebug(fmt, arg...) \
147 #endif /* pr_vdebug */
150 #define pr_vdebug(fmt, arg...) \
151 ({ if (0) pr_debug(fmt, ##arg); })
152 #endif /* pr_vdebug */
155 /*-------------------------------------------------------------------------*/
157 /* I/O glue between TTY (upper) and USB function (lower) driver layers */
162 * Allocate a usb_request and its buffer. Returns a pointer to the
163 * usb_request or NULL if there is an error.
166 gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
168 struct usb_request *req;
170 req = usb_ep_alloc_request(ep, kmalloc_flags);
174 req->buf = kmalloc(len, kmalloc_flags);
175 if (req->buf == NULL) {
176 usb_ep_free_request(ep, req);
183 EXPORT_SYMBOL_GPL(gs_alloc_req);
188 * Free a usb_request and its buffer.
190 void gs_free_req(struct usb_ep *ep, struct usb_request *req)
193 usb_ep_free_request(ep, req);
195 EXPORT_SYMBOL_GPL(gs_free_req);
200 * If there is data to send, a packet is built in the given
201 * buffer and the size is returned. If there is no data to
202 * send, 0 is returned.
204 * Called with port_lock held.
207 gs_send_packet(struct gs_port *port, char *packet, unsigned size)
211 len = kfifo_len(&port->port_write_buf);
215 size = kfifo_out(&port->port_write_buf, packet, size);
222 * This function finds available write requests, calls
223 * gs_send_packet to fill these packets with data, and
224 * continues until either there are no more write requests
225 * available or no more data to send. This function is
226 * run whenever data arrives or write requests are available.
228 * Context: caller owns port_lock; port_usb is non-null.
230 static int gs_start_tx(struct gs_port *port)
232 __releases(&port->port_lock)
233 __acquires(&port->port_lock)
236 struct list_head *pool = &port->write_pool;
239 bool do_tty_wake = false;
244 in = port->port_usb->in;
246 while (!port->write_busy && !list_empty(pool)) {
247 struct usb_request *req;
250 if (port->write_started >= QUEUE_SIZE)
253 req = list_entry(pool->next, struct usb_request, list);
254 len = gs_send_packet(port, req->buf, in->maxpacket);
256 wake_up_interruptible(&port->drain_wait);
262 list_del(&req->list);
263 req->zero = kfifo_is_empty(&port->port_write_buf);
265 pr_vdebug("ttyGS%d: tx len=%d, %3ph ...\n", port->port_num, len, req->buf);
267 /* Drop lock while we call out of driver; completions
268 * could be issued while we do so. Disconnection may
269 * happen too; maybe immediately before we queue this!
271 * NOTE that we may keep sending data for a while after
272 * the TTY closed (dev->ioport->port_tty is NULL).
274 port->write_busy = true;
275 spin_unlock(&port->port_lock);
276 status = usb_ep_queue(in, req, GFP_ATOMIC);
277 spin_lock(&port->port_lock);
278 port->write_busy = false;
281 pr_debug("%s: %s %s err %d\n",
282 __func__, "queue", in->name, status);
283 list_add(&req->list, pool);
287 port->write_started++;
289 /* abort immediately after disconnect */
294 if (do_tty_wake && port->port.tty)
295 tty_wakeup(port->port.tty);
300 * Context: caller owns port_lock, and port_usb is set
302 static unsigned gs_start_rx(struct gs_port *port)
304 __releases(&port->port_lock)
305 __acquires(&port->port_lock)
308 struct list_head *pool = &port->read_pool;
309 struct usb_ep *out = port->port_usb->out;
311 while (!list_empty(pool)) {
312 struct usb_request *req;
314 struct tty_struct *tty;
316 /* no more rx if closed */
317 tty = port->port.tty;
321 if (port->read_started >= QUEUE_SIZE)
324 req = list_entry(pool->next, struct usb_request, list);
325 list_del(&req->list);
326 req->length = out->maxpacket;
328 /* drop lock while we call out; the controller driver
329 * may need to call us back (e.g. for disconnect)
331 spin_unlock(&port->port_lock);
332 status = usb_ep_queue(out, req, GFP_ATOMIC);
333 spin_lock(&port->port_lock);
336 pr_debug("%s: %s %s err %d\n",
337 __func__, "queue", out->name, status);
338 list_add(&req->list, pool);
341 port->read_started++;
343 /* abort immediately after disconnect */
347 return port->read_started;
351 * RX work takes data out of the RX queue and hands it up to the TTY
352 * layer until it refuses to take any more data (or is throttled back).
353 * Then it issues reads for any further data.
355 * If the RX queue becomes full enough that no usb_request is queued,
356 * the OUT endpoint may begin NAKing as soon as its FIFO fills up.
357 * So QUEUE_SIZE packets plus however many the FIFO holds (usually two)
358 * can be buffered before the TTY layer's buffers (currently 64 KB).
360 static void gs_rx_push(struct work_struct *work)
362 struct delayed_work *w = to_delayed_work(work);
363 struct gs_port *port = container_of(w, struct gs_port, push);
364 struct tty_struct *tty;
365 struct list_head *queue = &port->read_queue;
366 bool disconnect = false;
367 bool do_push = false;
369 /* hand any queued data to the tty */
370 spin_lock_irq(&port->port_lock);
371 tty = port->port.tty;
372 while (!list_empty(queue)) {
373 struct usb_request *req;
375 req = list_first_entry(queue, struct usb_request, list);
377 /* leave data queued if tty was rx throttled */
378 if (tty && tty_throttled(tty))
381 switch (req->status) {
384 pr_vdebug("ttyGS%d: shutdown\n", port->port_num);
388 /* presumably a transient fault */
389 pr_warn("ttyGS%d: unexpected RX status %d\n",
390 port->port_num, req->status);
393 /* normal completion */
397 /* push data to (open) tty */
398 if (req->actual && tty) {
399 char *packet = req->buf;
400 unsigned size = req->actual;
404 /* we may have pushed part of this packet already... */
411 count = tty_insert_flip_string(&port->port, packet,
416 /* stop pushing; TTY layer can't handle more */
417 port->n_read += count;
418 pr_vdebug("ttyGS%d: rx block %d/%d\n",
419 port->port_num, count, req->actual);
425 list_move(&req->list, &port->read_pool);
426 port->read_started--;
429 /* Push from tty to ldisc; this is handled by a workqueue,
430 * so we won't get callbacks and can hold port_lock
433 tty_flip_buffer_push(&port->port);
436 /* We want our data queue to become empty ASAP, keeping data
437 * in the tty and ldisc (not here). If we couldn't push any
438 * this time around, RX may be starved, so wait until next jiffy.
440 * We may leave non-empty queue only when there is a tty, and
441 * either it is throttled or there is no more room in flip buffer.
443 if (!list_empty(queue) && !tty_throttled(tty))
444 schedule_delayed_work(&port->push, 1);
446 /* If we're still connected, refill the USB RX queue. */
447 if (!disconnect && port->port_usb)
450 spin_unlock_irq(&port->port_lock);
453 static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
455 struct gs_port *port = ep->driver_data;
457 /* Queue all received data until the tty layer is ready for it. */
458 spin_lock(&port->port_lock);
459 list_add_tail(&req->list, &port->read_queue);
460 schedule_delayed_work(&port->push, 0);
461 spin_unlock(&port->port_lock);
464 static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
466 struct gs_port *port = ep->driver_data;
468 spin_lock(&port->port_lock);
469 list_add(&req->list, &port->write_pool);
470 port->write_started--;
472 switch (req->status) {
474 /* presumably a transient fault */
475 pr_warn("%s: unexpected %s status %d\n",
476 __func__, ep->name, req->status);
479 /* normal completion */
485 pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
489 spin_unlock(&port->port_lock);
492 static void gs_free_requests(struct usb_ep *ep, struct list_head *head,
495 struct usb_request *req;
497 while (!list_empty(head)) {
498 req = list_entry(head->next, struct usb_request, list);
499 list_del(&req->list);
500 gs_free_req(ep, req);
506 static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head,
507 void (*fn)(struct usb_ep *, struct usb_request *),
511 struct usb_request *req;
512 int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE;
514 /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
515 * do quite that many this time, don't fail ... we just won't
516 * be as speedy as we might otherwise be.
518 for (i = 0; i < n; i++) {
519 req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
521 return list_empty(head) ? -ENOMEM : 0;
523 list_add_tail(&req->list, head);
531 * gs_start_io - start USB I/O streams
533 * Context: holding port_lock; port_tty and port_usb are non-null
535 * We only start I/O when something is connected to both sides of
536 * this port. If nothing is listening on the host side, we may
537 * be pointlessly filling up our TX buffers and FIFO.
539 static int gs_start_io(struct gs_port *port)
541 struct list_head *head = &port->read_pool;
546 if (!port->port_usb || !port->port.tty)
549 /* Allocate RX and TX I/O buffers. We can't easily do this much
550 * earlier (with GFP_KERNEL) because the requests are coupled to
551 * endpoints, as are the packet sizes we'll be using. Different
552 * configurations may use different endpoints with a given port;
553 * and high speed vs full speed changes packet sizes too.
555 ep = port->port_usb->out;
556 status = gs_alloc_requests(ep, head, gs_read_complete,
557 &port->read_allocated);
561 status = gs_alloc_requests(port->port_usb->in, &port->write_pool,
562 gs_write_complete, &port->write_allocated);
564 gs_free_requests(ep, head, &port->read_allocated);
568 /* queue read requests */
570 started = gs_start_rx(port);
574 /* Unblock any pending writes into our circular buffer, in case
575 * we didn't in gs_start_tx() */
576 tty_wakeup(port->port.tty);
578 gs_free_requests(ep, head, &port->read_allocated);
579 gs_free_requests(port->port_usb->in, &port->write_pool,
580 &port->write_allocated);
587 /*-------------------------------------------------------------------------*/
592 * gs_open sets up the link between a gs_port and its associated TTY.
593 * That link is broken *only* by TTY close(), and all driver methods
596 static int gs_open(struct tty_struct *tty, struct file *file)
598 int port_num = tty->index;
599 struct gs_port *port;
602 mutex_lock(&ports[port_num].lock);
603 port = ports[port_num].port;
609 spin_lock_irq(&port->port_lock);
611 /* allocate circular buffer on first open */
612 if (!kfifo_initialized(&port->port_write_buf)) {
614 spin_unlock_irq(&port->port_lock);
617 * portmaster's mutex still protects from simultaneous open(),
618 * and close() can't happen, yet.
621 status = kfifo_alloc(&port->port_write_buf,
622 WRITE_BUF_SIZE, GFP_KERNEL);
624 pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n",
625 port_num, tty, file);
629 spin_lock_irq(&port->port_lock);
632 /* already open? Great. */
633 if (port->port.count++)
634 goto exit_unlock_port;
636 tty->driver_data = port;
637 port->port.tty = tty;
639 /* if connected, start the I/O stream */
640 if (port->port_usb) {
641 /* if port is suspended, wait resume to start I/0 stream */
642 if (!port->suspended) {
643 struct gserial *gser = port->port_usb;
645 pr_debug("gs_open: start ttyGS%d\n", port->port_num);
651 pr_debug("delay start of ttyGS%d\n", port->port_num);
652 port->start_delayed = true;
656 pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file);
659 spin_unlock_irq(&port->port_lock);
661 mutex_unlock(&ports[port_num].lock);
665 static int gs_close_flush_done(struct gs_port *p)
669 /* return true on disconnect or empty buffer or if raced with open() */
670 spin_lock_irq(&p->port_lock);
671 cond = p->port_usb == NULL || !kfifo_len(&p->port_write_buf) ||
673 spin_unlock_irq(&p->port_lock);
678 static void gs_close(struct tty_struct *tty, struct file *file)
680 struct gs_port *port = tty->driver_data;
681 struct gserial *gser;
683 spin_lock_irq(&port->port_lock);
685 if (port->port.count != 1) {
687 if (port->port.count == 0)
694 pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file);
696 gser = port->port_usb;
697 if (gser && !port->suspended && gser->disconnect)
698 gser->disconnect(gser);
700 /* wait for circular write buffer to drain, disconnect, or at
701 * most GS_CLOSE_TIMEOUT seconds; then discard the rest
703 if (kfifo_len(&port->port_write_buf) > 0 && gser) {
704 spin_unlock_irq(&port->port_lock);
705 wait_event_interruptible_timeout(port->drain_wait,
706 gs_close_flush_done(port),
707 GS_CLOSE_TIMEOUT * HZ);
708 spin_lock_irq(&port->port_lock);
710 if (port->port.count != 1)
711 goto raced_with_open;
713 gser = port->port_usb;
716 /* Iff we're disconnected, there can be no I/O in flight so it's
717 * ok to free the circular buffer; else just scrub it. And don't
718 * let the push async work fire again until we're re-opened.
721 kfifo_free(&port->port_write_buf);
723 kfifo_reset(&port->port_write_buf);
725 port->start_delayed = false;
726 port->port.count = 0;
727 port->port.tty = NULL;
729 pr_debug("gs_close: ttyGS%d (%p,%p) done!\n",
730 port->port_num, tty, file);
732 wake_up(&port->close_wait);
734 spin_unlock_irq(&port->port_lock);
737 static ssize_t gs_write(struct tty_struct *tty, const u8 *buf, size_t count)
739 struct gs_port *port = tty->driver_data;
742 pr_vdebug("gs_write: ttyGS%d (%p) writing %zu bytes\n",
743 port->port_num, tty, count);
745 spin_lock_irqsave(&port->port_lock, flags);
747 count = kfifo_in(&port->port_write_buf, buf, count);
748 /* treat count == 0 as flush_chars() */
751 spin_unlock_irqrestore(&port->port_lock, flags);
756 static int gs_put_char(struct tty_struct *tty, u8 ch)
758 struct gs_port *port = tty->driver_data;
762 pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %ps\n",
763 port->port_num, tty, ch, __builtin_return_address(0));
765 spin_lock_irqsave(&port->port_lock, flags);
766 status = kfifo_put(&port->port_write_buf, ch);
767 spin_unlock_irqrestore(&port->port_lock, flags);
772 static void gs_flush_chars(struct tty_struct *tty)
774 struct gs_port *port = tty->driver_data;
777 pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty);
779 spin_lock_irqsave(&port->port_lock, flags);
782 spin_unlock_irqrestore(&port->port_lock, flags);
785 static unsigned int gs_write_room(struct tty_struct *tty)
787 struct gs_port *port = tty->driver_data;
789 unsigned int room = 0;
791 spin_lock_irqsave(&port->port_lock, flags);
793 room = kfifo_avail(&port->port_write_buf);
794 spin_unlock_irqrestore(&port->port_lock, flags);
796 pr_vdebug("gs_write_room: (%d,%p) room=%u\n",
797 port->port_num, tty, room);
802 static unsigned int gs_chars_in_buffer(struct tty_struct *tty)
804 struct gs_port *port = tty->driver_data;
808 spin_lock_irqsave(&port->port_lock, flags);
809 chars = kfifo_len(&port->port_write_buf);
810 spin_unlock_irqrestore(&port->port_lock, flags);
812 pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%u\n",
813 port->port_num, tty, chars);
818 /* undo side effects of setting TTY_THROTTLED */
819 static void gs_unthrottle(struct tty_struct *tty)
821 struct gs_port *port = tty->driver_data;
824 spin_lock_irqsave(&port->port_lock, flags);
825 if (port->port_usb) {
826 /* Kickstart read queue processing. We don't do xon/xoff,
827 * rts/cts, or other handshaking with the host, but if the
828 * read queue backs up enough we'll be NAKing OUT packets.
830 pr_vdebug("ttyGS%d: unthrottle\n", port->port_num);
831 schedule_delayed_work(&port->push, 0);
833 spin_unlock_irqrestore(&port->port_lock, flags);
836 static int gs_break_ctl(struct tty_struct *tty, int duration)
838 struct gs_port *port = tty->driver_data;
840 struct gserial *gser;
842 pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n",
843 port->port_num, duration);
845 spin_lock_irq(&port->port_lock);
846 gser = port->port_usb;
847 if (gser && gser->send_break)
848 status = gser->send_break(gser, duration);
849 spin_unlock_irq(&port->port_lock);
854 static const struct tty_operations gs_tty_ops = {
858 .put_char = gs_put_char,
859 .flush_chars = gs_flush_chars,
860 .write_room = gs_write_room,
861 .chars_in_buffer = gs_chars_in_buffer,
862 .unthrottle = gs_unthrottle,
863 .break_ctl = gs_break_ctl,
866 /*-------------------------------------------------------------------------*/
868 static struct tty_driver *gs_tty_driver;
870 #ifdef CONFIG_U_SERIAL_CONSOLE
872 static void gs_console_complete_out(struct usb_ep *ep, struct usb_request *req)
874 struct gs_console *cons = req->context;
876 switch (req->status) {
878 pr_warn("%s: unexpected %s status %d\n",
879 __func__, ep->name, req->status);
882 /* normal completion */
883 spin_lock(&cons->lock);
885 schedule_work(&cons->work);
886 spin_unlock(&cons->lock);
891 pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
896 static void __gs_console_push(struct gs_console *cons)
898 struct usb_request *req = cons->req;
903 return; /* disconnected */
908 ep = cons->console.data;
909 size = kfifo_out(&cons->buf, req->buf, ep->maxpacket);
913 if (cons->missed && ep->maxpacket >= 64) {
917 len = sprintf(buf, "\n[missed %zu bytes]\n", cons->missed);
918 kfifo_in(&cons->buf, buf, len);
924 spin_unlock_irq(&cons->lock);
925 if (usb_ep_queue(ep, req, GFP_ATOMIC))
927 spin_lock_irq(&cons->lock);
930 static void gs_console_work(struct work_struct *work)
932 struct gs_console *cons = container_of(work, struct gs_console, work);
934 spin_lock_irq(&cons->lock);
936 __gs_console_push(cons);
938 spin_unlock_irq(&cons->lock);
941 static void gs_console_write(struct console *co,
942 const char *buf, unsigned count)
944 struct gs_console *cons = container_of(co, struct gs_console, console);
948 spin_lock_irqsave(&cons->lock, flags);
950 n = kfifo_in(&cons->buf, buf, count);
952 cons->missed += count - n;
954 if (cons->req && !cons->req->length)
955 schedule_work(&cons->work);
957 spin_unlock_irqrestore(&cons->lock, flags);
960 static struct tty_driver *gs_console_device(struct console *co, int *index)
963 return gs_tty_driver;
966 static int gs_console_connect(struct gs_port *port)
968 struct gs_console *cons = port->console;
969 struct usb_request *req;
975 ep = port->port_usb->in;
976 req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
979 req->complete = gs_console_complete_out;
983 spin_lock(&cons->lock);
985 cons->console.data = ep;
986 spin_unlock(&cons->lock);
988 pr_debug("ttyGS%d: console connected!\n", port->port_num);
990 schedule_work(&cons->work);
995 static void gs_console_disconnect(struct gs_port *port)
997 struct gs_console *cons = port->console;
998 struct usb_request *req;
1004 spin_lock(&cons->lock);
1007 ep = cons->console.data;
1010 spin_unlock(&cons->lock);
1015 usb_ep_dequeue(ep, req);
1016 gs_free_req(ep, req);
1019 static int gs_console_init(struct gs_port *port)
1021 struct gs_console *cons;
1027 cons = kzalloc(sizeof(*port->console), GFP_KERNEL);
1031 strcpy(cons->console.name, "ttyGS");
1032 cons->console.write = gs_console_write;
1033 cons->console.device = gs_console_device;
1034 cons->console.flags = CON_PRINTBUFFER;
1035 cons->console.index = port->port_num;
1037 INIT_WORK(&cons->work, gs_console_work);
1038 spin_lock_init(&cons->lock);
1040 err = kfifo_alloc(&cons->buf, GS_CONSOLE_BUF_SIZE, GFP_KERNEL);
1042 pr_err("ttyGS%d: allocate console buffer failed\n", port->port_num);
1047 port->console = cons;
1048 register_console(&cons->console);
1050 spin_lock_irq(&port->port_lock);
1052 gs_console_connect(port);
1053 spin_unlock_irq(&port->port_lock);
1058 static void gs_console_exit(struct gs_port *port)
1060 struct gs_console *cons = port->console;
1065 unregister_console(&cons->console);
1067 spin_lock_irq(&port->port_lock);
1069 gs_console_disconnect(port);
1070 spin_unlock_irq(&port->port_lock);
1072 cancel_work_sync(&cons->work);
1073 kfifo_free(&cons->buf);
1075 port->console = NULL;
1078 ssize_t gserial_set_console(unsigned char port_num, const char *page, size_t count)
1080 struct gs_port *port;
1084 ret = kstrtobool(page, &enable);
1088 mutex_lock(&ports[port_num].lock);
1089 port = ports[port_num].port;
1091 if (WARN_ON(port == NULL)) {
1097 ret = gs_console_init(port);
1099 gs_console_exit(port);
1101 mutex_unlock(&ports[port_num].lock);
1103 return ret < 0 ? ret : count;
1105 EXPORT_SYMBOL_GPL(gserial_set_console);
1107 ssize_t gserial_get_console(unsigned char port_num, char *page)
1109 struct gs_port *port;
1112 mutex_lock(&ports[port_num].lock);
1113 port = ports[port_num].port;
1115 if (WARN_ON(port == NULL))
1118 ret = sprintf(page, "%u\n", !!port->console);
1120 mutex_unlock(&ports[port_num].lock);
1124 EXPORT_SYMBOL_GPL(gserial_get_console);
1128 static int gs_console_connect(struct gs_port *port)
1133 static void gs_console_disconnect(struct gs_port *port)
1137 static int gs_console_init(struct gs_port *port)
1142 static void gs_console_exit(struct gs_port *port)
1149 gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
1151 struct gs_port *port;
1154 mutex_lock(&ports[port_num].lock);
1155 if (ports[port_num].port) {
1160 port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
1166 tty_port_init(&port->port);
1167 spin_lock_init(&port->port_lock);
1168 init_waitqueue_head(&port->drain_wait);
1169 init_waitqueue_head(&port->close_wait);
1171 INIT_DELAYED_WORK(&port->push, gs_rx_push);
1173 INIT_LIST_HEAD(&port->read_pool);
1174 INIT_LIST_HEAD(&port->read_queue);
1175 INIT_LIST_HEAD(&port->write_pool);
1177 port->port_num = port_num;
1178 port->port_line_coding = *coding;
1180 ports[port_num].port = port;
1182 mutex_unlock(&ports[port_num].lock);
1186 static int gs_closed(struct gs_port *port)
1190 spin_lock_irq(&port->port_lock);
1191 cond = port->port.count == 0;
1192 spin_unlock_irq(&port->port_lock);
1197 static void gserial_free_port(struct gs_port *port)
1199 cancel_delayed_work_sync(&port->push);
1200 /* wait for old opens to finish */
1201 wait_event(port->close_wait, gs_closed(port));
1202 WARN_ON(port->port_usb != NULL);
1203 tty_port_destroy(&port->port);
1207 void gserial_free_line(unsigned char port_num)
1209 struct gs_port *port;
1211 mutex_lock(&ports[port_num].lock);
1212 if (!ports[port_num].port) {
1213 mutex_unlock(&ports[port_num].lock);
1216 port = ports[port_num].port;
1217 gs_console_exit(port);
1218 ports[port_num].port = NULL;
1219 mutex_unlock(&ports[port_num].lock);
1221 gserial_free_port(port);
1222 tty_unregister_device(gs_tty_driver, port_num);
1224 EXPORT_SYMBOL_GPL(gserial_free_line);
1226 int gserial_alloc_line_no_console(unsigned char *line_num)
1228 struct usb_cdc_line_coding coding;
1229 struct gs_port *port;
1230 struct device *tty_dev;
1234 coding.dwDTERate = cpu_to_le32(9600);
1235 coding.bCharFormat = 8;
1236 coding.bParityType = USB_CDC_NO_PARITY;
1237 coding.bDataBits = USB_CDC_1_STOP_BITS;
1239 for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
1240 ret = gs_port_alloc(port_num, &coding);
1250 /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
1252 port = ports[port_num].port;
1253 tty_dev = tty_port_register_device(&port->port,
1254 gs_tty_driver, port_num, NULL);
1255 if (IS_ERR(tty_dev)) {
1256 pr_err("%s: failed to register tty for port %d, err %ld\n",
1257 __func__, port_num, PTR_ERR(tty_dev));
1259 ret = PTR_ERR(tty_dev);
1260 mutex_lock(&ports[port_num].lock);
1261 ports[port_num].port = NULL;
1262 mutex_unlock(&ports[port_num].lock);
1263 gserial_free_port(port);
1266 *line_num = port_num;
1270 EXPORT_SYMBOL_GPL(gserial_alloc_line_no_console);
1272 int gserial_alloc_line(unsigned char *line_num)
1274 int ret = gserial_alloc_line_no_console(line_num);
1276 if (!ret && !*line_num)
1277 gs_console_init(ports[*line_num].port);
1281 EXPORT_SYMBOL_GPL(gserial_alloc_line);
1284 * gserial_connect - notify TTY I/O glue that USB link is active
1285 * @gser: the function, set up with endpoints and descriptors
1286 * @port_num: which port is active
1287 * Context: any (usually from irq)
1289 * This is called activate endpoints and let the TTY layer know that
1290 * the connection is active ... not unlike "carrier detect". It won't
1291 * necessarily start I/O queues; unless the TTY is held open by any
1292 * task, there would be no point. However, the endpoints will be
1293 * activated so the USB host can perform I/O, subject to basic USB
1294 * hardware flow control.
1296 * Caller needs to have set up the endpoints and USB function in @dev
1297 * before calling this, as well as the appropriate (speed-specific)
1298 * endpoint descriptors, and also have allocate @port_num by calling
1299 * @gserial_alloc_line().
1301 * Returns negative errno or zero.
1302 * On success, ep->driver_data will be overwritten.
1304 int gserial_connect(struct gserial *gser, u8 port_num)
1306 struct gs_port *port;
1307 unsigned long flags;
1310 if (port_num >= MAX_U_SERIAL_PORTS)
1313 port = ports[port_num].port;
1315 pr_err("serial line %d not allocated.\n", port_num);
1318 if (port->port_usb) {
1319 pr_err("serial line %d is in use.\n", port_num);
1323 /* activate the endpoints */
1324 status = usb_ep_enable(gser->in);
1327 gser->in->driver_data = port;
1329 status = usb_ep_enable(gser->out);
1332 gser->out->driver_data = port;
1334 /* then tell the tty glue that I/O can work */
1335 spin_lock_irqsave(&port->port_lock, flags);
1336 gser->ioport = port;
1337 port->port_usb = gser;
1339 /* REVISIT unclear how best to handle this state...
1340 * we don't really couple it with the Linux TTY.
1342 gser->port_line_coding = port->port_line_coding;
1344 /* REVISIT if waiting on "carrier detect", signal. */
1346 /* if it's already open, start I/O ... and notify the serial
1347 * protocol about open/close status (connect/disconnect).
1349 if (port->port.count) {
1350 pr_debug("gserial_connect: start ttyGS%d\n", port->port_num);
1353 gser->connect(gser);
1355 if (gser->disconnect)
1356 gser->disconnect(gser);
1359 status = gs_console_connect(port);
1360 spin_unlock_irqrestore(&port->port_lock, flags);
1365 usb_ep_disable(gser->in);
1368 EXPORT_SYMBOL_GPL(gserial_connect);
1370 * gserial_disconnect - notify TTY I/O glue that USB link is inactive
1371 * @gser: the function, on which gserial_connect() was called
1372 * Context: any (usually from irq)
1374 * This is called to deactivate endpoints and let the TTY layer know
1375 * that the connection went inactive ... not unlike "hangup".
1377 * On return, the state is as if gserial_connect() had never been called;
1378 * there is no active USB I/O on these endpoints.
1380 void gserial_disconnect(struct gserial *gser)
1382 struct gs_port *port = gser->ioport;
1383 unsigned long flags;
1388 spin_lock_irqsave(&serial_port_lock, flags);
1390 /* tell the TTY glue not to do I/O here any more */
1391 spin_lock(&port->port_lock);
1393 gs_console_disconnect(port);
1395 /* REVISIT as above: how best to track this? */
1396 port->port_line_coding = gser->port_line_coding;
1398 port->port_usb = NULL;
1399 gser->ioport = NULL;
1400 if (port->port.count > 0) {
1401 wake_up_interruptible(&port->drain_wait);
1403 tty_hangup(port->port.tty);
1405 port->suspended = false;
1406 spin_unlock(&port->port_lock);
1407 spin_unlock_irqrestore(&serial_port_lock, flags);
1409 /* disable endpoints, aborting down any active I/O */
1410 usb_ep_disable(gser->out);
1411 usb_ep_disable(gser->in);
1413 /* finally, free any unused/unusable I/O buffers */
1414 spin_lock_irqsave(&port->port_lock, flags);
1415 if (port->port.count == 0)
1416 kfifo_free(&port->port_write_buf);
1417 gs_free_requests(gser->out, &port->read_pool, NULL);
1418 gs_free_requests(gser->out, &port->read_queue, NULL);
1419 gs_free_requests(gser->in, &port->write_pool, NULL);
1421 port->read_allocated = port->read_started =
1422 port->write_allocated = port->write_started = 0;
1424 spin_unlock_irqrestore(&port->port_lock, flags);
1426 EXPORT_SYMBOL_GPL(gserial_disconnect);
1428 void gserial_suspend(struct gserial *gser)
1430 struct gs_port *port;
1431 unsigned long flags;
1433 spin_lock_irqsave(&serial_port_lock, flags);
1434 port = gser->ioport;
1437 spin_unlock_irqrestore(&serial_port_lock, flags);
1441 spin_lock(&port->port_lock);
1442 spin_unlock(&serial_port_lock);
1443 port->suspended = true;
1444 spin_unlock_irqrestore(&port->port_lock, flags);
1446 EXPORT_SYMBOL_GPL(gserial_suspend);
1448 void gserial_resume(struct gserial *gser)
1450 struct gs_port *port;
1451 unsigned long flags;
1453 spin_lock_irqsave(&serial_port_lock, flags);
1454 port = gser->ioport;
1457 spin_unlock_irqrestore(&serial_port_lock, flags);
1461 spin_lock(&port->port_lock);
1462 spin_unlock(&serial_port_lock);
1463 port->suspended = false;
1464 if (!port->start_delayed) {
1465 spin_unlock_irqrestore(&port->port_lock, flags);
1469 pr_debug("delayed start ttyGS%d\n", port->port_num);
1472 gser->connect(gser);
1473 port->start_delayed = false;
1474 spin_unlock_irqrestore(&port->port_lock, flags);
1476 EXPORT_SYMBOL_GPL(gserial_resume);
1478 static int __init userial_init(void)
1480 struct tty_driver *driver;
1484 driver = tty_alloc_driver(MAX_U_SERIAL_PORTS, TTY_DRIVER_REAL_RAW |
1485 TTY_DRIVER_DYNAMIC_DEV);
1487 return PTR_ERR(driver);
1489 driver->driver_name = "g_serial";
1490 driver->name = "ttyGS";
1491 /* uses dynamically assigned dev_t values */
1493 driver->type = TTY_DRIVER_TYPE_SERIAL;
1494 driver->subtype = SERIAL_TYPE_NORMAL;
1495 driver->init_termios = tty_std_termios;
1497 /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
1498 * MS-Windows. Otherwise, most of these flags shouldn't affect
1499 * anything unless we were to actually hook up to a serial line.
1501 driver->init_termios.c_cflag =
1502 B9600 | CS8 | CREAD | HUPCL | CLOCAL;
1503 driver->init_termios.c_ispeed = 9600;
1504 driver->init_termios.c_ospeed = 9600;
1506 tty_set_operations(driver, &gs_tty_ops);
1507 for (i = 0; i < MAX_U_SERIAL_PORTS; i++)
1508 mutex_init(&ports[i].lock);
1510 /* export the driver ... */
1511 status = tty_register_driver(driver);
1513 pr_err("%s: cannot register, err %d\n",
1518 gs_tty_driver = driver;
1520 pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
1522 (MAX_U_SERIAL_PORTS == 1) ? "" : "s");
1526 tty_driver_kref_put(driver);
1529 module_init(userial_init);
1531 static void __exit userial_cleanup(void)
1533 tty_unregister_driver(gs_tty_driver);
1534 tty_driver_kref_put(gs_tty_driver);
1535 gs_tty_driver = NULL;
1537 module_exit(userial_cleanup);
1539 MODULE_LICENSE("GPL");