2 * u_serial.c - utilities for USB gadget "serial port"/TTY support
4 * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
5 * Copyright (C) 2008 David Brownell
6 * Copyright (C) 2008 by Nokia Corporation
8 * This code also borrows from usbserial.c, which is
9 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
10 * Copyright (C) 2000 Peter Berger (pberger@brimson.com)
11 * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
13 * This software is distributed under the terms of the GNU General
14 * Public License ("GPL") as published by the Free Software Foundation,
15 * either version 2 of that License or (at your option) any later version.
18 /* #define VERBOSE_DEBUG */
20 #include <linux/kernel.h>
21 #include <linux/sched.h>
22 #include <linux/interrupt.h>
23 #include <linux/device.h>
24 #include <linux/delay.h>
25 #include <linux/tty.h>
26 #include <linux/tty_flip.h>
27 #include <linux/slab.h>
28 #include <linux/export.h>
29 #include <linux/module.h>
35 * This component encapsulates the TTY layer glue needed to provide basic
36 * "serial port" functionality through the USB gadget stack. Each such
37 * port is exposed through a /dev/ttyGS* node.
39 * After this module has been loaded, the individual TTY port can be requested
40 * (gserial_alloc_line()) and it will stay available until they are removed
41 * (gserial_free_line()). Each one may be connected to a USB function
42 * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
43 * host issues a config change event. Data can only flow when the port is
44 * connected to the host.
46 * A given TTY port can be made available in multiple configurations.
47 * For example, each one might expose a ttyGS0 node which provides a
48 * login application. In one case that might use CDC ACM interface 0,
49 * while another configuration might use interface 3 for that. The
50 * work to handle that (including descriptor management) is not part
53 * Configurations may expose more than one TTY port. For example, if
54 * ttyGS0 provides login service, then ttyGS1 might provide dialer access
55 * for a telephone or fax link. And ttyGS2 might be something that just
56 * needs a simple byte stream interface for some messaging protocol that
57 * is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
60 * gserial is the lifecycle interface, used by USB functions
61 * gs_port is the I/O nexus, used by the tty driver
62 * tty_struct links to the tty/filesystem framework
64 * gserial <---> gs_port ... links will be null when the USB link is
65 * inactive; managed by gserial_{connect,disconnect}(). each gserial
66 * instance can wrap its own USB control protocol.
67 * gserial->ioport == usb_ep->driver_data ... gs_port
68 * gs_port->port_usb ... gserial
70 * gs_port <---> tty_struct ... links will be null when the TTY file
71 * isn't opened; managed by gs_open()/gs_close()
72 * gserial->port_tty ... tty_struct
73 * tty_struct->driver_data ... gserial
76 /* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
77 * next layer of buffering. For TX that's a circular buffer; for RX
78 * consider it a NOP. A third layer is provided by the TTY code.
81 #define WRITE_BUF_SIZE 8192 /* TX only */
92 * The port structure holds info for each port, one for each minor number
93 * (and thus for each /dev/ node).
97 spinlock_t port_lock
; /* guard port_* access */
99 struct gserial
*port_usb
;
101 bool openclose
; /* open/close in progress */
104 struct list_head read_pool
;
107 struct list_head read_queue
;
109 struct tasklet_struct push
;
111 struct list_head write_pool
;
114 struct gs_buf port_write_buf
;
115 wait_queue_head_t drain_wait
; /* wait while writes drain */
117 /* REVISIT this state ... */
118 struct usb_cdc_line_coding port_line_coding
; /* 8-N-1 etc */
121 static struct portmaster
{
122 struct mutex lock
; /* protect open/close */
123 struct gs_port
*port
;
124 } ports
[MAX_U_SERIAL_PORTS
];
126 #define GS_CLOSE_TIMEOUT 15 /* seconds */
132 #define pr_vdebug(fmt, arg...) \
134 #endif /* pr_vdebug */
137 #define pr_vdebug(fmt, arg...) \
138 ({ if (0) pr_debug(fmt, ##arg); })
139 #endif /* pr_vdebug */
142 /*-------------------------------------------------------------------------*/
144 /* Circular Buffer */
149 * Allocate a circular buffer and all associated memory.
151 static int gs_buf_alloc(struct gs_buf
*gb
, unsigned size
)
153 gb
->buf_buf
= kmalloc(size
, GFP_KERNEL
);
154 if (gb
->buf_buf
== NULL
)
158 gb
->buf_put
= gb
->buf_buf
;
159 gb
->buf_get
= gb
->buf_buf
;
167 * Free the buffer and all associated memory.
169 static void gs_buf_free(struct gs_buf
*gb
)
178 * Clear out all data in the circular buffer.
180 static void gs_buf_clear(struct gs_buf
*gb
)
182 gb
->buf_get
= gb
->buf_put
;
183 /* equivalent to a get of all data available */
189 * Return the number of bytes of data written into the circular
192 static unsigned gs_buf_data_avail(struct gs_buf
*gb
)
194 return (gb
->buf_size
+ gb
->buf_put
- gb
->buf_get
) % gb
->buf_size
;
200 * Return the number of bytes of space available in the circular
203 static unsigned gs_buf_space_avail(struct gs_buf
*gb
)
205 return (gb
->buf_size
+ gb
->buf_get
- gb
->buf_put
- 1) % gb
->buf_size
;
211 * Copy data data from a user buffer and put it into the circular buffer.
212 * Restrict to the amount of space available.
214 * Return the number of bytes copied.
217 gs_buf_put(struct gs_buf
*gb
, const char *buf
, unsigned count
)
221 len
= gs_buf_space_avail(gb
);
228 len
= gb
->buf_buf
+ gb
->buf_size
- gb
->buf_put
;
230 memcpy(gb
->buf_put
, buf
, len
);
231 memcpy(gb
->buf_buf
, buf
+len
, count
- len
);
232 gb
->buf_put
= gb
->buf_buf
+ count
- len
;
234 memcpy(gb
->buf_put
, buf
, count
);
236 gb
->buf_put
+= count
;
237 else /* count == len */
238 gb
->buf_put
= gb
->buf_buf
;
247 * Get data from the circular buffer and copy to the given buffer.
248 * Restrict to the amount of data available.
250 * Return the number of bytes copied.
253 gs_buf_get(struct gs_buf
*gb
, char *buf
, unsigned count
)
257 len
= gs_buf_data_avail(gb
);
264 len
= gb
->buf_buf
+ gb
->buf_size
- gb
->buf_get
;
266 memcpy(buf
, gb
->buf_get
, len
);
267 memcpy(buf
+len
, gb
->buf_buf
, count
- len
);
268 gb
->buf_get
= gb
->buf_buf
+ count
- len
;
270 memcpy(buf
, gb
->buf_get
, count
);
272 gb
->buf_get
+= count
;
273 else /* count == len */
274 gb
->buf_get
= gb
->buf_buf
;
280 /*-------------------------------------------------------------------------*/
282 /* I/O glue between TTY (upper) and USB function (lower) driver layers */
287 * Allocate a usb_request and its buffer. Returns a pointer to the
288 * usb_request or NULL if there is an error.
291 gs_alloc_req(struct usb_ep
*ep
, unsigned len
, gfp_t kmalloc_flags
)
293 struct usb_request
*req
;
295 req
= usb_ep_alloc_request(ep
, kmalloc_flags
);
299 req
->buf
= kmalloc(len
, kmalloc_flags
);
300 if (req
->buf
== NULL
) {
301 usb_ep_free_request(ep
, req
);
308 EXPORT_SYMBOL_GPL(gs_alloc_req
);
313 * Free a usb_request and its buffer.
315 void gs_free_req(struct usb_ep
*ep
, struct usb_request
*req
)
318 usb_ep_free_request(ep
, req
);
320 EXPORT_SYMBOL_GPL(gs_free_req
);
325 * If there is data to send, a packet is built in the given
326 * buffer and the size is returned. If there is no data to
327 * send, 0 is returned.
329 * Called with port_lock held.
332 gs_send_packet(struct gs_port
*port
, char *packet
, unsigned size
)
336 len
= gs_buf_data_avail(&port
->port_write_buf
);
340 size
= gs_buf_get(&port
->port_write_buf
, packet
, size
);
347 * This function finds available write requests, calls
348 * gs_send_packet to fill these packets with data, and
349 * continues until either there are no more write requests
350 * available or no more data to send. This function is
351 * run whenever data arrives or write requests are available.
353 * Context: caller owns port_lock; port_usb is non-null.
355 static int gs_start_tx(struct gs_port
*port
)
357 __releases(&port->port_lock)
358 __acquires(&port->port_lock)
361 struct list_head
*pool
= &port
->write_pool
;
362 struct usb_ep
*in
= port
->port_usb
->in
;
364 bool do_tty_wake
= false;
366 while (!list_empty(pool
)) {
367 struct usb_request
*req
;
370 if (port
->write_started
>= QUEUE_SIZE
)
373 req
= list_entry(pool
->next
, struct usb_request
, list
);
374 len
= gs_send_packet(port
, req
->buf
, in
->maxpacket
);
376 wake_up_interruptible(&port
->drain_wait
);
382 list_del(&req
->list
);
383 req
->zero
= (gs_buf_data_avail(&port
->port_write_buf
) == 0);
385 pr_vdebug("ttyGS%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
386 port
->port_num
, len
, *((u8
*)req
->buf
),
387 *((u8
*)req
->buf
+1), *((u8
*)req
->buf
+2));
389 /* Drop lock while we call out of driver; completions
390 * could be issued while we do so. Disconnection may
391 * happen too; maybe immediately before we queue this!
393 * NOTE that we may keep sending data for a while after
394 * the TTY closed (dev->ioport->port_tty is NULL).
396 spin_unlock(&port
->port_lock
);
397 status
= usb_ep_queue(in
, req
, GFP_ATOMIC
);
398 spin_lock(&port
->port_lock
);
401 pr_debug("%s: %s %s err %d\n",
402 __func__
, "queue", in
->name
, status
);
403 list_add(&req
->list
, pool
);
407 port
->write_started
++;
409 /* abort immediately after disconnect */
414 if (do_tty_wake
&& port
->port
.tty
)
415 tty_wakeup(port
->port
.tty
);
420 * Context: caller owns port_lock, and port_usb is set
422 static unsigned gs_start_rx(struct gs_port
*port
)
424 __releases(&port->port_lock)
425 __acquires(&port->port_lock)
428 struct list_head
*pool
= &port
->read_pool
;
429 struct usb_ep
*out
= port
->port_usb
->out
;
431 while (!list_empty(pool
)) {
432 struct usb_request
*req
;
434 struct tty_struct
*tty
;
436 /* no more rx if closed */
437 tty
= port
->port
.tty
;
441 if (port
->read_started
>= QUEUE_SIZE
)
444 req
= list_entry(pool
->next
, struct usb_request
, list
);
445 list_del(&req
->list
);
446 req
->length
= out
->maxpacket
;
448 /* drop lock while we call out; the controller driver
449 * may need to call us back (e.g. for disconnect)
451 spin_unlock(&port
->port_lock
);
452 status
= usb_ep_queue(out
, req
, GFP_ATOMIC
);
453 spin_lock(&port
->port_lock
);
456 pr_debug("%s: %s %s err %d\n",
457 __func__
, "queue", out
->name
, status
);
458 list_add(&req
->list
, pool
);
461 port
->read_started
++;
463 /* abort immediately after disconnect */
467 return port
->read_started
;
471 * RX tasklet takes data out of the RX queue and hands it up to the TTY
472 * layer until it refuses to take any more data (or is throttled back).
473 * Then it issues reads for any further data.
475 * If the RX queue becomes full enough that no usb_request is queued,
476 * the OUT endpoint may begin NAKing as soon as its FIFO fills up.
477 * So QUEUE_SIZE packets plus however many the FIFO holds (usually two)
478 * can be buffered before the TTY layer's buffers (currently 64 KB).
480 static void gs_rx_push(unsigned long _port
)
482 struct gs_port
*port
= (void *)_port
;
483 struct tty_struct
*tty
;
484 struct list_head
*queue
= &port
->read_queue
;
485 bool disconnect
= false;
486 bool do_push
= false;
488 /* hand any queued data to the tty */
489 spin_lock_irq(&port
->port_lock
);
490 tty
= port
->port
.tty
;
491 while (!list_empty(queue
)) {
492 struct usb_request
*req
;
494 req
= list_first_entry(queue
, struct usb_request
, list
);
496 /* leave data queued if tty was rx throttled */
497 if (tty
&& test_bit(TTY_THROTTLED
, &tty
->flags
))
500 switch (req
->status
) {
503 pr_vdebug("ttyGS%d: shutdown\n", port
->port_num
);
507 /* presumably a transient fault */
508 pr_warn("ttyGS%d: unexpected RX status %d\n",
509 port
->port_num
, req
->status
);
512 /* normal completion */
516 /* push data to (open) tty */
518 char *packet
= req
->buf
;
519 unsigned size
= req
->actual
;
523 /* we may have pushed part of this packet already... */
530 count
= tty_insert_flip_string(&port
->port
, packet
,
535 /* stop pushing; TTY layer can't handle more */
536 port
->n_read
+= count
;
537 pr_vdebug("ttyGS%d: rx block %d/%d\n",
538 port
->port_num
, count
, req
->actual
);
544 list_move(&req
->list
, &port
->read_pool
);
545 port
->read_started
--;
548 /* Push from tty to ldisc; this is handled by a workqueue,
549 * so we won't get callbacks and can hold port_lock
552 tty_flip_buffer_push(&port
->port
);
555 /* We want our data queue to become empty ASAP, keeping data
556 * in the tty and ldisc (not here). If we couldn't push any
557 * this time around, there may be trouble unless there's an
558 * implicit tty_unthrottle() call on its way...
560 * REVISIT we should probably add a timer to keep the tasklet
561 * from starving ... but it's not clear that case ever happens.
563 if (!list_empty(queue
) && tty
) {
564 if (!test_bit(TTY_THROTTLED
, &tty
->flags
)) {
566 tasklet_schedule(&port
->push
);
568 pr_warn("ttyGS%d: RX not scheduled?\n",
573 /* If we're still connected, refill the USB RX queue. */
574 if (!disconnect
&& port
->port_usb
)
577 spin_unlock_irq(&port
->port_lock
);
580 static void gs_read_complete(struct usb_ep
*ep
, struct usb_request
*req
)
582 struct gs_port
*port
= ep
->driver_data
;
584 /* Queue all received data until the tty layer is ready for it. */
585 spin_lock(&port
->port_lock
);
586 list_add_tail(&req
->list
, &port
->read_queue
);
587 tasklet_schedule(&port
->push
);
588 spin_unlock(&port
->port_lock
);
591 static void gs_write_complete(struct usb_ep
*ep
, struct usb_request
*req
)
593 struct gs_port
*port
= ep
->driver_data
;
595 spin_lock(&port
->port_lock
);
596 list_add(&req
->list
, &port
->write_pool
);
597 port
->write_started
--;
599 switch (req
->status
) {
601 /* presumably a transient fault */
602 pr_warning("%s: unexpected %s status %d\n",
603 __func__
, ep
->name
, req
->status
);
606 /* normal completion */
612 pr_vdebug("%s: %s shutdown\n", __func__
, ep
->name
);
616 spin_unlock(&port
->port_lock
);
619 static void gs_free_requests(struct usb_ep
*ep
, struct list_head
*head
,
622 struct usb_request
*req
;
624 while (!list_empty(head
)) {
625 req
= list_entry(head
->next
, struct usb_request
, list
);
626 list_del(&req
->list
);
627 gs_free_req(ep
, req
);
633 static int gs_alloc_requests(struct usb_ep
*ep
, struct list_head
*head
,
634 void (*fn
)(struct usb_ep
*, struct usb_request
*),
638 struct usb_request
*req
;
639 int n
= allocated
? QUEUE_SIZE
- *allocated
: QUEUE_SIZE
;
641 /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
642 * do quite that many this time, don't fail ... we just won't
643 * be as speedy as we might otherwise be.
645 for (i
= 0; i
< n
; i
++) {
646 req
= gs_alloc_req(ep
, ep
->maxpacket
, GFP_ATOMIC
);
648 return list_empty(head
) ? -ENOMEM
: 0;
650 list_add_tail(&req
->list
, head
);
658 * gs_start_io - start USB I/O streams
659 * @dev: encapsulates endpoints to use
660 * Context: holding port_lock; port_tty and port_usb are non-null
662 * We only start I/O when something is connected to both sides of
663 * this port. If nothing is listening on the host side, we may
664 * be pointlessly filling up our TX buffers and FIFO.
666 static int gs_start_io(struct gs_port
*port
)
668 struct list_head
*head
= &port
->read_pool
;
669 struct usb_ep
*ep
= port
->port_usb
->out
;
673 /* Allocate RX and TX I/O buffers. We can't easily do this much
674 * earlier (with GFP_KERNEL) because the requests are coupled to
675 * endpoints, as are the packet sizes we'll be using. Different
676 * configurations may use different endpoints with a given port;
677 * and high speed vs full speed changes packet sizes too.
679 status
= gs_alloc_requests(ep
, head
, gs_read_complete
,
680 &port
->read_allocated
);
684 status
= gs_alloc_requests(port
->port_usb
->in
, &port
->write_pool
,
685 gs_write_complete
, &port
->write_allocated
);
687 gs_free_requests(ep
, head
, &port
->read_allocated
);
691 /* queue read requests */
693 started
= gs_start_rx(port
);
695 /* unblock any pending writes into our circular buffer */
697 tty_wakeup(port
->port
.tty
);
699 gs_free_requests(ep
, head
, &port
->read_allocated
);
700 gs_free_requests(port
->port_usb
->in
, &port
->write_pool
,
701 &port
->write_allocated
);
708 /*-------------------------------------------------------------------------*/
713 * gs_open sets up the link between a gs_port and its associated TTY.
714 * That link is broken *only* by TTY close(), and all driver methods
717 static int gs_open(struct tty_struct
*tty
, struct file
*file
)
719 int port_num
= tty
->index
;
720 struct gs_port
*port
;
724 mutex_lock(&ports
[port_num
].lock
);
725 port
= ports
[port_num
].port
;
729 spin_lock_irq(&port
->port_lock
);
731 /* already open? Great. */
732 if (port
->port
.count
) {
736 /* currently opening/closing? wait ... */
737 } else if (port
->openclose
) {
740 /* ... else we do the work */
743 port
->openclose
= true;
745 spin_unlock_irq(&port
->port_lock
);
747 mutex_unlock(&ports
[port_num
].lock
);
754 /* must do the work */
757 /* wait for EAGAIN task to finish */
759 /* REVISIT could have a waitchannel here, if
760 * concurrent open performance is important
764 } while (status
!= -EAGAIN
);
766 /* Do the "real open" */
767 spin_lock_irq(&port
->port_lock
);
769 /* allocate circular buffer on first open */
770 if (port
->port_write_buf
.buf_buf
== NULL
) {
772 spin_unlock_irq(&port
->port_lock
);
773 status
= gs_buf_alloc(&port
->port_write_buf
, WRITE_BUF_SIZE
);
774 spin_lock_irq(&port
->port_lock
);
777 pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n",
778 port
->port_num
, tty
, file
);
779 port
->openclose
= false;
780 goto exit_unlock_port
;
784 /* REVISIT if REMOVED (ports[].port NULL), abort the open
785 * to let rmmod work faster (but this way isn't wrong).
788 /* REVISIT maybe wait for "carrier detect" */
790 tty
->driver_data
= port
;
791 port
->port
.tty
= tty
;
793 port
->port
.count
= 1;
794 port
->openclose
= false;
796 /* if connected, start the I/O stream */
797 if (port
->port_usb
) {
798 struct gserial
*gser
= port
->port_usb
;
800 pr_debug("gs_open: start ttyGS%d\n", port
->port_num
);
807 pr_debug("gs_open: ttyGS%d (%p,%p)\n", port
->port_num
, tty
, file
);
812 spin_unlock_irq(&port
->port_lock
);
816 static int gs_writes_finished(struct gs_port
*p
)
820 /* return true on disconnect or empty buffer */
821 spin_lock_irq(&p
->port_lock
);
822 cond
= (p
->port_usb
== NULL
) || !gs_buf_data_avail(&p
->port_write_buf
);
823 spin_unlock_irq(&p
->port_lock
);
828 static void gs_close(struct tty_struct
*tty
, struct file
*file
)
830 struct gs_port
*port
= tty
->driver_data
;
831 struct gserial
*gser
;
833 spin_lock_irq(&port
->port_lock
);
835 if (port
->port
.count
!= 1) {
836 if (port
->port
.count
== 0)
843 pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port
->port_num
, tty
, file
);
845 /* mark port as closing but in use; we can drop port lock
846 * and sleep if necessary
848 port
->openclose
= true;
849 port
->port
.count
= 0;
851 gser
= port
->port_usb
;
852 if (gser
&& gser
->disconnect
)
853 gser
->disconnect(gser
);
855 /* wait for circular write buffer to drain, disconnect, or at
856 * most GS_CLOSE_TIMEOUT seconds; then discard the rest
858 if (gs_buf_data_avail(&port
->port_write_buf
) > 0 && gser
) {
859 spin_unlock_irq(&port
->port_lock
);
860 wait_event_interruptible_timeout(port
->drain_wait
,
861 gs_writes_finished(port
),
862 GS_CLOSE_TIMEOUT
* HZ
);
863 spin_lock_irq(&port
->port_lock
);
864 gser
= port
->port_usb
;
867 /* Iff we're disconnected, there can be no I/O in flight so it's
868 * ok to free the circular buffer; else just scrub it. And don't
869 * let the push tasklet fire again until we're re-opened.
872 gs_buf_free(&port
->port_write_buf
);
874 gs_buf_clear(&port
->port_write_buf
);
876 tty
->driver_data
= NULL
;
877 port
->port
.tty
= NULL
;
879 port
->openclose
= false;
881 pr_debug("gs_close: ttyGS%d (%p,%p) done!\n",
882 port
->port_num
, tty
, file
);
884 wake_up(&port
->port
.close_wait
);
886 spin_unlock_irq(&port
->port_lock
);
889 static int gs_write(struct tty_struct
*tty
, const unsigned char *buf
, int count
)
891 struct gs_port
*port
= tty
->driver_data
;
895 pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n",
896 port
->port_num
, tty
, count
);
898 spin_lock_irqsave(&port
->port_lock
, flags
);
900 count
= gs_buf_put(&port
->port_write_buf
, buf
, count
);
901 /* treat count == 0 as flush_chars() */
903 status
= gs_start_tx(port
);
904 spin_unlock_irqrestore(&port
->port_lock
, flags
);
909 static int gs_put_char(struct tty_struct
*tty
, unsigned char ch
)
911 struct gs_port
*port
= tty
->driver_data
;
915 pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n",
916 port
->port_num
, tty
, ch
, __builtin_return_address(0));
918 spin_lock_irqsave(&port
->port_lock
, flags
);
919 status
= gs_buf_put(&port
->port_write_buf
, &ch
, 1);
920 spin_unlock_irqrestore(&port
->port_lock
, flags
);
925 static void gs_flush_chars(struct tty_struct
*tty
)
927 struct gs_port
*port
= tty
->driver_data
;
930 pr_vdebug("gs_flush_chars: (%d,%p)\n", port
->port_num
, tty
);
932 spin_lock_irqsave(&port
->port_lock
, flags
);
935 spin_unlock_irqrestore(&port
->port_lock
, flags
);
938 static int gs_write_room(struct tty_struct
*tty
)
940 struct gs_port
*port
= tty
->driver_data
;
944 spin_lock_irqsave(&port
->port_lock
, flags
);
946 room
= gs_buf_space_avail(&port
->port_write_buf
);
947 spin_unlock_irqrestore(&port
->port_lock
, flags
);
949 pr_vdebug("gs_write_room: (%d,%p) room=%d\n",
950 port
->port_num
, tty
, room
);
955 static int gs_chars_in_buffer(struct tty_struct
*tty
)
957 struct gs_port
*port
= tty
->driver_data
;
961 spin_lock_irqsave(&port
->port_lock
, flags
);
962 chars
= gs_buf_data_avail(&port
->port_write_buf
);
963 spin_unlock_irqrestore(&port
->port_lock
, flags
);
965 pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n",
966 port
->port_num
, tty
, chars
);
971 /* undo side effects of setting TTY_THROTTLED */
972 static void gs_unthrottle(struct tty_struct
*tty
)
974 struct gs_port
*port
= tty
->driver_data
;
977 spin_lock_irqsave(&port
->port_lock
, flags
);
978 if (port
->port_usb
) {
979 /* Kickstart read queue processing. We don't do xon/xoff,
980 * rts/cts, or other handshaking with the host, but if the
981 * read queue backs up enough we'll be NAKing OUT packets.
983 tasklet_schedule(&port
->push
);
984 pr_vdebug("ttyGS%d: unthrottle\n", port
->port_num
);
986 spin_unlock_irqrestore(&port
->port_lock
, flags
);
989 static int gs_break_ctl(struct tty_struct
*tty
, int duration
)
991 struct gs_port
*port
= tty
->driver_data
;
993 struct gserial
*gser
;
995 pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n",
996 port
->port_num
, duration
);
998 spin_lock_irq(&port
->port_lock
);
999 gser
= port
->port_usb
;
1000 if (gser
&& gser
->send_break
)
1001 status
= gser
->send_break(gser
, duration
);
1002 spin_unlock_irq(&port
->port_lock
);
1007 static const struct tty_operations gs_tty_ops
= {
1011 .put_char
= gs_put_char
,
1012 .flush_chars
= gs_flush_chars
,
1013 .write_room
= gs_write_room
,
1014 .chars_in_buffer
= gs_chars_in_buffer
,
1015 .unthrottle
= gs_unthrottle
,
1016 .break_ctl
= gs_break_ctl
,
1019 /*-------------------------------------------------------------------------*/
1021 static struct tty_driver
*gs_tty_driver
;
1024 gs_port_alloc(unsigned port_num
, struct usb_cdc_line_coding
*coding
)
1026 struct gs_port
*port
;
1029 mutex_lock(&ports
[port_num
].lock
);
1030 if (ports
[port_num
].port
) {
1035 port
= kzalloc(sizeof(struct gs_port
), GFP_KERNEL
);
1041 tty_port_init(&port
->port
);
1042 spin_lock_init(&port
->port_lock
);
1043 init_waitqueue_head(&port
->drain_wait
);
1045 tasklet_init(&port
->push
, gs_rx_push
, (unsigned long) port
);
1047 INIT_LIST_HEAD(&port
->read_pool
);
1048 INIT_LIST_HEAD(&port
->read_queue
);
1049 INIT_LIST_HEAD(&port
->write_pool
);
1051 port
->port_num
= port_num
;
1052 port
->port_line_coding
= *coding
;
1054 ports
[port_num
].port
= port
;
1056 mutex_unlock(&ports
[port_num
].lock
);
1060 static int gs_closed(struct gs_port
*port
)
1064 spin_lock_irq(&port
->port_lock
);
1065 cond
= (port
->port
.count
== 0) && !port
->openclose
;
1066 spin_unlock_irq(&port
->port_lock
);
1070 static void gserial_free_port(struct gs_port
*port
)
1072 tasklet_kill(&port
->push
);
1073 /* wait for old opens to finish */
1074 wait_event(port
->port
.close_wait
, gs_closed(port
));
1075 WARN_ON(port
->port_usb
!= NULL
);
1076 tty_port_destroy(&port
->port
);
1080 void gserial_free_line(unsigned char port_num
)
1082 struct gs_port
*port
;
1084 mutex_lock(&ports
[port_num
].lock
);
1085 if (WARN_ON(!ports
[port_num
].port
)) {
1086 mutex_unlock(&ports
[port_num
].lock
);
1089 port
= ports
[port_num
].port
;
1090 ports
[port_num
].port
= NULL
;
1091 mutex_unlock(&ports
[port_num
].lock
);
1093 gserial_free_port(port
);
1094 tty_unregister_device(gs_tty_driver
, port_num
);
1096 EXPORT_SYMBOL_GPL(gserial_free_line
);
1098 int gserial_alloc_line(unsigned char *line_num
)
1100 struct usb_cdc_line_coding coding
;
1101 struct device
*tty_dev
;
1105 coding
.dwDTERate
= cpu_to_le32(9600);
1106 coding
.bCharFormat
= 8;
1107 coding
.bParityType
= USB_CDC_NO_PARITY
;
1108 coding
.bDataBits
= USB_CDC_1_STOP_BITS
;
1110 for (port_num
= 0; port_num
< MAX_U_SERIAL_PORTS
; port_num
++) {
1111 ret
= gs_port_alloc(port_num
, &coding
);
1121 /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
1123 tty_dev
= tty_port_register_device(&ports
[port_num
].port
->port
,
1124 gs_tty_driver
, port_num
, NULL
);
1125 if (IS_ERR(tty_dev
)) {
1126 struct gs_port
*port
;
1127 pr_err("%s: failed to register tty for port %d, err %ld\n",
1128 __func__
, port_num
, PTR_ERR(tty_dev
));
1130 ret
= PTR_ERR(tty_dev
);
1131 port
= ports
[port_num
].port
;
1132 ports
[port_num
].port
= NULL
;
1133 gserial_free_port(port
);
1136 *line_num
= port_num
;
1140 EXPORT_SYMBOL_GPL(gserial_alloc_line
);
1143 * gserial_connect - notify TTY I/O glue that USB link is active
1144 * @gser: the function, set up with endpoints and descriptors
1145 * @port_num: which port is active
1146 * Context: any (usually from irq)
1148 * This is called activate endpoints and let the TTY layer know that
1149 * the connection is active ... not unlike "carrier detect". It won't
1150 * necessarily start I/O queues; unless the TTY is held open by any
1151 * task, there would be no point. However, the endpoints will be
1152 * activated so the USB host can perform I/O, subject to basic USB
1153 * hardware flow control.
1155 * Caller needs to have set up the endpoints and USB function in @dev
1156 * before calling this, as well as the appropriate (speed-specific)
1157 * endpoint descriptors, and also have allocate @port_num by calling
1158 * @gserial_alloc_line().
1160 * Returns negative errno or zero.
1161 * On success, ep->driver_data will be overwritten.
1163 int gserial_connect(struct gserial
*gser
, u8 port_num
)
1165 struct gs_port
*port
;
1166 unsigned long flags
;
1169 if (port_num
>= MAX_U_SERIAL_PORTS
)
1172 port
= ports
[port_num
].port
;
1174 pr_err("serial line %d not allocated.\n", port_num
);
1177 if (port
->port_usb
) {
1178 pr_err("serial line %d is in use.\n", port_num
);
1182 /* activate the endpoints */
1183 status
= usb_ep_enable(gser
->in
);
1186 gser
->in
->driver_data
= port
;
1188 status
= usb_ep_enable(gser
->out
);
1191 gser
->out
->driver_data
= port
;
1193 /* then tell the tty glue that I/O can work */
1194 spin_lock_irqsave(&port
->port_lock
, flags
);
1195 gser
->ioport
= port
;
1196 port
->port_usb
= gser
;
1198 /* REVISIT unclear how best to handle this state...
1199 * we don't really couple it with the Linux TTY.
1201 gser
->port_line_coding
= port
->port_line_coding
;
1203 /* REVISIT if waiting on "carrier detect", signal. */
1205 /* if it's already open, start I/O ... and notify the serial
1206 * protocol about open/close status (connect/disconnect).
1208 if (port
->port
.count
) {
1209 pr_debug("gserial_connect: start ttyGS%d\n", port
->port_num
);
1212 gser
->connect(gser
);
1214 if (gser
->disconnect
)
1215 gser
->disconnect(gser
);
1218 spin_unlock_irqrestore(&port
->port_lock
, flags
);
1223 usb_ep_disable(gser
->in
);
1224 gser
->in
->driver_data
= NULL
;
1227 EXPORT_SYMBOL_GPL(gserial_connect
);
1229 * gserial_disconnect - notify TTY I/O glue that USB link is inactive
1230 * @gser: the function, on which gserial_connect() was called
1231 * Context: any (usually from irq)
1233 * This is called to deactivate endpoints and let the TTY layer know
1234 * that the connection went inactive ... not unlike "hangup".
1236 * On return, the state is as if gserial_connect() had never been called;
1237 * there is no active USB I/O on these endpoints.
1239 void gserial_disconnect(struct gserial
*gser
)
1241 struct gs_port
*port
= gser
->ioport
;
1242 unsigned long flags
;
1247 /* tell the TTY glue not to do I/O here any more */
1248 spin_lock_irqsave(&port
->port_lock
, flags
);
1250 /* REVISIT as above: how best to track this? */
1251 port
->port_line_coding
= gser
->port_line_coding
;
1253 port
->port_usb
= NULL
;
1254 gser
->ioport
= NULL
;
1255 if (port
->port
.count
> 0 || port
->openclose
) {
1256 wake_up_interruptible(&port
->drain_wait
);
1258 tty_hangup(port
->port
.tty
);
1260 spin_unlock_irqrestore(&port
->port_lock
, flags
);
1262 /* disable endpoints, aborting down any active I/O */
1263 usb_ep_disable(gser
->out
);
1264 gser
->out
->driver_data
= NULL
;
1266 usb_ep_disable(gser
->in
);
1267 gser
->in
->driver_data
= NULL
;
1269 /* finally, free any unused/unusable I/O buffers */
1270 spin_lock_irqsave(&port
->port_lock
, flags
);
1271 if (port
->port
.count
== 0 && !port
->openclose
)
1272 gs_buf_free(&port
->port_write_buf
);
1273 gs_free_requests(gser
->out
, &port
->read_pool
, NULL
);
1274 gs_free_requests(gser
->out
, &port
->read_queue
, NULL
);
1275 gs_free_requests(gser
->in
, &port
->write_pool
, NULL
);
1277 port
->read_allocated
= port
->read_started
=
1278 port
->write_allocated
= port
->write_started
= 0;
1280 spin_unlock_irqrestore(&port
->port_lock
, flags
);
1282 EXPORT_SYMBOL_GPL(gserial_disconnect
);
1284 static int userial_init(void)
1289 gs_tty_driver
= alloc_tty_driver(MAX_U_SERIAL_PORTS
);
1293 gs_tty_driver
->driver_name
= "g_serial";
1294 gs_tty_driver
->name
= "ttyGS";
1295 /* uses dynamically assigned dev_t values */
1297 gs_tty_driver
->type
= TTY_DRIVER_TYPE_SERIAL
;
1298 gs_tty_driver
->subtype
= SERIAL_TYPE_NORMAL
;
1299 gs_tty_driver
->flags
= TTY_DRIVER_REAL_RAW
| TTY_DRIVER_DYNAMIC_DEV
;
1300 gs_tty_driver
->init_termios
= tty_std_termios
;
1302 /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
1303 * MS-Windows. Otherwise, most of these flags shouldn't affect
1304 * anything unless we were to actually hook up to a serial line.
1306 gs_tty_driver
->init_termios
.c_cflag
=
1307 B9600
| CS8
| CREAD
| HUPCL
| CLOCAL
;
1308 gs_tty_driver
->init_termios
.c_ispeed
= 9600;
1309 gs_tty_driver
->init_termios
.c_ospeed
= 9600;
1311 tty_set_operations(gs_tty_driver
, &gs_tty_ops
);
1312 for (i
= 0; i
< MAX_U_SERIAL_PORTS
; i
++)
1313 mutex_init(&ports
[i
].lock
);
1315 /* export the driver ... */
1316 status
= tty_register_driver(gs_tty_driver
);
1318 pr_err("%s: cannot register, err %d\n",
1323 pr_debug("%s: registered %d ttyGS* device%s\n", __func__
,
1325 (MAX_U_SERIAL_PORTS
== 1) ? "" : "s");
1329 put_tty_driver(gs_tty_driver
);
1330 gs_tty_driver
= NULL
;
1333 module_init(userial_init
);
1335 static void userial_cleanup(void)
1337 tty_unregister_driver(gs_tty_driver
);
1338 put_tty_driver(gs_tty_driver
);
1339 gs_tty_driver
= NULL
;
1341 module_exit(userial_cleanup
);
1343 MODULE_LICENSE("GPL");