2 * USB Serial Converter Generic functions
4 * Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com)
5 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
12 #include <linux/kernel.h>
13 #include <linux/sched/signal.h>
14 #include <linux/errno.h>
15 #include <linux/slab.h>
16 #include <linux/sysrq.h>
17 #include <linux/tty.h>
18 #include <linux/tty_flip.h>
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/usb.h>
22 #include <linux/usb/serial.h>
23 #include <linux/uaccess.h>
24 #include <linux/kfifo.h>
25 #include <linux/serial.h>
27 #ifdef CONFIG_USB_SERIAL_GENERIC
29 static __u16 vendor = 0x05f9;
30 static __u16 product = 0xffff;
32 module_param(vendor, ushort, 0);
33 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
35 module_param(product, ushort, 0);
36 MODULE_PARM_DESC(product, "User specified USB idProduct");
38 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
40 static int usb_serial_generic_probe(struct usb_serial *serial,
41 const struct usb_device_id *id)
43 struct device *dev = &serial->interface->dev;
45 dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
46 dev_info(dev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n");
51 static int usb_serial_generic_calc_num_ports(struct usb_serial *serial,
52 struct usb_serial_endpoints *epds)
54 struct device *dev = &serial->interface->dev;
57 num_ports = max(epds->num_bulk_in, epds->num_bulk_out);
60 dev_err(dev, "device has no bulk endpoints\n");
67 static struct usb_serial_driver usb_serial_generic_device = {
72 .id_table = generic_device_ids,
73 .probe = usb_serial_generic_probe,
74 .calc_num_ports = usb_serial_generic_calc_num_ports,
75 .throttle = usb_serial_generic_throttle,
76 .unthrottle = usb_serial_generic_unthrottle,
77 .resume = usb_serial_generic_resume,
80 static struct usb_serial_driver * const serial_drivers[] = {
81 &usb_serial_generic_device, NULL
86 int usb_serial_generic_register(void)
90 #ifdef CONFIG_USB_SERIAL_GENERIC
91 generic_device_ids[0].idVendor = vendor;
92 generic_device_ids[0].idProduct = product;
93 generic_device_ids[0].match_flags =
94 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
96 retval = usb_serial_register_drivers(serial_drivers,
97 "usbserial_generic", generic_device_ids);
102 void usb_serial_generic_deregister(void)
104 #ifdef CONFIG_USB_SERIAL_GENERIC
105 usb_serial_deregister_drivers(serial_drivers);
109 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
114 spin_lock_irqsave(&port->lock, flags);
116 port->throttle_req = 0;
117 spin_unlock_irqrestore(&port->lock, flags);
119 if (port->bulk_in_size)
120 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
124 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
126 void usb_serial_generic_close(struct usb_serial_port *port)
131 if (port->bulk_out_size) {
132 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
133 usb_kill_urb(port->write_urbs[i]);
135 spin_lock_irqsave(&port->lock, flags);
136 kfifo_reset_out(&port->write_fifo);
137 spin_unlock_irqrestore(&port->lock, flags);
139 if (port->bulk_in_size) {
140 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
141 usb_kill_urb(port->read_urbs[i]);
144 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
146 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
147 void *dest, size_t size)
149 return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
153 * usb_serial_generic_write_start - start writing buffered data
154 * @port: usb-serial port
155 * @mem_flags: flags to use for memory allocations
157 * Serialised using USB_SERIAL_WRITE_BUSY flag.
159 * Return: Zero on success or if busy, otherwise a negative errno value.
161 int usb_serial_generic_write_start(struct usb_serial_port *port,
169 if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
172 spin_lock_irqsave(&port->lock, flags);
173 if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
174 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
175 spin_unlock_irqrestore(&port->lock, flags);
178 i = (int)find_first_bit(&port->write_urbs_free,
179 ARRAY_SIZE(port->write_urbs));
180 spin_unlock_irqrestore(&port->lock, flags);
182 urb = port->write_urbs[i];
183 count = port->serial->type->prepare_write_buffer(port,
184 urb->transfer_buffer,
185 port->bulk_out_size);
186 urb->transfer_buffer_length = count;
187 usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
188 spin_lock_irqsave(&port->lock, flags);
189 port->tx_bytes += count;
190 spin_unlock_irqrestore(&port->lock, flags);
192 clear_bit(i, &port->write_urbs_free);
193 result = usb_submit_urb(urb, mem_flags);
195 dev_err_console(port, "%s - error submitting urb: %d\n",
197 set_bit(i, &port->write_urbs_free);
198 spin_lock_irqsave(&port->lock, flags);
199 port->tx_bytes -= count;
200 spin_unlock_irqrestore(&port->lock, flags);
202 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
206 goto retry; /* try sending off another urb */
208 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
211 * usb_serial_generic_write - generic write function
212 * @tty: tty for the port
213 * @port: usb-serial port
214 * @buf: data to write
215 * @count: number of bytes to write
217 * Return: The number of characters buffered, which may be anything from
218 * zero to @count, or a negative errno value.
220 int usb_serial_generic_write(struct tty_struct *tty,
221 struct usb_serial_port *port, const unsigned char *buf, int count)
225 if (!port->bulk_out_size)
231 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
232 result = usb_serial_generic_write_start(port, GFP_ATOMIC);
238 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
240 int usb_serial_generic_write_room(struct tty_struct *tty)
242 struct usb_serial_port *port = tty->driver_data;
246 if (!port->bulk_out_size)
249 spin_lock_irqsave(&port->lock, flags);
250 room = kfifo_avail(&port->write_fifo);
251 spin_unlock_irqrestore(&port->lock, flags);
253 dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
257 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
259 struct usb_serial_port *port = tty->driver_data;
263 if (!port->bulk_out_size)
266 spin_lock_irqsave(&port->lock, flags);
267 chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
268 spin_unlock_irqrestore(&port->lock, flags);
270 dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
273 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
275 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
277 struct usb_serial_port *port = tty->driver_data;
279 unsigned long period;
280 unsigned long expire;
282 bps = tty_get_baud_rate(tty);
286 * Use a poll-period of roughly the time it takes to send one
287 * character or at least one jiffy.
289 period = max_t(unsigned long, (10 * HZ / bps), 1);
291 period = min_t(unsigned long, period, timeout);
293 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
294 __func__, jiffies_to_msecs(timeout),
295 jiffies_to_msecs(period));
296 expire = jiffies + timeout;
297 while (!port->serial->type->tx_empty(port)) {
298 schedule_timeout_interruptible(period);
299 if (signal_pending(current))
301 if (timeout && time_after(jiffies, expire))
305 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
307 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
308 int index, gfp_t mem_flags)
312 if (!test_and_clear_bit(index, &port->read_urbs_free))
315 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
317 res = usb_submit_urb(port->read_urbs[index], mem_flags);
319 if (res != -EPERM && res != -ENODEV) {
321 "%s - usb_submit_urb failed: %d\n",
324 set_bit(index, &port->read_urbs_free);
331 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
337 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
338 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
346 usb_kill_urb(port->read_urbs[i]);
350 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
352 void usb_serial_generic_process_read_urb(struct urb *urb)
354 struct usb_serial_port *port = urb->context;
355 char *ch = (char *)urb->transfer_buffer;
358 if (!urb->actual_length)
361 * The per character mucking around with sysrq path it too slow for
362 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
363 * cases where the USB serial is not a console anyway.
365 if (!port->port.console || !port->sysrq) {
366 tty_insert_flip_string(&port->port, ch, urb->actual_length);
368 for (i = 0; i < urb->actual_length; i++, ch++) {
369 if (!usb_serial_handle_sysrq_char(port, *ch))
370 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
373 tty_flip_buffer_push(&port->port);
375 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
377 void usb_serial_generic_read_bulk_callback(struct urb *urb)
379 struct usb_serial_port *port = urb->context;
380 unsigned char *data = urb->transfer_buffer;
382 bool stopped = false;
383 int status = urb->status;
386 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
387 if (urb == port->read_urbs[i])
391 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
395 usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
397 port->serial->type->process_read_urb(urb);
402 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
407 dev_err(&port->dev, "%s - urb stopped: %d\n",
412 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
418 * Make sure URB processing is done before marking as free to avoid
419 * racing with unthrottle() on another CPU. Matches the barriers
420 * implied by the test_and_clear_bit() in
421 * usb_serial_generic_submit_read_urb().
423 smp_mb__before_atomic();
424 set_bit(i, &port->read_urbs_free);
426 * Make sure URB is marked as free before checking the throttled flag
427 * to avoid racing with unthrottle() on another CPU. Matches the
428 * smp_mb() in unthrottle().
430 smp_mb__after_atomic();
435 /* Throttle the device if requested by tty */
436 spin_lock_irqsave(&port->lock, flags);
437 port->throttled = port->throttle_req;
438 if (!port->throttled) {
439 spin_unlock_irqrestore(&port->lock, flags);
440 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
442 spin_unlock_irqrestore(&port->lock, flags);
445 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
447 void usb_serial_generic_write_bulk_callback(struct urb *urb)
450 struct usb_serial_port *port = urb->context;
451 int status = urb->status;
454 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
455 if (port->write_urbs[i] == urb)
458 spin_lock_irqsave(&port->lock, flags);
459 port->tx_bytes -= urb->transfer_buffer_length;
460 set_bit(i, &port->write_urbs_free);
461 spin_unlock_irqrestore(&port->lock, flags);
469 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
473 dev_err_console(port, "%s - urb stopped: %d\n",
477 dev_err_console(port, "%s - nonzero urb status: %d\n",
483 usb_serial_generic_write_start(port, GFP_ATOMIC);
484 usb_serial_port_softint(port);
486 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
488 void usb_serial_generic_throttle(struct tty_struct *tty)
490 struct usb_serial_port *port = tty->driver_data;
493 spin_lock_irqsave(&port->lock, flags);
494 port->throttle_req = 1;
495 spin_unlock_irqrestore(&port->lock, flags);
497 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
499 void usb_serial_generic_unthrottle(struct tty_struct *tty)
501 struct usb_serial_port *port = tty->driver_data;
504 spin_lock_irq(&port->lock);
505 was_throttled = port->throttled;
506 port->throttled = port->throttle_req = 0;
507 spin_unlock_irq(&port->lock);
510 * Matches the smp_mb__after_atomic() in
511 * usb_serial_generic_read_bulk_callback().
516 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
518 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
520 static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
521 unsigned long arg, struct async_icount *cprev)
523 struct usb_serial_port *port = tty->driver_data;
524 struct async_icount cnow;
529 * Use tty-port initialised flag to detect all hangups including the
530 * one generated at USB-device disconnect.
532 if (!tty_port_initialized(&port->port))
535 spin_lock_irqsave(&port->lock, flags);
536 cnow = port->icount; /* atomic copy*/
537 spin_unlock_irqrestore(&port->lock, flags);
539 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
540 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
541 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) ||
542 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
549 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
551 struct usb_serial_port *port = tty->driver_data;
552 struct async_icount cnow;
556 spin_lock_irqsave(&port->lock, flags);
557 cnow = port->icount; /* atomic copy */
558 spin_unlock_irqrestore(&port->lock, flags);
560 ret = wait_event_interruptible(port->port.delta_msr_wait,
561 usb_serial_generic_msr_changed(tty, arg, &cnow));
562 if (!ret && !tty_port_initialized(&port->port))
567 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
569 int usb_serial_generic_get_icount(struct tty_struct *tty,
570 struct serial_icounter_struct *icount)
572 struct usb_serial_port *port = tty->driver_data;
573 struct async_icount cnow;
576 spin_lock_irqsave(&port->lock, flags);
577 cnow = port->icount; /* atomic copy */
578 spin_unlock_irqrestore(&port->lock, flags);
580 icount->cts = cnow.cts;
581 icount->dsr = cnow.dsr;
582 icount->rng = cnow.rng;
583 icount->dcd = cnow.dcd;
584 icount->tx = cnow.tx;
585 icount->rx = cnow.rx;
586 icount->frame = cnow.frame;
587 icount->parity = cnow.parity;
588 icount->overrun = cnow.overrun;
589 icount->brk = cnow.brk;
590 icount->buf_overrun = cnow.buf_overrun;
594 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
596 #ifdef CONFIG_MAGIC_SYSRQ
597 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
599 if (port->sysrq && port->port.console) {
600 if (ch && time_before(jiffies, port->sysrq)) {
610 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
615 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
617 int usb_serial_handle_break(struct usb_serial_port *port)
620 port->sysrq = jiffies + HZ*5;
626 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
629 * usb_serial_handle_dcd_change - handle a change of carrier detect state
630 * @port: usb-serial port
631 * @tty: tty for the port
632 * @status: new carrier detect status, nonzero if active
634 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
635 struct tty_struct *tty, unsigned int status)
637 struct tty_port *port = &usb_port->port;
639 dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
642 struct tty_ldisc *ld = tty_ldisc_ref(tty);
645 if (ld->ops->dcd_change)
646 ld->ops->dcd_change(tty, status);
652 wake_up_interruptible(&port->open_wait);
653 else if (tty && !C_CLOCAL(tty))
656 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
658 int usb_serial_generic_resume(struct usb_serial *serial)
660 struct usb_serial_port *port;
663 for (i = 0; i < serial->num_ports; i++) {
664 port = serial->port[i];
665 if (!tty_port_initialized(&port->port))
668 if (port->bulk_in_size) {
669 r = usb_serial_generic_submit_read_urbs(port,
675 if (port->bulk_out_size) {
676 r = usb_serial_generic_write_start(port, GFP_NOIO);
684 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);