5 #include <linux/types.h>
6 #include <linux/errno.h>
8 #include <linux/tty_driver.h>
9 #include <linux/tty_flip.h>
10 #include <linux/serial.h>
11 #include <linux/timer.h>
12 #include <linux/string.h>
13 #include <linux/slab.h>
14 #include <linux/sched.h>
15 #include <linux/wait.h>
16 #include <linux/bitops.h>
17 #include <linux/delay.h>
18 #include <linux/module.h>
20 void tty_port_init(struct tty_port *port)
22 memset(port, 0, sizeof(*port));
23 tty_buffer_init(port);
24 init_waitqueue_head(&port->open_wait);
25 init_waitqueue_head(&port->close_wait);
26 init_waitqueue_head(&port->delta_msr_wait);
27 mutex_init(&port->mutex);
28 mutex_init(&port->buf_mutex);
29 spin_lock_init(&port->lock);
30 port->close_delay = (50 * HZ) / 100;
31 port->closing_wait = (3000 * HZ) / 100;
32 kref_init(&port->kref);
34 EXPORT_SYMBOL(tty_port_init);
37 * tty_port_link_device - link tty and tty_port
38 * @port: tty_port of the device
39 * @driver: tty_driver for this device
40 * @index: index of the tty
42 * Provide the tty layer wit ha link from a tty (specified by @index) to a
43 * tty_port (@port). Use this only if neither tty_port_register_device nor
44 * tty_port_install is used in the driver. If used, this has to be called before
45 * tty_register_driver.
47 void tty_port_link_device(struct tty_port *port,
48 struct tty_driver *driver, unsigned index)
50 if (WARN_ON(index >= driver->num))
52 driver->ports[index] = port;
54 EXPORT_SYMBOL_GPL(tty_port_link_device);
57 * tty_port_register_device - register tty device
58 * @port: tty_port of the device
59 * @driver: tty_driver for this device
60 * @index: index of the tty
61 * @device: parent if exists, otherwise NULL
63 * It is the same as tty_register_device except the provided @port is linked to
64 * a concrete tty specified by @index. Use this or tty_port_install (or both).
65 * Call tty_port_link_device as a last resort.
67 struct device *tty_port_register_device(struct tty_port *port,
68 struct tty_driver *driver, unsigned index,
69 struct device *device)
71 tty_port_link_device(port, driver, index);
72 return tty_register_device(driver, index, device);
74 EXPORT_SYMBOL_GPL(tty_port_register_device);
77 * tty_port_register_device_attr - register tty device
78 * @port: tty_port of the device
79 * @driver: tty_driver for this device
80 * @index: index of the tty
81 * @device: parent if exists, otherwise NULL
82 * @drvdata: Driver data to be set to device.
83 * @attr_grp: Attribute group to be set on device.
85 * It is the same as tty_register_device_attr except the provided @port is
86 * linked to a concrete tty specified by @index. Use this or tty_port_install
87 * (or both). Call tty_port_link_device as a last resort.
89 struct device *tty_port_register_device_attr(struct tty_port *port,
90 struct tty_driver *driver, unsigned index,
91 struct device *device, void *drvdata,
92 const struct attribute_group **attr_grp)
94 tty_port_link_device(port, driver, index);
95 return tty_register_device_attr(driver, index, device, drvdata,
98 EXPORT_SYMBOL_GPL(tty_port_register_device_attr);
100 int tty_port_alloc_xmit_buf(struct tty_port *port)
102 /* We may sleep in get_zeroed_page() */
103 mutex_lock(&port->buf_mutex);
104 if (port->xmit_buf == NULL)
105 port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
106 mutex_unlock(&port->buf_mutex);
107 if (port->xmit_buf == NULL)
111 EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
113 void tty_port_free_xmit_buf(struct tty_port *port)
115 mutex_lock(&port->buf_mutex);
116 if (port->xmit_buf != NULL) {
117 free_page((unsigned long)port->xmit_buf);
118 port->xmit_buf = NULL;
120 mutex_unlock(&port->buf_mutex);
122 EXPORT_SYMBOL(tty_port_free_xmit_buf);
125 * tty_port_destroy -- destroy inited port
126 * @port: tty port to be doestroyed
128 * When a port was initialized using tty_port_init, one has to destroy the
129 * port by this function. Either indirectly by using tty_port refcounting
130 * (tty_port_put) or directly if refcounting is not used.
132 void tty_port_destroy(struct tty_port *port)
134 cancel_work_sync(&port->buf.work);
135 tty_buffer_free_all(port);
137 EXPORT_SYMBOL(tty_port_destroy);
139 static void tty_port_destructor(struct kref *kref)
141 struct tty_port *port = container_of(kref, struct tty_port, kref);
143 /* check if last port ref was dropped before tty release */
144 if (WARN_ON(port->itty))
147 free_page((unsigned long)port->xmit_buf);
148 tty_port_destroy(port);
149 if (port->ops && port->ops->destruct)
150 port->ops->destruct(port);
155 void tty_port_put(struct tty_port *port)
158 kref_put(&port->kref, tty_port_destructor);
160 EXPORT_SYMBOL(tty_port_put);
163 * tty_port_tty_get - get a tty reference
166 * Return a refcount protected tty instance or NULL if the port is not
167 * associated with a tty (eg due to close or hangup)
170 struct tty_struct *tty_port_tty_get(struct tty_port *port)
173 struct tty_struct *tty;
175 spin_lock_irqsave(&port->lock, flags);
176 tty = tty_kref_get(port->tty);
177 spin_unlock_irqrestore(&port->lock, flags);
180 EXPORT_SYMBOL(tty_port_tty_get);
183 * tty_port_tty_set - set the tty of a port
187 * Associate the port and tty pair. Manages any internal refcounts.
188 * Pass NULL to deassociate a port
191 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
195 spin_lock_irqsave(&port->lock, flags);
197 tty_kref_put(port->tty);
198 port->tty = tty_kref_get(tty);
199 spin_unlock_irqrestore(&port->lock, flags);
201 EXPORT_SYMBOL(tty_port_tty_set);
203 static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
205 mutex_lock(&port->mutex);
209 if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
211 * Drop DTR/RTS if HUPCL is set. This causes any attached
212 * modem to hang up the line.
214 if (tty && C_HUPCL(tty))
215 tty_port_lower_dtr_rts(port);
217 if (port->ops->shutdown)
218 port->ops->shutdown(port);
221 mutex_unlock(&port->mutex);
225 * tty_port_hangup - hangup helper
228 * Perform port level tty hangup flag and count changes. Drop the tty
232 void tty_port_hangup(struct tty_port *port)
234 struct tty_struct *tty;
237 spin_lock_irqsave(&port->lock, flags);
239 port->flags &= ~ASYNC_NORMAL_ACTIVE;
242 set_bit(TTY_IO_ERROR, &tty->flags);
244 spin_unlock_irqrestore(&port->lock, flags);
245 tty_port_shutdown(port, tty);
247 wake_up_interruptible(&port->open_wait);
248 wake_up_interruptible(&port->delta_msr_wait);
250 EXPORT_SYMBOL(tty_port_hangup);
253 * tty_port_tty_hangup - helper to hang up a tty
256 * @check_clocal: hang only ttys with CLOCAL unset?
258 void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
260 struct tty_struct *tty = tty_port_tty_get(port);
262 if (tty && (!check_clocal || !C_CLOCAL(tty)))
266 EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
269 * tty_port_tty_wakeup - helper to wake up a tty
273 void tty_port_tty_wakeup(struct tty_port *port)
275 struct tty_struct *tty = tty_port_tty_get(port);
282 EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
285 * tty_port_carrier_raised - carrier raised check
288 * Wrapper for the carrier detect logic. For the moment this is used
289 * to hide some internal details. This will eventually become entirely
290 * internal to the tty port.
293 int tty_port_carrier_raised(struct tty_port *port)
295 if (port->ops->carrier_raised == NULL)
297 return port->ops->carrier_raised(port);
299 EXPORT_SYMBOL(tty_port_carrier_raised);
302 * tty_port_raise_dtr_rts - Raise DTR/RTS
305 * Wrapper for the DTR/RTS raise logic. For the moment this is used
306 * to hide some internal details. This will eventually become entirely
307 * internal to the tty port.
310 void tty_port_raise_dtr_rts(struct tty_port *port)
312 if (port->ops->dtr_rts)
313 port->ops->dtr_rts(port, 1);
315 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
318 * tty_port_lower_dtr_rts - Lower DTR/RTS
321 * Wrapper for the DTR/RTS raise logic. For the moment this is used
322 * to hide some internal details. This will eventually become entirely
323 * internal to the tty port.
326 void tty_port_lower_dtr_rts(struct tty_port *port)
328 if (port->ops->dtr_rts)
329 port->ops->dtr_rts(port, 0);
331 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
334 * tty_port_block_til_ready - Waiting logic for tty open
335 * @port: the tty port being opened
336 * @tty: the tty device being bound
337 * @filp: the file pointer of the opener
339 * Implement the core POSIX/SuS tty behaviour when opening a tty device.
341 * - hangup (both before and during)
342 * - non blocking open
345 * - port flags and counts
347 * The passed tty_port must implement the carrier_raised method if it can
348 * do carrier detect and the dtr_rts method if it supports software
349 * management of these lines. Note that the dtr/rts raise is done each
350 * iteration as a hangup may have previously dropped them while we wait.
352 * Caller holds tty lock.
354 * NB: May drop and reacquire tty lock when blocking, so tty and tty_port
355 * may have changed state (eg., may have been hung up).
358 int tty_port_block_til_ready(struct tty_port *port,
359 struct tty_struct *tty, struct file *filp)
361 int do_clocal = 0, retval;
365 /* block if port is in the process of being closed */
366 if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
367 wait_event_interruptible_tty(tty, port->close_wait,
368 !(port->flags & ASYNC_CLOSING));
369 if (port->flags & ASYNC_HUP_NOTIFY)
375 /* if non-blocking mode is set we can pass directly to open unless
376 the port has just hung up or is in another error state */
377 if (tty->flags & (1 << TTY_IO_ERROR)) {
378 port->flags |= ASYNC_NORMAL_ACTIVE;
381 if (filp->f_flags & O_NONBLOCK) {
382 /* Indicate we are open */
383 if (tty->termios.c_cflag & CBAUD)
384 tty_port_raise_dtr_rts(port);
385 port->flags |= ASYNC_NORMAL_ACTIVE;
392 /* Block waiting until we can proceed. We may need to wait for the
393 carrier, but we must also wait for any close that is in progress
394 before the next open may complete */
398 /* The port lock protects the port counts */
399 spin_lock_irqsave(&port->lock, flags);
400 if (!tty_hung_up_p(filp))
402 port->blocked_open++;
403 spin_unlock_irqrestore(&port->lock, flags);
406 /* Indicate we are open */
407 if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
408 tty_port_raise_dtr_rts(port);
410 prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
411 /* Check for a hangup or uninitialised port.
412 Return accordingly */
413 if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
414 if (port->flags & ASYNC_HUP_NOTIFY)
417 retval = -ERESTARTSYS;
421 * Probe the carrier. For devices with no carrier detect
422 * tty_port_carrier_raised will always return true.
423 * Never ask drivers if CLOCAL is set, this causes troubles
426 if (!(port->flags & ASYNC_CLOSING) &&
427 (do_clocal || tty_port_carrier_raised(port)))
429 if (signal_pending(current)) {
430 retval = -ERESTARTSYS;
437 finish_wait(&port->open_wait, &wait);
439 /* Update counts. A parallel hangup will have set count to zero and
440 we must not mess that up further */
441 spin_lock_irqsave(&port->lock, flags);
442 if (!tty_hung_up_p(filp))
444 port->blocked_open--;
446 port->flags |= ASYNC_NORMAL_ACTIVE;
447 spin_unlock_irqrestore(&port->lock, flags);
450 EXPORT_SYMBOL(tty_port_block_til_ready);
452 static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty)
454 unsigned int bps = tty_get_baud_rate(tty);
458 timeout = (HZ * 10 * port->drain_delay) / bps;
459 timeout = max_t(long, timeout, HZ / 10);
463 schedule_timeout_interruptible(timeout);
466 /* Caller holds tty lock.
467 * NB: may drop and reacquire tty lock (in tty_wait_until_sent_from_close())
468 * so tty and tty port may have changed state (but not hung up or reopened).
470 int tty_port_close_start(struct tty_port *port,
471 struct tty_struct *tty, struct file *filp)
475 spin_lock_irqsave(&port->lock, flags);
476 if (tty_hung_up_p(filp)) {
477 spin_unlock_irqrestore(&port->lock, flags);
481 if (tty->count == 1 && port->count != 1) {
483 "tty_port_close_start: tty->count = 1 port count = %d.\n",
487 if (--port->count < 0) {
488 printk(KERN_WARNING "tty_port_close_start: count = %d\n",
494 spin_unlock_irqrestore(&port->lock, flags);
497 set_bit(ASYNCB_CLOSING, &port->flags);
499 spin_unlock_irqrestore(&port->lock, flags);
501 if (test_bit(ASYNCB_INITIALIZED, &port->flags)) {
502 /* Don't block on a stalled port, just pull the chain */
503 if (tty->flow_stopped)
504 tty_driver_flush_buffer(tty);
505 if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
506 tty_wait_until_sent_from_close(tty, port->closing_wait);
507 if (port->drain_delay)
508 tty_port_drain_delay(port, tty);
510 /* Flush the ldisc buffering */
511 tty_ldisc_flush(tty);
513 /* Report to caller this is the last port reference */
516 EXPORT_SYMBOL(tty_port_close_start);
518 /* Caller holds tty lock */
519 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
523 spin_lock_irqsave(&port->lock, flags);
526 if (port->blocked_open) {
527 spin_unlock_irqrestore(&port->lock, flags);
528 if (port->close_delay) {
529 msleep_interruptible(
530 jiffies_to_msecs(port->close_delay));
532 spin_lock_irqsave(&port->lock, flags);
533 wake_up_interruptible(&port->open_wait);
535 port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
536 wake_up_interruptible(&port->close_wait);
537 spin_unlock_irqrestore(&port->lock, flags);
539 EXPORT_SYMBOL(tty_port_close_end);
544 * Caller holds tty lock
546 * NB: may drop and reacquire tty lock (in tty_port_close_start()->
547 * tty_wait_until_sent_from_close()) so tty and tty_port may have changed
548 * state (but not hung up or reopened).
550 void tty_port_close(struct tty_port *port, struct tty_struct *tty,
553 if (tty_port_close_start(port, tty, filp) == 0)
555 tty_port_shutdown(port, tty);
556 set_bit(TTY_IO_ERROR, &tty->flags);
557 tty_port_close_end(port, tty);
558 tty_port_tty_set(port, NULL);
560 EXPORT_SYMBOL(tty_port_close);
563 * tty_port_install - generic tty->ops->install handler
564 * @port: tty_port of the device
565 * @driver: tty_driver for this device
566 * @tty: tty to be installed
568 * It is the same as tty_standard_install except the provided @port is linked
569 * to a concrete tty specified by @tty. Use this or tty_port_register_device
570 * (or both). Call tty_port_link_device as a last resort.
572 int tty_port_install(struct tty_port *port, struct tty_driver *driver,
573 struct tty_struct *tty)
576 return tty_standard_install(driver, tty);
578 EXPORT_SYMBOL_GPL(tty_port_install);
583 * Caller holds tty lock.
585 * NB: may drop and reacquire tty lock (in tty_port_block_til_ready()) so
586 * tty and tty_port may have changed state (eg., may be hung up now)
588 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
591 spin_lock_irq(&port->lock);
592 if (!tty_hung_up_p(filp))
594 spin_unlock_irq(&port->lock);
595 tty_port_tty_set(port, tty);
598 * Do the device-specific open only if the hardware isn't
599 * already initialized. Serialize open and shutdown using the
603 mutex_lock(&port->mutex);
605 if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) {
606 clear_bit(TTY_IO_ERROR, &tty->flags);
607 if (port->ops->activate) {
608 int retval = port->ops->activate(port, tty);
610 mutex_unlock(&port->mutex);
614 set_bit(ASYNCB_INITIALIZED, &port->flags);
616 mutex_unlock(&port->mutex);
617 return tty_port_block_til_ready(port, tty, filp);
620 EXPORT_SYMBOL(tty_port_open);