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/init.h>
16 #include <linux/wait.h>
17 #include <linux/bitops.h>
18 #include <linux/delay.h>
19 #include <linux/module.h>
21 void tty_port_init(struct tty_port *port)
23 memset(port, 0, sizeof(*port));
24 tty_buffer_init(port);
25 init_waitqueue_head(&port->open_wait);
26 init_waitqueue_head(&port->close_wait);
27 init_waitqueue_head(&port->delta_msr_wait);
28 mutex_init(&port->mutex);
29 mutex_init(&port->buf_mutex);
30 spin_lock_init(&port->lock);
31 port->close_delay = (50 * HZ) / 100;
32 port->closing_wait = (3000 * HZ) / 100;
33 kref_init(&port->kref);
35 EXPORT_SYMBOL(tty_port_init);
38 * tty_port_link_device - link tty and tty_port
39 * @port: tty_port of the device
40 * @driver: tty_driver for this device
41 * @index: index of the tty
43 * Provide the tty layer wit ha link from a tty (specified by @index) to a
44 * tty_port (@port). Use this only if neither tty_port_register_device nor
45 * tty_port_install is used in the driver. If used, this has to be called before
46 * tty_register_driver.
48 void tty_port_link_device(struct tty_port *port,
49 struct tty_driver *driver, unsigned index)
51 if (WARN_ON(index >= driver->num))
53 driver->ports[index] = port;
55 EXPORT_SYMBOL_GPL(tty_port_link_device);
58 * tty_port_register_device - register tty device
59 * @port: tty_port of the device
60 * @driver: tty_driver for this device
61 * @index: index of the tty
62 * @device: parent if exists, otherwise NULL
64 * It is the same as tty_register_device except the provided @port is linked to
65 * a concrete tty specified by @index. Use this or tty_port_install (or both).
66 * Call tty_port_link_device as a last resort.
68 struct device *tty_port_register_device(struct tty_port *port,
69 struct tty_driver *driver, unsigned index,
70 struct device *device)
72 tty_port_link_device(port, driver, index);
73 return tty_register_device(driver, index, device);
75 EXPORT_SYMBOL_GPL(tty_port_register_device);
78 * tty_port_register_device_attr - register tty device
79 * @port: tty_port of the device
80 * @driver: tty_driver for this device
81 * @index: index of the tty
82 * @device: parent if exists, otherwise NULL
83 * @drvdata: Driver data to be set to device.
84 * @attr_grp: Attribute group to be set on device.
86 * It is the same as tty_register_device_attr except the provided @port is
87 * linked to a concrete tty specified by @index. Use this or tty_port_install
88 * (or both). Call tty_port_link_device as a last resort.
90 struct device *tty_port_register_device_attr(struct tty_port *port,
91 struct tty_driver *driver, unsigned index,
92 struct device *device, void *drvdata,
93 const struct attribute_group **attr_grp)
95 tty_port_link_device(port, driver, index);
96 return tty_register_device_attr(driver, index, device, drvdata,
99 EXPORT_SYMBOL_GPL(tty_port_register_device_attr);
101 int tty_port_alloc_xmit_buf(struct tty_port *port)
103 /* We may sleep in get_zeroed_page() */
104 mutex_lock(&port->buf_mutex);
105 if (port->xmit_buf == NULL)
106 port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
107 mutex_unlock(&port->buf_mutex);
108 if (port->xmit_buf == NULL)
112 EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
114 void tty_port_free_xmit_buf(struct tty_port *port)
116 mutex_lock(&port->buf_mutex);
117 if (port->xmit_buf != NULL) {
118 free_page((unsigned long)port->xmit_buf);
119 port->xmit_buf = NULL;
121 mutex_unlock(&port->buf_mutex);
123 EXPORT_SYMBOL(tty_port_free_xmit_buf);
126 * tty_port_destroy -- destroy inited port
127 * @port: tty port to be doestroyed
129 * When a port was initialized using tty_port_init, one has to destroy the
130 * port by this function. Either indirectly by using tty_port refcounting
131 * (tty_port_put) or directly if refcounting is not used.
133 void tty_port_destroy(struct tty_port *port)
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 free_page((unsigned long)port->xmit_buf);
144 tty_port_destroy(port);
145 if (port->ops && port->ops->destruct)
146 port->ops->destruct(port);
151 void tty_port_put(struct tty_port *port)
154 kref_put(&port->kref, tty_port_destructor);
156 EXPORT_SYMBOL(tty_port_put);
159 * tty_port_tty_get - get a tty reference
162 * Return a refcount protected tty instance or NULL if the port is not
163 * associated with a tty (eg due to close or hangup)
166 struct tty_struct *tty_port_tty_get(struct tty_port *port)
169 struct tty_struct *tty;
171 spin_lock_irqsave(&port->lock, flags);
172 tty = tty_kref_get(port->tty);
173 spin_unlock_irqrestore(&port->lock, flags);
176 EXPORT_SYMBOL(tty_port_tty_get);
179 * tty_port_tty_set - set the tty of a port
183 * Associate the port and tty pair. Manages any internal refcounts.
184 * Pass NULL to deassociate a port
187 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
191 spin_lock_irqsave(&port->lock, flags);
193 tty_kref_put(port->tty);
194 port->tty = tty_kref_get(tty);
195 spin_unlock_irqrestore(&port->lock, flags);
197 EXPORT_SYMBOL(tty_port_tty_set);
199 static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
201 mutex_lock(&port->mutex);
205 if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
207 * Drop DTR/RTS if HUPCL is set. This causes any attached
208 * modem to hang up the line.
210 if (tty && C_HUPCL(tty))
211 tty_port_lower_dtr_rts(port);
213 if (port->ops->shutdown)
214 port->ops->shutdown(port);
217 mutex_unlock(&port->mutex);
221 * tty_port_hangup - hangup helper
224 * Perform port level tty hangup flag and count changes. Drop the tty
228 void tty_port_hangup(struct tty_port *port)
230 struct tty_struct *tty;
233 spin_lock_irqsave(&port->lock, flags);
235 port->flags &= ~ASYNC_NORMAL_ACTIVE;
238 set_bit(TTY_IO_ERROR, &tty->flags);
240 spin_unlock_irqrestore(&port->lock, flags);
241 tty_port_shutdown(port, tty);
243 wake_up_interruptible(&port->open_wait);
244 wake_up_interruptible(&port->delta_msr_wait);
246 EXPORT_SYMBOL(tty_port_hangup);
249 * tty_port_tty_hangup - helper to hang up a tty
252 * @check_clocal: hang only ttys with CLOCAL unset?
254 void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
256 struct tty_struct *tty = tty_port_tty_get(port);
258 if (tty && (!check_clocal || !C_CLOCAL(tty))) {
263 EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
266 * tty_port_tty_wakeup - helper to wake up a tty
270 void tty_port_tty_wakeup(struct tty_port *port)
272 struct tty_struct *tty = tty_port_tty_get(port);
279 EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
282 * tty_port_carrier_raised - carrier raised check
285 * Wrapper for the carrier detect logic. For the moment this is used
286 * to hide some internal details. This will eventually become entirely
287 * internal to the tty port.
290 int tty_port_carrier_raised(struct tty_port *port)
292 if (port->ops->carrier_raised == NULL)
294 return port->ops->carrier_raised(port);
296 EXPORT_SYMBOL(tty_port_carrier_raised);
299 * tty_port_raise_dtr_rts - Raise DTR/RTS
302 * Wrapper for the DTR/RTS raise logic. For the moment this is used
303 * to hide some internal details. This will eventually become entirely
304 * internal to the tty port.
307 void tty_port_raise_dtr_rts(struct tty_port *port)
309 if (port->ops->dtr_rts)
310 port->ops->dtr_rts(port, 1);
312 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
315 * tty_port_lower_dtr_rts - Lower DTR/RTS
318 * Wrapper for the DTR/RTS raise logic. For the moment this is used
319 * to hide some internal details. This will eventually become entirely
320 * internal to the tty port.
323 void tty_port_lower_dtr_rts(struct tty_port *port)
325 if (port->ops->dtr_rts)
326 port->ops->dtr_rts(port, 0);
328 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
331 * tty_port_block_til_ready - Waiting logic for tty open
332 * @port: the tty port being opened
333 * @tty: the tty device being bound
334 * @filp: the file pointer of the opener
336 * Implement the core POSIX/SuS tty behaviour when opening a tty device.
338 * - hangup (both before and during)
339 * - non blocking open
342 * - port flags and counts
344 * The passed tty_port must implement the carrier_raised method if it can
345 * do carrier detect and the dtr_rts method if it supports software
346 * management of these lines. Note that the dtr/rts raise is done each
347 * iteration as a hangup may have previously dropped them while we wait.
350 int tty_port_block_til_ready(struct tty_port *port,
351 struct tty_struct *tty, struct file *filp)
353 int do_clocal = 0, retval;
357 /* block if port is in the process of being closed */
358 if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
359 wait_event_interruptible_tty(tty, port->close_wait,
360 !(port->flags & ASYNC_CLOSING));
361 if (port->flags & ASYNC_HUP_NOTIFY)
367 /* if non-blocking mode is set we can pass directly to open unless
368 the port has just hung up or is in another error state */
369 if (tty->flags & (1 << TTY_IO_ERROR)) {
370 port->flags |= ASYNC_NORMAL_ACTIVE;
373 if (filp->f_flags & O_NONBLOCK) {
374 /* Indicate we are open */
375 if (tty->termios.c_cflag & CBAUD)
376 tty_port_raise_dtr_rts(port);
377 port->flags |= ASYNC_NORMAL_ACTIVE;
384 /* Block waiting until we can proceed. We may need to wait for the
385 carrier, but we must also wait for any close that is in progress
386 before the next open may complete */
390 /* The port lock protects the port counts */
391 spin_lock_irqsave(&port->lock, flags);
392 if (!tty_hung_up_p(filp))
394 port->blocked_open++;
395 spin_unlock_irqrestore(&port->lock, flags);
398 /* Indicate we are open */
399 if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
400 tty_port_raise_dtr_rts(port);
402 prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
403 /* Check for a hangup or uninitialised port.
404 Return accordingly */
405 if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
406 if (port->flags & ASYNC_HUP_NOTIFY)
409 retval = -ERESTARTSYS;
413 * Probe the carrier. For devices with no carrier detect
414 * tty_port_carrier_raised will always return true.
415 * Never ask drivers if CLOCAL is set, this causes troubles
418 if (!(port->flags & ASYNC_CLOSING) &&
419 (do_clocal || tty_port_carrier_raised(port)))
421 if (signal_pending(current)) {
422 retval = -ERESTARTSYS;
429 finish_wait(&port->open_wait, &wait);
431 /* Update counts. A parallel hangup will have set count to zero and
432 we must not mess that up further */
433 spin_lock_irqsave(&port->lock, flags);
434 if (!tty_hung_up_p(filp))
436 port->blocked_open--;
438 port->flags |= ASYNC_NORMAL_ACTIVE;
439 spin_unlock_irqrestore(&port->lock, flags);
442 EXPORT_SYMBOL(tty_port_block_til_ready);
444 int tty_port_close_start(struct tty_port *port,
445 struct tty_struct *tty, struct file *filp)
449 spin_lock_irqsave(&port->lock, flags);
450 if (tty_hung_up_p(filp)) {
451 spin_unlock_irqrestore(&port->lock, flags);
455 if (tty->count == 1 && port->count != 1) {
457 "tty_port_close_start: tty->count = 1 port count = %d.\n",
461 if (--port->count < 0) {
462 printk(KERN_WARNING "tty_port_close_start: count = %d\n",
468 spin_unlock_irqrestore(&port->lock, flags);
470 port->ops->drop(port);
473 set_bit(ASYNCB_CLOSING, &port->flags);
475 spin_unlock_irqrestore(&port->lock, flags);
476 /* Don't block on a stalled port, just pull the chain */
477 if (tty->flow_stopped)
478 tty_driver_flush_buffer(tty);
479 if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
480 port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
481 tty_wait_until_sent_from_close(tty, port->closing_wait);
482 if (port->drain_delay) {
483 unsigned int bps = tty_get_baud_rate(tty);
487 timeout = max_t(long,
488 (HZ * 10 * port->drain_delay) / bps, HZ / 10);
491 schedule_timeout_interruptible(timeout);
493 /* Flush the ldisc buffering */
494 tty_ldisc_flush(tty);
496 /* Don't call port->drop for the last reference. Callers will want
497 to drop the last active reference in ->shutdown() or the tty
501 EXPORT_SYMBOL(tty_port_close_start);
503 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
507 spin_lock_irqsave(&port->lock, flags);
510 if (port->blocked_open) {
511 spin_unlock_irqrestore(&port->lock, flags);
512 if (port->close_delay) {
513 msleep_interruptible(
514 jiffies_to_msecs(port->close_delay));
516 spin_lock_irqsave(&port->lock, flags);
517 wake_up_interruptible(&port->open_wait);
519 port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
520 wake_up_interruptible(&port->close_wait);
521 spin_unlock_irqrestore(&port->lock, flags);
523 EXPORT_SYMBOL(tty_port_close_end);
525 void tty_port_close(struct tty_port *port, struct tty_struct *tty,
528 if (tty_port_close_start(port, tty, filp) == 0)
530 tty_port_shutdown(port, tty);
531 set_bit(TTY_IO_ERROR, &tty->flags);
532 tty_port_close_end(port, tty);
533 tty_port_tty_set(port, NULL);
535 EXPORT_SYMBOL(tty_port_close);
538 * tty_port_install - generic tty->ops->install handler
539 * @port: tty_port of the device
540 * @driver: tty_driver for this device
541 * @tty: tty to be installed
543 * It is the same as tty_standard_install except the provided @port is linked
544 * to a concrete tty specified by @tty. Use this or tty_port_register_device
545 * (or both). Call tty_port_link_device as a last resort.
547 int tty_port_install(struct tty_port *port, struct tty_driver *driver,
548 struct tty_struct *tty)
551 return tty_standard_install(driver, tty);
553 EXPORT_SYMBOL_GPL(tty_port_install);
555 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
558 spin_lock_irq(&port->lock);
559 if (!tty_hung_up_p(filp))
561 spin_unlock_irq(&port->lock);
562 tty_port_tty_set(port, tty);
565 * Do the device-specific open only if the hardware isn't
566 * already initialized. Serialize open and shutdown using the
570 mutex_lock(&port->mutex);
572 if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) {
573 clear_bit(TTY_IO_ERROR, &tty->flags);
574 if (port->ops->activate) {
575 int retval = port->ops->activate(port, tty);
577 mutex_unlock(&port->mutex);
581 set_bit(ASYNCB_INITIALIZED, &port->flags);
583 mutex_unlock(&port->mutex);
584 return tty_port_block_til_ready(port, tty, filp);
587 EXPORT_SYMBOL(tty_port_open);