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)
201 mutex_lock(&port->mutex);
205 if (test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) {
206 if (port->ops->shutdown)
207 port->ops->shutdown(port);
210 mutex_unlock(&port->mutex);
214 * tty_port_hangup - hangup helper
217 * Perform port level tty hangup flag and count changes. Drop the tty
221 void tty_port_hangup(struct tty_port *port)
225 spin_lock_irqsave(&port->lock, flags);
227 port->flags &= ~ASYNC_NORMAL_ACTIVE;
229 set_bit(TTY_IO_ERROR, &port->tty->flags);
230 tty_kref_put(port->tty);
233 spin_unlock_irqrestore(&port->lock, flags);
234 tty_port_shutdown(port);
235 wake_up_interruptible(&port->open_wait);
236 wake_up_interruptible(&port->delta_msr_wait);
238 EXPORT_SYMBOL(tty_port_hangup);
241 * tty_port_tty_hangup - helper to hang up a tty
244 * @check_clocal: hang only ttys with CLOCAL unset?
246 void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
248 struct tty_struct *tty = tty_port_tty_get(port);
250 if (tty && (!check_clocal || !C_CLOCAL(tty))) {
255 EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
258 * tty_port_tty_wakeup - helper to wake up a tty
262 void tty_port_tty_wakeup(struct tty_port *port)
264 struct tty_struct *tty = tty_port_tty_get(port);
271 EXPORT_SYMBOL_GPL(tty_port_tty_wakeup);
274 * tty_port_carrier_raised - carrier raised check
277 * Wrapper for the carrier detect logic. For the moment this is used
278 * to hide some internal details. This will eventually become entirely
279 * internal to the tty port.
282 int tty_port_carrier_raised(struct tty_port *port)
284 if (port->ops->carrier_raised == NULL)
286 return port->ops->carrier_raised(port);
288 EXPORT_SYMBOL(tty_port_carrier_raised);
291 * tty_port_raise_dtr_rts - Raise DTR/RTS
294 * Wrapper for the DTR/RTS raise logic. For the moment this is used
295 * to hide some internal details. This will eventually become entirely
296 * internal to the tty port.
299 void tty_port_raise_dtr_rts(struct tty_port *port)
301 if (port->ops->dtr_rts)
302 port->ops->dtr_rts(port, 1);
304 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
307 * tty_port_lower_dtr_rts - Lower DTR/RTS
310 * Wrapper for the DTR/RTS raise logic. For the moment this is used
311 * to hide some internal details. This will eventually become entirely
312 * internal to the tty port.
315 void tty_port_lower_dtr_rts(struct tty_port *port)
317 if (port->ops->dtr_rts)
318 port->ops->dtr_rts(port, 0);
320 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
323 * tty_port_block_til_ready - Waiting logic for tty open
324 * @port: the tty port being opened
325 * @tty: the tty device being bound
326 * @filp: the file pointer of the opener
328 * Implement the core POSIX/SuS tty behaviour when opening a tty device.
330 * - hangup (both before and during)
331 * - non blocking open
334 * - port flags and counts
336 * The passed tty_port must implement the carrier_raised method if it can
337 * do carrier detect and the dtr_rts method if it supports software
338 * management of these lines. Note that the dtr/rts raise is done each
339 * iteration as a hangup may have previously dropped them while we wait.
342 int tty_port_block_til_ready(struct tty_port *port,
343 struct tty_struct *tty, struct file *filp)
345 int do_clocal = 0, retval;
349 /* block if port is in the process of being closed */
350 if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
351 wait_event_interruptible_tty(tty, port->close_wait,
352 !(port->flags & ASYNC_CLOSING));
353 if (port->flags & ASYNC_HUP_NOTIFY)
359 /* if non-blocking mode is set we can pass directly to open unless
360 the port has just hung up or is in another error state */
361 if (tty->flags & (1 << TTY_IO_ERROR)) {
362 port->flags |= ASYNC_NORMAL_ACTIVE;
365 if (filp->f_flags & O_NONBLOCK) {
366 /* Indicate we are open */
367 if (tty->termios.c_cflag & CBAUD)
368 tty_port_raise_dtr_rts(port);
369 port->flags |= ASYNC_NORMAL_ACTIVE;
376 /* Block waiting until we can proceed. We may need to wait for the
377 carrier, but we must also wait for any close that is in progress
378 before the next open may complete */
382 /* The port lock protects the port counts */
383 spin_lock_irqsave(&port->lock, flags);
384 if (!tty_hung_up_p(filp))
386 port->blocked_open++;
387 spin_unlock_irqrestore(&port->lock, flags);
390 /* Indicate we are open */
391 if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
392 tty_port_raise_dtr_rts(port);
394 prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
395 /* Check for a hangup or uninitialised port.
396 Return accordingly */
397 if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
398 if (port->flags & ASYNC_HUP_NOTIFY)
401 retval = -ERESTARTSYS;
405 * Probe the carrier. For devices with no carrier detect
406 * tty_port_carrier_raised will always return true.
407 * Never ask drivers if CLOCAL is set, this causes troubles
410 if (!(port->flags & ASYNC_CLOSING) &&
411 (do_clocal || tty_port_carrier_raised(port)))
413 if (signal_pending(current)) {
414 retval = -ERESTARTSYS;
421 finish_wait(&port->open_wait, &wait);
423 /* Update counts. A parallel hangup will have set count to zero and
424 we must not mess that up further */
425 spin_lock_irqsave(&port->lock, flags);
426 if (!tty_hung_up_p(filp))
428 port->blocked_open--;
430 port->flags |= ASYNC_NORMAL_ACTIVE;
431 spin_unlock_irqrestore(&port->lock, flags);
434 EXPORT_SYMBOL(tty_port_block_til_ready);
436 int tty_port_close_start(struct tty_port *port,
437 struct tty_struct *tty, struct file *filp)
441 spin_lock_irqsave(&port->lock, flags);
442 if (tty_hung_up_p(filp)) {
443 spin_unlock_irqrestore(&port->lock, flags);
447 if (tty->count == 1 && port->count != 1) {
449 "tty_port_close_start: tty->count = 1 port count = %d.\n",
453 if (--port->count < 0) {
454 printk(KERN_WARNING "tty_port_close_start: count = %d\n",
460 spin_unlock_irqrestore(&port->lock, flags);
462 port->ops->drop(port);
465 set_bit(ASYNCB_CLOSING, &port->flags);
467 spin_unlock_irqrestore(&port->lock, flags);
468 /* Don't block on a stalled port, just pull the chain */
469 if (tty->flow_stopped)
470 tty_driver_flush_buffer(tty);
471 if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
472 port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
473 tty_wait_until_sent_from_close(tty, port->closing_wait);
474 if (port->drain_delay) {
475 unsigned int bps = tty_get_baud_rate(tty);
479 timeout = max_t(long,
480 (HZ * 10 * port->drain_delay) / bps, HZ / 10);
483 schedule_timeout_interruptible(timeout);
485 /* Flush the ldisc buffering */
486 tty_ldisc_flush(tty);
488 /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
490 if (tty->termios.c_cflag & HUPCL)
491 tty_port_lower_dtr_rts(port);
493 /* Don't call port->drop for the last reference. Callers will want
494 to drop the last active reference in ->shutdown() or the tty
498 EXPORT_SYMBOL(tty_port_close_start);
500 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
504 spin_lock_irqsave(&port->lock, flags);
507 if (port->blocked_open) {
508 spin_unlock_irqrestore(&port->lock, flags);
509 if (port->close_delay) {
510 msleep_interruptible(
511 jiffies_to_msecs(port->close_delay));
513 spin_lock_irqsave(&port->lock, flags);
514 wake_up_interruptible(&port->open_wait);
516 port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
517 wake_up_interruptible(&port->close_wait);
518 spin_unlock_irqrestore(&port->lock, flags);
520 EXPORT_SYMBOL(tty_port_close_end);
522 void tty_port_close(struct tty_port *port, struct tty_struct *tty,
525 if (tty_port_close_start(port, tty, filp) == 0)
527 tty_port_shutdown(port);
528 set_bit(TTY_IO_ERROR, &tty->flags);
529 tty_port_close_end(port, tty);
530 tty_port_tty_set(port, NULL);
532 EXPORT_SYMBOL(tty_port_close);
535 * tty_port_install - generic tty->ops->install handler
536 * @port: tty_port of the device
537 * @driver: tty_driver for this device
538 * @tty: tty to be installed
540 * It is the same as tty_standard_install except the provided @port is linked
541 * to a concrete tty specified by @tty. Use this or tty_port_register_device
542 * (or both). Call tty_port_link_device as a last resort.
544 int tty_port_install(struct tty_port *port, struct tty_driver *driver,
545 struct tty_struct *tty)
548 return tty_standard_install(driver, tty);
550 EXPORT_SYMBOL_GPL(tty_port_install);
552 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
555 spin_lock_irq(&port->lock);
556 if (!tty_hung_up_p(filp))
558 spin_unlock_irq(&port->lock);
559 tty_port_tty_set(port, tty);
562 * Do the device-specific open only if the hardware isn't
563 * already initialized. Serialize open and shutdown using the
567 mutex_lock(&port->mutex);
569 if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) {
570 clear_bit(TTY_IO_ERROR, &tty->flags);
571 if (port->ops->activate) {
572 int retval = port->ops->activate(port, tty);
574 mutex_unlock(&port->mutex);
578 set_bit(ASYNCB_INITIALIZED, &port->flags);
580 mutex_unlock(&port->mutex);
581 return tty_port_block_til_ready(port, tty, filp);
584 EXPORT_SYMBOL(tty_port_open);