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);
202 if (port->ops->shutdown && !port->console &&
203 test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags))
204 port->ops->shutdown(port);
205 mutex_unlock(&port->mutex);
209 * tty_port_hangup - hangup helper
212 * Perform port level tty hangup flag and count changes. Drop the tty
216 void tty_port_hangup(struct tty_port *port)
220 spin_lock_irqsave(&port->lock, flags);
222 port->flags &= ~ASYNC_NORMAL_ACTIVE;
224 set_bit(TTY_IO_ERROR, &port->tty->flags);
225 tty_kref_put(port->tty);
228 spin_unlock_irqrestore(&port->lock, flags);
229 wake_up_interruptible(&port->open_wait);
230 wake_up_interruptible(&port->delta_msr_wait);
231 tty_port_shutdown(port);
233 EXPORT_SYMBOL(tty_port_hangup);
236 * tty_port_carrier_raised - carrier raised check
239 * Wrapper for the carrier detect logic. For the moment this is used
240 * to hide some internal details. This will eventually become entirely
241 * internal to the tty port.
244 int tty_port_carrier_raised(struct tty_port *port)
246 if (port->ops->carrier_raised == NULL)
248 return port->ops->carrier_raised(port);
250 EXPORT_SYMBOL(tty_port_carrier_raised);
253 * tty_port_raise_dtr_rts - Raise DTR/RTS
256 * Wrapper for the DTR/RTS raise logic. For the moment this is used
257 * to hide some internal details. This will eventually become entirely
258 * internal to the tty port.
261 void tty_port_raise_dtr_rts(struct tty_port *port)
263 if (port->ops->dtr_rts)
264 port->ops->dtr_rts(port, 1);
266 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
269 * tty_port_lower_dtr_rts - Lower DTR/RTS
272 * Wrapper for the DTR/RTS raise logic. For the moment this is used
273 * to hide some internal details. This will eventually become entirely
274 * internal to the tty port.
277 void tty_port_lower_dtr_rts(struct tty_port *port)
279 if (port->ops->dtr_rts)
280 port->ops->dtr_rts(port, 0);
282 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
285 * tty_port_block_til_ready - Waiting logic for tty open
286 * @port: the tty port being opened
287 * @tty: the tty device being bound
288 * @filp: the file pointer of the opener
290 * Implement the core POSIX/SuS tty behaviour when opening a tty device.
292 * - hangup (both before and during)
293 * - non blocking open
296 * - port flags and counts
298 * The passed tty_port must implement the carrier_raised method if it can
299 * do carrier detect and the dtr_rts method if it supports software
300 * management of these lines. Note that the dtr/rts raise is done each
301 * iteration as a hangup may have previously dropped them while we wait.
304 int tty_port_block_til_ready(struct tty_port *port,
305 struct tty_struct *tty, struct file *filp)
307 int do_clocal = 0, retval;
311 /* block if port is in the process of being closed */
312 if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
313 wait_event_interruptible_tty(tty, port->close_wait,
314 !(port->flags & ASYNC_CLOSING));
315 if (port->flags & ASYNC_HUP_NOTIFY)
321 /* if non-blocking mode is set we can pass directly to open unless
322 the port has just hung up or is in another error state */
323 if (tty->flags & (1 << TTY_IO_ERROR)) {
324 port->flags |= ASYNC_NORMAL_ACTIVE;
327 if (filp->f_flags & O_NONBLOCK) {
328 /* Indicate we are open */
329 if (tty->termios.c_cflag & CBAUD)
330 tty_port_raise_dtr_rts(port);
331 port->flags |= ASYNC_NORMAL_ACTIVE;
338 /* Block waiting until we can proceed. We may need to wait for the
339 carrier, but we must also wait for any close that is in progress
340 before the next open may complete */
344 /* The port lock protects the port counts */
345 spin_lock_irqsave(&port->lock, flags);
346 if (!tty_hung_up_p(filp))
348 port->blocked_open++;
349 spin_unlock_irqrestore(&port->lock, flags);
352 /* Indicate we are open */
353 if (tty->termios.c_cflag & CBAUD)
354 tty_port_raise_dtr_rts(port);
356 prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE);
357 /* Check for a hangup or uninitialised port.
358 Return accordingly */
359 if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
360 if (port->flags & ASYNC_HUP_NOTIFY)
363 retval = -ERESTARTSYS;
367 * Probe the carrier. For devices with no carrier detect
368 * tty_port_carrier_raised will always return true.
369 * Never ask drivers if CLOCAL is set, this causes troubles
372 if (!(port->flags & ASYNC_CLOSING) &&
373 (do_clocal || tty_port_carrier_raised(port)))
375 if (signal_pending(current)) {
376 retval = -ERESTARTSYS;
383 finish_wait(&port->open_wait, &wait);
385 /* Update counts. A parallel hangup will have set count to zero and
386 we must not mess that up further */
387 spin_lock_irqsave(&port->lock, flags);
388 if (!tty_hung_up_p(filp))
390 port->blocked_open--;
392 port->flags |= ASYNC_NORMAL_ACTIVE;
393 spin_unlock_irqrestore(&port->lock, flags);
396 EXPORT_SYMBOL(tty_port_block_til_ready);
398 int tty_port_close_start(struct tty_port *port,
399 struct tty_struct *tty, struct file *filp)
403 spin_lock_irqsave(&port->lock, flags);
404 if (tty_hung_up_p(filp)) {
405 spin_unlock_irqrestore(&port->lock, flags);
409 if (tty->count == 1 && port->count != 1) {
411 "tty_port_close_start: tty->count = 1 port count = %d.\n",
415 if (--port->count < 0) {
416 printk(KERN_WARNING "tty_port_close_start: count = %d\n",
422 spin_unlock_irqrestore(&port->lock, flags);
424 port->ops->drop(port);
427 set_bit(ASYNCB_CLOSING, &port->flags);
429 spin_unlock_irqrestore(&port->lock, flags);
430 /* Don't block on a stalled port, just pull the chain */
431 if (tty->flow_stopped)
432 tty_driver_flush_buffer(tty);
433 if (test_bit(ASYNCB_INITIALIZED, &port->flags) &&
434 port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
435 tty_wait_until_sent_from_close(tty, port->closing_wait);
436 if (port->drain_delay) {
437 unsigned int bps = tty_get_baud_rate(tty);
441 timeout = max_t(long,
442 (HZ * 10 * port->drain_delay) / bps, HZ / 10);
445 schedule_timeout_interruptible(timeout);
447 /* Flush the ldisc buffering */
448 tty_ldisc_flush(tty);
450 /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to
452 if (tty->termios.c_cflag & HUPCL)
453 tty_port_lower_dtr_rts(port);
455 /* Don't call port->drop for the last reference. Callers will want
456 to drop the last active reference in ->shutdown() or the tty
460 EXPORT_SYMBOL(tty_port_close_start);
462 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
466 spin_lock_irqsave(&port->lock, flags);
469 if (port->blocked_open) {
470 spin_unlock_irqrestore(&port->lock, flags);
471 if (port->close_delay) {
472 msleep_interruptible(
473 jiffies_to_msecs(port->close_delay));
475 spin_lock_irqsave(&port->lock, flags);
476 wake_up_interruptible(&port->open_wait);
478 port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
479 wake_up_interruptible(&port->close_wait);
480 spin_unlock_irqrestore(&port->lock, flags);
482 EXPORT_SYMBOL(tty_port_close_end);
484 void tty_port_close(struct tty_port *port, struct tty_struct *tty,
487 if (tty_port_close_start(port, tty, filp) == 0)
489 tty_port_shutdown(port);
490 set_bit(TTY_IO_ERROR, &tty->flags);
491 tty_port_close_end(port, tty);
492 tty_port_tty_set(port, NULL);
494 EXPORT_SYMBOL(tty_port_close);
497 * tty_port_install - generic tty->ops->install handler
498 * @port: tty_port of the device
499 * @driver: tty_driver for this device
500 * @tty: tty to be installed
502 * It is the same as tty_standard_install except the provided @port is linked
503 * to a concrete tty specified by @tty. Use this or tty_port_register_device
504 * (or both). Call tty_port_link_device as a last resort.
506 int tty_port_install(struct tty_port *port, struct tty_driver *driver,
507 struct tty_struct *tty)
510 return tty_standard_install(driver, tty);
512 EXPORT_SYMBOL_GPL(tty_port_install);
514 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
517 spin_lock_irq(&port->lock);
518 if (!tty_hung_up_p(filp))
520 spin_unlock_irq(&port->lock);
521 tty_port_tty_set(port, tty);
524 * Do the device-specific open only if the hardware isn't
525 * already initialized. Serialize open and shutdown using the
529 mutex_lock(&port->mutex);
531 if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) {
532 clear_bit(TTY_IO_ERROR, &tty->flags);
533 if (port->ops->activate) {
534 int retval = port->ops->activate(port, tty);
536 mutex_unlock(&port->mutex);
540 set_bit(ASYNCB_INITIALIZED, &port->flags);
542 mutex_unlock(&port->mutex);
543 return tty_port_block_til_ready(port, tty, filp);
546 EXPORT_SYMBOL(tty_port_open);