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 init_waitqueue_head(&port->open_wait);
25 init_waitqueue_head(&port->close_wait);
26 mutex_init(&port->mutex);
27 spin_lock_init(&port->lock);
28 port->close_delay = (50 * HZ) / 100;
29 port->closing_wait = (3000 * HZ) / 100;
31 EXPORT_SYMBOL(tty_port_init);
33 int tty_port_alloc_xmit_buf(struct tty_port *port)
35 /* We may sleep in get_zeroed_page() */
36 mutex_lock(&port->mutex);
37 if (port->xmit_buf == NULL)
38 port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL);
39 mutex_unlock(&port->mutex);
40 if (port->xmit_buf == NULL)
44 EXPORT_SYMBOL(tty_port_alloc_xmit_buf);
46 void tty_port_free_xmit_buf(struct tty_port *port)
48 mutex_lock(&port->mutex);
49 if (port->xmit_buf != NULL) {
50 free_page((unsigned long)port->xmit_buf);
51 port->xmit_buf = NULL;
53 mutex_unlock(&port->mutex);
55 EXPORT_SYMBOL(tty_port_free_xmit_buf);
59 * tty_port_tty_get - get a tty reference
62 * Return a refcount protected tty instance or NULL if the port is not
63 * associated with a tty (eg due to close or hangup)
66 struct tty_struct *tty_port_tty_get(struct tty_port *port)
69 struct tty_struct *tty;
71 spin_lock_irqsave(&port->lock, flags);
72 tty = tty_kref_get(port->tty);
73 spin_unlock_irqrestore(&port->lock, flags);
76 EXPORT_SYMBOL(tty_port_tty_get);
79 * tty_port_tty_set - set the tty of a port
83 * Associate the port and tty pair. Manages any internal refcounts.
84 * Pass NULL to deassociate a port
87 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
91 spin_lock_irqsave(&port->lock, flags);
93 tty_kref_put(port->tty);
94 port->tty = tty_kref_get(tty);
95 spin_unlock_irqrestore(&port->lock, flags);
97 EXPORT_SYMBOL(tty_port_tty_set);
100 * tty_port_hangup - hangup helper
103 * Perform port level tty hangup flag and count changes. Drop the tty
107 void tty_port_hangup(struct tty_port *port)
111 spin_lock_irqsave(&port->lock, flags);
113 port->flags &= ~ASYNC_NORMAL_ACTIVE;
115 tty_kref_put(port->tty);
117 spin_unlock_irqrestore(&port->lock, flags);
118 wake_up_interruptible(&port->open_wait);
120 EXPORT_SYMBOL(tty_port_hangup);
123 * tty_port_carrier_raised - carrier raised check
126 * Wrapper for the carrier detect logic. For the moment this is used
127 * to hide some internal details. This will eventually become entirely
128 * internal to the tty port.
131 int tty_port_carrier_raised(struct tty_port *port)
133 if (port->ops->carrier_raised == NULL)
135 return port->ops->carrier_raised(port);
137 EXPORT_SYMBOL(tty_port_carrier_raised);
140 * tty_port_raise_dtr_rts - Raise DTR/RTS
143 * Wrapper for the DTR/RTS raise logic. For the moment this is used
144 * to hide some internal details. This will eventually become entirely
145 * internal to the tty port.
148 void tty_port_raise_dtr_rts(struct tty_port *port)
150 if (port->ops->dtr_rts)
151 port->ops->dtr_rts(port, 1);
153 EXPORT_SYMBOL(tty_port_raise_dtr_rts);
156 * tty_port_lower_dtr_rts - Lower DTR/RTS
159 * Wrapper for the DTR/RTS raise logic. For the moment this is used
160 * to hide some internal details. This will eventually become entirely
161 * internal to the tty port.
164 void tty_port_lower_dtr_rts(struct tty_port *port)
166 if (port->ops->dtr_rts)
167 port->ops->dtr_rts(port, 0);
169 EXPORT_SYMBOL(tty_port_lower_dtr_rts);
172 * tty_port_block_til_ready - Waiting logic for tty open
173 * @port: the tty port being opened
174 * @tty: the tty device being bound
175 * @filp: the file pointer of the opener
177 * Implement the core POSIX/SuS tty behaviour when opening a tty device.
179 * - hangup (both before and during)
180 * - non blocking open
183 * - port flags and counts
185 * The passed tty_port must implement the carrier_raised method if it can
186 * do carrier detect and the dtr_rts method if it supports software
187 * management of these lines. Note that the dtr/rts raise is done each
188 * iteration as a hangup may have previously dropped them while we wait.
191 int tty_port_block_til_ready(struct tty_port *port,
192 struct tty_struct *tty, struct file *filp)
194 int do_clocal = 0, retval;
196 DECLARE_WAITQUEUE(wait, current);
199 /* block if port is in the process of being closed */
200 if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
201 wait_event_interruptible(port->close_wait,
202 !(port->flags & ASYNC_CLOSING));
203 if (port->flags & ASYNC_HUP_NOTIFY)
209 /* if non-blocking mode is set we can pass directly to open unless
210 the port has just hung up or is in another error state */
211 if ((filp->f_flags & O_NONBLOCK) ||
212 (tty->flags & (1 << TTY_IO_ERROR))) {
213 port->flags |= ASYNC_NORMAL_ACTIVE;
220 /* Block waiting until we can proceed. We may need to wait for the
221 carrier, but we must also wait for any close that is in progress
222 before the next open may complete */
225 add_wait_queue(&port->open_wait, &wait);
227 /* The port lock protects the port counts */
228 spin_lock_irqsave(&port->lock, flags);
229 if (!tty_hung_up_p(filp))
231 port->blocked_open++;
232 spin_unlock_irqrestore(&port->lock, flags);
235 /* Indicate we are open */
236 if (tty->termios->c_cflag & CBAUD)
237 tty_port_raise_dtr_rts(port);
239 set_current_state(TASK_INTERRUPTIBLE);
240 /* Check for a hangup or uninitialised port. Return accordingly */
241 if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) {
242 if (port->flags & ASYNC_HUP_NOTIFY)
245 retval = -ERESTARTSYS;
248 /* Probe the carrier. For devices with no carrier detect this
249 will always return true */
250 cd = tty_port_carrier_raised(port);
251 if (!(port->flags & ASYNC_CLOSING) &&
254 if (signal_pending(current)) {
255 retval = -ERESTARTSYS;
260 set_current_state(TASK_RUNNING);
261 remove_wait_queue(&port->open_wait, &wait);
263 /* Update counts. A parallel hangup will have set count to zero and
264 we must not mess that up further */
265 spin_lock_irqsave(&port->lock, flags);
266 if (!tty_hung_up_p(filp))
268 port->blocked_open--;
270 port->flags |= ASYNC_NORMAL_ACTIVE;
271 spin_unlock_irqrestore(&port->lock, flags);
275 EXPORT_SYMBOL(tty_port_block_til_ready);
277 int tty_port_close_start(struct tty_port *port, struct tty_struct *tty, struct file *filp)
281 spin_lock_irqsave(&port->lock, flags);
282 if (tty_hung_up_p(filp)) {
283 spin_unlock_irqrestore(&port->lock, flags);
287 if( tty->count == 1 && port->count != 1) {
289 "tty_port_close_start: tty->count = 1 port count = %d.\n",
293 if (--port->count < 0) {
294 printk(KERN_WARNING "tty_port_close_start: count = %d\n",
300 spin_unlock_irqrestore(&port->lock, flags);
303 port->flags |= ASYNC_CLOSING;
305 spin_unlock_irqrestore(&port->lock, flags);
306 /* Don't block on a stalled port, just pull the chain */
307 if (tty->flow_stopped)
308 tty_driver_flush_buffer(tty);
309 if (port->flags & ASYNC_INITIALIZED &&
310 port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
311 tty_wait_until_sent(tty, port->closing_wait);
312 if (port->drain_delay) {
313 unsigned int bps = tty_get_baud_rate(tty);
317 timeout = max_t(long, (HZ * 10 * port->drain_delay) / bps,
321 schedule_timeout_interruptible(timeout);
325 EXPORT_SYMBOL(tty_port_close_start);
327 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
331 tty_ldisc_flush(tty);
333 if (tty->termios->c_cflag & HUPCL)
334 tty_port_lower_dtr_rts(port);
336 spin_lock_irqsave(&port->lock, flags);
339 if (port->blocked_open) {
340 spin_unlock_irqrestore(&port->lock, flags);
341 if (port->close_delay) {
342 msleep_interruptible(
343 jiffies_to_msecs(port->close_delay));
345 spin_lock_irqsave(&port->lock, flags);
346 wake_up_interruptible(&port->open_wait);
348 port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING);
349 wake_up_interruptible(&port->close_wait);
350 spin_unlock_irqrestore(&port->lock, flags);
352 EXPORT_SYMBOL(tty_port_close_end);