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Commit | Line | Data |
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9e48565d AC |
1 | /* |
2 | * Tty port functions | |
3 | */ | |
4 | ||
5 | #include <linux/types.h> | |
6 | #include <linux/errno.h> | |
7 | #include <linux/tty.h> | |
8 | #include <linux/tty_driver.h> | |
9 | #include <linux/tty_flip.h> | |
3e61696b | 10 | #include <linux/serial.h> |
9e48565d AC |
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> | |
20 | ||
21 | void tty_port_init(struct tty_port *port) | |
22 | { | |
23 | memset(port, 0, sizeof(*port)); | |
24 | init_waitqueue_head(&port->open_wait); | |
25 | init_waitqueue_head(&port->close_wait); | |
bdc04e31 | 26 | init_waitqueue_head(&port->delta_msr_wait); |
9e48565d | 27 | mutex_init(&port->mutex); |
44e4909e | 28 | mutex_init(&port->buf_mutex); |
4a90f09b | 29 | spin_lock_init(&port->lock); |
9e48565d AC |
30 | port->close_delay = (50 * HZ) / 100; |
31 | port->closing_wait = (3000 * HZ) / 100; | |
568aafc6 | 32 | kref_init(&port->kref); |
9e48565d AC |
33 | } |
34 | EXPORT_SYMBOL(tty_port_init); | |
35 | ||
36 | int tty_port_alloc_xmit_buf(struct tty_port *port) | |
37 | { | |
38 | /* We may sleep in get_zeroed_page() */ | |
44e4909e | 39 | mutex_lock(&port->buf_mutex); |
9e48565d AC |
40 | if (port->xmit_buf == NULL) |
41 | port->xmit_buf = (unsigned char *)get_zeroed_page(GFP_KERNEL); | |
44e4909e | 42 | mutex_unlock(&port->buf_mutex); |
9e48565d AC |
43 | if (port->xmit_buf == NULL) |
44 | return -ENOMEM; | |
45 | return 0; | |
46 | } | |
47 | EXPORT_SYMBOL(tty_port_alloc_xmit_buf); | |
48 | ||
49 | void tty_port_free_xmit_buf(struct tty_port *port) | |
50 | { | |
44e4909e | 51 | mutex_lock(&port->buf_mutex); |
9e48565d AC |
52 | if (port->xmit_buf != NULL) { |
53 | free_page((unsigned long)port->xmit_buf); | |
54 | port->xmit_buf = NULL; | |
55 | } | |
44e4909e | 56 | mutex_unlock(&port->buf_mutex); |
9e48565d AC |
57 | } |
58 | EXPORT_SYMBOL(tty_port_free_xmit_buf); | |
59 | ||
568aafc6 AC |
60 | static void tty_port_destructor(struct kref *kref) |
61 | { | |
62 | struct tty_port *port = container_of(kref, struct tty_port, kref); | |
63 | if (port->xmit_buf) | |
64 | free_page((unsigned long)port->xmit_buf); | |
65 | if (port->ops->destruct) | |
66 | port->ops->destruct(port); | |
67 | else | |
68 | kfree(port); | |
69 | } | |
70 | ||
71 | void tty_port_put(struct tty_port *port) | |
72 | { | |
73 | if (port) | |
74 | kref_put(&port->kref, tty_port_destructor); | |
75 | } | |
76 | EXPORT_SYMBOL(tty_port_put); | |
9e48565d | 77 | |
4a90f09b AC |
78 | /** |
79 | * tty_port_tty_get - get a tty reference | |
80 | * @port: tty port | |
81 | * | |
82 | * Return a refcount protected tty instance or NULL if the port is not | |
83 | * associated with a tty (eg due to close or hangup) | |
84 | */ | |
85 | ||
86 | struct tty_struct *tty_port_tty_get(struct tty_port *port) | |
87 | { | |
88 | unsigned long flags; | |
89 | struct tty_struct *tty; | |
90 | ||
91 | spin_lock_irqsave(&port->lock, flags); | |
92 | tty = tty_kref_get(port->tty); | |
93 | spin_unlock_irqrestore(&port->lock, flags); | |
94 | return tty; | |
95 | } | |
96 | EXPORT_SYMBOL(tty_port_tty_get); | |
97 | ||
98 | /** | |
99 | * tty_port_tty_set - set the tty of a port | |
100 | * @port: tty port | |
101 | * @tty: the tty | |
102 | * | |
103 | * Associate the port and tty pair. Manages any internal refcounts. | |
104 | * Pass NULL to deassociate a port | |
105 | */ | |
106 | ||
107 | void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty) | |
108 | { | |
109 | unsigned long flags; | |
110 | ||
111 | spin_lock_irqsave(&port->lock, flags); | |
112 | if (port->tty) | |
113 | tty_kref_put(port->tty); | |
cb4bca35 | 114 | port->tty = tty_kref_get(tty); |
4a90f09b AC |
115 | spin_unlock_irqrestore(&port->lock, flags); |
116 | } | |
117 | EXPORT_SYMBOL(tty_port_tty_set); | |
31f35939 | 118 | |
7ca0ff9a AC |
119 | static void tty_port_shutdown(struct tty_port *port) |
120 | { | |
64bc3979 | 121 | mutex_lock(&port->mutex); |
7ca0ff9a | 122 | if (port->ops->shutdown && |
1f5c13fa | 123 | test_and_clear_bit(ASYNCB_INITIALIZED, &port->flags)) |
7ca0ff9a | 124 | port->ops->shutdown(port); |
64bc3979 | 125 | mutex_unlock(&port->mutex); |
7ca0ff9a AC |
126 | } |
127 | ||
3e61696b AC |
128 | /** |
129 | * tty_port_hangup - hangup helper | |
130 | * @port: tty port | |
131 | * | |
132 | * Perform port level tty hangup flag and count changes. Drop the tty | |
133 | * reference. | |
134 | */ | |
135 | ||
136 | void tty_port_hangup(struct tty_port *port) | |
137 | { | |
138 | unsigned long flags; | |
139 | ||
140 | spin_lock_irqsave(&port->lock, flags); | |
141 | port->count = 0; | |
142 | port->flags &= ~ASYNC_NORMAL_ACTIVE; | |
d74e8286 AC |
143 | if (port->tty) { |
144 | set_bit(TTY_IO_ERROR, &port->tty->flags); | |
3e61696b | 145 | tty_kref_put(port->tty); |
d74e8286 | 146 | } |
3e61696b AC |
147 | port->tty = NULL; |
148 | spin_unlock_irqrestore(&port->lock, flags); | |
149 | wake_up_interruptible(&port->open_wait); | |
bdc04e31 | 150 | wake_up_interruptible(&port->delta_msr_wait); |
7ca0ff9a | 151 | tty_port_shutdown(port); |
3e61696b AC |
152 | } |
153 | EXPORT_SYMBOL(tty_port_hangup); | |
154 | ||
31f35939 AC |
155 | /** |
156 | * tty_port_carrier_raised - carrier raised check | |
157 | * @port: tty port | |
158 | * | |
159 | * Wrapper for the carrier detect logic. For the moment this is used | |
160 | * to hide some internal details. This will eventually become entirely | |
161 | * internal to the tty port. | |
162 | */ | |
163 | ||
164 | int tty_port_carrier_raised(struct tty_port *port) | |
165 | { | |
166 | if (port->ops->carrier_raised == NULL) | |
167 | return 1; | |
168 | return port->ops->carrier_raised(port); | |
169 | } | |
170 | EXPORT_SYMBOL(tty_port_carrier_raised); | |
5d951fb4 AC |
171 | |
172 | /** | |
fcc8ac18 | 173 | * tty_port_raise_dtr_rts - Raise DTR/RTS |
5d951fb4 AC |
174 | * @port: tty port |
175 | * | |
176 | * Wrapper for the DTR/RTS raise logic. For the moment this is used | |
177 | * to hide some internal details. This will eventually become entirely | |
178 | * internal to the tty port. | |
179 | */ | |
180 | ||
181 | void tty_port_raise_dtr_rts(struct tty_port *port) | |
182 | { | |
fcc8ac18 AC |
183 | if (port->ops->dtr_rts) |
184 | port->ops->dtr_rts(port, 1); | |
5d951fb4 AC |
185 | } |
186 | EXPORT_SYMBOL(tty_port_raise_dtr_rts); | |
36c621d8 | 187 | |
fcc8ac18 AC |
188 | /** |
189 | * tty_port_lower_dtr_rts - Lower DTR/RTS | |
190 | * @port: tty port | |
191 | * | |
192 | * Wrapper for the DTR/RTS raise logic. For the moment this is used | |
193 | * to hide some internal details. This will eventually become entirely | |
194 | * internal to the tty port. | |
195 | */ | |
196 | ||
197 | void tty_port_lower_dtr_rts(struct tty_port *port) | |
198 | { | |
199 | if (port->ops->dtr_rts) | |
200 | port->ops->dtr_rts(port, 0); | |
201 | } | |
202 | EXPORT_SYMBOL(tty_port_lower_dtr_rts); | |
203 | ||
36c621d8 AC |
204 | /** |
205 | * tty_port_block_til_ready - Waiting logic for tty open | |
206 | * @port: the tty port being opened | |
207 | * @tty: the tty device being bound | |
208 | * @filp: the file pointer of the opener | |
209 | * | |
210 | * Implement the core POSIX/SuS tty behaviour when opening a tty device. | |
211 | * Handles: | |
212 | * - hangup (both before and during) | |
213 | * - non blocking open | |
214 | * - rts/dtr/dcd | |
215 | * - signals | |
216 | * - port flags and counts | |
217 | * | |
218 | * The passed tty_port must implement the carrier_raised method if it can | |
fcc8ac18 | 219 | * do carrier detect and the dtr_rts method if it supports software |
36c621d8 AC |
220 | * management of these lines. Note that the dtr/rts raise is done each |
221 | * iteration as a hangup may have previously dropped them while we wait. | |
222 | */ | |
d774a56d | 223 | |
36c621d8 AC |
224 | int tty_port_block_til_ready(struct tty_port *port, |
225 | struct tty_struct *tty, struct file *filp) | |
226 | { | |
227 | int do_clocal = 0, retval; | |
228 | unsigned long flags; | |
6af9a43d | 229 | DEFINE_WAIT(wait); |
36c621d8 AC |
230 | int cd; |
231 | ||
232 | /* block if port is in the process of being closed */ | |
233 | if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) { | |
5fc5b42a JS |
234 | wait_event_interruptible(port->close_wait, |
235 | !(port->flags & ASYNC_CLOSING)); | |
36c621d8 AC |
236 | if (port->flags & ASYNC_HUP_NOTIFY) |
237 | return -EAGAIN; | |
238 | else | |
239 | return -ERESTARTSYS; | |
240 | } | |
241 | ||
242 | /* if non-blocking mode is set we can pass directly to open unless | |
243 | the port has just hung up or is in another error state */ | |
8627b96d AC |
244 | if (tty->flags & (1 << TTY_IO_ERROR)) { |
245 | port->flags |= ASYNC_NORMAL_ACTIVE; | |
246 | return 0; | |
247 | } | |
248 | if (filp->f_flags & O_NONBLOCK) { | |
4175f3e3 AC |
249 | /* Indicate we are open */ |
250 | if (tty->termios->c_cflag & CBAUD) | |
251 | tty_port_raise_dtr_rts(port); | |
36c621d8 AC |
252 | port->flags |= ASYNC_NORMAL_ACTIVE; |
253 | return 0; | |
254 | } | |
255 | ||
256 | if (C_CLOCAL(tty)) | |
257 | do_clocal = 1; | |
258 | ||
259 | /* Block waiting until we can proceed. We may need to wait for the | |
260 | carrier, but we must also wait for any close that is in progress | |
261 | before the next open may complete */ | |
262 | ||
263 | retval = 0; | |
36c621d8 AC |
264 | |
265 | /* The port lock protects the port counts */ | |
266 | spin_lock_irqsave(&port->lock, flags); | |
267 | if (!tty_hung_up_p(filp)) | |
268 | port->count--; | |
269 | port->blocked_open++; | |
270 | spin_unlock_irqrestore(&port->lock, flags); | |
271 | ||
272 | while (1) { | |
273 | /* Indicate we are open */ | |
7834909f AC |
274 | if (tty->termios->c_cflag & CBAUD) |
275 | tty_port_raise_dtr_rts(port); | |
36c621d8 | 276 | |
3e3b5c08 | 277 | prepare_to_wait(&port->open_wait, &wait, TASK_INTERRUPTIBLE); |
d774a56d AC |
278 | /* Check for a hangup or uninitialised port. |
279 | Return accordingly */ | |
36c621d8 AC |
280 | if (tty_hung_up_p(filp) || !(port->flags & ASYNC_INITIALIZED)) { |
281 | if (port->flags & ASYNC_HUP_NOTIFY) | |
282 | retval = -EAGAIN; | |
283 | else | |
284 | retval = -ERESTARTSYS; | |
285 | break; | |
286 | } | |
287 | /* Probe the carrier. For devices with no carrier detect this | |
288 | will always return true */ | |
289 | cd = tty_port_carrier_raised(port); | |
290 | if (!(port->flags & ASYNC_CLOSING) && | |
291 | (do_clocal || cd)) | |
292 | break; | |
293 | if (signal_pending(current)) { | |
294 | retval = -ERESTARTSYS; | |
295 | break; | |
296 | } | |
297 | schedule(); | |
298 | } | |
3e3b5c08 | 299 | finish_wait(&port->open_wait, &wait); |
36c621d8 AC |
300 | |
301 | /* Update counts. A parallel hangup will have set count to zero and | |
302 | we must not mess that up further */ | |
303 | spin_lock_irqsave(&port->lock, flags); | |
304 | if (!tty_hung_up_p(filp)) | |
305 | port->count++; | |
306 | port->blocked_open--; | |
307 | if (retval == 0) | |
308 | port->flags |= ASYNC_NORMAL_ACTIVE; | |
309 | spin_unlock_irqrestore(&port->lock, flags); | |
ecc2e05e | 310 | return retval; |
36c621d8 AC |
311 | } |
312 | EXPORT_SYMBOL(tty_port_block_til_ready); | |
313 | ||
d774a56d AC |
314 | int tty_port_close_start(struct tty_port *port, |
315 | struct tty_struct *tty, struct file *filp) | |
a6614999 AC |
316 | { |
317 | unsigned long flags; | |
318 | ||
319 | spin_lock_irqsave(&port->lock, flags); | |
320 | if (tty_hung_up_p(filp)) { | |
321 | spin_unlock_irqrestore(&port->lock, flags); | |
322 | return 0; | |
323 | } | |
324 | ||
d774a56d | 325 | if (tty->count == 1 && port->count != 1) { |
a6614999 AC |
326 | printk(KERN_WARNING |
327 | "tty_port_close_start: tty->count = 1 port count = %d.\n", | |
328 | port->count); | |
329 | port->count = 1; | |
330 | } | |
331 | if (--port->count < 0) { | |
332 | printk(KERN_WARNING "tty_port_close_start: count = %d\n", | |
333 | port->count); | |
334 | port->count = 0; | |
335 | } | |
336 | ||
337 | if (port->count) { | |
338 | spin_unlock_irqrestore(&port->lock, flags); | |
7ca0ff9a AC |
339 | if (port->ops->drop) |
340 | port->ops->drop(port); | |
a6614999 AC |
341 | return 0; |
342 | } | |
1f5c13fa | 343 | set_bit(ASYNCB_CLOSING, &port->flags); |
a6614999 AC |
344 | tty->closing = 1; |
345 | spin_unlock_irqrestore(&port->lock, flags); | |
fba85e01 AC |
346 | /* Don't block on a stalled port, just pull the chain */ |
347 | if (tty->flow_stopped) | |
348 | tty_driver_flush_buffer(tty); | |
7ca0ff9a | 349 | if (test_bit(ASYNCB_INITIALIZED, &port->flags) && |
6ed1dbae | 350 | port->closing_wait != ASYNC_CLOSING_WAIT_NONE) |
a6614999 | 351 | tty_wait_until_sent(tty, port->closing_wait); |
1ec739be AC |
352 | if (port->drain_delay) { |
353 | unsigned int bps = tty_get_baud_rate(tty); | |
354 | long timeout; | |
355 | ||
356 | if (bps > 1200) | |
d774a56d AC |
357 | timeout = max_t(long, |
358 | (HZ * 10 * port->drain_delay) / bps, HZ / 10); | |
1ec739be AC |
359 | else |
360 | timeout = 2 * HZ; | |
361 | schedule_timeout_interruptible(timeout); | |
362 | } | |
e707c35c AC |
363 | /* Flush the ldisc buffering */ |
364 | tty_ldisc_flush(tty); | |
365 | ||
366 | /* Drop DTR/RTS if HUPCL is set. This causes any attached modem to | |
367 | hang up the line */ | |
368 | if (tty->termios->c_cflag & HUPCL) | |
369 | tty_port_lower_dtr_rts(port); | |
370 | ||
7ca0ff9a AC |
371 | /* Don't call port->drop for the last reference. Callers will want |
372 | to drop the last active reference in ->shutdown() or the tty | |
373 | shutdown path */ | |
a6614999 AC |
374 | return 1; |
375 | } | |
376 | EXPORT_SYMBOL(tty_port_close_start); | |
377 | ||
378 | void tty_port_close_end(struct tty_port *port, struct tty_struct *tty) | |
379 | { | |
380 | unsigned long flags; | |
381 | ||
a6614999 AC |
382 | spin_lock_irqsave(&port->lock, flags); |
383 | tty->closing = 0; | |
384 | ||
385 | if (port->blocked_open) { | |
386 | spin_unlock_irqrestore(&port->lock, flags); | |
387 | if (port->close_delay) { | |
388 | msleep_interruptible( | |
389 | jiffies_to_msecs(port->close_delay)); | |
390 | } | |
391 | spin_lock_irqsave(&port->lock, flags); | |
392 | wake_up_interruptible(&port->open_wait); | |
393 | } | |
394 | port->flags &= ~(ASYNC_NORMAL_ACTIVE | ASYNC_CLOSING); | |
395 | wake_up_interruptible(&port->close_wait); | |
396 | spin_unlock_irqrestore(&port->lock, flags); | |
397 | } | |
398 | EXPORT_SYMBOL(tty_port_close_end); | |
7ca0ff9a AC |
399 | |
400 | void tty_port_close(struct tty_port *port, struct tty_struct *tty, | |
401 | struct file *filp) | |
402 | { | |
403 | if (tty_port_close_start(port, tty, filp) == 0) | |
404 | return; | |
405 | tty_port_shutdown(port); | |
d74e8286 | 406 | set_bit(TTY_IO_ERROR, &tty->flags); |
7ca0ff9a AC |
407 | tty_port_close_end(port, tty); |
408 | tty_port_tty_set(port, NULL); | |
409 | } | |
410 | EXPORT_SYMBOL(tty_port_close); | |
64bc3979 AC |
411 | |
412 | int tty_port_open(struct tty_port *port, struct tty_struct *tty, | |
d774a56d | 413 | struct file *filp) |
64bc3979 AC |
414 | { |
415 | spin_lock_irq(&port->lock); | |
416 | if (!tty_hung_up_p(filp)) | |
417 | ++port->count; | |
418 | spin_unlock_irq(&port->lock); | |
419 | tty_port_tty_set(port, tty); | |
420 | ||
421 | /* | |
422 | * Do the device-specific open only if the hardware isn't | |
423 | * already initialized. Serialize open and shutdown using the | |
424 | * port mutex. | |
425 | */ | |
426 | ||
427 | mutex_lock(&port->mutex); | |
428 | ||
429 | if (!test_bit(ASYNCB_INITIALIZED, &port->flags)) { | |
a9a37ec3 | 430 | clear_bit(TTY_IO_ERROR, &tty->flags); |
64bc3979 AC |
431 | if (port->ops->activate) { |
432 | int retval = port->ops->activate(port, tty); | |
433 | if (retval) { | |
d774a56d AC |
434 | mutex_unlock(&port->mutex); |
435 | return retval; | |
436 | } | |
437 | } | |
64bc3979 AC |
438 | set_bit(ASYNCB_INITIALIZED, &port->flags); |
439 | } | |
440 | mutex_unlock(&port->mutex); | |
441 | return tty_port_block_til_ready(port, tty, filp); | |
442 | } | |
443 | ||
444 | EXPORT_SYMBOL(tty_port_open); |