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Commit | Line | Data |
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8200e38a JH |
1 | /* |
2 | * dashtty.c - tty driver for Dash channels interface. | |
3 | * | |
4 | * Copyright (C) 2007,2008,2012 Imagination Technologies | |
5 | * | |
6 | * This file is subject to the terms and conditions of the GNU General Public | |
7 | * License. See the file COPYING in the main directory of this archive | |
8 | * for more details. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/atomic.h> | |
13 | #include <linux/completion.h> | |
14 | #include <linux/console.h> | |
15 | #include <linux/delay.h> | |
16 | #include <linux/export.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/kthread.h> | |
20 | #include <linux/mutex.h> | |
21 | #include <linux/sched.h> | |
22 | #include <linux/serial.h> | |
23 | #include <linux/slab.h> | |
24 | #include <linux/spinlock.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/timer.h> | |
27 | #include <linux/tty.h> | |
28 | #include <linux/tty_driver.h> | |
29 | #include <linux/tty_flip.h> | |
30 | #include <linux/uaccess.h> | |
31 | ||
32 | #include <asm/da.h> | |
33 | ||
34 | /* Channel error codes */ | |
35 | #define CONAOK 0 | |
36 | #define CONERR 1 | |
37 | #define CONBAD 2 | |
38 | #define CONPRM 3 | |
39 | #define CONADR 4 | |
40 | #define CONCNT 5 | |
41 | #define CONCBF 6 | |
42 | #define CONCBE 7 | |
43 | #define CONBSY 8 | |
44 | ||
45 | /* Default channel for the console */ | |
46 | #define CONSOLE_CHANNEL 1 | |
47 | ||
48 | #define NUM_TTY_CHANNELS 6 | |
49 | ||
50 | /* Auto allocate */ | |
51 | #define DA_TTY_MAJOR 0 | |
52 | ||
53 | /* A speedy poll rate helps the userland debug process connection response. | |
54 | * But, if you set it too high then no other userland processes get much | |
55 | * of a look in. | |
56 | */ | |
57 | #define DA_TTY_POLL (HZ / 50) | |
58 | ||
59 | /* | |
60 | * A short put delay improves latency but has a high throughput overhead | |
61 | */ | |
62 | #define DA_TTY_PUT_DELAY (HZ / 100) | |
63 | ||
64 | static atomic_t num_channels_need_poll = ATOMIC_INIT(0); | |
65 | ||
66 | static struct timer_list poll_timer; | |
67 | ||
68 | static struct tty_driver *channel_driver; | |
69 | ||
70 | static struct timer_list put_timer; | |
71 | static struct task_struct *dashtty_thread; | |
72 | ||
73 | #define RX_BUF_SIZE 1024 | |
74 | ||
75 | enum { | |
76 | INCHR = 1, | |
77 | OUTCHR, | |
78 | RDBUF, | |
79 | WRBUF, | |
80 | RDSTAT | |
81 | }; | |
82 | ||
83 | /** | |
84 | * struct dashtty_port - Wrapper struct for dashtty tty_port. | |
85 | * @port: TTY port data | |
86 | * @rx_lock: Lock for rx_buf. | |
87 | * This protects between the poll timer and user context. | |
88 | * It's also held during read SWITCH operations. | |
89 | * @rx_buf: Read buffer | |
90 | * @xmit_lock: Lock for xmit_*, and port.xmit_buf. | |
91 | * This protects between user context and kernel thread. | |
92 | * It's also held during write SWITCH operations. | |
93 | * @xmit_cnt: Size of xmit buffer contents | |
94 | * @xmit_head: Head of xmit buffer where data is written | |
95 | * @xmit_tail: Tail of xmit buffer where data is read | |
96 | * @xmit_empty: Completion for xmit buffer being empty | |
97 | */ | |
98 | struct dashtty_port { | |
99 | struct tty_port port; | |
100 | spinlock_t rx_lock; | |
101 | void *rx_buf; | |
102 | struct mutex xmit_lock; | |
103 | unsigned int xmit_cnt; | |
104 | unsigned int xmit_head; | |
105 | unsigned int xmit_tail; | |
106 | struct completion xmit_empty; | |
107 | }; | |
108 | ||
109 | static struct dashtty_port dashtty_ports[NUM_TTY_CHANNELS]; | |
110 | ||
111 | static atomic_t dashtty_xmit_cnt = ATOMIC_INIT(0); | |
112 | static wait_queue_head_t dashtty_waitqueue; | |
113 | ||
114 | /* | |
115 | * Low-level DA channel access routines | |
116 | */ | |
117 | static int chancall(int in_bios_function, int in_channel, | |
118 | int in_arg2, void *in_arg3, | |
119 | void *in_arg4) | |
120 | { | |
121 | register int bios_function asm("D1Ar1") = in_bios_function; | |
122 | register int channel asm("D0Ar2") = in_channel; | |
123 | register int arg2 asm("D1Ar3") = in_arg2; | |
124 | register void *arg3 asm("D0Ar4") = in_arg3; | |
125 | register void *arg4 asm("D1Ar5") = in_arg4; | |
126 | register int bios_call asm("D0Ar6") = 3; | |
127 | register int result asm("D0Re0"); | |
128 | ||
129 | asm volatile ( | |
130 | "MSETL [A0StP++], %6,%4,%2\n\t" | |
131 | "ADD A0StP, A0StP, #8\n\t" | |
132 | "SWITCH #0x0C30208\n\t" | |
133 | "GETD %0, [A0StP+#-8]\n\t" | |
134 | "SUB A0StP, A0StP, #(4*6)+8\n\t" | |
135 | : "=d" (result) /* outs */ | |
136 | : "d" (bios_function), | |
137 | "d" (channel), | |
138 | "d" (arg2), | |
139 | "d" (arg3), | |
140 | "d" (arg4), | |
141 | "d" (bios_call) /* ins */ | |
142 | : "memory"); | |
143 | ||
144 | return result; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Attempts to fetch count bytes from channel and returns actual count. | |
149 | */ | |
a8cd9858 | 150 | static int fetch_data(unsigned int channel) |
8200e38a | 151 | { |
8200e38a JH |
152 | struct dashtty_port *dport = &dashtty_ports[channel]; |
153 | int received = 0; | |
154 | ||
155 | spin_lock_bh(&dport->rx_lock); | |
156 | /* check the port isn't being shut down */ | |
157 | if (!dport->rx_buf) | |
158 | goto unlock; | |
159 | if (chancall(RDBUF, channel, RX_BUF_SIZE, | |
160 | (void *)dport->rx_buf, &received) == CONAOK) { | |
161 | if (received) { | |
162 | int space; | |
163 | unsigned char *cbuf; | |
164 | ||
165 | space = tty_prepare_flip_string(&dport->port, &cbuf, | |
166 | received); | |
167 | ||
168 | if (space <= 0) | |
169 | goto unlock; | |
170 | ||
171 | memcpy(cbuf, dport->rx_buf, space); | |
172 | tty_flip_buffer_push(&dport->port); | |
173 | } | |
174 | } | |
175 | unlock: | |
176 | spin_unlock_bh(&dport->rx_lock); | |
177 | ||
178 | return received; | |
179 | } | |
180 | ||
181 | /** | |
a8cd9858 JH |
182 | * find_channel_to_poll() - Returns number of the next channel to poll. |
183 | * Returns: The number of the next channel to poll, or -1 if none need | |
184 | * polling. | |
8200e38a | 185 | */ |
a8cd9858 | 186 | static int find_channel_to_poll(void) |
8200e38a JH |
187 | { |
188 | static int last_polled_channel; | |
189 | int last = last_polled_channel; | |
190 | int chan; | |
a8cd9858 | 191 | struct dashtty_port *dport; |
8200e38a JH |
192 | |
193 | for (chan = last + 1; ; ++chan) { | |
194 | if (chan >= NUM_TTY_CHANNELS) | |
195 | chan = 0; | |
196 | ||
a8cd9858 JH |
197 | dport = &dashtty_ports[chan]; |
198 | if (dport->rx_buf) { | |
8200e38a | 199 | last_polled_channel = chan; |
a8cd9858 | 200 | return chan; |
8200e38a JH |
201 | } |
202 | ||
203 | if (chan == last) | |
204 | break; | |
205 | } | |
a8cd9858 | 206 | return -1; |
8200e38a JH |
207 | } |
208 | ||
209 | /** | |
210 | * put_channel_data() - Write out a block of channel data. | |
211 | * @chan: DA channel number. | |
212 | * | |
213 | * Write a single block of data out to the debug adapter. If the circular buffer | |
214 | * is wrapped then only the first block is written. | |
215 | * | |
216 | * Returns: 1 if the remote buffer was too full to accept data. | |
217 | * 0 otherwise. | |
218 | */ | |
219 | static int put_channel_data(unsigned int chan) | |
220 | { | |
221 | struct dashtty_port *dport; | |
222 | struct tty_struct *tty; | |
223 | int number_written; | |
224 | unsigned int count = 0; | |
225 | ||
226 | dport = &dashtty_ports[chan]; | |
227 | mutex_lock(&dport->xmit_lock); | |
228 | if (dport->xmit_cnt) { | |
229 | count = min((unsigned int)(SERIAL_XMIT_SIZE - dport->xmit_tail), | |
230 | dport->xmit_cnt); | |
231 | chancall(WRBUF, chan, count, | |
232 | dport->port.xmit_buf + dport->xmit_tail, | |
233 | &number_written); | |
234 | dport->xmit_cnt -= number_written; | |
235 | if (!dport->xmit_cnt) { | |
236 | /* reset pointers to avoid wraps */ | |
237 | dport->xmit_head = 0; | |
238 | dport->xmit_tail = 0; | |
239 | complete(&dport->xmit_empty); | |
240 | } else { | |
241 | dport->xmit_tail += number_written; | |
242 | if (dport->xmit_tail >= SERIAL_XMIT_SIZE) | |
243 | dport->xmit_tail -= SERIAL_XMIT_SIZE; | |
244 | } | |
245 | atomic_sub(number_written, &dashtty_xmit_cnt); | |
246 | } | |
247 | mutex_unlock(&dport->xmit_lock); | |
248 | ||
249 | /* if we've made more data available, wake up tty */ | |
250 | if (count && number_written) { | |
251 | tty = tty_port_tty_get(&dport->port); | |
252 | if (tty) { | |
253 | tty_wakeup(tty); | |
254 | tty_kref_put(tty); | |
255 | } | |
256 | } | |
257 | ||
258 | /* did the write fail? */ | |
259 | return count && !number_written; | |
260 | } | |
261 | ||
262 | /** | |
263 | * put_data() - Kernel thread to write out blocks of channel data to DA. | |
264 | * @arg: Unused. | |
265 | * | |
266 | * This kernel thread runs while @dashtty_xmit_cnt != 0, and loops over the | |
267 | * channels to write out any buffered data. If any of the channels stall due to | |
268 | * the remote buffer being full, a hold off happens to allow the debugger to | |
269 | * drain the buffer. | |
270 | */ | |
271 | static int put_data(void *arg) | |
272 | { | |
273 | unsigned int chan, stall; | |
274 | ||
275 | __set_current_state(TASK_RUNNING); | |
276 | while (!kthread_should_stop()) { | |
277 | /* | |
278 | * For each channel see if there's anything to transmit in the | |
279 | * port's xmit_buf. | |
280 | */ | |
281 | stall = 0; | |
282 | for (chan = 0; chan < NUM_TTY_CHANNELS; ++chan) | |
283 | stall += put_channel_data(chan); | |
284 | ||
285 | /* | |
286 | * If some of the buffers are full, hold off for a short while | |
287 | * to allow them to empty. | |
288 | */ | |
289 | if (stall) | |
290 | msleep(25); | |
291 | ||
292 | wait_event_interruptible(dashtty_waitqueue, | |
293 | atomic_read(&dashtty_xmit_cnt)); | |
294 | } | |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | /* | |
300 | * This gets called every DA_TTY_POLL and polls the channels for data | |
301 | */ | |
302 | static void dashtty_timer(unsigned long ignored) | |
303 | { | |
a8cd9858 | 304 | int channel; |
8200e38a JH |
305 | |
306 | /* If there are no ports open do nothing and don't poll again. */ | |
307 | if (!atomic_read(&num_channels_need_poll)) | |
308 | return; | |
309 | ||
a8cd9858 | 310 | channel = find_channel_to_poll(); |
8200e38a JH |
311 | |
312 | /* Did we find a channel to poll? */ | |
a8cd9858 JH |
313 | if (channel >= 0) |
314 | fetch_data(channel); | |
8200e38a JH |
315 | |
316 | mod_timer_pinned(&poll_timer, jiffies + DA_TTY_POLL); | |
317 | } | |
318 | ||
319 | static void add_poll_timer(struct timer_list *poll_timer) | |
320 | { | |
321 | setup_timer(poll_timer, dashtty_timer, 0); | |
322 | poll_timer->expires = jiffies + DA_TTY_POLL; | |
323 | ||
324 | /* | |
325 | * Always attach the timer to the boot CPU. The DA channels are per-CPU | |
326 | * so all polling should be from a single CPU. | |
327 | */ | |
328 | add_timer_on(poll_timer, 0); | |
329 | } | |
330 | ||
331 | static int dashtty_port_activate(struct tty_port *port, struct tty_struct *tty) | |
332 | { | |
333 | struct dashtty_port *dport = container_of(port, struct dashtty_port, | |
334 | port); | |
335 | void *rx_buf; | |
336 | ||
337 | /* Allocate the buffer we use for writing data */ | |
338 | if (tty_port_alloc_xmit_buf(port) < 0) | |
339 | goto err; | |
340 | ||
341 | /* Allocate the buffer we use for reading data */ | |
342 | rx_buf = kzalloc(RX_BUF_SIZE, GFP_KERNEL); | |
343 | if (!rx_buf) | |
344 | goto err_free_xmit; | |
345 | ||
346 | spin_lock_bh(&dport->rx_lock); | |
347 | dport->rx_buf = rx_buf; | |
348 | spin_unlock_bh(&dport->rx_lock); | |
349 | ||
350 | /* | |
351 | * Don't add the poll timer if we're opening a console. This | |
352 | * avoids the overhead of polling the Dash but means it is not | |
353 | * possible to have a login on /dev/console. | |
354 | * | |
355 | */ | |
356 | if (dport != &dashtty_ports[CONSOLE_CHANNEL]) | |
357 | if (atomic_inc_return(&num_channels_need_poll) == 1) | |
358 | add_poll_timer(&poll_timer); | |
359 | ||
360 | return 0; | |
361 | err_free_xmit: | |
362 | tty_port_free_xmit_buf(port); | |
363 | err: | |
364 | return -ENOMEM; | |
365 | } | |
366 | ||
367 | static void dashtty_port_shutdown(struct tty_port *port) | |
368 | { | |
369 | struct dashtty_port *dport = container_of(port, struct dashtty_port, | |
370 | port); | |
371 | void *rx_buf; | |
372 | unsigned int count; | |
373 | ||
374 | /* stop reading */ | |
375 | if (dport != &dashtty_ports[CONSOLE_CHANNEL]) | |
376 | if (atomic_dec_and_test(&num_channels_need_poll)) | |
377 | del_timer_sync(&poll_timer); | |
378 | ||
379 | mutex_lock(&dport->xmit_lock); | |
380 | count = dport->xmit_cnt; | |
381 | mutex_unlock(&dport->xmit_lock); | |
382 | if (count) { | |
383 | /* | |
384 | * There's still data to write out, so wake and wait for the | |
385 | * writer thread to drain the buffer. | |
386 | */ | |
387 | del_timer(&put_timer); | |
388 | wake_up_interruptible(&dashtty_waitqueue); | |
389 | wait_for_completion(&dport->xmit_empty); | |
390 | } | |
391 | ||
392 | /* Null the read buffer (timer could still be running!) */ | |
393 | spin_lock_bh(&dport->rx_lock); | |
394 | rx_buf = dport->rx_buf; | |
395 | dport->rx_buf = NULL; | |
396 | spin_unlock_bh(&dport->rx_lock); | |
397 | /* Free the read buffer */ | |
398 | kfree(rx_buf); | |
399 | ||
400 | /* Free the write buffer */ | |
401 | tty_port_free_xmit_buf(port); | |
402 | } | |
403 | ||
404 | static const struct tty_port_operations dashtty_port_ops = { | |
405 | .activate = dashtty_port_activate, | |
406 | .shutdown = dashtty_port_shutdown, | |
407 | }; | |
408 | ||
409 | static int dashtty_install(struct tty_driver *driver, struct tty_struct *tty) | |
410 | { | |
411 | return tty_port_install(&dashtty_ports[tty->index].port, driver, tty); | |
412 | } | |
413 | ||
414 | static int dashtty_open(struct tty_struct *tty, struct file *filp) | |
415 | { | |
416 | return tty_port_open(tty->port, tty, filp); | |
417 | } | |
418 | ||
419 | static void dashtty_close(struct tty_struct *tty, struct file *filp) | |
420 | { | |
421 | return tty_port_close(tty->port, tty, filp); | |
422 | } | |
423 | ||
424 | static void dashtty_hangup(struct tty_struct *tty) | |
425 | { | |
426 | int channel; | |
427 | struct dashtty_port *dport; | |
428 | ||
429 | channel = tty->index; | |
430 | dport = &dashtty_ports[channel]; | |
431 | ||
432 | /* drop any data in the xmit buffer */ | |
433 | mutex_lock(&dport->xmit_lock); | |
434 | if (dport->xmit_cnt) { | |
435 | atomic_sub(dport->xmit_cnt, &dashtty_xmit_cnt); | |
436 | dport->xmit_cnt = 0; | |
437 | dport->xmit_head = 0; | |
438 | dport->xmit_tail = 0; | |
439 | complete(&dport->xmit_empty); | |
440 | } | |
441 | mutex_unlock(&dport->xmit_lock); | |
442 | ||
443 | tty_port_hangup(tty->port); | |
444 | } | |
445 | ||
446 | /** | |
447 | * dashtty_put_timer() - Delayed wake up of kernel thread. | |
448 | * @ignored: unused | |
449 | * | |
450 | * This timer function wakes up the kernel thread if any data exists in the | |
451 | * buffers. It is used to delay the expensive writeout until the writer has | |
452 | * stopped writing. | |
453 | */ | |
454 | static void dashtty_put_timer(unsigned long ignored) | |
455 | { | |
456 | if (atomic_read(&dashtty_xmit_cnt)) | |
457 | wake_up_interruptible(&dashtty_waitqueue); | |
458 | } | |
459 | ||
460 | static int dashtty_write(struct tty_struct *tty, const unsigned char *buf, | |
461 | int total) | |
462 | { | |
463 | int channel, count, block; | |
464 | struct dashtty_port *dport; | |
465 | ||
466 | /* Determine the channel */ | |
467 | channel = tty->index; | |
468 | dport = &dashtty_ports[channel]; | |
469 | ||
470 | /* | |
471 | * Write to output buffer. | |
472 | * | |
473 | * The reason that we asynchronously write the buffer is because if we | |
474 | * were to write the buffer synchronously then because DA channels are | |
475 | * per-CPU the buffer would be written to the channel of whatever CPU | |
476 | * we're running on. | |
477 | * | |
478 | * What we actually want to happen is have all input and output done on | |
479 | * one CPU. | |
480 | */ | |
481 | mutex_lock(&dport->xmit_lock); | |
482 | /* work out how many bytes we can write to the xmit buffer */ | |
483 | total = min(total, (int)(SERIAL_XMIT_SIZE - dport->xmit_cnt)); | |
484 | atomic_add(total, &dashtty_xmit_cnt); | |
485 | dport->xmit_cnt += total; | |
486 | /* write the actual bytes (may need splitting if it wraps) */ | |
487 | for (count = total; count; count -= block) { | |
488 | block = min(count, (int)(SERIAL_XMIT_SIZE - dport->xmit_head)); | |
489 | memcpy(dport->port.xmit_buf + dport->xmit_head, buf, block); | |
490 | dport->xmit_head += block; | |
491 | if (dport->xmit_head >= SERIAL_XMIT_SIZE) | |
492 | dport->xmit_head -= SERIAL_XMIT_SIZE; | |
493 | buf += block; | |
494 | } | |
495 | count = dport->xmit_cnt; | |
496 | /* xmit buffer no longer empty? */ | |
497 | if (count) | |
498 | INIT_COMPLETION(dport->xmit_empty); | |
499 | mutex_unlock(&dport->xmit_lock); | |
500 | ||
501 | if (total) { | |
502 | /* | |
503 | * If the buffer is full, wake up the kthread, otherwise allow | |
504 | * some more time for the buffer to fill up a bit before waking | |
505 | * it. | |
506 | */ | |
507 | if (count == SERIAL_XMIT_SIZE) { | |
508 | del_timer(&put_timer); | |
509 | wake_up_interruptible(&dashtty_waitqueue); | |
510 | } else { | |
511 | mod_timer(&put_timer, jiffies + DA_TTY_PUT_DELAY); | |
512 | } | |
513 | } | |
514 | return total; | |
515 | } | |
516 | ||
517 | static int dashtty_write_room(struct tty_struct *tty) | |
518 | { | |
519 | struct dashtty_port *dport; | |
520 | int channel; | |
521 | int room; | |
522 | ||
523 | channel = tty->index; | |
524 | dport = &dashtty_ports[channel]; | |
525 | ||
526 | /* report the space in the xmit buffer */ | |
527 | mutex_lock(&dport->xmit_lock); | |
528 | room = SERIAL_XMIT_SIZE - dport->xmit_cnt; | |
529 | mutex_unlock(&dport->xmit_lock); | |
530 | ||
531 | return room; | |
532 | } | |
533 | ||
534 | static int dashtty_chars_in_buffer(struct tty_struct *tty) | |
535 | { | |
536 | struct dashtty_port *dport; | |
537 | int channel; | |
538 | int chars; | |
539 | ||
540 | channel = tty->index; | |
541 | dport = &dashtty_ports[channel]; | |
542 | ||
543 | /* report the number of bytes in the xmit buffer */ | |
544 | mutex_lock(&dport->xmit_lock); | |
545 | chars = dport->xmit_cnt; | |
546 | mutex_unlock(&dport->xmit_lock); | |
547 | ||
548 | return chars; | |
549 | } | |
550 | ||
551 | static const struct tty_operations dashtty_ops = { | |
552 | .install = dashtty_install, | |
553 | .open = dashtty_open, | |
554 | .close = dashtty_close, | |
555 | .hangup = dashtty_hangup, | |
556 | .write = dashtty_write, | |
557 | .write_room = dashtty_write_room, | |
558 | .chars_in_buffer = dashtty_chars_in_buffer, | |
559 | }; | |
560 | ||
561 | static int __init dashtty_init(void) | |
562 | { | |
563 | int ret; | |
564 | int nport; | |
565 | struct dashtty_port *dport; | |
566 | ||
567 | if (!metag_da_enabled()) | |
568 | return -ENODEV; | |
569 | ||
570 | channel_driver = tty_alloc_driver(NUM_TTY_CHANNELS, | |
571 | TTY_DRIVER_REAL_RAW); | |
572 | if (IS_ERR(channel_driver)) | |
573 | return PTR_ERR(channel_driver); | |
574 | ||
575 | channel_driver->driver_name = "metag_da"; | |
576 | channel_driver->name = "ttyDA"; | |
577 | channel_driver->major = DA_TTY_MAJOR; | |
578 | channel_driver->minor_start = 0; | |
579 | channel_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
580 | channel_driver->subtype = SERIAL_TYPE_NORMAL; | |
581 | channel_driver->init_termios = tty_std_termios; | |
582 | channel_driver->init_termios.c_cflag |= CLOCAL; | |
583 | ||
584 | tty_set_operations(channel_driver, &dashtty_ops); | |
585 | for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) { | |
586 | dport = &dashtty_ports[nport]; | |
587 | tty_port_init(&dport->port); | |
588 | dport->port.ops = &dashtty_port_ops; | |
589 | spin_lock_init(&dport->rx_lock); | |
590 | mutex_init(&dport->xmit_lock); | |
591 | /* the xmit buffer starts empty, i.e. completely written */ | |
592 | init_completion(&dport->xmit_empty); | |
593 | complete(&dport->xmit_empty); | |
594 | } | |
595 | ||
596 | setup_timer(&put_timer, dashtty_put_timer, 0); | |
597 | ||
598 | init_waitqueue_head(&dashtty_waitqueue); | |
599 | dashtty_thread = kthread_create(put_data, NULL, "ttyDA"); | |
600 | if (IS_ERR(dashtty_thread)) { | |
601 | pr_err("Couldn't create dashtty thread\n"); | |
602 | ret = PTR_ERR(dashtty_thread); | |
603 | goto err_destroy_ports; | |
604 | } | |
605 | /* | |
606 | * Bind the writer thread to the boot CPU so it can't migrate. | |
607 | * DA channels are per-CPU and we want all channel I/O to be on a single | |
608 | * predictable CPU. | |
609 | */ | |
610 | kthread_bind(dashtty_thread, 0); | |
611 | wake_up_process(dashtty_thread); | |
612 | ||
613 | ret = tty_register_driver(channel_driver); | |
614 | ||
615 | if (ret < 0) { | |
616 | pr_err("Couldn't install dashtty driver: err %d\n", | |
617 | ret); | |
618 | goto err_stop_kthread; | |
619 | } | |
620 | ||
621 | return 0; | |
622 | ||
623 | err_stop_kthread: | |
624 | kthread_stop(dashtty_thread); | |
625 | err_destroy_ports: | |
626 | for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) { | |
627 | dport = &dashtty_ports[nport]; | |
628 | tty_port_destroy(&dport->port); | |
629 | } | |
630 | put_tty_driver(channel_driver); | |
631 | return ret; | |
632 | } | |
633 | ||
634 | static void dashtty_exit(void) | |
635 | { | |
636 | int nport; | |
637 | struct dashtty_port *dport; | |
638 | ||
639 | del_timer_sync(&put_timer); | |
640 | kthread_stop(dashtty_thread); | |
641 | del_timer_sync(&poll_timer); | |
642 | tty_unregister_driver(channel_driver); | |
643 | for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) { | |
644 | dport = &dashtty_ports[nport]; | |
645 | tty_port_destroy(&dport->port); | |
646 | } | |
647 | put_tty_driver(channel_driver); | |
648 | } | |
649 | ||
650 | module_init(dashtty_init); | |
651 | module_exit(dashtty_exit); | |
652 | ||
653 | #ifdef CONFIG_DA_CONSOLE | |
654 | ||
655 | static void dash_console_write(struct console *co, const char *s, | |
656 | unsigned int count) | |
657 | { | |
658 | int actually_written; | |
659 | ||
660 | chancall(WRBUF, CONSOLE_CHANNEL, count, (void *)s, &actually_written); | |
661 | } | |
662 | ||
663 | static struct tty_driver *dash_console_device(struct console *c, int *index) | |
664 | { | |
665 | *index = c->index; | |
666 | return channel_driver; | |
667 | } | |
668 | ||
669 | struct console dash_console = { | |
670 | .name = "ttyDA", | |
671 | .write = dash_console_write, | |
672 | .device = dash_console_device, | |
673 | .flags = CON_PRINTBUFFER, | |
674 | .index = 1, | |
675 | }; | |
676 | ||
677 | #endif |