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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-2.0 |
8200e38a JH |
2 | /* |
3 | * dashtty.c - tty driver for Dash channels interface. | |
4 | * | |
5 | * Copyright (C) 2007,2008,2012 Imagination Technologies | |
8200e38a JH |
6 | */ |
7 | ||
8 | #include <linux/atomic.h> | |
9 | #include <linux/completion.h> | |
10 | #include <linux/console.h> | |
11 | #include <linux/delay.h> | |
12 | #include <linux/export.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/kthread.h> | |
c3f43eec | 16 | #include <linux/moduleparam.h> |
8200e38a JH |
17 | #include <linux/mutex.h> |
18 | #include <linux/sched.h> | |
19 | #include <linux/serial.h> | |
20 | #include <linux/slab.h> | |
21 | #include <linux/spinlock.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/timer.h> | |
24 | #include <linux/tty.h> | |
25 | #include <linux/tty_driver.h> | |
26 | #include <linux/tty_flip.h> | |
27 | #include <linux/uaccess.h> | |
28 | ||
29 | #include <asm/da.h> | |
30 | ||
31 | /* Channel error codes */ | |
32 | #define CONAOK 0 | |
33 | #define CONERR 1 | |
34 | #define CONBAD 2 | |
35 | #define CONPRM 3 | |
36 | #define CONADR 4 | |
37 | #define CONCNT 5 | |
38 | #define CONCBF 6 | |
39 | #define CONCBE 7 | |
40 | #define CONBSY 8 | |
41 | ||
42 | /* Default channel for the console */ | |
43 | #define CONSOLE_CHANNEL 1 | |
44 | ||
45 | #define NUM_TTY_CHANNELS 6 | |
46 | ||
47 | /* Auto allocate */ | |
48 | #define DA_TTY_MAJOR 0 | |
49 | ||
50 | /* A speedy poll rate helps the userland debug process connection response. | |
51 | * But, if you set it too high then no other userland processes get much | |
52 | * of a look in. | |
53 | */ | |
54 | #define DA_TTY_POLL (HZ / 50) | |
55 | ||
56 | /* | |
57 | * A short put delay improves latency but has a high throughput overhead | |
58 | */ | |
59 | #define DA_TTY_PUT_DELAY (HZ / 100) | |
60 | ||
61 | static atomic_t num_channels_need_poll = ATOMIC_INIT(0); | |
62 | ||
63 | static struct timer_list poll_timer; | |
64 | ||
65 | static struct tty_driver *channel_driver; | |
66 | ||
67 | static struct timer_list put_timer; | |
68 | static struct task_struct *dashtty_thread; | |
69 | ||
c3f43eec JH |
70 | /* |
71 | * The console_poll parameter determines whether the console channel should be | |
72 | * polled for input. | |
73 | * By default the console channel isn't polled at all, in order to avoid the | |
74 | * overhead, but that means it isn't possible to have a login on /dev/console. | |
75 | */ | |
76 | static bool console_poll; | |
77 | module_param(console_poll, bool, S_IRUGO); | |
78 | ||
8200e38a JH |
79 | #define RX_BUF_SIZE 1024 |
80 | ||
81 | enum { | |
82 | INCHR = 1, | |
83 | OUTCHR, | |
84 | RDBUF, | |
85 | WRBUF, | |
86 | RDSTAT | |
87 | }; | |
88 | ||
89 | /** | |
90 | * struct dashtty_port - Wrapper struct for dashtty tty_port. | |
91 | * @port: TTY port data | |
92 | * @rx_lock: Lock for rx_buf. | |
93 | * This protects between the poll timer and user context. | |
94 | * It's also held during read SWITCH operations. | |
95 | * @rx_buf: Read buffer | |
96 | * @xmit_lock: Lock for xmit_*, and port.xmit_buf. | |
97 | * This protects between user context and kernel thread. | |
98 | * It's also held during write SWITCH operations. | |
99 | * @xmit_cnt: Size of xmit buffer contents | |
100 | * @xmit_head: Head of xmit buffer where data is written | |
101 | * @xmit_tail: Tail of xmit buffer where data is read | |
102 | * @xmit_empty: Completion for xmit buffer being empty | |
103 | */ | |
104 | struct dashtty_port { | |
105 | struct tty_port port; | |
106 | spinlock_t rx_lock; | |
107 | void *rx_buf; | |
108 | struct mutex xmit_lock; | |
109 | unsigned int xmit_cnt; | |
110 | unsigned int xmit_head; | |
111 | unsigned int xmit_tail; | |
112 | struct completion xmit_empty; | |
113 | }; | |
114 | ||
115 | static struct dashtty_port dashtty_ports[NUM_TTY_CHANNELS]; | |
116 | ||
117 | static atomic_t dashtty_xmit_cnt = ATOMIC_INIT(0); | |
118 | static wait_queue_head_t dashtty_waitqueue; | |
119 | ||
120 | /* | |
121 | * Low-level DA channel access routines | |
122 | */ | |
123 | static int chancall(int in_bios_function, int in_channel, | |
124 | int in_arg2, void *in_arg3, | |
125 | void *in_arg4) | |
126 | { | |
127 | register int bios_function asm("D1Ar1") = in_bios_function; | |
128 | register int channel asm("D0Ar2") = in_channel; | |
129 | register int arg2 asm("D1Ar3") = in_arg2; | |
130 | register void *arg3 asm("D0Ar4") = in_arg3; | |
131 | register void *arg4 asm("D1Ar5") = in_arg4; | |
132 | register int bios_call asm("D0Ar6") = 3; | |
133 | register int result asm("D0Re0"); | |
134 | ||
135 | asm volatile ( | |
136 | "MSETL [A0StP++], %6,%4,%2\n\t" | |
137 | "ADD A0StP, A0StP, #8\n\t" | |
138 | "SWITCH #0x0C30208\n\t" | |
139 | "GETD %0, [A0StP+#-8]\n\t" | |
140 | "SUB A0StP, A0StP, #(4*6)+8\n\t" | |
141 | : "=d" (result) /* outs */ | |
142 | : "d" (bios_function), | |
143 | "d" (channel), | |
144 | "d" (arg2), | |
145 | "d" (arg3), | |
146 | "d" (arg4), | |
147 | "d" (bios_call) /* ins */ | |
148 | : "memory"); | |
149 | ||
150 | return result; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Attempts to fetch count bytes from channel and returns actual count. | |
155 | */ | |
a8cd9858 | 156 | static int fetch_data(unsigned int channel) |
8200e38a | 157 | { |
8200e38a JH |
158 | struct dashtty_port *dport = &dashtty_ports[channel]; |
159 | int received = 0; | |
160 | ||
161 | spin_lock_bh(&dport->rx_lock); | |
162 | /* check the port isn't being shut down */ | |
163 | if (!dport->rx_buf) | |
164 | goto unlock; | |
165 | if (chancall(RDBUF, channel, RX_BUF_SIZE, | |
166 | (void *)dport->rx_buf, &received) == CONAOK) { | |
167 | if (received) { | |
168 | int space; | |
169 | unsigned char *cbuf; | |
170 | ||
171 | space = tty_prepare_flip_string(&dport->port, &cbuf, | |
172 | received); | |
173 | ||
174 | if (space <= 0) | |
175 | goto unlock; | |
176 | ||
177 | memcpy(cbuf, dport->rx_buf, space); | |
178 | tty_flip_buffer_push(&dport->port); | |
179 | } | |
180 | } | |
181 | unlock: | |
182 | spin_unlock_bh(&dport->rx_lock); | |
183 | ||
184 | return received; | |
185 | } | |
186 | ||
187 | /** | |
a8cd9858 JH |
188 | * find_channel_to_poll() - Returns number of the next channel to poll. |
189 | * Returns: The number of the next channel to poll, or -1 if none need | |
190 | * polling. | |
8200e38a | 191 | */ |
a8cd9858 | 192 | static int find_channel_to_poll(void) |
8200e38a JH |
193 | { |
194 | static int last_polled_channel; | |
195 | int last = last_polled_channel; | |
196 | int chan; | |
a8cd9858 | 197 | struct dashtty_port *dport; |
8200e38a JH |
198 | |
199 | for (chan = last + 1; ; ++chan) { | |
200 | if (chan >= NUM_TTY_CHANNELS) | |
201 | chan = 0; | |
202 | ||
a8cd9858 JH |
203 | dport = &dashtty_ports[chan]; |
204 | if (dport->rx_buf) { | |
8200e38a | 205 | last_polled_channel = chan; |
a8cd9858 | 206 | return chan; |
8200e38a JH |
207 | } |
208 | ||
209 | if (chan == last) | |
210 | break; | |
211 | } | |
a8cd9858 | 212 | return -1; |
8200e38a JH |
213 | } |
214 | ||
215 | /** | |
216 | * put_channel_data() - Write out a block of channel data. | |
217 | * @chan: DA channel number. | |
218 | * | |
219 | * Write a single block of data out to the debug adapter. If the circular buffer | |
220 | * is wrapped then only the first block is written. | |
221 | * | |
222 | * Returns: 1 if the remote buffer was too full to accept data. | |
223 | * 0 otherwise. | |
224 | */ | |
225 | static int put_channel_data(unsigned int chan) | |
226 | { | |
227 | struct dashtty_port *dport; | |
228 | struct tty_struct *tty; | |
229 | int number_written; | |
230 | unsigned int count = 0; | |
231 | ||
232 | dport = &dashtty_ports[chan]; | |
233 | mutex_lock(&dport->xmit_lock); | |
234 | if (dport->xmit_cnt) { | |
235 | count = min((unsigned int)(SERIAL_XMIT_SIZE - dport->xmit_tail), | |
236 | dport->xmit_cnt); | |
237 | chancall(WRBUF, chan, count, | |
238 | dport->port.xmit_buf + dport->xmit_tail, | |
239 | &number_written); | |
240 | dport->xmit_cnt -= number_written; | |
241 | if (!dport->xmit_cnt) { | |
242 | /* reset pointers to avoid wraps */ | |
243 | dport->xmit_head = 0; | |
244 | dport->xmit_tail = 0; | |
245 | complete(&dport->xmit_empty); | |
246 | } else { | |
247 | dport->xmit_tail += number_written; | |
248 | if (dport->xmit_tail >= SERIAL_XMIT_SIZE) | |
249 | dport->xmit_tail -= SERIAL_XMIT_SIZE; | |
250 | } | |
251 | atomic_sub(number_written, &dashtty_xmit_cnt); | |
252 | } | |
253 | mutex_unlock(&dport->xmit_lock); | |
254 | ||
255 | /* if we've made more data available, wake up tty */ | |
256 | if (count && number_written) { | |
257 | tty = tty_port_tty_get(&dport->port); | |
258 | if (tty) { | |
259 | tty_wakeup(tty); | |
260 | tty_kref_put(tty); | |
261 | } | |
262 | } | |
263 | ||
264 | /* did the write fail? */ | |
265 | return count && !number_written; | |
266 | } | |
267 | ||
268 | /** | |
269 | * put_data() - Kernel thread to write out blocks of channel data to DA. | |
270 | * @arg: Unused. | |
271 | * | |
272 | * This kernel thread runs while @dashtty_xmit_cnt != 0, and loops over the | |
273 | * channels to write out any buffered data. If any of the channels stall due to | |
274 | * the remote buffer being full, a hold off happens to allow the debugger to | |
275 | * drain the buffer. | |
276 | */ | |
277 | static int put_data(void *arg) | |
278 | { | |
279 | unsigned int chan, stall; | |
280 | ||
281 | __set_current_state(TASK_RUNNING); | |
282 | while (!kthread_should_stop()) { | |
283 | /* | |
284 | * For each channel see if there's anything to transmit in the | |
285 | * port's xmit_buf. | |
286 | */ | |
287 | stall = 0; | |
288 | for (chan = 0; chan < NUM_TTY_CHANNELS; ++chan) | |
289 | stall += put_channel_data(chan); | |
290 | ||
291 | /* | |
292 | * If some of the buffers are full, hold off for a short while | |
293 | * to allow them to empty. | |
294 | */ | |
295 | if (stall) | |
296 | msleep(25); | |
297 | ||
298 | wait_event_interruptible(dashtty_waitqueue, | |
299 | atomic_read(&dashtty_xmit_cnt)); | |
300 | } | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | /* | |
306 | * This gets called every DA_TTY_POLL and polls the channels for data | |
307 | */ | |
54ff200e | 308 | static void dashtty_timer(struct timer_list *poll_timer) |
8200e38a | 309 | { |
a8cd9858 | 310 | int channel; |
8200e38a JH |
311 | |
312 | /* If there are no ports open do nothing and don't poll again. */ | |
313 | if (!atomic_read(&num_channels_need_poll)) | |
314 | return; | |
315 | ||
a8cd9858 | 316 | channel = find_channel_to_poll(); |
8200e38a JH |
317 | |
318 | /* Did we find a channel to poll? */ | |
a8cd9858 JH |
319 | if (channel >= 0) |
320 | fetch_data(channel); | |
8200e38a | 321 | |
54ff200e | 322 | mod_timer(poll_timer, jiffies + DA_TTY_POLL); |
8200e38a JH |
323 | } |
324 | ||
325 | static void add_poll_timer(struct timer_list *poll_timer) | |
326 | { | |
54ff200e | 327 | timer_setup(poll_timer, dashtty_timer, TIMER_PINNED); |
8200e38a JH |
328 | poll_timer->expires = jiffies + DA_TTY_POLL; |
329 | ||
330 | /* | |
331 | * Always attach the timer to the boot CPU. The DA channels are per-CPU | |
332 | * so all polling should be from a single CPU. | |
333 | */ | |
334 | add_timer_on(poll_timer, 0); | |
335 | } | |
336 | ||
337 | static int dashtty_port_activate(struct tty_port *port, struct tty_struct *tty) | |
338 | { | |
339 | struct dashtty_port *dport = container_of(port, struct dashtty_port, | |
340 | port); | |
341 | void *rx_buf; | |
342 | ||
343 | /* Allocate the buffer we use for writing data */ | |
344 | if (tty_port_alloc_xmit_buf(port) < 0) | |
345 | goto err; | |
346 | ||
347 | /* Allocate the buffer we use for reading data */ | |
348 | rx_buf = kzalloc(RX_BUF_SIZE, GFP_KERNEL); | |
349 | if (!rx_buf) | |
350 | goto err_free_xmit; | |
351 | ||
352 | spin_lock_bh(&dport->rx_lock); | |
353 | dport->rx_buf = rx_buf; | |
354 | spin_unlock_bh(&dport->rx_lock); | |
355 | ||
356 | /* | |
357 | * Don't add the poll timer if we're opening a console. This | |
358 | * avoids the overhead of polling the Dash but means it is not | |
359 | * possible to have a login on /dev/console. | |
360 | * | |
361 | */ | |
c3f43eec | 362 | if (console_poll || dport != &dashtty_ports[CONSOLE_CHANNEL]) |
8200e38a JH |
363 | if (atomic_inc_return(&num_channels_need_poll) == 1) |
364 | add_poll_timer(&poll_timer); | |
365 | ||
366 | return 0; | |
367 | err_free_xmit: | |
368 | tty_port_free_xmit_buf(port); | |
369 | err: | |
370 | return -ENOMEM; | |
371 | } | |
372 | ||
373 | static void dashtty_port_shutdown(struct tty_port *port) | |
374 | { | |
375 | struct dashtty_port *dport = container_of(port, struct dashtty_port, | |
376 | port); | |
377 | void *rx_buf; | |
378 | unsigned int count; | |
379 | ||
380 | /* stop reading */ | |
c3f43eec | 381 | if (console_poll || dport != &dashtty_ports[CONSOLE_CHANNEL]) |
8200e38a JH |
382 | if (atomic_dec_and_test(&num_channels_need_poll)) |
383 | del_timer_sync(&poll_timer); | |
384 | ||
385 | mutex_lock(&dport->xmit_lock); | |
386 | count = dport->xmit_cnt; | |
387 | mutex_unlock(&dport->xmit_lock); | |
388 | if (count) { | |
389 | /* | |
390 | * There's still data to write out, so wake and wait for the | |
391 | * writer thread to drain the buffer. | |
392 | */ | |
393 | del_timer(&put_timer); | |
394 | wake_up_interruptible(&dashtty_waitqueue); | |
395 | wait_for_completion(&dport->xmit_empty); | |
396 | } | |
397 | ||
398 | /* Null the read buffer (timer could still be running!) */ | |
399 | spin_lock_bh(&dport->rx_lock); | |
400 | rx_buf = dport->rx_buf; | |
401 | dport->rx_buf = NULL; | |
402 | spin_unlock_bh(&dport->rx_lock); | |
403 | /* Free the read buffer */ | |
404 | kfree(rx_buf); | |
405 | ||
406 | /* Free the write buffer */ | |
407 | tty_port_free_xmit_buf(port); | |
408 | } | |
409 | ||
410 | static const struct tty_port_operations dashtty_port_ops = { | |
411 | .activate = dashtty_port_activate, | |
412 | .shutdown = dashtty_port_shutdown, | |
413 | }; | |
414 | ||
415 | static int dashtty_install(struct tty_driver *driver, struct tty_struct *tty) | |
416 | { | |
417 | return tty_port_install(&dashtty_ports[tty->index].port, driver, tty); | |
418 | } | |
419 | ||
420 | static int dashtty_open(struct tty_struct *tty, struct file *filp) | |
421 | { | |
422 | return tty_port_open(tty->port, tty, filp); | |
423 | } | |
424 | ||
425 | static void dashtty_close(struct tty_struct *tty, struct file *filp) | |
426 | { | |
427 | return tty_port_close(tty->port, tty, filp); | |
428 | } | |
429 | ||
430 | static void dashtty_hangup(struct tty_struct *tty) | |
431 | { | |
432 | int channel; | |
433 | struct dashtty_port *dport; | |
434 | ||
435 | channel = tty->index; | |
436 | dport = &dashtty_ports[channel]; | |
437 | ||
438 | /* drop any data in the xmit buffer */ | |
439 | mutex_lock(&dport->xmit_lock); | |
440 | if (dport->xmit_cnt) { | |
441 | atomic_sub(dport->xmit_cnt, &dashtty_xmit_cnt); | |
442 | dport->xmit_cnt = 0; | |
443 | dport->xmit_head = 0; | |
444 | dport->xmit_tail = 0; | |
445 | complete(&dport->xmit_empty); | |
446 | } | |
447 | mutex_unlock(&dport->xmit_lock); | |
448 | ||
449 | tty_port_hangup(tty->port); | |
450 | } | |
451 | ||
452 | /** | |
453 | * dashtty_put_timer() - Delayed wake up of kernel thread. | |
454 | * @ignored: unused | |
455 | * | |
456 | * This timer function wakes up the kernel thread if any data exists in the | |
457 | * buffers. It is used to delay the expensive writeout until the writer has | |
458 | * stopped writing. | |
459 | */ | |
54ff200e | 460 | static void dashtty_put_timer(struct timer_list *unused) |
8200e38a JH |
461 | { |
462 | if (atomic_read(&dashtty_xmit_cnt)) | |
463 | wake_up_interruptible(&dashtty_waitqueue); | |
464 | } | |
465 | ||
466 | static int dashtty_write(struct tty_struct *tty, const unsigned char *buf, | |
467 | int total) | |
468 | { | |
469 | int channel, count, block; | |
470 | struct dashtty_port *dport; | |
471 | ||
472 | /* Determine the channel */ | |
473 | channel = tty->index; | |
474 | dport = &dashtty_ports[channel]; | |
475 | ||
476 | /* | |
477 | * Write to output buffer. | |
478 | * | |
479 | * The reason that we asynchronously write the buffer is because if we | |
480 | * were to write the buffer synchronously then because DA channels are | |
481 | * per-CPU the buffer would be written to the channel of whatever CPU | |
482 | * we're running on. | |
483 | * | |
484 | * What we actually want to happen is have all input and output done on | |
485 | * one CPU. | |
486 | */ | |
487 | mutex_lock(&dport->xmit_lock); | |
488 | /* work out how many bytes we can write to the xmit buffer */ | |
489 | total = min(total, (int)(SERIAL_XMIT_SIZE - dport->xmit_cnt)); | |
490 | atomic_add(total, &dashtty_xmit_cnt); | |
491 | dport->xmit_cnt += total; | |
492 | /* write the actual bytes (may need splitting if it wraps) */ | |
493 | for (count = total; count; count -= block) { | |
494 | block = min(count, (int)(SERIAL_XMIT_SIZE - dport->xmit_head)); | |
495 | memcpy(dport->port.xmit_buf + dport->xmit_head, buf, block); | |
496 | dport->xmit_head += block; | |
497 | if (dport->xmit_head >= SERIAL_XMIT_SIZE) | |
498 | dport->xmit_head -= SERIAL_XMIT_SIZE; | |
499 | buf += block; | |
500 | } | |
501 | count = dport->xmit_cnt; | |
502 | /* xmit buffer no longer empty? */ | |
503 | if (count) | |
16735d02 | 504 | reinit_completion(&dport->xmit_empty); |
8200e38a JH |
505 | mutex_unlock(&dport->xmit_lock); |
506 | ||
507 | if (total) { | |
508 | /* | |
509 | * If the buffer is full, wake up the kthread, otherwise allow | |
510 | * some more time for the buffer to fill up a bit before waking | |
511 | * it. | |
512 | */ | |
513 | if (count == SERIAL_XMIT_SIZE) { | |
514 | del_timer(&put_timer); | |
515 | wake_up_interruptible(&dashtty_waitqueue); | |
516 | } else { | |
517 | mod_timer(&put_timer, jiffies + DA_TTY_PUT_DELAY); | |
518 | } | |
519 | } | |
520 | return total; | |
521 | } | |
522 | ||
523 | static int dashtty_write_room(struct tty_struct *tty) | |
524 | { | |
525 | struct dashtty_port *dport; | |
526 | int channel; | |
527 | int room; | |
528 | ||
529 | channel = tty->index; | |
530 | dport = &dashtty_ports[channel]; | |
531 | ||
532 | /* report the space in the xmit buffer */ | |
533 | mutex_lock(&dport->xmit_lock); | |
534 | room = SERIAL_XMIT_SIZE - dport->xmit_cnt; | |
535 | mutex_unlock(&dport->xmit_lock); | |
536 | ||
537 | return room; | |
538 | } | |
539 | ||
540 | static int dashtty_chars_in_buffer(struct tty_struct *tty) | |
541 | { | |
542 | struct dashtty_port *dport; | |
543 | int channel; | |
544 | int chars; | |
545 | ||
546 | channel = tty->index; | |
547 | dport = &dashtty_ports[channel]; | |
548 | ||
549 | /* report the number of bytes in the xmit buffer */ | |
550 | mutex_lock(&dport->xmit_lock); | |
551 | chars = dport->xmit_cnt; | |
552 | mutex_unlock(&dport->xmit_lock); | |
553 | ||
554 | return chars; | |
555 | } | |
556 | ||
557 | static const struct tty_operations dashtty_ops = { | |
558 | .install = dashtty_install, | |
559 | .open = dashtty_open, | |
560 | .close = dashtty_close, | |
561 | .hangup = dashtty_hangup, | |
562 | .write = dashtty_write, | |
563 | .write_room = dashtty_write_room, | |
564 | .chars_in_buffer = dashtty_chars_in_buffer, | |
565 | }; | |
566 | ||
567 | static int __init dashtty_init(void) | |
568 | { | |
569 | int ret; | |
570 | int nport; | |
571 | struct dashtty_port *dport; | |
572 | ||
573 | if (!metag_da_enabled()) | |
574 | return -ENODEV; | |
575 | ||
576 | channel_driver = tty_alloc_driver(NUM_TTY_CHANNELS, | |
577 | TTY_DRIVER_REAL_RAW); | |
578 | if (IS_ERR(channel_driver)) | |
579 | return PTR_ERR(channel_driver); | |
580 | ||
581 | channel_driver->driver_name = "metag_da"; | |
582 | channel_driver->name = "ttyDA"; | |
583 | channel_driver->major = DA_TTY_MAJOR; | |
584 | channel_driver->minor_start = 0; | |
585 | channel_driver->type = TTY_DRIVER_TYPE_SERIAL; | |
586 | channel_driver->subtype = SERIAL_TYPE_NORMAL; | |
587 | channel_driver->init_termios = tty_std_termios; | |
588 | channel_driver->init_termios.c_cflag |= CLOCAL; | |
589 | ||
590 | tty_set_operations(channel_driver, &dashtty_ops); | |
591 | for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) { | |
592 | dport = &dashtty_ports[nport]; | |
593 | tty_port_init(&dport->port); | |
594 | dport->port.ops = &dashtty_port_ops; | |
595 | spin_lock_init(&dport->rx_lock); | |
596 | mutex_init(&dport->xmit_lock); | |
597 | /* the xmit buffer starts empty, i.e. completely written */ | |
598 | init_completion(&dport->xmit_empty); | |
599 | complete(&dport->xmit_empty); | |
600 | } | |
601 | ||
54ff200e | 602 | timer_setup(&put_timer, dashtty_put_timer, 0); |
8200e38a JH |
603 | |
604 | init_waitqueue_head(&dashtty_waitqueue); | |
605 | dashtty_thread = kthread_create(put_data, NULL, "ttyDA"); | |
606 | if (IS_ERR(dashtty_thread)) { | |
607 | pr_err("Couldn't create dashtty thread\n"); | |
608 | ret = PTR_ERR(dashtty_thread); | |
609 | goto err_destroy_ports; | |
610 | } | |
611 | /* | |
612 | * Bind the writer thread to the boot CPU so it can't migrate. | |
613 | * DA channels are per-CPU and we want all channel I/O to be on a single | |
614 | * predictable CPU. | |
615 | */ | |
616 | kthread_bind(dashtty_thread, 0); | |
617 | wake_up_process(dashtty_thread); | |
618 | ||
619 | ret = tty_register_driver(channel_driver); | |
620 | ||
621 | if (ret < 0) { | |
622 | pr_err("Couldn't install dashtty driver: err %d\n", | |
623 | ret); | |
624 | goto err_stop_kthread; | |
625 | } | |
626 | ||
627 | return 0; | |
628 | ||
629 | err_stop_kthread: | |
630 | kthread_stop(dashtty_thread); | |
631 | err_destroy_ports: | |
632 | for (nport = 0; nport < NUM_TTY_CHANNELS; nport++) { | |
633 | dport = &dashtty_ports[nport]; | |
634 | tty_port_destroy(&dport->port); | |
635 | } | |
636 | put_tty_driver(channel_driver); | |
637 | return ret; | |
638 | } | |
4d38e5c4 | 639 | device_initcall(dashtty_init); |
8200e38a JH |
640 | |
641 | #ifdef CONFIG_DA_CONSOLE | |
642 | ||
643 | static void dash_console_write(struct console *co, const char *s, | |
644 | unsigned int count) | |
645 | { | |
646 | int actually_written; | |
647 | ||
648 | chancall(WRBUF, CONSOLE_CHANNEL, count, (void *)s, &actually_written); | |
649 | } | |
650 | ||
651 | static struct tty_driver *dash_console_device(struct console *c, int *index) | |
652 | { | |
653 | *index = c->index; | |
654 | return channel_driver; | |
655 | } | |
656 | ||
657 | struct console dash_console = { | |
658 | .name = "ttyDA", | |
659 | .write = dash_console_write, | |
660 | .device = dash_console_device, | |
661 | .flags = CON_PRINTBUFFER, | |
662 | .index = 1, | |
663 | }; | |
664 | ||
665 | #endif |