1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * UART driver for the Greybus "generic" UART module.
4 *
5 * Copyright 2014 Google Inc.
6 * Copyright 2014 Linaro Ltd.
7 *
8 * Heavily based on drivers/usb/class/cdc-acm.c and
9 * drivers/usb/serial/usb-serial.c.
10 */
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/sched/signal.h>
17 #include <linux/wait.h>
18 #include <linux/slab.h>
19 #include <linux/uaccess.h>
20 #include <linux/mutex.h>
21 #include <linux/tty.h>
22 #include <linux/serial.h>
23 #include <linux/tty_driver.h>
24 #include <linux/tty_flip.h>
25 #include <linux/idr.h>
26 #include <linux/fs.h>
27 #include <linux/kdev_t.h>
28 #include <linux/kfifo.h>
29 #include <linux/workqueue.h>
30 #include <linux/completion.h>
31 #include <linux/greybus.h>
32
33 #include "gbphy.h"
34
35 #define GB_NUM_MINORS 16 /* 16 is more than enough */
36 #define GB_NAME "ttyGB"
37
38 #define GB_UART_WRITE_FIFO_SIZE PAGE_SIZE
39 #define GB_UART_WRITE_ROOM_MARGIN 1 /* leave some space in fifo */
40 #define GB_UART_FIRMWARE_CREDITS 4096
41 #define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC 10000
42
43 struct gb_tty {
44 struct gbphy_device *gbphy_dev;
45 struct tty_port port;
46 void *buffer;
47 size_t buffer_payload_max;
48 struct gb_connection *connection;
49 u16 cport_id;
50 unsigned int minor;
51 unsigned char clocal;
52 bool disconnected;
53 spinlock_t read_lock;
54 spinlock_t write_lock;
55 struct async_icount iocount;
56 struct async_icount oldcount;
57 wait_queue_head_t wioctl;
58 struct mutex mutex;
59 u8 ctrlin; /* input control lines */
60 u8 ctrlout; /* output control lines */
61 struct gb_uart_set_line_coding_request line_coding;
62 struct work_struct tx_work;
63 struct kfifo write_fifo;
64 bool close_pending;
65 unsigned int credits;
66 struct completion credits_complete;
67 };
68
69 static struct tty_driver *gb_tty_driver;
70 static DEFINE_IDR(tty_minors);
71 static DEFINE_MUTEX(table_lock);
72
gb_uart_receive_data_handler(struct gb_operation * op)73 static int gb_uart_receive_data_handler(struct gb_operation *op)
74 {
75 struct gb_connection *connection = op->connection;
76 struct gb_tty *gb_tty = gb_connection_get_data(connection);
77 struct tty_port *port = &gb_tty->port;
78 struct gb_message *request = op->request;
79 struct gb_uart_recv_data_request *receive_data;
80 u16 recv_data_size;
81 int count;
82 unsigned long tty_flags = TTY_NORMAL;
83
84 if (request->payload_size < sizeof(*receive_data)) {
85 dev_err(&gb_tty->gbphy_dev->dev,
86 "short receive-data request received (%zu < %zu)\n",
87 request->payload_size, sizeof(*receive_data));
88 return -EINVAL;
89 }
90
91 receive_data = op->request->payload;
92 recv_data_size = le16_to_cpu(receive_data->size);
93
94 if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
95 dev_err(&gb_tty->gbphy_dev->dev,
96 "malformed receive-data request received (%u != %zu)\n",
97 recv_data_size,
98 request->payload_size - sizeof(*receive_data));
99 return -EINVAL;
100 }
101
102 if (!recv_data_size)
103 return -EINVAL;
104
105 if (receive_data->flags) {
106 if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
107 tty_flags = TTY_BREAK;
108 else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
109 tty_flags = TTY_PARITY;
110 else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
111 tty_flags = TTY_FRAME;
112
113 /* overrun is special, not associated with a char */
114 if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
115 tty_insert_flip_char(port, 0, TTY_OVERRUN);
116 }
117 count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
118 tty_flags, recv_data_size);
119 if (count != recv_data_size) {
120 dev_err(&gb_tty->gbphy_dev->dev,
121 "UART: RX 0x%08x bytes only wrote 0x%08x\n",
122 recv_data_size, count);
123 }
124 if (count)
125 tty_flip_buffer_push(port);
126 return 0;
127 }
128
gb_uart_serial_state_handler(struct gb_operation * op)129 static int gb_uart_serial_state_handler(struct gb_operation *op)
130 {
131 struct gb_connection *connection = op->connection;
132 struct gb_tty *gb_tty = gb_connection_get_data(connection);
133 struct gb_message *request = op->request;
134 struct gb_uart_serial_state_request *serial_state;
135
136 if (request->payload_size < sizeof(*serial_state)) {
137 dev_err(&gb_tty->gbphy_dev->dev,
138 "short serial-state event received (%zu < %zu)\n",
139 request->payload_size, sizeof(*serial_state));
140 return -EINVAL;
141 }
142
143 serial_state = request->payload;
144 gb_tty->ctrlin = serial_state->control;
145
146 return 0;
147 }
148
gb_uart_receive_credits_handler(struct gb_operation * op)149 static int gb_uart_receive_credits_handler(struct gb_operation *op)
150 {
151 struct gb_connection *connection = op->connection;
152 struct gb_tty *gb_tty = gb_connection_get_data(connection);
153 struct gb_message *request = op->request;
154 struct gb_uart_receive_credits_request *credit_request;
155 unsigned long flags;
156 unsigned int incoming_credits;
157 int ret = 0;
158
159 if (request->payload_size < sizeof(*credit_request)) {
160 dev_err(&gb_tty->gbphy_dev->dev,
161 "short receive_credits event received (%zu < %zu)\n",
162 request->payload_size,
163 sizeof(*credit_request));
164 return -EINVAL;
165 }
166
167 credit_request = request->payload;
168 incoming_credits = le16_to_cpu(credit_request->count);
169
170 spin_lock_irqsave(&gb_tty->write_lock, flags);
171 gb_tty->credits += incoming_credits;
172 if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
173 gb_tty->credits -= incoming_credits;
174 ret = -EINVAL;
175 }
176 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
177
178 if (ret) {
179 dev_err(&gb_tty->gbphy_dev->dev,
180 "invalid number of incoming credits: %d\n",
181 incoming_credits);
182 return ret;
183 }
184
185 if (!gb_tty->close_pending)
186 schedule_work(&gb_tty->tx_work);
187
188 /*
189 * the port the tty layer may be waiting for credits
190 */
191 tty_port_tty_wakeup(&gb_tty->port);
192
193 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
194 complete(&gb_tty->credits_complete);
195
196 return ret;
197 }
198
gb_uart_request_handler(struct gb_operation * op)199 static int gb_uart_request_handler(struct gb_operation *op)
200 {
201 struct gb_connection *connection = op->connection;
202 struct gb_tty *gb_tty = gb_connection_get_data(connection);
203 int type = op->type;
204 int ret;
205
206 switch (type) {
207 case GB_UART_TYPE_RECEIVE_DATA:
208 ret = gb_uart_receive_data_handler(op);
209 break;
210 case GB_UART_TYPE_SERIAL_STATE:
211 ret = gb_uart_serial_state_handler(op);
212 break;
213 case GB_UART_TYPE_RECEIVE_CREDITS:
214 ret = gb_uart_receive_credits_handler(op);
215 break;
216 default:
217 dev_err(&gb_tty->gbphy_dev->dev,
218 "unsupported unsolicited request: 0x%02x\n", type);
219 ret = -EINVAL;
220 }
221
222 return ret;
223 }
224
gb_uart_tx_write_work(struct work_struct * work)225 static void gb_uart_tx_write_work(struct work_struct *work)
226 {
227 struct gb_uart_send_data_request *request;
228 struct gb_tty *gb_tty;
229 unsigned long flags;
230 unsigned int send_size;
231 int ret;
232
233 gb_tty = container_of(work, struct gb_tty, tx_work);
234 request = gb_tty->buffer;
235
236 while (1) {
237 if (gb_tty->close_pending)
238 break;
239
240 spin_lock_irqsave(&gb_tty->write_lock, flags);
241 send_size = gb_tty->buffer_payload_max;
242 if (send_size > gb_tty->credits)
243 send_size = gb_tty->credits;
244
245 send_size = kfifo_out_peek(&gb_tty->write_fifo,
246 &request->data[0],
247 send_size);
248 if (!send_size) {
249 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
250 break;
251 }
252
253 gb_tty->credits -= send_size;
254 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
255
256 request->size = cpu_to_le16(send_size);
257 ret = gb_operation_sync(gb_tty->connection,
258 GB_UART_TYPE_SEND_DATA,
259 request, sizeof(*request) + send_size,
260 NULL, 0);
261 if (ret) {
262 dev_err(&gb_tty->gbphy_dev->dev,
263 "send data error: %d\n", ret);
264 spin_lock_irqsave(&gb_tty->write_lock, flags);
265 gb_tty->credits += send_size;
266 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
267 if (!gb_tty->close_pending)
268 schedule_work(work);
269 return;
270 }
271
272 spin_lock_irqsave(&gb_tty->write_lock, flags);
273 ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
274 send_size);
275 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
276
277 tty_port_tty_wakeup(&gb_tty->port);
278 }
279 }
280
send_line_coding(struct gb_tty * tty)281 static int send_line_coding(struct gb_tty *tty)
282 {
283 return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
284 &tty->line_coding, sizeof(tty->line_coding),
285 NULL, 0);
286 }
287
send_control(struct gb_tty * gb_tty,u8 control)288 static int send_control(struct gb_tty *gb_tty, u8 control)
289 {
290 struct gb_uart_set_control_line_state_request request;
291
292 request.control = control;
293 return gb_operation_sync(gb_tty->connection,
294 GB_UART_TYPE_SET_CONTROL_LINE_STATE,
295 &request, sizeof(request), NULL, 0);
296 }
297
send_break(struct gb_tty * gb_tty,u8 state)298 static int send_break(struct gb_tty *gb_tty, u8 state)
299 {
300 struct gb_uart_set_break_request request;
301
302 if ((state != 0) && (state != 1)) {
303 dev_err(&gb_tty->gbphy_dev->dev,
304 "invalid break state of %d\n", state);
305 return -EINVAL;
306 }
307
308 request.state = state;
309 return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
310 &request, sizeof(request), NULL, 0);
311 }
312
gb_uart_wait_for_all_credits(struct gb_tty * gb_tty)313 static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
314 {
315 int ret;
316
317 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
318 return 0;
319
320 ret = wait_for_completion_timeout(&gb_tty->credits_complete,
321 msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
322 if (!ret) {
323 dev_err(&gb_tty->gbphy_dev->dev,
324 "time out waiting for credits\n");
325 return -ETIMEDOUT;
326 }
327
328 return 0;
329 }
330
gb_uart_flush(struct gb_tty * gb_tty,u8 flags)331 static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
332 {
333 struct gb_uart_serial_flush_request request;
334
335 request.flags = flags;
336 return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
337 &request, sizeof(request), NULL, 0);
338 }
339
get_gb_by_minor(unsigned int minor)340 static struct gb_tty *get_gb_by_minor(unsigned int minor)
341 {
342 struct gb_tty *gb_tty;
343
344 mutex_lock(&table_lock);
345 gb_tty = idr_find(&tty_minors, minor);
346 if (gb_tty) {
347 mutex_lock(&gb_tty->mutex);
348 if (gb_tty->disconnected) {
349 mutex_unlock(&gb_tty->mutex);
350 gb_tty = NULL;
351 } else {
352 tty_port_get(&gb_tty->port);
353 mutex_unlock(&gb_tty->mutex);
354 }
355 }
356 mutex_unlock(&table_lock);
357 return gb_tty;
358 }
359
alloc_minor(struct gb_tty * gb_tty)360 static int alloc_minor(struct gb_tty *gb_tty)
361 {
362 int minor;
363
364 mutex_lock(&table_lock);
365 minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
366 mutex_unlock(&table_lock);
367 if (minor >= 0)
368 gb_tty->minor = minor;
369 return minor;
370 }
371
release_minor(struct gb_tty * gb_tty)372 static void release_minor(struct gb_tty *gb_tty)
373 {
374 int minor = gb_tty->minor;
375
376 gb_tty->minor = 0; /* Maybe should use an invalid value instead */
377 mutex_lock(&table_lock);
378 idr_remove(&tty_minors, minor);
379 mutex_unlock(&table_lock);
380 }
381
gb_tty_install(struct tty_driver * driver,struct tty_struct * tty)382 static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
383 {
384 struct gb_tty *gb_tty;
385 int retval;
386
387 gb_tty = get_gb_by_minor(tty->index);
388 if (!gb_tty)
389 return -ENODEV;
390
391 retval = tty_standard_install(driver, tty);
392 if (retval)
393 goto error;
394
395 tty->driver_data = gb_tty;
396 return 0;
397 error:
398 tty_port_put(&gb_tty->port);
399 return retval;
400 }
401
gb_tty_open(struct tty_struct * tty,struct file * file)402 static int gb_tty_open(struct tty_struct *tty, struct file *file)
403 {
404 struct gb_tty *gb_tty = tty->driver_data;
405
406 return tty_port_open(&gb_tty->port, tty, file);
407 }
408
gb_tty_close(struct tty_struct * tty,struct file * file)409 static void gb_tty_close(struct tty_struct *tty, struct file *file)
410 {
411 struct gb_tty *gb_tty = tty->driver_data;
412
413 tty_port_close(&gb_tty->port, tty, file);
414 }
415
gb_tty_cleanup(struct tty_struct * tty)416 static void gb_tty_cleanup(struct tty_struct *tty)
417 {
418 struct gb_tty *gb_tty = tty->driver_data;
419
420 tty_port_put(&gb_tty->port);
421 }
422
gb_tty_hangup(struct tty_struct * tty)423 static void gb_tty_hangup(struct tty_struct *tty)
424 {
425 struct gb_tty *gb_tty = tty->driver_data;
426
427 tty_port_hangup(&gb_tty->port);
428 }
429
gb_tty_write(struct tty_struct * tty,const unsigned char * buf,int count)430 static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
431 int count)
432 {
433 struct gb_tty *gb_tty = tty->driver_data;
434
435 count = kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
436 &gb_tty->write_lock);
437 if (count && !gb_tty->close_pending)
438 schedule_work(&gb_tty->tx_work);
439
440 return count;
441 }
442
gb_tty_write_room(struct tty_struct * tty)443 static int gb_tty_write_room(struct tty_struct *tty)
444 {
445 struct gb_tty *gb_tty = tty->driver_data;
446 unsigned long flags;
447 int room;
448
449 spin_lock_irqsave(&gb_tty->write_lock, flags);
450 room = kfifo_avail(&gb_tty->write_fifo);
451 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
452
453 room -= GB_UART_WRITE_ROOM_MARGIN;
454 if (room < 0)
455 return 0;
456
457 return room;
458 }
459
gb_tty_chars_in_buffer(struct tty_struct * tty)460 static int gb_tty_chars_in_buffer(struct tty_struct *tty)
461 {
462 struct gb_tty *gb_tty = tty->driver_data;
463 unsigned long flags;
464 int chars;
465
466 spin_lock_irqsave(&gb_tty->write_lock, flags);
467 chars = kfifo_len(&gb_tty->write_fifo);
468 if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
469 chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
470 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
471
472 return chars;
473 }
474
gb_tty_break_ctl(struct tty_struct * tty,int state)475 static int gb_tty_break_ctl(struct tty_struct *tty, int state)
476 {
477 struct gb_tty *gb_tty = tty->driver_data;
478
479 return send_break(gb_tty, state ? 1 : 0);
480 }
481
gb_tty_set_termios(struct tty_struct * tty,struct ktermios * termios_old)482 static void gb_tty_set_termios(struct tty_struct *tty,
483 struct ktermios *termios_old)
484 {
485 struct gb_uart_set_line_coding_request newline;
486 struct gb_tty *gb_tty = tty->driver_data;
487 struct ktermios *termios = &tty->termios;
488 u8 newctrl = gb_tty->ctrlout;
489
490 newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
491 newline.format = termios->c_cflag & CSTOPB ?
492 GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
493 newline.parity = termios->c_cflag & PARENB ?
494 (termios->c_cflag & PARODD ? 1 : 2) +
495 (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
496
497 switch (termios->c_cflag & CSIZE) {
498 case CS5:
499 newline.data_bits = 5;
500 break;
501 case CS6:
502 newline.data_bits = 6;
503 break;
504 case CS7:
505 newline.data_bits = 7;
506 break;
507 case CS8:
508 default:
509 newline.data_bits = 8;
510 break;
511 }
512
513 /* FIXME: needs to clear unsupported bits in the termios */
514 gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
515
516 if (C_BAUD(tty) == B0) {
517 newline.rate = gb_tty->line_coding.rate;
518 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
519 } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
520 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
521 }
522
523 if (newctrl != gb_tty->ctrlout) {
524 gb_tty->ctrlout = newctrl;
525 send_control(gb_tty, newctrl);
526 }
527
528 if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
529 newline.flow_control = GB_SERIAL_AUTO_RTSCTS_EN;
530 else
531 newline.flow_control = 0;
532
533 if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
534 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
535 send_line_coding(gb_tty);
536 }
537 }
538
gb_tty_tiocmget(struct tty_struct * tty)539 static int gb_tty_tiocmget(struct tty_struct *tty)
540 {
541 struct gb_tty *gb_tty = tty->driver_data;
542
543 return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
544 (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
545 (gb_tty->ctrlin & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
546 (gb_tty->ctrlin & GB_UART_CTRL_RI ? TIOCM_RI : 0) |
547 (gb_tty->ctrlin & GB_UART_CTRL_DCD ? TIOCM_CD : 0) |
548 TIOCM_CTS;
549 }
550
gb_tty_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)551 static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
552 unsigned int clear)
553 {
554 struct gb_tty *gb_tty = tty->driver_data;
555 u8 newctrl = gb_tty->ctrlout;
556
557 set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
558 (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
559 clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
560 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
561
562 newctrl = (newctrl & ~clear) | set;
563 if (gb_tty->ctrlout == newctrl)
564 return 0;
565
566 gb_tty->ctrlout = newctrl;
567 return send_control(gb_tty, newctrl);
568 }
569
gb_tty_throttle(struct tty_struct * tty)570 static void gb_tty_throttle(struct tty_struct *tty)
571 {
572 struct gb_tty *gb_tty = tty->driver_data;
573 unsigned char stop_char;
574 int retval;
575
576 if (I_IXOFF(tty)) {
577 stop_char = STOP_CHAR(tty);
578 retval = gb_tty_write(tty, &stop_char, 1);
579 if (retval <= 0)
580 return;
581 }
582
583 if (tty->termios.c_cflag & CRTSCTS) {
584 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
585 retval = send_control(gb_tty, gb_tty->ctrlout);
586 }
587 }
588
gb_tty_unthrottle(struct tty_struct * tty)589 static void gb_tty_unthrottle(struct tty_struct *tty)
590 {
591 struct gb_tty *gb_tty = tty->driver_data;
592 unsigned char start_char;
593 int retval;
594
595 if (I_IXOFF(tty)) {
596 start_char = START_CHAR(tty);
597 retval = gb_tty_write(tty, &start_char, 1);
598 if (retval <= 0)
599 return;
600 }
601
602 if (tty->termios.c_cflag & CRTSCTS) {
603 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
604 retval = send_control(gb_tty, gb_tty->ctrlout);
605 }
606 }
607
get_serial_info(struct tty_struct * tty,struct serial_struct * ss)608 static int get_serial_info(struct tty_struct *tty,
609 struct serial_struct *ss)
610 {
611 struct gb_tty *gb_tty = tty->driver_data;
612
613 ss->line = gb_tty->minor;
614 ss->close_delay = jiffies_to_msecs(gb_tty->port.close_delay) / 10;
615 ss->closing_wait =
616 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
617 ASYNC_CLOSING_WAIT_NONE :
618 jiffies_to_msecs(gb_tty->port.closing_wait) / 10;
619
620 return 0;
621 }
622
set_serial_info(struct tty_struct * tty,struct serial_struct * ss)623 static int set_serial_info(struct tty_struct *tty,
624 struct serial_struct *ss)
625 {
626 struct gb_tty *gb_tty = tty->driver_data;
627 unsigned int closing_wait;
628 unsigned int close_delay;
629 int retval = 0;
630
631 close_delay = msecs_to_jiffies(ss->close_delay * 10);
632 closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
633 ASYNC_CLOSING_WAIT_NONE :
634 msecs_to_jiffies(ss->closing_wait * 10);
635
636 mutex_lock(&gb_tty->port.mutex);
637 if (!capable(CAP_SYS_ADMIN)) {
638 if ((close_delay != gb_tty->port.close_delay) ||
639 (closing_wait != gb_tty->port.closing_wait))
640 retval = -EPERM;
641 } else {
642 gb_tty->port.close_delay = close_delay;
643 gb_tty->port.closing_wait = closing_wait;
644 }
645 mutex_unlock(&gb_tty->port.mutex);
646 return retval;
647 }
648
wait_serial_change(struct gb_tty * gb_tty,unsigned long arg)649 static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
650 {
651 int retval = 0;
652 DECLARE_WAITQUEUE(wait, current);
653 struct async_icount old;
654 struct async_icount new;
655
656 if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
657 return -EINVAL;
658
659 do {
660 spin_lock_irq(&gb_tty->read_lock);
661 old = gb_tty->oldcount;
662 new = gb_tty->iocount;
663 gb_tty->oldcount = new;
664 spin_unlock_irq(&gb_tty->read_lock);
665
666 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
667 break;
668 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
669 break;
670 if ((arg & TIOCM_RI) && (old.rng != new.rng))
671 break;
672
673 add_wait_queue(&gb_tty->wioctl, &wait);
674 set_current_state(TASK_INTERRUPTIBLE);
675 schedule();
676 remove_wait_queue(&gb_tty->wioctl, &wait);
677 if (gb_tty->disconnected) {
678 if (arg & TIOCM_CD)
679 break;
680 retval = -ENODEV;
681 } else if (signal_pending(current)) {
682 retval = -ERESTARTSYS;
683 }
684 } while (!retval);
685
686 return retval;
687 }
688
gb_tty_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)689 static int gb_tty_get_icount(struct tty_struct *tty,
690 struct serial_icounter_struct *icount)
691 {
692 struct gb_tty *gb_tty = tty->driver_data;
693
694 icount->dsr = gb_tty->iocount.dsr;
695 icount->rng = gb_tty->iocount.rng;
696 icount->dcd = gb_tty->iocount.dcd;
697 icount->frame = gb_tty->iocount.frame;
698 icount->overrun = gb_tty->iocount.overrun;
699 icount->parity = gb_tty->iocount.parity;
700 icount->brk = gb_tty->iocount.brk;
701
702 return 0;
703 }
704
gb_tty_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)705 static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
706 unsigned long arg)
707 {
708 struct gb_tty *gb_tty = tty->driver_data;
709
710 switch (cmd) {
711 case TIOCMIWAIT:
712 return wait_serial_change(gb_tty, arg);
713 }
714
715 return -ENOIOCTLCMD;
716 }
717
gb_tty_dtr_rts(struct tty_port * port,int on)718 static void gb_tty_dtr_rts(struct tty_port *port, int on)
719 {
720 struct gb_tty *gb_tty;
721 u8 newctrl;
722
723 gb_tty = container_of(port, struct gb_tty, port);
724 newctrl = gb_tty->ctrlout;
725
726 if (on)
727 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
728 else
729 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
730
731 gb_tty->ctrlout = newctrl;
732 send_control(gb_tty, newctrl);
733 }
734
gb_tty_port_activate(struct tty_port * port,struct tty_struct * tty)735 static int gb_tty_port_activate(struct tty_port *port,
736 struct tty_struct *tty)
737 {
738 struct gb_tty *gb_tty;
739
740 gb_tty = container_of(port, struct gb_tty, port);
741
742 return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
743 }
744
gb_tty_port_shutdown(struct tty_port * port)745 static void gb_tty_port_shutdown(struct tty_port *port)
746 {
747 struct gb_tty *gb_tty;
748 unsigned long flags;
749 int ret;
750
751 gb_tty = container_of(port, struct gb_tty, port);
752
753 gb_tty->close_pending = true;
754
755 cancel_work_sync(&gb_tty->tx_work);
756
757 spin_lock_irqsave(&gb_tty->write_lock, flags);
758 kfifo_reset_out(&gb_tty->write_fifo);
759 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
760
761 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
762 goto out;
763
764 ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
765 if (ret) {
766 dev_err(&gb_tty->gbphy_dev->dev,
767 "error flushing transmitter: %d\n", ret);
768 }
769
770 gb_uart_wait_for_all_credits(gb_tty);
771
772 out:
773 gb_tty->close_pending = false;
774
775 gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
776 }
777
778 static const struct tty_operations gb_ops = {
779 .install = gb_tty_install,
780 .open = gb_tty_open,
781 .close = gb_tty_close,
782 .cleanup = gb_tty_cleanup,
783 .hangup = gb_tty_hangup,
784 .write = gb_tty_write,
785 .write_room = gb_tty_write_room,
786 .ioctl = gb_tty_ioctl,
787 .throttle = gb_tty_throttle,
788 .unthrottle = gb_tty_unthrottle,
789 .chars_in_buffer = gb_tty_chars_in_buffer,
790 .break_ctl = gb_tty_break_ctl,
791 .set_termios = gb_tty_set_termios,
792 .tiocmget = gb_tty_tiocmget,
793 .tiocmset = gb_tty_tiocmset,
794 .get_icount = gb_tty_get_icount,
795 .set_serial = set_serial_info,
796 .get_serial = get_serial_info,
797 };
798
799 static const struct tty_port_operations gb_port_ops = {
800 .dtr_rts = gb_tty_dtr_rts,
801 .activate = gb_tty_port_activate,
802 .shutdown = gb_tty_port_shutdown,
803 };
804
gb_uart_probe(struct gbphy_device * gbphy_dev,const struct gbphy_device_id * id)805 static int gb_uart_probe(struct gbphy_device *gbphy_dev,
806 const struct gbphy_device_id *id)
807 {
808 struct gb_connection *connection;
809 size_t max_payload;
810 struct gb_tty *gb_tty;
811 struct device *tty_dev;
812 int retval;
813 int minor;
814
815 gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
816 if (!gb_tty)
817 return -ENOMEM;
818
819 connection = gb_connection_create(gbphy_dev->bundle,
820 le16_to_cpu(gbphy_dev->cport_desc->id),
821 gb_uart_request_handler);
822 if (IS_ERR(connection)) {
823 retval = PTR_ERR(connection);
824 goto exit_tty_free;
825 }
826
827 max_payload = gb_operation_get_payload_size_max(connection);
828 if (max_payload < sizeof(struct gb_uart_send_data_request)) {
829 retval = -EINVAL;
830 goto exit_connection_destroy;
831 }
832
833 gb_tty->buffer_payload_max = max_payload -
834 sizeof(struct gb_uart_send_data_request);
835
836 gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
837 if (!gb_tty->buffer) {
838 retval = -ENOMEM;
839 goto exit_connection_destroy;
840 }
841
842 INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
843
844 retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
845 GFP_KERNEL);
846 if (retval)
847 goto exit_buf_free;
848
849 gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
850 init_completion(&gb_tty->credits_complete);
851
852 minor = alloc_minor(gb_tty);
853 if (minor < 0) {
854 if (minor == -ENOSPC) {
855 dev_err(&gbphy_dev->dev,
856 "no more free minor numbers\n");
857 retval = -ENODEV;
858 } else {
859 retval = minor;
860 }
861 goto exit_kfifo_free;
862 }
863
864 gb_tty->minor = minor;
865 spin_lock_init(&gb_tty->write_lock);
866 spin_lock_init(&gb_tty->read_lock);
867 init_waitqueue_head(&gb_tty->wioctl);
868 mutex_init(&gb_tty->mutex);
869
870 tty_port_init(&gb_tty->port);
871 gb_tty->port.ops = &gb_port_ops;
872
873 gb_tty->connection = connection;
874 gb_tty->gbphy_dev = gbphy_dev;
875 gb_connection_set_data(connection, gb_tty);
876 gb_gbphy_set_data(gbphy_dev, gb_tty);
877
878 retval = gb_connection_enable_tx(connection);
879 if (retval)
880 goto exit_release_minor;
881
882 send_control(gb_tty, gb_tty->ctrlout);
883
884 /* initialize the uart to be 9600n81 */
885 gb_tty->line_coding.rate = cpu_to_le32(9600);
886 gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
887 gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
888 gb_tty->line_coding.data_bits = 8;
889 send_line_coding(gb_tty);
890
891 retval = gb_connection_enable(connection);
892 if (retval)
893 goto exit_connection_disable;
894
895 tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
896 &gbphy_dev->dev);
897 if (IS_ERR(tty_dev)) {
898 retval = PTR_ERR(tty_dev);
899 goto exit_connection_disable;
900 }
901
902 gbphy_runtime_put_autosuspend(gbphy_dev);
903 return 0;
904
905 exit_connection_disable:
906 gb_connection_disable(connection);
907 exit_release_minor:
908 release_minor(gb_tty);
909 exit_kfifo_free:
910 kfifo_free(&gb_tty->write_fifo);
911 exit_buf_free:
912 kfree(gb_tty->buffer);
913 exit_connection_destroy:
914 gb_connection_destroy(connection);
915 exit_tty_free:
916 kfree(gb_tty);
917
918 return retval;
919 }
920
gb_uart_remove(struct gbphy_device * gbphy_dev)921 static void gb_uart_remove(struct gbphy_device *gbphy_dev)
922 {
923 struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
924 struct gb_connection *connection = gb_tty->connection;
925 struct tty_struct *tty;
926 int ret;
927
928 ret = gbphy_runtime_get_sync(gbphy_dev);
929 if (ret)
930 gbphy_runtime_get_noresume(gbphy_dev);
931
932 mutex_lock(&gb_tty->mutex);
933 gb_tty->disconnected = true;
934
935 wake_up_all(&gb_tty->wioctl);
936 mutex_unlock(&gb_tty->mutex);
937
938 tty = tty_port_tty_get(&gb_tty->port);
939 if (tty) {
940 tty_vhangup(tty);
941 tty_kref_put(tty);
942 }
943
944 gb_connection_disable_rx(connection);
945 tty_unregister_device(gb_tty_driver, gb_tty->minor);
946
947 /* FIXME - free transmit / receive buffers */
948
949 gb_connection_disable(connection);
950 tty_port_destroy(&gb_tty->port);
951 gb_connection_destroy(connection);
952 release_minor(gb_tty);
953 kfifo_free(&gb_tty->write_fifo);
954 kfree(gb_tty->buffer);
955 kfree(gb_tty);
956 }
957
gb_tty_init(void)958 static int gb_tty_init(void)
959 {
960 int retval = 0;
961
962 gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
963 if (IS_ERR(gb_tty_driver)) {
964 pr_err("Can not allocate tty driver\n");
965 retval = -ENOMEM;
966 goto fail_unregister_dev;
967 }
968
969 gb_tty_driver->driver_name = "gb";
970 gb_tty_driver->name = GB_NAME;
971 gb_tty_driver->major = 0;
972 gb_tty_driver->minor_start = 0;
973 gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
974 gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
975 gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
976 gb_tty_driver->init_termios = tty_std_termios;
977 gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
978 CREAD | HUPCL | CLOCAL;
979 tty_set_operations(gb_tty_driver, &gb_ops);
980
981 retval = tty_register_driver(gb_tty_driver);
982 if (retval) {
983 pr_err("Can not register tty driver: %d\n", retval);
984 goto fail_put_gb_tty;
985 }
986
987 return 0;
988
989 fail_put_gb_tty:
990 put_tty_driver(gb_tty_driver);
991 fail_unregister_dev:
992 return retval;
993 }
994
gb_tty_exit(void)995 static void gb_tty_exit(void)
996 {
997 tty_unregister_driver(gb_tty_driver);
998 put_tty_driver(gb_tty_driver);
999 idr_destroy(&tty_minors);
1000 }
1001
1002 static const struct gbphy_device_id gb_uart_id_table[] = {
1003 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
1004 { },
1005 };
1006 MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
1007
1008 static struct gbphy_driver uart_driver = {
1009 .name = "uart",
1010 .probe = gb_uart_probe,
1011 .remove = gb_uart_remove,
1012 .id_table = gb_uart_id_table,
1013 };
1014
gb_uart_driver_init(void)1015 static int gb_uart_driver_init(void)
1016 {
1017 int ret;
1018
1019 ret = gb_tty_init();
1020 if (ret)
1021 return ret;
1022
1023 ret = gb_gbphy_register(&uart_driver);
1024 if (ret) {
1025 gb_tty_exit();
1026 return ret;
1027 }
1028
1029 return 0;
1030 }
1031 module_init(gb_uart_driver_init);
1032
gb_uart_driver_exit(void)1033 static void gb_uart_driver_exit(void)
1034 {
1035 gb_gbphy_deregister(&uart_driver);
1036 gb_tty_exit();
1037 }
1038
1039 module_exit(gb_uart_driver_exit);
1040 MODULE_LICENSE("GPL v2");
1041