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 u8 * buf,size_t count)430 static ssize_t gb_tty_write(struct tty_struct *tty, const u8 *buf, size_t count)
431 {
432 struct gb_tty *gb_tty = tty->driver_data;
433
434 count = kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
435 &gb_tty->write_lock);
436 if (count && !gb_tty->close_pending)
437 schedule_work(&gb_tty->tx_work);
438
439 return count;
440 }
441
gb_tty_write_room(struct tty_struct * tty)442 static unsigned int gb_tty_write_room(struct tty_struct *tty)
443 {
444 struct gb_tty *gb_tty = tty->driver_data;
445 unsigned long flags;
446 int room;
447
448 spin_lock_irqsave(&gb_tty->write_lock, flags);
449 room = kfifo_avail(&gb_tty->write_fifo);
450 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
451
452 room -= GB_UART_WRITE_ROOM_MARGIN;
453 if (room < 0)
454 return 0;
455
456 return room;
457 }
458
gb_tty_chars_in_buffer(struct tty_struct * tty)459 static unsigned int gb_tty_chars_in_buffer(struct tty_struct *tty)
460 {
461 struct gb_tty *gb_tty = tty->driver_data;
462 unsigned long flags;
463 unsigned int chars;
464
465 spin_lock_irqsave(&gb_tty->write_lock, flags);
466 chars = kfifo_len(&gb_tty->write_fifo);
467 if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
468 chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
469 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
470
471 return chars;
472 }
473
gb_tty_break_ctl(struct tty_struct * tty,int state)474 static int gb_tty_break_ctl(struct tty_struct *tty, int state)
475 {
476 struct gb_tty *gb_tty = tty->driver_data;
477
478 return send_break(gb_tty, state ? 1 : 0);
479 }
480
gb_tty_set_termios(struct tty_struct * tty,const struct ktermios * termios_old)481 static void gb_tty_set_termios(struct tty_struct *tty,
482 const struct ktermios *termios_old)
483 {
484 struct gb_uart_set_line_coding_request newline;
485 struct gb_tty *gb_tty = tty->driver_data;
486 struct ktermios *termios = &tty->termios;
487 u8 newctrl = gb_tty->ctrlout;
488
489 newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
490 newline.format = termios->c_cflag & CSTOPB ?
491 GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
492 newline.parity = termios->c_cflag & PARENB ?
493 (termios->c_cflag & PARODD ? 1 : 2) +
494 (termios->c_cflag & CMSPAR ? 2 : 0) : 0;
495
496 newline.data_bits = tty_get_char_size(termios->c_cflag);
497
498 /* FIXME: needs to clear unsupported bits in the termios */
499 gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
500
501 if (C_BAUD(tty) == B0) {
502 newline.rate = gb_tty->line_coding.rate;
503 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
504 } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
505 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
506 }
507
508 if (newctrl != gb_tty->ctrlout) {
509 gb_tty->ctrlout = newctrl;
510 send_control(gb_tty, newctrl);
511 }
512
513 if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
514 newline.flow_control = GB_SERIAL_AUTO_RTSCTS_EN;
515 else
516 newline.flow_control = 0;
517
518 if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
519 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
520 send_line_coding(gb_tty);
521 }
522 }
523
gb_tty_tiocmget(struct tty_struct * tty)524 static int gb_tty_tiocmget(struct tty_struct *tty)
525 {
526 struct gb_tty *gb_tty = tty->driver_data;
527
528 return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
529 (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
530 (gb_tty->ctrlin & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
531 (gb_tty->ctrlin & GB_UART_CTRL_RI ? TIOCM_RI : 0) |
532 (gb_tty->ctrlin & GB_UART_CTRL_DCD ? TIOCM_CD : 0) |
533 TIOCM_CTS;
534 }
535
gb_tty_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)536 static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
537 unsigned int clear)
538 {
539 struct gb_tty *gb_tty = tty->driver_data;
540 u8 newctrl = gb_tty->ctrlout;
541
542 set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
543 (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
544 clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
545 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
546
547 newctrl = (newctrl & ~clear) | set;
548 if (gb_tty->ctrlout == newctrl)
549 return 0;
550
551 gb_tty->ctrlout = newctrl;
552 return send_control(gb_tty, newctrl);
553 }
554
gb_tty_throttle(struct tty_struct * tty)555 static void gb_tty_throttle(struct tty_struct *tty)
556 {
557 struct gb_tty *gb_tty = tty->driver_data;
558 unsigned char stop_char;
559 int retval;
560
561 if (I_IXOFF(tty)) {
562 stop_char = STOP_CHAR(tty);
563 retval = gb_tty_write(tty, &stop_char, 1);
564 if (retval <= 0)
565 return;
566 }
567
568 if (tty->termios.c_cflag & CRTSCTS) {
569 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
570 retval = send_control(gb_tty, gb_tty->ctrlout);
571 }
572 }
573
gb_tty_unthrottle(struct tty_struct * tty)574 static void gb_tty_unthrottle(struct tty_struct *tty)
575 {
576 struct gb_tty *gb_tty = tty->driver_data;
577 unsigned char start_char;
578 int retval;
579
580 if (I_IXOFF(tty)) {
581 start_char = START_CHAR(tty);
582 retval = gb_tty_write(tty, &start_char, 1);
583 if (retval <= 0)
584 return;
585 }
586
587 if (tty->termios.c_cflag & CRTSCTS) {
588 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
589 retval = send_control(gb_tty, gb_tty->ctrlout);
590 }
591 }
592
get_serial_info(struct tty_struct * tty,struct serial_struct * ss)593 static int get_serial_info(struct tty_struct *tty,
594 struct serial_struct *ss)
595 {
596 struct gb_tty *gb_tty = tty->driver_data;
597
598 ss->line = gb_tty->minor;
599 mutex_lock(&gb_tty->port.mutex);
600 ss->close_delay = jiffies_to_msecs(gb_tty->port.close_delay) / 10;
601 ss->closing_wait =
602 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
603 ASYNC_CLOSING_WAIT_NONE :
604 jiffies_to_msecs(gb_tty->port.closing_wait) / 10;
605 mutex_unlock(&gb_tty->port.mutex);
606
607 return 0;
608 }
609
set_serial_info(struct tty_struct * tty,struct serial_struct * ss)610 static int set_serial_info(struct tty_struct *tty,
611 struct serial_struct *ss)
612 {
613 struct gb_tty *gb_tty = tty->driver_data;
614 unsigned int closing_wait;
615 unsigned int close_delay;
616 int retval = 0;
617
618 close_delay = msecs_to_jiffies(ss->close_delay * 10);
619 closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
620 ASYNC_CLOSING_WAIT_NONE :
621 msecs_to_jiffies(ss->closing_wait * 10);
622
623 mutex_lock(&gb_tty->port.mutex);
624 if (!capable(CAP_SYS_ADMIN)) {
625 if ((close_delay != gb_tty->port.close_delay) ||
626 (closing_wait != gb_tty->port.closing_wait))
627 retval = -EPERM;
628 } else {
629 gb_tty->port.close_delay = close_delay;
630 gb_tty->port.closing_wait = closing_wait;
631 }
632 mutex_unlock(&gb_tty->port.mutex);
633 return retval;
634 }
635
wait_serial_change(struct gb_tty * gb_tty,unsigned long arg)636 static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
637 {
638 int retval = 0;
639 DECLARE_WAITQUEUE(wait, current);
640 struct async_icount old;
641 struct async_icount new;
642
643 if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
644 return -EINVAL;
645
646 do {
647 spin_lock_irq(&gb_tty->read_lock);
648 old = gb_tty->oldcount;
649 new = gb_tty->iocount;
650 gb_tty->oldcount = new;
651 spin_unlock_irq(&gb_tty->read_lock);
652
653 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
654 break;
655 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
656 break;
657 if ((arg & TIOCM_RI) && (old.rng != new.rng))
658 break;
659
660 add_wait_queue(&gb_tty->wioctl, &wait);
661 set_current_state(TASK_INTERRUPTIBLE);
662 schedule();
663 remove_wait_queue(&gb_tty->wioctl, &wait);
664 if (gb_tty->disconnected) {
665 if (arg & TIOCM_CD)
666 break;
667 retval = -ENODEV;
668 } else if (signal_pending(current)) {
669 retval = -ERESTARTSYS;
670 }
671 } while (!retval);
672
673 return retval;
674 }
675
gb_tty_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)676 static int gb_tty_get_icount(struct tty_struct *tty,
677 struct serial_icounter_struct *icount)
678 {
679 struct gb_tty *gb_tty = tty->driver_data;
680
681 icount->dsr = gb_tty->iocount.dsr;
682 icount->rng = gb_tty->iocount.rng;
683 icount->dcd = gb_tty->iocount.dcd;
684 icount->frame = gb_tty->iocount.frame;
685 icount->overrun = gb_tty->iocount.overrun;
686 icount->parity = gb_tty->iocount.parity;
687 icount->brk = gb_tty->iocount.brk;
688
689 return 0;
690 }
691
gb_tty_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)692 static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
693 unsigned long arg)
694 {
695 struct gb_tty *gb_tty = tty->driver_data;
696
697 switch (cmd) {
698 case TIOCMIWAIT:
699 return wait_serial_change(gb_tty, arg);
700 }
701
702 return -ENOIOCTLCMD;
703 }
704
gb_tty_dtr_rts(struct tty_port * port,bool active)705 static void gb_tty_dtr_rts(struct tty_port *port, bool active)
706 {
707 struct gb_tty *gb_tty;
708 u8 newctrl;
709
710 gb_tty = container_of(port, struct gb_tty, port);
711 newctrl = gb_tty->ctrlout;
712
713 if (active)
714 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
715 else
716 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
717
718 gb_tty->ctrlout = newctrl;
719 send_control(gb_tty, newctrl);
720 }
721
gb_tty_port_activate(struct tty_port * port,struct tty_struct * tty)722 static int gb_tty_port_activate(struct tty_port *port,
723 struct tty_struct *tty)
724 {
725 struct gb_tty *gb_tty;
726
727 gb_tty = container_of(port, struct gb_tty, port);
728
729 return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
730 }
731
gb_tty_port_shutdown(struct tty_port * port)732 static void gb_tty_port_shutdown(struct tty_port *port)
733 {
734 struct gb_tty *gb_tty;
735 unsigned long flags;
736 int ret;
737
738 gb_tty = container_of(port, struct gb_tty, port);
739
740 gb_tty->close_pending = true;
741
742 cancel_work_sync(&gb_tty->tx_work);
743
744 spin_lock_irqsave(&gb_tty->write_lock, flags);
745 kfifo_reset_out(&gb_tty->write_fifo);
746 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
747
748 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
749 goto out;
750
751 ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
752 if (ret) {
753 dev_err(&gb_tty->gbphy_dev->dev,
754 "error flushing transmitter: %d\n", ret);
755 }
756
757 gb_uart_wait_for_all_credits(gb_tty);
758
759 out:
760 gb_tty->close_pending = false;
761
762 gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
763 }
764
gb_tty_port_destruct(struct tty_port * port)765 static void gb_tty_port_destruct(struct tty_port *port)
766 {
767 struct gb_tty *gb_tty = container_of(port, struct gb_tty, port);
768
769 if (gb_tty->minor != GB_NUM_MINORS)
770 release_minor(gb_tty);
771 kfifo_free(&gb_tty->write_fifo);
772 kfree(gb_tty->buffer);
773 kfree(gb_tty);
774 }
775
776 static const struct tty_operations gb_ops = {
777 .install = gb_tty_install,
778 .open = gb_tty_open,
779 .close = gb_tty_close,
780 .cleanup = gb_tty_cleanup,
781 .hangup = gb_tty_hangup,
782 .write = gb_tty_write,
783 .write_room = gb_tty_write_room,
784 .ioctl = gb_tty_ioctl,
785 .throttle = gb_tty_throttle,
786 .unthrottle = gb_tty_unthrottle,
787 .chars_in_buffer = gb_tty_chars_in_buffer,
788 .break_ctl = gb_tty_break_ctl,
789 .set_termios = gb_tty_set_termios,
790 .tiocmget = gb_tty_tiocmget,
791 .tiocmset = gb_tty_tiocmset,
792 .get_icount = gb_tty_get_icount,
793 .set_serial = set_serial_info,
794 .get_serial = get_serial_info,
795 };
796
797 static const struct tty_port_operations gb_port_ops = {
798 .dtr_rts = gb_tty_dtr_rts,
799 .activate = gb_tty_port_activate,
800 .shutdown = gb_tty_port_shutdown,
801 .destruct = gb_tty_port_destruct,
802 };
803
gb_uart_probe(struct gbphy_device * gbphy_dev,const struct gbphy_device_id * id)804 static int gb_uart_probe(struct gbphy_device *gbphy_dev,
805 const struct gbphy_device_id *id)
806 {
807 struct gb_connection *connection;
808 size_t max_payload;
809 struct gb_tty *gb_tty;
810 struct device *tty_dev;
811 int retval;
812 int minor;
813
814 connection = gb_connection_create(gbphy_dev->bundle,
815 le16_to_cpu(gbphy_dev->cport_desc->id),
816 gb_uart_request_handler);
817 if (IS_ERR(connection))
818 return PTR_ERR(connection);
819
820 max_payload = gb_operation_get_payload_size_max(connection);
821 if (max_payload < sizeof(struct gb_uart_send_data_request)) {
822 retval = -EINVAL;
823 goto exit_connection_destroy;
824 }
825
826 gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
827 if (!gb_tty) {
828 retval = -ENOMEM;
829 goto exit_connection_destroy;
830 }
831
832 tty_port_init(&gb_tty->port);
833 gb_tty->port.ops = &gb_port_ops;
834 gb_tty->minor = GB_NUM_MINORS;
835
836 gb_tty->buffer_payload_max = max_payload -
837 sizeof(struct gb_uart_send_data_request);
838
839 gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
840 if (!gb_tty->buffer) {
841 retval = -ENOMEM;
842 goto exit_put_port;
843 }
844
845 INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
846
847 retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
848 GFP_KERNEL);
849 if (retval)
850 goto exit_put_port;
851
852 gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
853 init_completion(&gb_tty->credits_complete);
854
855 minor = alloc_minor(gb_tty);
856 if (minor < 0) {
857 if (minor == -ENOSPC) {
858 dev_err(&gbphy_dev->dev,
859 "no more free minor numbers\n");
860 retval = -ENODEV;
861 } else {
862 retval = minor;
863 }
864 goto exit_put_port;
865 }
866
867 gb_tty->minor = minor;
868 spin_lock_init(&gb_tty->write_lock);
869 spin_lock_init(&gb_tty->read_lock);
870 init_waitqueue_head(&gb_tty->wioctl);
871 mutex_init(&gb_tty->mutex);
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_put_port;
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_put_port:
908 tty_port_put(&gb_tty->port);
909 exit_connection_destroy:
910 gb_connection_destroy(connection);
911
912 return retval;
913 }
914
gb_uart_remove(struct gbphy_device * gbphy_dev)915 static void gb_uart_remove(struct gbphy_device *gbphy_dev)
916 {
917 struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
918 struct gb_connection *connection = gb_tty->connection;
919 struct tty_struct *tty;
920 int ret;
921
922 ret = gbphy_runtime_get_sync(gbphy_dev);
923 if (ret)
924 gbphy_runtime_get_noresume(gbphy_dev);
925
926 mutex_lock(&gb_tty->mutex);
927 gb_tty->disconnected = true;
928
929 wake_up_all(&gb_tty->wioctl);
930 mutex_unlock(&gb_tty->mutex);
931
932 tty = tty_port_tty_get(&gb_tty->port);
933 if (tty) {
934 tty_vhangup(tty);
935 tty_kref_put(tty);
936 }
937
938 gb_connection_disable_rx(connection);
939 tty_unregister_device(gb_tty_driver, gb_tty->minor);
940
941 gb_connection_disable(connection);
942 gb_connection_destroy(connection);
943
944 tty_port_put(&gb_tty->port);
945 }
946
gb_tty_init(void)947 static int gb_tty_init(void)
948 {
949 int retval = 0;
950
951 gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
952 if (IS_ERR(gb_tty_driver)) {
953 pr_err("Can not allocate tty driver\n");
954 retval = -ENOMEM;
955 goto fail_unregister_dev;
956 }
957
958 gb_tty_driver->driver_name = "gb";
959 gb_tty_driver->name = GB_NAME;
960 gb_tty_driver->major = 0;
961 gb_tty_driver->minor_start = 0;
962 gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
963 gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
964 gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
965 gb_tty_driver->init_termios = tty_std_termios;
966 gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
967 CREAD | HUPCL | CLOCAL;
968 tty_set_operations(gb_tty_driver, &gb_ops);
969
970 retval = tty_register_driver(gb_tty_driver);
971 if (retval) {
972 pr_err("Can not register tty driver: %d\n", retval);
973 goto fail_put_gb_tty;
974 }
975
976 return 0;
977
978 fail_put_gb_tty:
979 tty_driver_kref_put(gb_tty_driver);
980 fail_unregister_dev:
981 return retval;
982 }
983
gb_tty_exit(void)984 static void gb_tty_exit(void)
985 {
986 tty_unregister_driver(gb_tty_driver);
987 tty_driver_kref_put(gb_tty_driver);
988 idr_destroy(&tty_minors);
989 }
990
991 static const struct gbphy_device_id gb_uart_id_table[] = {
992 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
993 { },
994 };
995 MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
996
997 static struct gbphy_driver uart_driver = {
998 .name = "uart",
999 .probe = gb_uart_probe,
1000 .remove = gb_uart_remove,
1001 .id_table = gb_uart_id_table,
1002 };
1003
gb_uart_driver_init(void)1004 static int gb_uart_driver_init(void)
1005 {
1006 int ret;
1007
1008 ret = gb_tty_init();
1009 if (ret)
1010 return ret;
1011
1012 ret = gb_gbphy_register(&uart_driver);
1013 if (ret) {
1014 gb_tty_exit();
1015 return ret;
1016 }
1017
1018 return 0;
1019 }
1020 module_init(gb_uart_driver_init);
1021
gb_uart_driver_exit(void)1022 static void gb_uart_driver_exit(void)
1023 {
1024 gb_gbphy_deregister(&uart_driver);
1025 gb_tty_exit();
1026 }
1027
1028 module_exit(gb_uart_driver_exit);
1029 MODULE_DESCRIPTION("UART driver for the Greybus 'generic' UART module");
1030 MODULE_LICENSE("GPL v2");
1031