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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
43struct 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
69static struct tty_driver *gb_tty_driver;
70static DEFINE_IDR(tty_minors);
71static DEFINE_MUTEX(table_lock);
72
73static 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
129static 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
149static 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
199static 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
225static 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
281static 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
288static 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
298static 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
313static 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
331static 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
340static 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
360static 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
372static 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
382static 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;
397error:
398 tty_port_put(&gb_tty->port);
399 return retval;
400}
401
402static 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
409static 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
416static 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
423static 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
430static 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
443static 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
460static 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
475static 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
482static 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
539static 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
551static 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
570static 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
589static 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
608static 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->type = PORT_16550A;
614 ss->line = gb_tty->minor;
615 ss->xmit_fifo_size = 16;
616 ss->baud_base = 9600;
617 ss->close_delay = gb_tty->port.close_delay / 10;
618 ss->closing_wait =
619 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
620 ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
621 return 0;
622}
623
624static int set_serial_info(struct tty_struct *tty,
625 struct serial_struct *ss)
626{
627 struct gb_tty *gb_tty = tty->driver_data;
628 unsigned int closing_wait;
629 unsigned int close_delay;
630 int retval = 0;
631
632 close_delay = ss->close_delay * 10;
633 closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
634 ASYNC_CLOSING_WAIT_NONE : 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 retval = -EOPNOTSUPP;
643 } else {
644 gb_tty->port.close_delay = close_delay;
645 gb_tty->port.closing_wait = closing_wait;
646 }
647 mutex_unlock(&gb_tty->port.mutex);
648 return retval;
649}
650
651static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
652{
653 int retval = 0;
654 DECLARE_WAITQUEUE(wait, current);
655 struct async_icount old;
656 struct async_icount new;
657
658 if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
659 return -EINVAL;
660
661 do {
662 spin_lock_irq(&gb_tty->read_lock);
663 old = gb_tty->oldcount;
664 new = gb_tty->iocount;
665 gb_tty->oldcount = new;
666 spin_unlock_irq(&gb_tty->read_lock);
667
668 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
669 break;
670 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
671 break;
672 if ((arg & TIOCM_RI) && (old.rng != new.rng))
673 break;
674
675 add_wait_queue(&gb_tty->wioctl, &wait);
676 set_current_state(TASK_INTERRUPTIBLE);
677 schedule();
678 remove_wait_queue(&gb_tty->wioctl, &wait);
679 if (gb_tty->disconnected) {
680 if (arg & TIOCM_CD)
681 break;
682 retval = -ENODEV;
683 } else if (signal_pending(current)) {
684 retval = -ERESTARTSYS;
685 }
686 } while (!retval);
687
688 return retval;
689}
690
691static int gb_tty_get_icount(struct tty_struct *tty,
692 struct serial_icounter_struct *icount)
693{
694 struct gb_tty *gb_tty = tty->driver_data;
695
696 icount->dsr = gb_tty->iocount.dsr;
697 icount->rng = gb_tty->iocount.rng;
698 icount->dcd = gb_tty->iocount.dcd;
699 icount->frame = gb_tty->iocount.frame;
700 icount->overrun = gb_tty->iocount.overrun;
701 icount->parity = gb_tty->iocount.parity;
702 icount->brk = gb_tty->iocount.brk;
703
704 return 0;
705}
706
707static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
708 unsigned long arg)
709{
710 struct gb_tty *gb_tty = tty->driver_data;
711
712 switch (cmd) {
713 case TIOCMIWAIT:
714 return wait_serial_change(gb_tty, arg);
715 }
716
717 return -ENOIOCTLCMD;
718}
719
720static void gb_tty_dtr_rts(struct tty_port *port, int on)
721{
722 struct gb_tty *gb_tty;
723 u8 newctrl;
724
725 gb_tty = container_of(port, struct gb_tty, port);
726 newctrl = gb_tty->ctrlout;
727
728 if (on)
729 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
730 else
731 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
732
733 gb_tty->ctrlout = newctrl;
734 send_control(gb_tty, newctrl);
735}
736
737static int gb_tty_port_activate(struct tty_port *port,
738 struct tty_struct *tty)
739{
740 struct gb_tty *gb_tty;
741
742 gb_tty = container_of(port, struct gb_tty, port);
743
744 return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
745}
746
747static void gb_tty_port_shutdown(struct tty_port *port)
748{
749 struct gb_tty *gb_tty;
750 unsigned long flags;
751 int ret;
752
753 gb_tty = container_of(port, struct gb_tty, port);
754
755 gb_tty->close_pending = true;
756
757 cancel_work_sync(&gb_tty->tx_work);
758
759 spin_lock_irqsave(&gb_tty->write_lock, flags);
760 kfifo_reset_out(&gb_tty->write_fifo);
761 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
762
763 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
764 goto out;
765
766 ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
767 if (ret) {
768 dev_err(&gb_tty->gbphy_dev->dev,
769 "error flushing transmitter: %d\n", ret);
770 }
771
772 gb_uart_wait_for_all_credits(gb_tty);
773
774out:
775 gb_tty->close_pending = false;
776
777 gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
778}
779
780static const struct tty_operations gb_ops = {
781 .install = gb_tty_install,
782 .open = gb_tty_open,
783 .close = gb_tty_close,
784 .cleanup = gb_tty_cleanup,
785 .hangup = gb_tty_hangup,
786 .write = gb_tty_write,
787 .write_room = gb_tty_write_room,
788 .ioctl = gb_tty_ioctl,
789 .throttle = gb_tty_throttle,
790 .unthrottle = gb_tty_unthrottle,
791 .chars_in_buffer = gb_tty_chars_in_buffer,
792 .break_ctl = gb_tty_break_ctl,
793 .set_termios = gb_tty_set_termios,
794 .tiocmget = gb_tty_tiocmget,
795 .tiocmset = gb_tty_tiocmset,
796 .get_icount = gb_tty_get_icount,
797 .set_serial = set_serial_info,
798 .get_serial = get_serial_info,
799};
800
801static const struct tty_port_operations gb_port_ops = {
802 .dtr_rts = gb_tty_dtr_rts,
803 .activate = gb_tty_port_activate,
804 .shutdown = gb_tty_port_shutdown,
805};
806
807static int gb_uart_probe(struct gbphy_device *gbphy_dev,
808 const struct gbphy_device_id *id)
809{
810 struct gb_connection *connection;
811 size_t max_payload;
812 struct gb_tty *gb_tty;
813 struct device *tty_dev;
814 int retval;
815 int minor;
816
817 gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
818 if (!gb_tty)
819 return -ENOMEM;
820
821 connection = gb_connection_create(gbphy_dev->bundle,
822 le16_to_cpu(gbphy_dev->cport_desc->id),
823 gb_uart_request_handler);
824 if (IS_ERR(connection)) {
825 retval = PTR_ERR(connection);
826 goto exit_tty_free;
827 }
828
829 max_payload = gb_operation_get_payload_size_max(connection);
830 if (max_payload < sizeof(struct gb_uart_send_data_request)) {
831 retval = -EINVAL;
832 goto exit_connection_destroy;
833 }
834
835 gb_tty->buffer_payload_max = max_payload -
836 sizeof(struct gb_uart_send_data_request);
837
838 gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
839 if (!gb_tty->buffer) {
840 retval = -ENOMEM;
841 goto exit_connection_destroy;
842 }
843
844 INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
845
846 retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
847 GFP_KERNEL);
848 if (retval)
849 goto exit_buf_free;
850
851 gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
852 init_completion(&gb_tty->credits_complete);
853
854 minor = alloc_minor(gb_tty);
855 if (minor < 0) {
856 if (minor == -ENOSPC) {
857 dev_err(&gbphy_dev->dev,
858 "no more free minor numbers\n");
859 retval = -ENODEV;
860 } else {
861 retval = minor;
862 }
863 goto exit_kfifo_free;
864 }
865
866 gb_tty->minor = minor;
867 spin_lock_init(&gb_tty->write_lock);
868 spin_lock_init(&gb_tty->read_lock);
869 init_waitqueue_head(&gb_tty->wioctl);
870 mutex_init(&gb_tty->mutex);
871
872 tty_port_init(&gb_tty->port);
873 gb_tty->port.ops = &gb_port_ops;
874
875 gb_tty->connection = connection;
876 gb_tty->gbphy_dev = gbphy_dev;
877 gb_connection_set_data(connection, gb_tty);
878 gb_gbphy_set_data(gbphy_dev, gb_tty);
879
880 retval = gb_connection_enable_tx(connection);
881 if (retval)
882 goto exit_release_minor;
883
884 send_control(gb_tty, gb_tty->ctrlout);
885
886 /* initialize the uart to be 9600n81 */
887 gb_tty->line_coding.rate = cpu_to_le32(9600);
888 gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
889 gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
890 gb_tty->line_coding.data_bits = 8;
891 send_line_coding(gb_tty);
892
893 retval = gb_connection_enable(connection);
894 if (retval)
895 goto exit_connection_disable;
896
897 tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
898 &gbphy_dev->dev);
899 if (IS_ERR(tty_dev)) {
900 retval = PTR_ERR(tty_dev);
901 goto exit_connection_disable;
902 }
903
904 gbphy_runtime_put_autosuspend(gbphy_dev);
905 return 0;
906
907exit_connection_disable:
908 gb_connection_disable(connection);
909exit_release_minor:
910 release_minor(gb_tty);
911exit_kfifo_free:
912 kfifo_free(&gb_tty->write_fifo);
913exit_buf_free:
914 kfree(gb_tty->buffer);
915exit_connection_destroy:
916 gb_connection_destroy(connection);
917exit_tty_free:
918 kfree(gb_tty);
919
920 return retval;
921}
922
923static void gb_uart_remove(struct gbphy_device *gbphy_dev)
924{
925 struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
926 struct gb_connection *connection = gb_tty->connection;
927 struct tty_struct *tty;
928 int ret;
929
930 ret = gbphy_runtime_get_sync(gbphy_dev);
931 if (ret)
932 gbphy_runtime_get_noresume(gbphy_dev);
933
934 mutex_lock(&gb_tty->mutex);
935 gb_tty->disconnected = true;
936
937 wake_up_all(&gb_tty->wioctl);
938 mutex_unlock(&gb_tty->mutex);
939
940 tty = tty_port_tty_get(&gb_tty->port);
941 if (tty) {
942 tty_vhangup(tty);
943 tty_kref_put(tty);
944 }
945
946 gb_connection_disable_rx(connection);
947 tty_unregister_device(gb_tty_driver, gb_tty->minor);
948
949 /* FIXME - free transmit / receive buffers */
950
951 gb_connection_disable(connection);
952 tty_port_destroy(&gb_tty->port);
953 gb_connection_destroy(connection);
954 release_minor(gb_tty);
955 kfifo_free(&gb_tty->write_fifo);
956 kfree(gb_tty->buffer);
957 kfree(gb_tty);
958}
959
960static int gb_tty_init(void)
961{
962 int retval = 0;
963
964 gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
965 if (IS_ERR(gb_tty_driver)) {
966 pr_err("Can not allocate tty driver\n");
967 retval = -ENOMEM;
968 goto fail_unregister_dev;
969 }
970
971 gb_tty_driver->driver_name = "gb";
972 gb_tty_driver->name = GB_NAME;
973 gb_tty_driver->major = 0;
974 gb_tty_driver->minor_start = 0;
975 gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
976 gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
977 gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
978 gb_tty_driver->init_termios = tty_std_termios;
979 gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
980 CREAD | HUPCL | CLOCAL;
981 tty_set_operations(gb_tty_driver, &gb_ops);
982
983 retval = tty_register_driver(gb_tty_driver);
984 if (retval) {
985 pr_err("Can not register tty driver: %d\n", retval);
986 goto fail_put_gb_tty;
987 }
988
989 return 0;
990
991fail_put_gb_tty:
992 put_tty_driver(gb_tty_driver);
993fail_unregister_dev:
994 return retval;
995}
996
997static void gb_tty_exit(void)
998{
999 tty_unregister_driver(gb_tty_driver);
1000 put_tty_driver(gb_tty_driver);
1001 idr_destroy(&tty_minors);
1002}
1003
1004static const struct gbphy_device_id gb_uart_id_table[] = {
1005 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
1006 { },
1007};
1008MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
1009
1010static struct gbphy_driver uart_driver = {
1011 .name = "uart",
1012 .probe = gb_uart_probe,
1013 .remove = gb_uart_remove,
1014 .id_table = gb_uart_id_table,
1015};
1016
1017static int gb_uart_driver_init(void)
1018{
1019 int ret;
1020
1021 ret = gb_tty_init();
1022 if (ret)
1023 return ret;
1024
1025 ret = gb_gbphy_register(&uart_driver);
1026 if (ret) {
1027 gb_tty_exit();
1028 return ret;
1029 }
1030
1031 return 0;
1032}
1033module_init(gb_uart_driver_init);
1034
1035static void gb_uart_driver_exit(void)
1036{
1037 gb_gbphy_deregister(&uart_driver);
1038 gb_tty_exit();
1039}
1040
1041module_exit(gb_uart_driver_exit);
1042MODULE_LICENSE("GPL v2");
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
43struct 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
69static struct tty_driver *gb_tty_driver;
70static DEFINE_IDR(tty_minors);
71static DEFINE_MUTEX(table_lock);
72
73static 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
129static 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
149static 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
199static 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
225static 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
281static 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
288static 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
298static 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
313static 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
331static 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
340static 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
360static 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
372static 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
382static 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;
397error:
398 tty_port_put(&gb_tty->port);
399 return retval;
400}
401
402static 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
409static 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
416static 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
423static 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
430static 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
443static unsigned 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
460static unsigned 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 unsigned 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
475static 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
482static void gb_tty_set_termios(struct tty_struct *tty,
483 const 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 newline.data_bits = tty_get_char_size(termios->c_cflag);
498
499 /* FIXME: needs to clear unsupported bits in the termios */
500 gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
501
502 if (C_BAUD(tty) == B0) {
503 newline.rate = gb_tty->line_coding.rate;
504 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
505 } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
506 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
507 }
508
509 if (newctrl != gb_tty->ctrlout) {
510 gb_tty->ctrlout = newctrl;
511 send_control(gb_tty, newctrl);
512 }
513
514 if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
515 newline.flow_control = GB_SERIAL_AUTO_RTSCTS_EN;
516 else
517 newline.flow_control = 0;
518
519 if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
520 memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
521 send_line_coding(gb_tty);
522 }
523}
524
525static int gb_tty_tiocmget(struct tty_struct *tty)
526{
527 struct gb_tty *gb_tty = tty->driver_data;
528
529 return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
530 (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
531 (gb_tty->ctrlin & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
532 (gb_tty->ctrlin & GB_UART_CTRL_RI ? TIOCM_RI : 0) |
533 (gb_tty->ctrlin & GB_UART_CTRL_DCD ? TIOCM_CD : 0) |
534 TIOCM_CTS;
535}
536
537static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
538 unsigned int clear)
539{
540 struct gb_tty *gb_tty = tty->driver_data;
541 u8 newctrl = gb_tty->ctrlout;
542
543 set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
544 (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
545 clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
546 (clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
547
548 newctrl = (newctrl & ~clear) | set;
549 if (gb_tty->ctrlout == newctrl)
550 return 0;
551
552 gb_tty->ctrlout = newctrl;
553 return send_control(gb_tty, newctrl);
554}
555
556static void gb_tty_throttle(struct tty_struct *tty)
557{
558 struct gb_tty *gb_tty = tty->driver_data;
559 unsigned char stop_char;
560 int retval;
561
562 if (I_IXOFF(tty)) {
563 stop_char = STOP_CHAR(tty);
564 retval = gb_tty_write(tty, &stop_char, 1);
565 if (retval <= 0)
566 return;
567 }
568
569 if (tty->termios.c_cflag & CRTSCTS) {
570 gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
571 retval = send_control(gb_tty, gb_tty->ctrlout);
572 }
573}
574
575static void gb_tty_unthrottle(struct tty_struct *tty)
576{
577 struct gb_tty *gb_tty = tty->driver_data;
578 unsigned char start_char;
579 int retval;
580
581 if (I_IXOFF(tty)) {
582 start_char = START_CHAR(tty);
583 retval = gb_tty_write(tty, &start_char, 1);
584 if (retval <= 0)
585 return;
586 }
587
588 if (tty->termios.c_cflag & CRTSCTS) {
589 gb_tty->ctrlout |= GB_UART_CTRL_RTS;
590 retval = send_control(gb_tty, gb_tty->ctrlout);
591 }
592}
593
594static int get_serial_info(struct tty_struct *tty,
595 struct serial_struct *ss)
596{
597 struct gb_tty *gb_tty = tty->driver_data;
598
599 ss->line = gb_tty->minor;
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
606 return 0;
607}
608
609static int set_serial_info(struct tty_struct *tty,
610 struct serial_struct *ss)
611{
612 struct gb_tty *gb_tty = tty->driver_data;
613 unsigned int closing_wait;
614 unsigned int close_delay;
615 int retval = 0;
616
617 close_delay = msecs_to_jiffies(ss->close_delay * 10);
618 closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
619 ASYNC_CLOSING_WAIT_NONE :
620 msecs_to_jiffies(ss->closing_wait * 10);
621
622 mutex_lock(&gb_tty->port.mutex);
623 if (!capable(CAP_SYS_ADMIN)) {
624 if ((close_delay != gb_tty->port.close_delay) ||
625 (closing_wait != gb_tty->port.closing_wait))
626 retval = -EPERM;
627 } else {
628 gb_tty->port.close_delay = close_delay;
629 gb_tty->port.closing_wait = closing_wait;
630 }
631 mutex_unlock(&gb_tty->port.mutex);
632 return retval;
633}
634
635static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
636{
637 int retval = 0;
638 DECLARE_WAITQUEUE(wait, current);
639 struct async_icount old;
640 struct async_icount new;
641
642 if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
643 return -EINVAL;
644
645 do {
646 spin_lock_irq(&gb_tty->read_lock);
647 old = gb_tty->oldcount;
648 new = gb_tty->iocount;
649 gb_tty->oldcount = new;
650 spin_unlock_irq(&gb_tty->read_lock);
651
652 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
653 break;
654 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
655 break;
656 if ((arg & TIOCM_RI) && (old.rng != new.rng))
657 break;
658
659 add_wait_queue(&gb_tty->wioctl, &wait);
660 set_current_state(TASK_INTERRUPTIBLE);
661 schedule();
662 remove_wait_queue(&gb_tty->wioctl, &wait);
663 if (gb_tty->disconnected) {
664 if (arg & TIOCM_CD)
665 break;
666 retval = -ENODEV;
667 } else if (signal_pending(current)) {
668 retval = -ERESTARTSYS;
669 }
670 } while (!retval);
671
672 return retval;
673}
674
675static int gb_tty_get_icount(struct tty_struct *tty,
676 struct serial_icounter_struct *icount)
677{
678 struct gb_tty *gb_tty = tty->driver_data;
679
680 icount->dsr = gb_tty->iocount.dsr;
681 icount->rng = gb_tty->iocount.rng;
682 icount->dcd = gb_tty->iocount.dcd;
683 icount->frame = gb_tty->iocount.frame;
684 icount->overrun = gb_tty->iocount.overrun;
685 icount->parity = gb_tty->iocount.parity;
686 icount->brk = gb_tty->iocount.brk;
687
688 return 0;
689}
690
691static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
692 unsigned long arg)
693{
694 struct gb_tty *gb_tty = tty->driver_data;
695
696 switch (cmd) {
697 case TIOCMIWAIT:
698 return wait_serial_change(gb_tty, arg);
699 }
700
701 return -ENOIOCTLCMD;
702}
703
704static void gb_tty_dtr_rts(struct tty_port *port, int on)
705{
706 struct gb_tty *gb_tty;
707 u8 newctrl;
708
709 gb_tty = container_of(port, struct gb_tty, port);
710 newctrl = gb_tty->ctrlout;
711
712 if (on)
713 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
714 else
715 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
716
717 gb_tty->ctrlout = newctrl;
718 send_control(gb_tty, newctrl);
719}
720
721static int gb_tty_port_activate(struct tty_port *port,
722 struct tty_struct *tty)
723{
724 struct gb_tty *gb_tty;
725
726 gb_tty = container_of(port, struct gb_tty, port);
727
728 return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
729}
730
731static void gb_tty_port_shutdown(struct tty_port *port)
732{
733 struct gb_tty *gb_tty;
734 unsigned long flags;
735 int ret;
736
737 gb_tty = container_of(port, struct gb_tty, port);
738
739 gb_tty->close_pending = true;
740
741 cancel_work_sync(&gb_tty->tx_work);
742
743 spin_lock_irqsave(&gb_tty->write_lock, flags);
744 kfifo_reset_out(&gb_tty->write_fifo);
745 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
746
747 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
748 goto out;
749
750 ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
751 if (ret) {
752 dev_err(&gb_tty->gbphy_dev->dev,
753 "error flushing transmitter: %d\n", ret);
754 }
755
756 gb_uart_wait_for_all_credits(gb_tty);
757
758out:
759 gb_tty->close_pending = false;
760
761 gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
762}
763
764static void gb_tty_port_destruct(struct tty_port *port)
765{
766 struct gb_tty *gb_tty = container_of(port, struct gb_tty, port);
767
768 if (gb_tty->minor != GB_NUM_MINORS)
769 release_minor(gb_tty);
770 kfifo_free(&gb_tty->write_fifo);
771 kfree(gb_tty->buffer);
772 kfree(gb_tty);
773}
774
775static const struct tty_operations gb_ops = {
776 .install = gb_tty_install,
777 .open = gb_tty_open,
778 .close = gb_tty_close,
779 .cleanup = gb_tty_cleanup,
780 .hangup = gb_tty_hangup,
781 .write = gb_tty_write,
782 .write_room = gb_tty_write_room,
783 .ioctl = gb_tty_ioctl,
784 .throttle = gb_tty_throttle,
785 .unthrottle = gb_tty_unthrottle,
786 .chars_in_buffer = gb_tty_chars_in_buffer,
787 .break_ctl = gb_tty_break_ctl,
788 .set_termios = gb_tty_set_termios,
789 .tiocmget = gb_tty_tiocmget,
790 .tiocmset = gb_tty_tiocmset,
791 .get_icount = gb_tty_get_icount,
792 .set_serial = set_serial_info,
793 .get_serial = get_serial_info,
794};
795
796static const struct tty_port_operations gb_port_ops = {
797 .dtr_rts = gb_tty_dtr_rts,
798 .activate = gb_tty_port_activate,
799 .shutdown = gb_tty_port_shutdown,
800 .destruct = gb_tty_port_destruct,
801};
802
803static int gb_uart_probe(struct gbphy_device *gbphy_dev,
804 const struct gbphy_device_id *id)
805{
806 struct gb_connection *connection;
807 size_t max_payload;
808 struct gb_tty *gb_tty;
809 struct device *tty_dev;
810 int retval;
811 int minor;
812
813 connection = gb_connection_create(gbphy_dev->bundle,
814 le16_to_cpu(gbphy_dev->cport_desc->id),
815 gb_uart_request_handler);
816 if (IS_ERR(connection))
817 return PTR_ERR(connection);
818
819 max_payload = gb_operation_get_payload_size_max(connection);
820 if (max_payload < sizeof(struct gb_uart_send_data_request)) {
821 retval = -EINVAL;
822 goto exit_connection_destroy;
823 }
824
825 gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
826 if (!gb_tty) {
827 retval = -ENOMEM;
828 goto exit_connection_destroy;
829 }
830
831 tty_port_init(&gb_tty->port);
832 gb_tty->port.ops = &gb_port_ops;
833 gb_tty->minor = GB_NUM_MINORS;
834
835 gb_tty->buffer_payload_max = max_payload -
836 sizeof(struct gb_uart_send_data_request);
837
838 gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
839 if (!gb_tty->buffer) {
840 retval = -ENOMEM;
841 goto exit_put_port;
842 }
843
844 INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
845
846 retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
847 GFP_KERNEL);
848 if (retval)
849 goto exit_put_port;
850
851 gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
852 init_completion(&gb_tty->credits_complete);
853
854 minor = alloc_minor(gb_tty);
855 if (minor < 0) {
856 if (minor == -ENOSPC) {
857 dev_err(&gbphy_dev->dev,
858 "no more free minor numbers\n");
859 retval = -ENODEV;
860 } else {
861 retval = minor;
862 }
863 goto exit_put_port;
864 }
865
866 gb_tty->minor = minor;
867 spin_lock_init(&gb_tty->write_lock);
868 spin_lock_init(&gb_tty->read_lock);
869 init_waitqueue_head(&gb_tty->wioctl);
870 mutex_init(&gb_tty->mutex);
871
872 gb_tty->connection = connection;
873 gb_tty->gbphy_dev = gbphy_dev;
874 gb_connection_set_data(connection, gb_tty);
875 gb_gbphy_set_data(gbphy_dev, gb_tty);
876
877 retval = gb_connection_enable_tx(connection);
878 if (retval)
879 goto exit_put_port;
880
881 send_control(gb_tty, gb_tty->ctrlout);
882
883 /* initialize the uart to be 9600n81 */
884 gb_tty->line_coding.rate = cpu_to_le32(9600);
885 gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
886 gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
887 gb_tty->line_coding.data_bits = 8;
888 send_line_coding(gb_tty);
889
890 retval = gb_connection_enable(connection);
891 if (retval)
892 goto exit_connection_disable;
893
894 tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
895 &gbphy_dev->dev);
896 if (IS_ERR(tty_dev)) {
897 retval = PTR_ERR(tty_dev);
898 goto exit_connection_disable;
899 }
900
901 gbphy_runtime_put_autosuspend(gbphy_dev);
902 return 0;
903
904exit_connection_disable:
905 gb_connection_disable(connection);
906exit_put_port:
907 tty_port_put(&gb_tty->port);
908exit_connection_destroy:
909 gb_connection_destroy(connection);
910
911 return retval;
912}
913
914static void gb_uart_remove(struct gbphy_device *gbphy_dev)
915{
916 struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
917 struct gb_connection *connection = gb_tty->connection;
918 struct tty_struct *tty;
919 int ret;
920
921 ret = gbphy_runtime_get_sync(gbphy_dev);
922 if (ret)
923 gbphy_runtime_get_noresume(gbphy_dev);
924
925 mutex_lock(&gb_tty->mutex);
926 gb_tty->disconnected = true;
927
928 wake_up_all(&gb_tty->wioctl);
929 mutex_unlock(&gb_tty->mutex);
930
931 tty = tty_port_tty_get(&gb_tty->port);
932 if (tty) {
933 tty_vhangup(tty);
934 tty_kref_put(tty);
935 }
936
937 gb_connection_disable_rx(connection);
938 tty_unregister_device(gb_tty_driver, gb_tty->minor);
939
940 gb_connection_disable(connection);
941 gb_connection_destroy(connection);
942
943 tty_port_put(&gb_tty->port);
944}
945
946static int gb_tty_init(void)
947{
948 int retval = 0;
949
950 gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
951 if (IS_ERR(gb_tty_driver)) {
952 pr_err("Can not allocate tty driver\n");
953 retval = -ENOMEM;
954 goto fail_unregister_dev;
955 }
956
957 gb_tty_driver->driver_name = "gb";
958 gb_tty_driver->name = GB_NAME;
959 gb_tty_driver->major = 0;
960 gb_tty_driver->minor_start = 0;
961 gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
962 gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
963 gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
964 gb_tty_driver->init_termios = tty_std_termios;
965 gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
966 CREAD | HUPCL | CLOCAL;
967 tty_set_operations(gb_tty_driver, &gb_ops);
968
969 retval = tty_register_driver(gb_tty_driver);
970 if (retval) {
971 pr_err("Can not register tty driver: %d\n", retval);
972 goto fail_put_gb_tty;
973 }
974
975 return 0;
976
977fail_put_gb_tty:
978 tty_driver_kref_put(gb_tty_driver);
979fail_unregister_dev:
980 return retval;
981}
982
983static void gb_tty_exit(void)
984{
985 tty_unregister_driver(gb_tty_driver);
986 tty_driver_kref_put(gb_tty_driver);
987 idr_destroy(&tty_minors);
988}
989
990static const struct gbphy_device_id gb_uart_id_table[] = {
991 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
992 { },
993};
994MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
995
996static struct gbphy_driver uart_driver = {
997 .name = "uart",
998 .probe = gb_uart_probe,
999 .remove = gb_uart_remove,
1000 .id_table = gb_uart_id_table,
1001};
1002
1003static int gb_uart_driver_init(void)
1004{
1005 int ret;
1006
1007 ret = gb_tty_init();
1008 if (ret)
1009 return ret;
1010
1011 ret = gb_gbphy_register(&uart_driver);
1012 if (ret) {
1013 gb_tty_exit();
1014 return ret;
1015 }
1016
1017 return 0;
1018}
1019module_init(gb_uart_driver_init);
1020
1021static void gb_uart_driver_exit(void)
1022{
1023 gb_gbphy_deregister(&uart_driver);
1024 gb_tty_exit();
1025}
1026
1027module_exit(gb_uart_driver_exit);
1028MODULE_LICENSE("GPL v2");