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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 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
442static 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
459static 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
474static 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
481static 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
524static 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
536static 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
555static 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
574static 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
593static 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 ss->close_delay = jiffies_to_msecs(gb_tty->port.close_delay) / 10;
600 ss->closing_wait =
601 gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
602 ASYNC_CLOSING_WAIT_NONE :
603 jiffies_to_msecs(gb_tty->port.closing_wait) / 10;
604
605 return 0;
606}
607
608static int set_serial_info(struct tty_struct *tty,
609 struct serial_struct *ss)
610{
611 struct gb_tty *gb_tty = tty->driver_data;
612 unsigned int closing_wait;
613 unsigned int close_delay;
614 int retval = 0;
615
616 close_delay = msecs_to_jiffies(ss->close_delay * 10);
617 closing_wait = ss->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
618 ASYNC_CLOSING_WAIT_NONE :
619 msecs_to_jiffies(ss->closing_wait * 10);
620
621 mutex_lock(&gb_tty->port.mutex);
622 if (!capable(CAP_SYS_ADMIN)) {
623 if ((close_delay != gb_tty->port.close_delay) ||
624 (closing_wait != gb_tty->port.closing_wait))
625 retval = -EPERM;
626 } else {
627 gb_tty->port.close_delay = close_delay;
628 gb_tty->port.closing_wait = closing_wait;
629 }
630 mutex_unlock(&gb_tty->port.mutex);
631 return retval;
632}
633
634static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
635{
636 int retval = 0;
637 DECLARE_WAITQUEUE(wait, current);
638 struct async_icount old;
639 struct async_icount new;
640
641 if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
642 return -EINVAL;
643
644 do {
645 spin_lock_irq(&gb_tty->read_lock);
646 old = gb_tty->oldcount;
647 new = gb_tty->iocount;
648 gb_tty->oldcount = new;
649 spin_unlock_irq(&gb_tty->read_lock);
650
651 if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
652 break;
653 if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
654 break;
655 if ((arg & TIOCM_RI) && (old.rng != new.rng))
656 break;
657
658 add_wait_queue(&gb_tty->wioctl, &wait);
659 set_current_state(TASK_INTERRUPTIBLE);
660 schedule();
661 remove_wait_queue(&gb_tty->wioctl, &wait);
662 if (gb_tty->disconnected) {
663 if (arg & TIOCM_CD)
664 break;
665 retval = -ENODEV;
666 } else if (signal_pending(current)) {
667 retval = -ERESTARTSYS;
668 }
669 } while (!retval);
670
671 return retval;
672}
673
674static int gb_tty_get_icount(struct tty_struct *tty,
675 struct serial_icounter_struct *icount)
676{
677 struct gb_tty *gb_tty = tty->driver_data;
678
679 icount->dsr = gb_tty->iocount.dsr;
680 icount->rng = gb_tty->iocount.rng;
681 icount->dcd = gb_tty->iocount.dcd;
682 icount->frame = gb_tty->iocount.frame;
683 icount->overrun = gb_tty->iocount.overrun;
684 icount->parity = gb_tty->iocount.parity;
685 icount->brk = gb_tty->iocount.brk;
686
687 return 0;
688}
689
690static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
691 unsigned long arg)
692{
693 struct gb_tty *gb_tty = tty->driver_data;
694
695 switch (cmd) {
696 case TIOCMIWAIT:
697 return wait_serial_change(gb_tty, arg);
698 }
699
700 return -ENOIOCTLCMD;
701}
702
703static void gb_tty_dtr_rts(struct tty_port *port, bool active)
704{
705 struct gb_tty *gb_tty;
706 u8 newctrl;
707
708 gb_tty = container_of(port, struct gb_tty, port);
709 newctrl = gb_tty->ctrlout;
710
711 if (active)
712 newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
713 else
714 newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
715
716 gb_tty->ctrlout = newctrl;
717 send_control(gb_tty, newctrl);
718}
719
720static int gb_tty_port_activate(struct tty_port *port,
721 struct tty_struct *tty)
722{
723 struct gb_tty *gb_tty;
724
725 gb_tty = container_of(port, struct gb_tty, port);
726
727 return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
728}
729
730static void gb_tty_port_shutdown(struct tty_port *port)
731{
732 struct gb_tty *gb_tty;
733 unsigned long flags;
734 int ret;
735
736 gb_tty = container_of(port, struct gb_tty, port);
737
738 gb_tty->close_pending = true;
739
740 cancel_work_sync(&gb_tty->tx_work);
741
742 spin_lock_irqsave(&gb_tty->write_lock, flags);
743 kfifo_reset_out(&gb_tty->write_fifo);
744 spin_unlock_irqrestore(&gb_tty->write_lock, flags);
745
746 if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
747 goto out;
748
749 ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
750 if (ret) {
751 dev_err(&gb_tty->gbphy_dev->dev,
752 "error flushing transmitter: %d\n", ret);
753 }
754
755 gb_uart_wait_for_all_credits(gb_tty);
756
757out:
758 gb_tty->close_pending = false;
759
760 gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
761}
762
763static void gb_tty_port_destruct(struct tty_port *port)
764{
765 struct gb_tty *gb_tty = container_of(port, struct gb_tty, port);
766
767 if (gb_tty->minor != GB_NUM_MINORS)
768 release_minor(gb_tty);
769 kfifo_free(&gb_tty->write_fifo);
770 kfree(gb_tty->buffer);
771 kfree(gb_tty);
772}
773
774static const struct tty_operations gb_ops = {
775 .install = gb_tty_install,
776 .open = gb_tty_open,
777 .close = gb_tty_close,
778 .cleanup = gb_tty_cleanup,
779 .hangup = gb_tty_hangup,
780 .write = gb_tty_write,
781 .write_room = gb_tty_write_room,
782 .ioctl = gb_tty_ioctl,
783 .throttle = gb_tty_throttle,
784 .unthrottle = gb_tty_unthrottle,
785 .chars_in_buffer = gb_tty_chars_in_buffer,
786 .break_ctl = gb_tty_break_ctl,
787 .set_termios = gb_tty_set_termios,
788 .tiocmget = gb_tty_tiocmget,
789 .tiocmset = gb_tty_tiocmset,
790 .get_icount = gb_tty_get_icount,
791 .set_serial = set_serial_info,
792 .get_serial = get_serial_info,
793};
794
795static const struct tty_port_operations gb_port_ops = {
796 .dtr_rts = gb_tty_dtr_rts,
797 .activate = gb_tty_port_activate,
798 .shutdown = gb_tty_port_shutdown,
799 .destruct = gb_tty_port_destruct,
800};
801
802static int gb_uart_probe(struct gbphy_device *gbphy_dev,
803 const struct gbphy_device_id *id)
804{
805 struct gb_connection *connection;
806 size_t max_payload;
807 struct gb_tty *gb_tty;
808 struct device *tty_dev;
809 int retval;
810 int minor;
811
812 connection = gb_connection_create(gbphy_dev->bundle,
813 le16_to_cpu(gbphy_dev->cport_desc->id),
814 gb_uart_request_handler);
815 if (IS_ERR(connection))
816 return PTR_ERR(connection);
817
818 max_payload = gb_operation_get_payload_size_max(connection);
819 if (max_payload < sizeof(struct gb_uart_send_data_request)) {
820 retval = -EINVAL;
821 goto exit_connection_destroy;
822 }
823
824 gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
825 if (!gb_tty) {
826 retval = -ENOMEM;
827 goto exit_connection_destroy;
828 }
829
830 tty_port_init(&gb_tty->port);
831 gb_tty->port.ops = &gb_port_ops;
832 gb_tty->minor = GB_NUM_MINORS;
833
834 gb_tty->buffer_payload_max = max_payload -
835 sizeof(struct gb_uart_send_data_request);
836
837 gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
838 if (!gb_tty->buffer) {
839 retval = -ENOMEM;
840 goto exit_put_port;
841 }
842
843 INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
844
845 retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
846 GFP_KERNEL);
847 if (retval)
848 goto exit_put_port;
849
850 gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
851 init_completion(&gb_tty->credits_complete);
852
853 minor = alloc_minor(gb_tty);
854 if (minor < 0) {
855 if (minor == -ENOSPC) {
856 dev_err(&gbphy_dev->dev,
857 "no more free minor numbers\n");
858 retval = -ENODEV;
859 } else {
860 retval = minor;
861 }
862 goto exit_put_port;
863 }
864
865 gb_tty->minor = minor;
866 spin_lock_init(&gb_tty->write_lock);
867 spin_lock_init(&gb_tty->read_lock);
868 init_waitqueue_head(&gb_tty->wioctl);
869 mutex_init(&gb_tty->mutex);
870
871 gb_tty->connection = connection;
872 gb_tty->gbphy_dev = gbphy_dev;
873 gb_connection_set_data(connection, gb_tty);
874 gb_gbphy_set_data(gbphy_dev, gb_tty);
875
876 retval = gb_connection_enable_tx(connection);
877 if (retval)
878 goto exit_put_port;
879
880 send_control(gb_tty, gb_tty->ctrlout);
881
882 /* initialize the uart to be 9600n81 */
883 gb_tty->line_coding.rate = cpu_to_le32(9600);
884 gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
885 gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
886 gb_tty->line_coding.data_bits = 8;
887 send_line_coding(gb_tty);
888
889 retval = gb_connection_enable(connection);
890 if (retval)
891 goto exit_connection_disable;
892
893 tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
894 &gbphy_dev->dev);
895 if (IS_ERR(tty_dev)) {
896 retval = PTR_ERR(tty_dev);
897 goto exit_connection_disable;
898 }
899
900 gbphy_runtime_put_autosuspend(gbphy_dev);
901 return 0;
902
903exit_connection_disable:
904 gb_connection_disable(connection);
905exit_put_port:
906 tty_port_put(&gb_tty->port);
907exit_connection_destroy:
908 gb_connection_destroy(connection);
909
910 return retval;
911}
912
913static void gb_uart_remove(struct gbphy_device *gbphy_dev)
914{
915 struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
916 struct gb_connection *connection = gb_tty->connection;
917 struct tty_struct *tty;
918 int ret;
919
920 ret = gbphy_runtime_get_sync(gbphy_dev);
921 if (ret)
922 gbphy_runtime_get_noresume(gbphy_dev);
923
924 mutex_lock(&gb_tty->mutex);
925 gb_tty->disconnected = true;
926
927 wake_up_all(&gb_tty->wioctl);
928 mutex_unlock(&gb_tty->mutex);
929
930 tty = tty_port_tty_get(&gb_tty->port);
931 if (tty) {
932 tty_vhangup(tty);
933 tty_kref_put(tty);
934 }
935
936 gb_connection_disable_rx(connection);
937 tty_unregister_device(gb_tty_driver, gb_tty->minor);
938
939 gb_connection_disable(connection);
940 gb_connection_destroy(connection);
941
942 tty_port_put(&gb_tty->port);
943}
944
945static int gb_tty_init(void)
946{
947 int retval = 0;
948
949 gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
950 if (IS_ERR(gb_tty_driver)) {
951 pr_err("Can not allocate tty driver\n");
952 retval = -ENOMEM;
953 goto fail_unregister_dev;
954 }
955
956 gb_tty_driver->driver_name = "gb";
957 gb_tty_driver->name = GB_NAME;
958 gb_tty_driver->major = 0;
959 gb_tty_driver->minor_start = 0;
960 gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
961 gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
962 gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
963 gb_tty_driver->init_termios = tty_std_termios;
964 gb_tty_driver->init_termios.c_cflag = B9600 | CS8 |
965 CREAD | HUPCL | CLOCAL;
966 tty_set_operations(gb_tty_driver, &gb_ops);
967
968 retval = tty_register_driver(gb_tty_driver);
969 if (retval) {
970 pr_err("Can not register tty driver: %d\n", retval);
971 goto fail_put_gb_tty;
972 }
973
974 return 0;
975
976fail_put_gb_tty:
977 tty_driver_kref_put(gb_tty_driver);
978fail_unregister_dev:
979 return retval;
980}
981
982static void gb_tty_exit(void)
983{
984 tty_unregister_driver(gb_tty_driver);
985 tty_driver_kref_put(gb_tty_driver);
986 idr_destroy(&tty_minors);
987}
988
989static const struct gbphy_device_id gb_uart_id_table[] = {
990 { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
991 { },
992};
993MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
994
995static struct gbphy_driver uart_driver = {
996 .name = "uart",
997 .probe = gb_uart_probe,
998 .remove = gb_uart_remove,
999 .id_table = gb_uart_id_table,
1000};
1001
1002static int gb_uart_driver_init(void)
1003{
1004 int ret;
1005
1006 ret = gb_tty_init();
1007 if (ret)
1008 return ret;
1009
1010 ret = gb_gbphy_register(&uart_driver);
1011 if (ret) {
1012 gb_tty_exit();
1013 return ret;
1014 }
1015
1016 return 0;
1017}
1018module_init(gb_uart_driver_init);
1019
1020static void gb_uart_driver_exit(void)
1021{
1022 gb_gbphy_deregister(&uart_driver);
1023 gb_tty_exit();
1024}
1025
1026module_exit(gb_uart_driver_exit);
1027MODULE_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");