1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
|
/*
* UART driver for the Greybus "generic" UART module.
*
* Copyright 2014 Google Inc.
*
* Released under the GPLv2 only.
*
* Heavily based on drivers/usb/class/cdc-acm.c and
* drivers/usb/serial/usb-serial.c.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/mutex.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/idr.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include "greybus.h"
#define GB_NUM_MINORS 255 /* 255 is enough for anyone... */
#define GB_NAME "ttyGB"
struct gb_tty {
struct tty_port port;
struct greybus_module *gmod;
u16 cport_id;
unsigned int minor;
unsigned char clocal;
unsigned int throttled:1;
unsigned int throttle_req:1;
bool disconnected;
int writesize; // FIXME - set this somehow.
spinlock_t read_lock;
spinlock_t write_lock;
struct async_icount iocount;
struct async_icount oldcount;
wait_queue_head_t wioctl;
struct mutex mutex;
};
static const struct greybus_module_id id_table[] = {
{ GREYBUS_DEVICE(0x45, 0x45) }, /* make shit up */
{ }, /* terminating NULL entry */
};
static struct tty_driver *gb_tty_driver;
static DEFINE_IDR(tty_minors);
static DEFINE_MUTEX(table_lock);
static struct gb_tty *get_gb_by_minor(unsigned minor)
{
struct gb_tty *gb_tty;
mutex_lock(&table_lock);
gb_tty = idr_find(&tty_minors, minor);
if (gb_tty) {
mutex_lock(&gb_tty->mutex);
if (gb_tty->disconnected) {
mutex_unlock(&gb_tty->mutex);
gb_tty = NULL;
} else {
tty_port_get(&gb_tty->port);
mutex_unlock(&gb_tty->mutex);
}
}
mutex_unlock(&table_lock);
return gb_tty;
}
static int alloc_minor(struct gb_tty *gb_tty)
{
int minor;
mutex_lock(&table_lock);
minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
mutex_unlock(&table_lock);
if (minor >= 0)
gb_tty->minor = minor;
return minor;
}
static void release_minor(struct gb_tty *gb_tty)
{
int minor = gb_tty->minor;
gb_tty->minor = 0; /* Maybe should use an invalid value instead */
mutex_lock(&table_lock);
idr_remove(&tty_minors, minor);
mutex_unlock(&table_lock);
}
static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
{
struct gb_tty *gb_tty;
int retval;
gb_tty = get_gb_by_minor(tty->index);
if (!gb_tty)
return -ENODEV;
retval = tty_standard_install(driver, tty);
if (retval)
goto error;
tty->driver_data = gb_tty;
return 0;
error:
tty_port_put(&gb_tty->port);
return retval;
}
static int gb_tty_open(struct tty_struct *tty, struct file *file)
{
struct gb_tty *gb_tty = tty->driver_data;
return tty_port_open(&gb_tty->port, tty, file);
}
static void gb_tty_close(struct tty_struct *tty, struct file *file)
{
struct gb_tty *gb_tty = tty->driver_data;
tty_port_close(&gb_tty->port, tty, file);
}
static void gb_tty_cleanup(struct tty_struct *tty)
{
struct gb_tty *gb_tty = tty->driver_data;
tty_port_put(&gb_tty->port);
}
static void gb_tty_hangup(struct tty_struct *tty)
{
struct gb_tty *gb_tty = tty->driver_data;
tty_port_hangup(&gb_tty->port);
}
static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
int count)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - actually implement...
return 0;
}
static int gb_tty_write_room(struct tty_struct *tty)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - how much do we want to say we have room for?
return 0;
}
static int gb_tty_chars_in_buffer(struct tty_struct *tty)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - how many left to send?
return 0;
}
static int gb_tty_break_ctl(struct tty_struct *tty, int state)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - send a break, if asked to...
return 0;
}
static void gb_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
{
// FIXME - is this it???
tty_termios_copy_hw(&tty->termios, old);
}
static int gb_tty_tiocmget(struct tty_struct *tty)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - get some tiocms!
return 0;
}
static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
unsigned int clear)
{
// struct gb_tty *gb_tty = tty->driver_data;
// FIXME - set some tiocms!
return 0;
}
static void gb_tty_throttle(struct tty_struct *tty)
{
struct gb_tty *gb_tty = tty->driver_data;
spin_lock_irq(&gb_tty->read_lock);
gb_tty->throttle_req = 1;
spin_unlock_irq(&gb_tty->read_lock);
}
static void gb_tty_unthrottle(struct tty_struct *tty)
{
struct gb_tty *gb_tty = tty->driver_data;
unsigned int was_throttled;
spin_lock_irq(&gb_tty->read_lock);
was_throttled = gb_tty->throttled;
gb_tty->throttle_req = 0;
gb_tty->throttled = 0;
spin_unlock_irq(&gb_tty->read_lock);
if (was_throttled) {
// FIXME - send more data
}
}
static int get_serial_info(struct gb_tty *gb_tty,
struct serial_struct __user *info)
{
struct serial_struct tmp;
if (!info)
return -EINVAL;
memset(&tmp, 0, sizeof(tmp));
tmp.flags = ASYNC_LOW_LATENCY;
tmp.xmit_fifo_size = gb_tty->writesize;
tmp.baud_base = 0; // FIXME
tmp.close_delay = gb_tty->port.close_delay / 10;
tmp.closing_wait = gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
if (copy_to_user(info, &tmp, sizeof(tmp)))
return -EFAULT;
return 0;
}
static int set_serial_info(struct gb_tty *gb_tty,
struct serial_struct __user *newinfo)
{
struct serial_struct new_serial;
unsigned int closing_wait;
unsigned int close_delay;
int retval = 0;
if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
return -EFAULT;
close_delay = new_serial.close_delay * 10;
closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
mutex_lock(&gb_tty->port.mutex);
if (!capable(CAP_SYS_ADMIN)) {
if ((close_delay != gb_tty->port.close_delay) ||
(closing_wait != gb_tty->port.closing_wait))
retval = -EPERM;
else
retval = -EOPNOTSUPP;
} else {
gb_tty->port.close_delay = close_delay;
gb_tty->port.closing_wait = closing_wait;
}
mutex_unlock(&gb_tty->port.mutex);
return retval;
}
static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
{
int retval = 0;
DECLARE_WAITQUEUE(wait, current);
struct async_icount old;
struct async_icount new;
if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
return -EINVAL;
do {
spin_lock_irq(&gb_tty->read_lock);
old = gb_tty->oldcount;
new = gb_tty->iocount;
gb_tty->oldcount = new;
spin_unlock_irq(&gb_tty->read_lock);
if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
break;
if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
break;
if ((arg & TIOCM_RI) && (old.rng != new.rng))
break;
add_wait_queue(&gb_tty->wioctl, &wait);
set_current_state(TASK_INTERRUPTIBLE);
schedule();
remove_wait_queue(&gb_tty->wioctl, &wait);
if (gb_tty->disconnected) {
if (arg & TIOCM_CD)
break;
retval = -ENODEV;
} else if (signal_pending(current)) {
retval = -ERESTARTSYS;
}
} while (!retval);
return retval;
}
static int get_serial_usage(struct gb_tty *gb_tty,
struct serial_icounter_struct __user *count)
{
struct serial_icounter_struct icount;
int retval = 0;
memset(&icount, 0, sizeof(icount));
icount.dsr = gb_tty->iocount.dsr;
icount.rng = gb_tty->iocount.rng;
icount.dcd = gb_tty->iocount.dcd;
icount.frame = gb_tty->iocount.frame;
icount.overrun = gb_tty->iocount.overrun;
icount.parity = gb_tty->iocount.parity;
icount.brk = gb_tty->iocount.brk;
if (copy_to_user(count, &icount, sizeof(icount)) > 0)
retval = -EFAULT;
return retval;
}
static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
unsigned long arg)
{
struct gb_tty *gb_tty = tty->driver_data;
switch (cmd) {
case TIOCGSERIAL:
return get_serial_info(gb_tty,
(struct serial_struct __user *)arg);
case TIOCSSERIAL:
return set_serial_info(gb_tty,
(struct serial_struct __user *)arg);
case TIOCMIWAIT:
return wait_serial_change(gb_tty, arg);
case TIOCGICOUNT:
return get_serial_usage(gb_tty,
(struct serial_icounter_struct __user *)arg);
}
return -ENOIOCTLCMD;
}
static const struct tty_operations gb_ops = {
.install = gb_tty_install,
.open = gb_tty_open,
.close = gb_tty_close,
.cleanup = gb_tty_cleanup,
.hangup = gb_tty_hangup,
.write = gb_tty_write,
.write_room = gb_tty_write_room,
.ioctl = gb_tty_ioctl,
.throttle = gb_tty_throttle,
.unthrottle = gb_tty_unthrottle,
.chars_in_buffer = gb_tty_chars_in_buffer,
.break_ctl = gb_tty_break_ctl,
.set_termios = gb_tty_set_termios,
.tiocmget = gb_tty_tiocmget,
.tiocmset = gb_tty_tiocmset,
};
int gb_tty_probe(struct greybus_module *gmod,
const struct greybus_module_id *id)
{
struct gb_tty *gb_tty;
struct device *tty_dev;
int retval;
int minor;
gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
if (!gb_tty)
return -ENOMEM;
minor = alloc_minor(gb_tty);
if (minor < 0) {
if (minor == -ENOSPC) {
dev_err(&gmod->dev, "no more free minor numbers\n");
return -ENODEV;
}
return minor;
}
gb_tty->minor = minor;
gb_tty->gmod = gmod;
spin_lock_init(&gb_tty->write_lock);
spin_lock_init(&gb_tty->read_lock);
init_waitqueue_head(&gb_tty->wioctl);
mutex_init(&gb_tty->mutex);
/* FIXME - allocate gb buffers */
gmod->gb_tty = gb_tty;
tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
&gmod->dev);
if (IS_ERR(tty_dev)) {
retval = PTR_ERR(tty_dev);
goto error;
}
return 0;
error:
gmod->gb_tty = NULL;
release_minor(gb_tty);
return retval;
}
void gb_tty_disconnect(struct greybus_module *gmod)
{
struct gb_tty *gb_tty = gmod->gb_tty;
struct tty_struct *tty;
if (!gb_tty)
return;
mutex_lock(&gb_tty->mutex);
gb_tty->disconnected = true;
wake_up_all(&gb_tty->wioctl);
gmod->gb_tty = NULL;
mutex_unlock(&gb_tty->mutex);
tty = tty_port_tty_get(&gb_tty->port);
if (tty) {
tty_vhangup(tty);
tty_kref_put(tty);
}
/* FIXME - stop all traffic */
tty_unregister_device(gb_tty_driver, gb_tty->minor);
/* FIXME - free transmit / recieve buffers */
tty_port_put(&gb_tty->port);
kfree(gb_tty);
}
#if 0
static struct greybus_driver tty_gb_driver = {
.probe = gb_tty_probe,
.disconnect = gb_tty_disconnect,
.id_table = id_table,
};
#endif
int __init gb_tty_init(void)
{
int retval = 0;
gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
if (IS_ERR(gb_tty_driver)) {
pr_err("Can not allocate tty driver\n");
retval = -ENOMEM;
goto fail_unregister_dev;
}
gb_tty_driver->driver_name = "gb";
gb_tty_driver->name = GB_NAME;
gb_tty_driver->major = 0;
gb_tty_driver->minor_start = 0;
gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
gb_tty_driver->init_termios = tty_std_termios;
gb_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
tty_set_operations(gb_tty_driver, &gb_ops);
retval = tty_register_driver(gb_tty_driver);
if (retval) {
pr_err("Can not register tty driver: %d\n", retval);
goto fail_put_gb_tty;
}
#if 0
retval = greybus_register(&tty_gb_driver);
if (retval) {
pr_err("Can not register greybus driver.\n");
goto fail_unregister_gb_tty;
}
#endif
return 0;
/* fail_unregister_gb_tty: */
tty_unregister_driver(gb_tty_driver);
fail_put_gb_tty:
put_tty_driver(gb_tty_driver);
fail_unregister_dev:
return retval;
}
void __exit gb_tty_exit(void)
{
int major = MAJOR(gb_tty_driver->major);
int minor = gb_tty_driver->minor_start;
#if 0
greybus_deregister(&tty_gb_driver);
#endif
tty_unregister_driver(gb_tty_driver);
put_tty_driver(gb_tty_driver);
unregister_chrdev_region(MKDEV(major, minor), GB_NUM_MINORS);
}
#if 0
module_init(gb_tty_init);
module_exit(gb_tty_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Greg Kroah-Hartman <gregkh@linuxfoundation.org>");
#endif
|