4
* Copyright (C) 1998/1999 R.E.Wolff@BitWizard.nl
6
* written for the SX serial driver.
7
* Contains the code that should be shared over all the serial drivers.
9
* Credit for the idea to do it this way might go to Alan Cox.
12
* Version 0.1 -- December, 1998. Initial version.
13
* Version 0.2 -- March, 1999. Some more routines. Bugfixes. Etc.
14
* Version 0.5 -- August, 1999. Some more fixes. Reformat for Linus.
16
* BitWizard is actively maintaining this file. We sometimes find
17
* that someone submitted changes to this file. We really appreciate
18
* your help, but please submit changes through us. We're doing our
19
* best to be responsive. -- REW
22
#include <linux/module.h>
23
#include <linux/kernel.h>
24
#include <linux/tty.h>
25
#include <linux/sched.h>
26
#include <linux/serial.h>
28
#include <linux/generic_serial.h>
29
#include <linux/interrupt.h>
30
#include <linux/tty_flip.h>
31
#include <linux/delay.h>
32
#include <linux/gfp.h>
33
#include <asm/uaccess.h>
40
#define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
42
#define gs_dprintk(f, str...) /* nothing */
45
#define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __func__)
46
#define func_exit() gs_dprintk (GS_DEBUG_FLOW, "gs: exit %s\n", __func__)
48
#define RS_EVENT_WRITE_WAKEUP 1
50
module_param(gs_debug, int, 0644);
53
int gs_put_char(struct tty_struct * tty, unsigned char ch)
59
port = tty->driver_data;
63
if (! (port->port.flags & ASYNC_INITIALIZED)) return 0;
65
/* Take a lock on the serial tranmit buffer! */
66
mutex_lock(& port->port_write_mutex);
68
if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
69
/* Sorry, buffer is full, drop character. Update statistics???? -- REW */
70
mutex_unlock(&port->port_write_mutex);
74
port->xmit_buf[port->xmit_head++] = ch;
75
port->xmit_head &= SERIAL_XMIT_SIZE - 1;
76
port->xmit_cnt++; /* Characters in buffer */
78
mutex_unlock(&port->port_write_mutex);
85
> Problems to take into account are:
86
> -1- Interrupts that empty part of the buffer.
87
> -2- page faults on the access to userspace.
88
> -3- Other processes that are also trying to do a "write".
91
int gs_write(struct tty_struct * tty,
92
const unsigned char *buf, int count)
100
port = tty->driver_data;
104
if (! (port->port.flags & ASYNC_INITIALIZED))
107
/* get exclusive "write" access to this port (problem 3) */
108
/* This is not a spinlock because we can have a disk access (page
109
fault) in copy_from_user */
110
mutex_lock(& port->port_write_mutex);
116
/* This is safe because we "OWN" the "head". No one else can
117
change the "head": we own the port_write_mutex. */
118
/* Don't overrun the end of the buffer */
119
t = SERIAL_XMIT_SIZE - port->xmit_head;
122
/* This is safe because the xmit_cnt can only decrease. This
123
would increase "t", so we might copy too little chars. */
124
/* Don't copy past the "head" of the buffer */
125
t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
128
/* Can't copy more? break out! */
131
memcpy (port->xmit_buf + port->xmit_head, buf, c);
133
port -> xmit_cnt += c;
134
port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
139
mutex_unlock(& port->port_write_mutex);
141
gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n",
142
(port->port.flags & GS_TX_INTEN)?"enabled": "disabled");
144
if (port->xmit_cnt &&
147
!(port->port.flags & GS_TX_INTEN)) {
148
port->port.flags |= GS_TX_INTEN;
149
port->rd->enable_tx_interrupts (port);
157
int gs_write_room(struct tty_struct * tty)
159
struct gs_port *port = tty->driver_data;
163
ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
171
int gs_chars_in_buffer(struct tty_struct *tty)
173
struct gs_port *port = tty->driver_data;
177
return port->xmit_cnt;
181
static int gs_real_chars_in_buffer(struct tty_struct *tty)
183
struct gs_port *port;
186
port = tty->driver_data;
188
if (!port->rd) return 0;
189
if (!port->rd->chars_in_buffer) return 0;
192
return port->xmit_cnt + port->rd->chars_in_buffer (port);
196
static int gs_wait_tx_flushed (void * ptr, unsigned long timeout)
198
struct gs_port *port = ptr;
199
unsigned long end_jiffies;
200
int jiffies_to_transmit, charsleft = 0, rv = 0;
205
gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
207
gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n",
208
port->xmit_cnt, port->xmit_buf, port->port.tty);
211
if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
212
gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
214
return -EINVAL; /* This is an error which we don't know how to handle. */
217
rcib = gs_real_chars_in_buffer(port->port.tty);
220
gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
224
/* stop trying: now + twice the time it would normally take + seconds */
225
if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
226
end_jiffies = jiffies;
227
if (timeout != MAX_SCHEDULE_TIMEOUT)
228
end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
229
end_jiffies += timeout;
231
gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n",
232
jiffies, end_jiffies, end_jiffies-jiffies);
234
/* the expression is actually jiffies < end_jiffies, but that won't
235
work around the wraparound. Tricky eh? */
236
while ((charsleft = gs_real_chars_in_buffer (port->port.tty)) &&
237
time_after (end_jiffies, jiffies)) {
239
chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
242
charsleft += 16; /* Allow 16 chars more to be transmitted ... */
243
jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
244
/* ^^^ Round up.... */
245
if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;
247
gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
248
"(%d chars).\n", jiffies_to_transmit, charsleft);
250
msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
251
if (signal_pending (current)) {
252
gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: ");
258
gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft);
259
set_current_state (TASK_RUNNING);
267
void gs_flush_buffer(struct tty_struct *tty)
269
struct gs_port *port;
274
port = tty->driver_data;
278
/* XXX Would the write semaphore do? */
279
spin_lock_irqsave (&port->driver_lock, flags);
280
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
281
spin_unlock_irqrestore (&port->driver_lock, flags);
288
void gs_flush_chars(struct tty_struct * tty)
290
struct gs_port *port;
294
port = tty->driver_data;
298
if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
304
/* Beats me -- REW */
305
port->port.flags |= GS_TX_INTEN;
306
port->rd->enable_tx_interrupts (port);
311
void gs_stop(struct tty_struct * tty)
313
struct gs_port *port;
317
port = tty->driver_data;
321
if (port->xmit_cnt &&
323
(port->port.flags & GS_TX_INTEN) ) {
324
port->port.flags &= ~GS_TX_INTEN;
325
port->rd->disable_tx_interrupts (port);
331
void gs_start(struct tty_struct * tty)
333
struct gs_port *port;
335
port = tty->driver_data;
339
if (port->xmit_cnt &&
341
!(port->port.flags & GS_TX_INTEN) ) {
342
port->port.flags |= GS_TX_INTEN;
343
port->rd->enable_tx_interrupts (port);
349
static void gs_shutdown_port (struct gs_port *port)
357
if (!(port->port.flags & ASYNC_INITIALIZED))
360
spin_lock_irqsave(&port->driver_lock, flags);
362
if (port->xmit_buf) {
363
free_page((unsigned long) port->xmit_buf);
364
port->xmit_buf = NULL;
368
set_bit(TTY_IO_ERROR, &port->port.tty->flags);
370
port->rd->shutdown_port (port);
372
port->port.flags &= ~ASYNC_INITIALIZED;
373
spin_unlock_irqrestore(&port->driver_lock, flags);
379
void gs_hangup(struct tty_struct *tty)
381
struct gs_port *port;
386
port = tty->driver_data;
387
tty = port->port.tty;
391
gs_shutdown_port (port);
392
spin_lock_irqsave(&port->port.lock, flags);
393
port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
394
port->port.tty = NULL;
395
port->port.count = 0;
396
spin_unlock_irqrestore(&port->port.lock, flags);
398
wake_up_interruptible(&port->port.open_wait);
403
int gs_block_til_ready(void *port_, struct file * filp)
405
struct gs_port *gp = port_;
406
struct tty_port *port = &gp->port;
407
DECLARE_WAITQUEUE(wait, current);
411
struct tty_struct *tty;
420
gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n");
422
* If the device is in the middle of being closed, then block
423
* until it's done, and then try again.
425
if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
426
interruptible_sleep_on(&port->close_wait);
427
if (port->flags & ASYNC_HUP_NOTIFY)
433
gs_dprintk (GS_DEBUG_BTR, "after hung up\n");
436
* If non-blocking mode is set, or the port is not enabled,
437
* then make the check up front and then exit.
439
if ((filp->f_flags & O_NONBLOCK) ||
440
(tty->flags & (1 << TTY_IO_ERROR))) {
441
port->flags |= ASYNC_NORMAL_ACTIVE;
445
gs_dprintk (GS_DEBUG_BTR, "after nonblock\n");
451
* Block waiting for the carrier detect and the line to become
452
* free (i.e., not in use by the callout). While we are in
453
* this loop, port->count is dropped by one, so that
454
* rs_close() knows when to free things. We restore it upon
455
* exit, either normal or abnormal.
459
add_wait_queue(&port->open_wait, &wait);
461
gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n");
462
spin_lock_irqsave(&port->lock, flags);
463
if (!tty_hung_up_p(filp)) {
466
port->blocked_open++;
467
spin_unlock_irqrestore(&port->lock, flags);
469
CD = tty_port_carrier_raised(port);
470
gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
471
set_current_state (TASK_INTERRUPTIBLE);
472
if (tty_hung_up_p(filp) ||
473
!(port->flags & ASYNC_INITIALIZED)) {
474
if (port->flags & ASYNC_HUP_NOTIFY)
477
retval = -ERESTARTSYS;
480
if (!(port->flags & ASYNC_CLOSING) &&
483
gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n",
484
(int)signal_pending (current), *(long*)(¤t->blocked));
485
if (signal_pending(current)) {
486
retval = -ERESTARTSYS;
491
gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
493
set_current_state (TASK_RUNNING);
494
remove_wait_queue(&port->open_wait, &wait);
496
spin_lock_irqsave(&port->lock, flags);
497
if (!tty_hung_up_p(filp)) {
500
port->blocked_open--;
502
port->flags |= ASYNC_NORMAL_ACTIVE;
503
spin_unlock_irqrestore(&port->lock, flags);
509
void gs_close(struct tty_struct * tty, struct file * filp)
512
struct gs_port *port;
516
port = tty->driver_data;
520
if (!port->port.tty) {
521
/* This seems to happen when this is called from vhangup. */
522
gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->port.tty is NULL\n");
523
port->port.tty = tty;
526
spin_lock_irqsave(&port->port.lock, flags);
528
if (tty_hung_up_p(filp)) {
529
spin_unlock_irqrestore(&port->port.lock, flags);
530
if (port->rd->hungup)
531
port->rd->hungup (port);
536
if ((tty->count == 1) && (port->port.count != 1)) {
537
printk(KERN_ERR "gs: gs_close port %p: bad port count;"
538
" tty->count is 1, port count is %d\n", port, port->port.count);
539
port->port.count = 1;
541
if (--port->port.count < 0) {
542
printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->port.count);
543
port->port.count = 0;
546
if (port->port.count) {
547
gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->port.count);
548
spin_unlock_irqrestore(&port->port.lock, flags);
552
port->port.flags |= ASYNC_CLOSING;
555
* Now we wait for the transmit buffer to clear; and we notify
556
* the line discipline to only process XON/XOFF characters.
559
/* if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
560
tty_wait_until_sent(tty, port->closing_wait); */
563
* At this point we stop accepting input. To do this, we
564
* disable the receive line status interrupts, and tell the
565
* interrupt driver to stop checking the data ready bit in the
566
* line status register.
569
spin_lock(&port->driver_lock);
570
port->rd->disable_rx_interrupts (port);
571
spin_unlock(&port->driver_lock);
572
spin_unlock_irqrestore(&port->port.lock, flags);
574
/* close has no way of returning "EINTR", so discard return value */
575
if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
576
gs_wait_tx_flushed (port, port->closing_wait);
578
port->port.flags &= ~GS_ACTIVE;
580
gs_flush_buffer(tty);
582
tty_ldisc_flush(tty);
585
spin_lock_irqsave(&port->driver_lock, flags);
587
port->rd->close (port);
588
port->rd->shutdown_port (port);
589
spin_unlock_irqrestore(&port->driver_lock, flags);
591
spin_lock_irqsave(&port->port.lock, flags);
592
port->port.tty = NULL;
594
if (port->port.blocked_open) {
595
if (port->close_delay) {
596
spin_unlock_irqrestore(&port->port.lock, flags);
597
msleep_interruptible(jiffies_to_msecs(port->close_delay));
598
spin_lock_irqsave(&port->port.lock, flags);
600
wake_up_interruptible(&port->port.open_wait);
602
port->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
603
spin_unlock_irqrestore(&port->port.lock, flags);
604
wake_up_interruptible(&port->port.close_wait);
610
void gs_set_termios (struct tty_struct * tty,
611
struct ktermios * old_termios)
613
struct gs_port *port;
614
int baudrate, tmp, rv;
615
struct ktermios *tiosp;
619
port = tty->driver_data;
622
if (!port->port.tty) {
623
/* This seems to happen when this is called after gs_close. */
624
gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->port.tty is NULL\n");
625
port->port.tty = tty;
629
tiosp = tty->termios;
631
if (gs_debug & GS_DEBUG_TERMIOS) {
632
gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
635
if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
636
if(tiosp->c_iflag != old_termios->c_iflag) printk("c_iflag changed\n");
637
if(tiosp->c_oflag != old_termios->c_oflag) printk("c_oflag changed\n");
638
if(tiosp->c_cflag != old_termios->c_cflag) printk("c_cflag changed\n");
639
if(tiosp->c_lflag != old_termios->c_lflag) printk("c_lflag changed\n");
640
if(tiosp->c_line != old_termios->c_line) printk("c_line changed\n");
641
if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
644
baudrate = tty_get_baud_rate(tty);
646
if ((tiosp->c_cflag & CBAUD) == B38400) {
647
if ( (port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
649
else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
651
else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
653
else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
655
else if ((port->port.flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
656
baudrate = (port->baud_base / port->custom_divisor);
659
/* I recommend using THIS instead of the mess in termios (and
660
duplicating the above code). Next we should create a clean
661
interface towards this variable. If your card supports arbitrary
662
baud rates, (e.g. CD1400 or 16550 based cards) then everything
663
will be very easy..... */
664
port->baud = baudrate;
666
/* Two timer ticks seems enough to wakeup something like SLIP driver */
667
/* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
668
tmp = (baudrate / 10 / HZ) * 2;
670
if (tmp < 0) tmp = 0;
671
if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;
673
port->wakeup_chars = tmp;
675
/* We should really wait for the characters to be all sent before
676
changing the settings. -- CAL */
677
rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
678
if (rv < 0) return /* rv */;
680
rv = port->rd->set_real_termios(port);
681
if (rv < 0) return /* rv */;
684
(old_termios->c_cflag & CRTSCTS)) &&
685
!( tiosp->c_cflag & CRTSCTS)) {
690
#ifdef tytso_patch_94Nov25_1726
691
/* This "makes sense", Why is it commented out? */
693
if (!(old_termios->c_cflag & CLOCAL) &&
694
(tty->termios->c_cflag & CLOCAL))
695
wake_up_interruptible(&port->gs.open_wait);
704
/* Must be called with interrupts enabled */
705
int gs_init_port(struct gs_port *port)
711
if (port->port.flags & ASYNC_INITIALIZED) {
715
if (!port->xmit_buf) {
716
/* We may sleep in get_zeroed_page() */
719
tmp = get_zeroed_page(GFP_KERNEL);
720
spin_lock_irqsave (&port->driver_lock, flags);
724
port->xmit_buf = (unsigned char *) tmp;
725
spin_unlock_irqrestore(&port->driver_lock, flags);
726
if (!port->xmit_buf) {
732
spin_lock_irqsave (&port->driver_lock, flags);
734
clear_bit(TTY_IO_ERROR, &port->port.tty->flags);
735
mutex_init(&port->port_write_mutex);
736
port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
737
spin_unlock_irqrestore(&port->driver_lock, flags);
738
gs_set_termios(port->port.tty, NULL);
739
spin_lock_irqsave (&port->driver_lock, flags);
740
port->port.flags |= ASYNC_INITIALIZED;
741
port->port.flags &= ~GS_TX_INTEN;
743
spin_unlock_irqrestore(&port->driver_lock, flags);
749
int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
751
struct serial_struct sio;
753
if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
756
if (!capable(CAP_SYS_ADMIN)) {
757
if ((sio.baud_base != port->baud_base) ||
758
(sio.close_delay != port->close_delay) ||
759
((sio.flags & ~ASYNC_USR_MASK) !=
760
(port->port.flags & ~ASYNC_USR_MASK)))
764
port->port.flags = (port->port.flags & ~ASYNC_USR_MASK) |
765
(sio.flags & ASYNC_USR_MASK);
767
port->baud_base = sio.baud_base;
768
port->close_delay = sio.close_delay;
769
port->closing_wait = sio.closing_wait;
770
port->custom_divisor = sio.custom_divisor;
772
gs_set_termios (port->port.tty, NULL);
778
/*****************************************************************************/
781
* Generate the serial struct info.
784
int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
786
struct serial_struct sio;
788
memset(&sio, 0, sizeof(struct serial_struct));
789
sio.flags = port->port.flags;
790
sio.baud_base = port->baud_base;
791
sio.close_delay = port->close_delay;
792
sio.closing_wait = port->closing_wait;
793
sio.custom_divisor = port->custom_divisor;
796
/* If you want you can override these. */
797
sio.type = PORT_UNKNOWN;
798
sio.xmit_fifo_size = -1;
803
if (port->rd->getserial)
804
port->rd->getserial (port, &sio);
806
if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
813
void gs_got_break(struct gs_port *port)
817
tty_insert_flip_char(port->port.tty, 0, TTY_BREAK);
818
tty_schedule_flip(port->port.tty);
819
if (port->port.flags & ASYNC_SAK) {
820
do_SAK (port->port.tty);
827
EXPORT_SYMBOL(gs_put_char);
828
EXPORT_SYMBOL(gs_write);
829
EXPORT_SYMBOL(gs_write_room);
830
EXPORT_SYMBOL(gs_chars_in_buffer);
831
EXPORT_SYMBOL(gs_flush_buffer);
832
EXPORT_SYMBOL(gs_flush_chars);
833
EXPORT_SYMBOL(gs_stop);
834
EXPORT_SYMBOL(gs_start);
835
EXPORT_SYMBOL(gs_hangup);
836
EXPORT_SYMBOL(gs_block_til_ready);
837
EXPORT_SYMBOL(gs_close);
838
EXPORT_SYMBOL(gs_set_termios);
839
EXPORT_SYMBOL(gs_init_port);
840
EXPORT_SYMBOL(gs_setserial);
841
EXPORT_SYMBOL(gs_getserial);
842
EXPORT_SYMBOL(gs_got_break);
844
MODULE_LICENSE("GPL");