1 // SPDX-License-Identifier: GPL-2.0+
2 /************************************************************************
3 * Copyright 2003 Digi International (www.digi.com)
4 *
5 * Copyright (C) 2004 IBM Corporation. All rights reserved.
6 *
7 * Contact Information:
8 * Scott H Kilau <Scott_Kilau@digi.com>
9 * Ananda Venkatarman <mansarov@us.ibm.com>
10 * Modifications:
11 * 01/19/06: changed jsm_input routine to use the dynamically allocated
12 * tty_buffer changes. Contributors: Scott Kilau and Ananda V.
13 ***********************************************************************/
14 #include <linux/tty.h>
15 #include <linux/tty_flip.h>
16 #include <linux/serial_reg.h>
17 #include <linux/delay.h> /* For udelay */
18 #include <linux/pci.h>
19 #include <linux/slab.h>
20
21 #include "jsm.h"
22
23 static DECLARE_BITMAP(linemap, MAXLINES);
24
25 static void jsm_carrier(struct jsm_channel *ch);
26
jsm_get_mstat(struct jsm_channel * ch)27 static inline int jsm_get_mstat(struct jsm_channel *ch)
28 {
29 unsigned char mstat;
30 int result;
31
32 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "start\n");
33
34 mstat = (ch->ch_mostat | ch->ch_mistat);
35
36 result = 0;
37
38 if (mstat & UART_MCR_DTR)
39 result |= TIOCM_DTR;
40 if (mstat & UART_MCR_RTS)
41 result |= TIOCM_RTS;
42 if (mstat & UART_MSR_CTS)
43 result |= TIOCM_CTS;
44 if (mstat & UART_MSR_DSR)
45 result |= TIOCM_DSR;
46 if (mstat & UART_MSR_RI)
47 result |= TIOCM_RI;
48 if (mstat & UART_MSR_DCD)
49 result |= TIOCM_CD;
50
51 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
52 return result;
53 }
54
jsm_tty_tx_empty(struct uart_port * port)55 static unsigned int jsm_tty_tx_empty(struct uart_port *port)
56 {
57 return TIOCSER_TEMT;
58 }
59
60 /*
61 * Return modem signals to ld.
62 */
jsm_tty_get_mctrl(struct uart_port * port)63 static unsigned int jsm_tty_get_mctrl(struct uart_port *port)
64 {
65 int result;
66 struct jsm_channel *channel =
67 container_of(port, struct jsm_channel, uart_port);
68
69 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
70
71 result = jsm_get_mstat(channel);
72
73 if (result < 0)
74 return -ENXIO;
75
76 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
77
78 return result;
79 }
80
81 /*
82 * jsm_set_modem_info()
83 *
84 * Set modem signals, called by ld.
85 */
jsm_tty_set_mctrl(struct uart_port * port,unsigned int mctrl)86 static void jsm_tty_set_mctrl(struct uart_port *port, unsigned int mctrl)
87 {
88 struct jsm_channel *channel =
89 container_of(port, struct jsm_channel, uart_port);
90
91 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
92
93 if (mctrl & TIOCM_RTS)
94 channel->ch_mostat |= UART_MCR_RTS;
95 else
96 channel->ch_mostat &= ~UART_MCR_RTS;
97
98 if (mctrl & TIOCM_DTR)
99 channel->ch_mostat |= UART_MCR_DTR;
100 else
101 channel->ch_mostat &= ~UART_MCR_DTR;
102
103 channel->ch_bd->bd_ops->assert_modem_signals(channel);
104
105 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
106 udelay(10);
107 }
108
109 /*
110 * jsm_tty_write()
111 *
112 * Take data from the user or kernel and send it out to the FEP.
113 * In here exists all the Transparent Print magic as well.
114 */
jsm_tty_write(struct uart_port * port)115 static void jsm_tty_write(struct uart_port *port)
116 {
117 struct jsm_channel *channel;
118
119 channel = container_of(port, struct jsm_channel, uart_port);
120 channel->ch_bd->bd_ops->copy_data_from_queue_to_uart(channel);
121 }
122
jsm_tty_start_tx(struct uart_port * port)123 static void jsm_tty_start_tx(struct uart_port *port)
124 {
125 struct jsm_channel *channel =
126 container_of(port, struct jsm_channel, uart_port);
127
128 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
129
130 channel->ch_flags &= ~(CH_STOP);
131 jsm_tty_write(port);
132
133 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
134 }
135
jsm_tty_stop_tx(struct uart_port * port)136 static void jsm_tty_stop_tx(struct uart_port *port)
137 {
138 struct jsm_channel *channel =
139 container_of(port, struct jsm_channel, uart_port);
140
141 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "start\n");
142
143 channel->ch_flags |= (CH_STOP);
144
145 jsm_dbg(IOCTL, &channel->ch_bd->pci_dev, "finish\n");
146 }
147
jsm_tty_send_xchar(struct uart_port * port,char ch)148 static void jsm_tty_send_xchar(struct uart_port *port, char ch)
149 {
150 unsigned long lock_flags;
151 struct jsm_channel *channel =
152 container_of(port, struct jsm_channel, uart_port);
153 struct ktermios *termios;
154
155 spin_lock_irqsave(&port->lock, lock_flags);
156 termios = &port->state->port.tty->termios;
157 if (ch == termios->c_cc[VSTART])
158 channel->ch_bd->bd_ops->send_start_character(channel);
159
160 if (ch == termios->c_cc[VSTOP])
161 channel->ch_bd->bd_ops->send_stop_character(channel);
162 spin_unlock_irqrestore(&port->lock, lock_flags);
163 }
164
jsm_tty_stop_rx(struct uart_port * port)165 static void jsm_tty_stop_rx(struct uart_port *port)
166 {
167 struct jsm_channel *channel =
168 container_of(port, struct jsm_channel, uart_port);
169
170 channel->ch_bd->bd_ops->disable_receiver(channel);
171 }
172
jsm_tty_break(struct uart_port * port,int break_state)173 static void jsm_tty_break(struct uart_port *port, int break_state)
174 {
175 unsigned long lock_flags;
176 struct jsm_channel *channel =
177 container_of(port, struct jsm_channel, uart_port);
178
179 spin_lock_irqsave(&port->lock, lock_flags);
180 if (break_state == -1)
181 channel->ch_bd->bd_ops->send_break(channel);
182 else
183 channel->ch_bd->bd_ops->clear_break(channel);
184
185 spin_unlock_irqrestore(&port->lock, lock_flags);
186 }
187
jsm_tty_open(struct uart_port * port)188 static int jsm_tty_open(struct uart_port *port)
189 {
190 unsigned long lock_flags;
191 struct jsm_board *brd;
192 struct jsm_channel *channel =
193 container_of(port, struct jsm_channel, uart_port);
194 struct ktermios *termios;
195
196 /* Get board pointer from our array of majors we have allocated */
197 brd = channel->ch_bd;
198
199 /*
200 * Allocate channel buffers for read/write/error.
201 * Set flag, so we don't get trounced on.
202 */
203 channel->ch_flags |= (CH_OPENING);
204
205 /* Drop locks, as malloc with GFP_KERNEL can sleep */
206
207 if (!channel->ch_rqueue) {
208 channel->ch_rqueue = kzalloc(RQUEUESIZE, GFP_KERNEL);
209 if (!channel->ch_rqueue) {
210 jsm_dbg(INIT, &channel->ch_bd->pci_dev,
211 "unable to allocate read queue buf\n");
212 return -ENOMEM;
213 }
214 }
215 if (!channel->ch_equeue) {
216 channel->ch_equeue = kzalloc(EQUEUESIZE, GFP_KERNEL);
217 if (!channel->ch_equeue) {
218 jsm_dbg(INIT, &channel->ch_bd->pci_dev,
219 "unable to allocate error queue buf\n");
220 return -ENOMEM;
221 }
222 }
223
224 channel->ch_flags &= ~(CH_OPENING);
225 /*
226 * Initialize if neither terminal is open.
227 */
228 jsm_dbg(OPEN, &channel->ch_bd->pci_dev,
229 "jsm_open: initializing channel in open...\n");
230
231 /*
232 * Flush input queues.
233 */
234 channel->ch_r_head = channel->ch_r_tail = 0;
235 channel->ch_e_head = channel->ch_e_tail = 0;
236
237 brd->bd_ops->flush_uart_write(channel);
238 brd->bd_ops->flush_uart_read(channel);
239
240 channel->ch_flags = 0;
241 channel->ch_cached_lsr = 0;
242 channel->ch_stops_sent = 0;
243
244 spin_lock_irqsave(&port->lock, lock_flags);
245 termios = &port->state->port.tty->termios;
246 channel->ch_c_cflag = termios->c_cflag;
247 channel->ch_c_iflag = termios->c_iflag;
248 channel->ch_c_oflag = termios->c_oflag;
249 channel->ch_c_lflag = termios->c_lflag;
250 channel->ch_startc = termios->c_cc[VSTART];
251 channel->ch_stopc = termios->c_cc[VSTOP];
252
253 /* Tell UART to init itself */
254 brd->bd_ops->uart_init(channel);
255
256 /*
257 * Run param in case we changed anything
258 */
259 brd->bd_ops->param(channel);
260
261 jsm_carrier(channel);
262
263 channel->ch_open_count++;
264 spin_unlock_irqrestore(&port->lock, lock_flags);
265
266 jsm_dbg(OPEN, &channel->ch_bd->pci_dev, "finish\n");
267 return 0;
268 }
269
jsm_tty_close(struct uart_port * port)270 static void jsm_tty_close(struct uart_port *port)
271 {
272 struct jsm_board *bd;
273 struct jsm_channel *channel =
274 container_of(port, struct jsm_channel, uart_port);
275
276 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "start\n");
277
278 bd = channel->ch_bd;
279
280 channel->ch_flags &= ~(CH_STOPI);
281
282 channel->ch_open_count--;
283
284 /*
285 * If we have HUPCL set, lower DTR and RTS
286 */
287 if (channel->ch_c_cflag & HUPCL) {
288 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev,
289 "Close. HUPCL set, dropping DTR/RTS\n");
290
291 /* Drop RTS/DTR */
292 channel->ch_mostat &= ~(UART_MCR_DTR | UART_MCR_RTS);
293 bd->bd_ops->assert_modem_signals(channel);
294 }
295
296 /* Turn off UART interrupts for this port */
297 channel->ch_bd->bd_ops->uart_off(channel);
298
299 jsm_dbg(CLOSE, &channel->ch_bd->pci_dev, "finish\n");
300 }
301
jsm_tty_set_termios(struct uart_port * port,struct ktermios * termios,const struct ktermios * old_termios)302 static void jsm_tty_set_termios(struct uart_port *port,
303 struct ktermios *termios,
304 const struct ktermios *old_termios)
305 {
306 unsigned long lock_flags;
307 struct jsm_channel *channel =
308 container_of(port, struct jsm_channel, uart_port);
309
310 spin_lock_irqsave(&port->lock, lock_flags);
311 channel->ch_c_cflag = termios->c_cflag;
312 channel->ch_c_iflag = termios->c_iflag;
313 channel->ch_c_oflag = termios->c_oflag;
314 channel->ch_c_lflag = termios->c_lflag;
315 channel->ch_startc = termios->c_cc[VSTART];
316 channel->ch_stopc = termios->c_cc[VSTOP];
317
318 channel->ch_bd->bd_ops->param(channel);
319 jsm_carrier(channel);
320 spin_unlock_irqrestore(&port->lock, lock_flags);
321 }
322
jsm_tty_type(struct uart_port * port)323 static const char *jsm_tty_type(struct uart_port *port)
324 {
325 return "jsm";
326 }
327
jsm_tty_release_port(struct uart_port * port)328 static void jsm_tty_release_port(struct uart_port *port)
329 {
330 }
331
jsm_tty_request_port(struct uart_port * port)332 static int jsm_tty_request_port(struct uart_port *port)
333 {
334 return 0;
335 }
336
jsm_config_port(struct uart_port * port,int flags)337 static void jsm_config_port(struct uart_port *port, int flags)
338 {
339 port->type = PORT_JSM;
340 }
341
342 static const struct uart_ops jsm_ops = {
343 .tx_empty = jsm_tty_tx_empty,
344 .set_mctrl = jsm_tty_set_mctrl,
345 .get_mctrl = jsm_tty_get_mctrl,
346 .stop_tx = jsm_tty_stop_tx,
347 .start_tx = jsm_tty_start_tx,
348 .send_xchar = jsm_tty_send_xchar,
349 .stop_rx = jsm_tty_stop_rx,
350 .break_ctl = jsm_tty_break,
351 .startup = jsm_tty_open,
352 .shutdown = jsm_tty_close,
353 .set_termios = jsm_tty_set_termios,
354 .type = jsm_tty_type,
355 .release_port = jsm_tty_release_port,
356 .request_port = jsm_tty_request_port,
357 .config_port = jsm_config_port,
358 };
359
360 /*
361 * jsm_tty_init()
362 *
363 * Init the tty subsystem. Called once per board after board has been
364 * downloaded and init'ed.
365 */
jsm_tty_init(struct jsm_board * brd)366 int jsm_tty_init(struct jsm_board *brd)
367 {
368 int i;
369 void __iomem *vaddr;
370 struct jsm_channel *ch;
371
372 if (!brd)
373 return -ENXIO;
374
375 jsm_dbg(INIT, &brd->pci_dev, "start\n");
376
377 /*
378 * Initialize board structure elements.
379 */
380
381 brd->nasync = brd->maxports;
382
383 /*
384 * Allocate channel memory that might not have been allocated
385 * when the driver was first loaded.
386 */
387 for (i = 0; i < brd->nasync; i++) {
388 if (!brd->channels[i]) {
389
390 /*
391 * Okay to malloc with GFP_KERNEL, we are not at
392 * interrupt context, and there are no locks held.
393 */
394 brd->channels[i] = kzalloc(sizeof(struct jsm_channel), GFP_KERNEL);
395 if (!brd->channels[i]) {
396 jsm_dbg(CORE, &brd->pci_dev,
397 "%s:%d Unable to allocate memory for channel struct\n",
398 __FILE__, __LINE__);
399 }
400 }
401 }
402
403 ch = brd->channels[0];
404 vaddr = brd->re_map_membase;
405
406 /* Set up channel variables */
407 for (i = 0; i < brd->nasync; i++, ch = brd->channels[i]) {
408
409 if (!brd->channels[i])
410 continue;
411
412 spin_lock_init(&ch->ch_lock);
413
414 if (brd->bd_uart_offset == 0x200)
415 ch->ch_neo_uart = vaddr + (brd->bd_uart_offset * i);
416 else
417 ch->ch_cls_uart = vaddr + (brd->bd_uart_offset * i);
418
419 ch->ch_bd = brd;
420 ch->ch_portnum = i;
421
422 /* .25 second delay */
423 ch->ch_close_delay = 250;
424
425 init_waitqueue_head(&ch->ch_flags_wait);
426 }
427
428 jsm_dbg(INIT, &brd->pci_dev, "finish\n");
429 return 0;
430 }
431
jsm_uart_port_init(struct jsm_board * brd)432 int jsm_uart_port_init(struct jsm_board *brd)
433 {
434 int i, rc;
435 unsigned int line;
436
437 if (!brd)
438 return -ENXIO;
439
440 jsm_dbg(INIT, &brd->pci_dev, "start\n");
441
442 /*
443 * Initialize board structure elements.
444 */
445
446 brd->nasync = brd->maxports;
447
448 /* Set up channel variables */
449 for (i = 0; i < brd->nasync; i++) {
450
451 if (!brd->channels[i])
452 continue;
453
454 brd->channels[i]->uart_port.irq = brd->irq;
455 brd->channels[i]->uart_port.uartclk = 14745600;
456 brd->channels[i]->uart_port.type = PORT_JSM;
457 brd->channels[i]->uart_port.iotype = UPIO_MEM;
458 brd->channels[i]->uart_port.membase = brd->re_map_membase;
459 brd->channels[i]->uart_port.fifosize = 16;
460 brd->channels[i]->uart_port.ops = &jsm_ops;
461 line = find_first_zero_bit(linemap, MAXLINES);
462 if (line >= MAXLINES) {
463 printk(KERN_INFO "jsm: linemap is full, added device failed\n");
464 continue;
465 } else
466 set_bit(line, linemap);
467 brd->channels[i]->uart_port.line = line;
468 rc = uart_add_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
469 if (rc) {
470 printk(KERN_INFO "jsm: Port %d failed. Aborting...\n", i);
471 return rc;
472 } else
473 printk(KERN_INFO "jsm: Port %d added\n", i);
474 }
475
476 jsm_dbg(INIT, &brd->pci_dev, "finish\n");
477 return 0;
478 }
479
jsm_remove_uart_port(struct jsm_board * brd)480 int jsm_remove_uart_port(struct jsm_board *brd)
481 {
482 int i;
483 struct jsm_channel *ch;
484
485 if (!brd)
486 return -ENXIO;
487
488 jsm_dbg(INIT, &brd->pci_dev, "start\n");
489
490 /*
491 * Initialize board structure elements.
492 */
493
494 brd->nasync = brd->maxports;
495
496 /* Set up channel variables */
497 for (i = 0; i < brd->nasync; i++) {
498
499 if (!brd->channels[i])
500 continue;
501
502 ch = brd->channels[i];
503
504 clear_bit(ch->uart_port.line, linemap);
505 uart_remove_one_port(&jsm_uart_driver, &brd->channels[i]->uart_port);
506 }
507
508 jsm_dbg(INIT, &brd->pci_dev, "finish\n");
509 return 0;
510 }
511
jsm_input(struct jsm_channel * ch)512 void jsm_input(struct jsm_channel *ch)
513 {
514 struct jsm_board *bd;
515 struct tty_struct *tp;
516 struct tty_port *port;
517 u32 rmask;
518 u16 head;
519 u16 tail;
520 int data_len;
521 unsigned long lock_flags;
522 int len = 0;
523 int s = 0;
524 int i = 0;
525
526 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
527
528 port = &ch->uart_port.state->port;
529 tp = port->tty;
530
531 bd = ch->ch_bd;
532 if (!bd)
533 return;
534
535 spin_lock_irqsave(&ch->ch_lock, lock_flags);
536
537 /*
538 *Figure the number of characters in the buffer.
539 *Exit immediately if none.
540 */
541
542 rmask = RQUEUEMASK;
543
544 head = ch->ch_r_head & rmask;
545 tail = ch->ch_r_tail & rmask;
546
547 data_len = (head - tail) & rmask;
548 if (data_len == 0) {
549 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
550 return;
551 }
552
553 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start\n");
554
555 /*
556 *If the device is not open, or CREAD is off, flush
557 *input data and return immediately.
558 */
559 if (!tp || !C_CREAD(tp)) {
560
561 jsm_dbg(READ, &ch->ch_bd->pci_dev,
562 "input. dropping %d bytes on port %d...\n",
563 data_len, ch->ch_portnum);
564 ch->ch_r_head = tail;
565
566 /* Force queue flow control to be released, if needed */
567 jsm_check_queue_flow_control(ch);
568
569 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
570 return;
571 }
572
573 /*
574 * If we are throttled, simply don't read any data.
575 */
576 if (ch->ch_flags & CH_STOPI) {
577 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
578 jsm_dbg(READ, &ch->ch_bd->pci_dev,
579 "Port %d throttled, not reading any data. head: %x tail: %x\n",
580 ch->ch_portnum, head, tail);
581 return;
582 }
583
584 jsm_dbg(READ, &ch->ch_bd->pci_dev, "start 2\n");
585
586 len = tty_buffer_request_room(port, data_len);
587
588 /*
589 * len now contains the most amount of data we can copy,
590 * bounded either by the flip buffer size or the amount
591 * of data the card actually has pending...
592 */
593 while (len) {
594 s = ((head >= tail) ? head : RQUEUESIZE) - tail;
595 s = min(s, len);
596
597 if (s <= 0)
598 break;
599
600 /*
601 * If conditions are such that ld needs to see all
602 * UART errors, we will have to walk each character
603 * and error byte and send them to the buffer one at
604 * a time.
605 */
606
607 if (I_PARMRK(tp) || I_BRKINT(tp) || I_INPCK(tp)) {
608 for (i = 0; i < s; i++) {
609 u8 chr = ch->ch_rqueue[tail + i];
610 u8 error = ch->ch_equeue[tail + i];
611 char flag = TTY_NORMAL;
612
613 /*
614 * Give the Linux ld the flags in the format it
615 * likes.
616 */
617 if (error & UART_LSR_BI)
618 flag = TTY_BREAK;
619 else if (error & UART_LSR_PE)
620 flag = TTY_PARITY;
621 else if (error & UART_LSR_FE)
622 flag = TTY_FRAME;
623
624 tty_insert_flip_char(port, chr, flag);
625 }
626 } else {
627 tty_insert_flip_string(port, ch->ch_rqueue + tail, s);
628 }
629 tail += s;
630 len -= s;
631 /* Flip queue if needed */
632 tail &= rmask;
633 }
634
635 ch->ch_r_tail = tail & rmask;
636 ch->ch_e_tail = tail & rmask;
637 jsm_check_queue_flow_control(ch);
638 spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
639
640 /* Tell the tty layer its okay to "eat" the data now */
641 tty_flip_buffer_push(port);
642
643 jsm_dbg(IOCTL, &ch->ch_bd->pci_dev, "finish\n");
644 }
645
jsm_carrier(struct jsm_channel * ch)646 static void jsm_carrier(struct jsm_channel *ch)
647 {
648 struct jsm_board *bd;
649
650 int virt_carrier = 0;
651 int phys_carrier = 0;
652
653 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "start\n");
654
655 bd = ch->ch_bd;
656 if (!bd)
657 return;
658
659 if (ch->ch_mistat & UART_MSR_DCD) {
660 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "mistat: %x D_CD: %x\n",
661 ch->ch_mistat, ch->ch_mistat & UART_MSR_DCD);
662 phys_carrier = 1;
663 }
664
665 if (ch->ch_c_cflag & CLOCAL)
666 virt_carrier = 1;
667
668 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "DCD: physical: %d virt: %d\n",
669 phys_carrier, virt_carrier);
670
671 /*
672 * Test for a VIRTUAL carrier transition to HIGH.
673 */
674 if (((ch->ch_flags & CH_FCAR) == 0) && (virt_carrier == 1)) {
675
676 /*
677 * When carrier rises, wake any threads waiting
678 * for carrier in the open routine.
679 */
680
681 jsm_dbg(CARR, &ch->ch_bd->pci_dev, "carrier: virt DCD rose\n");
682
683 if (waitqueue_active(&(ch->ch_flags_wait)))
684 wake_up_interruptible(&ch->ch_flags_wait);
685 }
686
687 /*
688 * Test for a PHYSICAL carrier transition to HIGH.
689 */
690 if (((ch->ch_flags & CH_CD) == 0) && (phys_carrier == 1)) {
691
692 /*
693 * When carrier rises, wake any threads waiting
694 * for carrier in the open routine.
695 */
696
697 jsm_dbg(CARR, &ch->ch_bd->pci_dev,
698 "carrier: physical DCD rose\n");
699
700 if (waitqueue_active(&(ch->ch_flags_wait)))
701 wake_up_interruptible(&ch->ch_flags_wait);
702 }
703
704 /*
705 * Test for a PHYSICAL transition to low, so long as we aren't
706 * currently ignoring physical transitions (which is what "virtual
707 * carrier" indicates).
708 *
709 * The transition of the virtual carrier to low really doesn't
710 * matter... it really only means "ignore carrier state", not
711 * "make pretend that carrier is there".
712 */
713 if ((virt_carrier == 0) && ((ch->ch_flags & CH_CD) != 0)
714 && (phys_carrier == 0)) {
715 /*
716 * When carrier drops:
717 *
718 * Drop carrier on all open units.
719 *
720 * Flush queues, waking up any task waiting in the
721 * line discipline.
722 *
723 * Send a hangup to the control terminal.
724 *
725 * Enable all select calls.
726 */
727 if (waitqueue_active(&(ch->ch_flags_wait)))
728 wake_up_interruptible(&ch->ch_flags_wait);
729 }
730
731 /*
732 * Make sure that our cached values reflect the current reality.
733 */
734 if (virt_carrier == 1)
735 ch->ch_flags |= CH_FCAR;
736 else
737 ch->ch_flags &= ~CH_FCAR;
738
739 if (phys_carrier == 1)
740 ch->ch_flags |= CH_CD;
741 else
742 ch->ch_flags &= ~CH_CD;
743 }
744
745
jsm_check_queue_flow_control(struct jsm_channel * ch)746 void jsm_check_queue_flow_control(struct jsm_channel *ch)
747 {
748 struct board_ops *bd_ops = ch->ch_bd->bd_ops;
749 int qleft;
750
751 /* Store how much space we have left in the queue */
752 qleft = ch->ch_r_tail - ch->ch_r_head - 1;
753 if (qleft < 0)
754 qleft += RQUEUEMASK + 1;
755
756 /*
757 * Check to see if we should enforce flow control on our queue because
758 * the ld (or user) isn't reading data out of our queue fast enuf.
759 *
760 * NOTE: This is done based on what the current flow control of the
761 * port is set for.
762 *
763 * 1) HWFLOW (RTS) - Turn off the UART's Receive interrupt.
764 * This will cause the UART's FIFO to back up, and force
765 * the RTS signal to be dropped.
766 * 2) SWFLOW (IXOFF) - Keep trying to send a stop character to
767 * the other side, in hopes it will stop sending data to us.
768 * 3) NONE - Nothing we can do. We will simply drop any extra data
769 * that gets sent into us when the queue fills up.
770 */
771 if (qleft < 256) {
772 /* HWFLOW */
773 if (ch->ch_c_cflag & CRTSCTS) {
774 if (!(ch->ch_flags & CH_RECEIVER_OFF)) {
775 bd_ops->disable_receiver(ch);
776 ch->ch_flags |= (CH_RECEIVER_OFF);
777 jsm_dbg(READ, &ch->ch_bd->pci_dev,
778 "Internal queue hit hilevel mark (%d)! Turning off interrupts\n",
779 qleft);
780 }
781 }
782 /* SWFLOW */
783 else if (ch->ch_c_iflag & IXOFF) {
784 if (ch->ch_stops_sent <= MAX_STOPS_SENT) {
785 bd_ops->send_stop_character(ch);
786 ch->ch_stops_sent++;
787 jsm_dbg(READ, &ch->ch_bd->pci_dev,
788 "Sending stop char! Times sent: %x\n",
789 ch->ch_stops_sent);
790 }
791 }
792 }
793
794 /*
795 * Check to see if we should unenforce flow control because
796 * ld (or user) finally read enuf data out of our queue.
797 *
798 * NOTE: This is done based on what the current flow control of the
799 * port is set for.
800 *
801 * 1) HWFLOW (RTS) - Turn back on the UART's Receive interrupt.
802 * This will cause the UART's FIFO to raise RTS back up,
803 * which will allow the other side to start sending data again.
804 * 2) SWFLOW (IXOFF) - Send a start character to
805 * the other side, so it will start sending data to us again.
806 * 3) NONE - Do nothing. Since we didn't do anything to turn off the
807 * other side, we don't need to do anything now.
808 */
809 if (qleft > (RQUEUESIZE / 2)) {
810 /* HWFLOW */
811 if (ch->ch_c_cflag & CRTSCTS) {
812 if (ch->ch_flags & CH_RECEIVER_OFF) {
813 bd_ops->enable_receiver(ch);
814 ch->ch_flags &= ~(CH_RECEIVER_OFF);
815 jsm_dbg(READ, &ch->ch_bd->pci_dev,
816 "Internal queue hit lowlevel mark (%d)! Turning on interrupts\n",
817 qleft);
818 }
819 }
820 /* SWFLOW */
821 else if (ch->ch_c_iflag & IXOFF && ch->ch_stops_sent) {
822 ch->ch_stops_sent = 0;
823 bd_ops->send_start_character(ch);
824 jsm_dbg(READ, &ch->ch_bd->pci_dev,
825 "Sending start char!\n");
826 }
827 }
828 }
829