xref: /openbmc/linux/drivers/tty/serial/jsm/jsm_neo.c (revision 799a545b)
1 /************************************************************************
2  * Copyright 2003 Digi International (www.digi.com)
3  *
4  * Copyright (C) 2004 IBM Corporation. All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2, or (at your option)
9  * any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
13  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
14  * PURPOSE.  See the GNU General Public License for more details.
15  *
16  * Contact Information:
17  * Scott H Kilau <Scott_Kilau@digi.com>
18  * Wendy Xiong   <wendyx@us.ibm.com>
19  *
20  ***********************************************************************/
21 #include <linux/delay.h>	/* For udelay */
22 #include <linux/serial_reg.h>	/* For the various UART offsets */
23 #include <linux/tty.h>
24 #include <linux/pci.h>
25 #include <asm/io.h>
26 
27 #include "jsm.h"		/* Driver main header file */
28 
29 static u32 jsm_offset_table[8] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
30 
31 /*
32  * This function allows calls to ensure that all outstanding
33  * PCI writes have been completed, by doing a PCI read against
34  * a non-destructive, read-only location on the Neo card.
35  *
36  * In this case, we are reading the DVID (Read-only Device Identification)
37  * value of the Neo card.
38  */
39 static inline void neo_pci_posting_flush(struct jsm_board *bd)
40 {
41       readb(bd->re_map_membase + 0x8D);
42 }
43 
44 static void neo_set_cts_flow_control(struct jsm_channel *ch)
45 {
46 	u8 ier, efr;
47 	ier = readb(&ch->ch_neo_uart->ier);
48 	efr = readb(&ch->ch_neo_uart->efr);
49 
50 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting CTSFLOW\n");
51 
52 	/* Turn on auto CTS flow control */
53 	ier |= (UART_17158_IER_CTSDSR);
54 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_CTSDSR);
55 
56 	/* Turn off auto Xon flow control */
57 	efr &= ~(UART_17158_EFR_IXON);
58 
59 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
60 	writeb(0, &ch->ch_neo_uart->efr);
61 
62 	/* Turn on UART enhanced bits */
63 	writeb(efr, &ch->ch_neo_uart->efr);
64 
65 	/* Turn on table D, with 8 char hi/low watermarks */
66 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
67 
68 	/* Feed the UART our trigger levels */
69 	writeb(8, &ch->ch_neo_uart->tfifo);
70 	ch->ch_t_tlevel = 8;
71 
72 	writeb(ier, &ch->ch_neo_uart->ier);
73 }
74 
75 static void neo_set_rts_flow_control(struct jsm_channel *ch)
76 {
77 	u8 ier, efr;
78 	ier = readb(&ch->ch_neo_uart->ier);
79 	efr = readb(&ch->ch_neo_uart->efr);
80 
81 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting RTSFLOW\n");
82 
83 	/* Turn on auto RTS flow control */
84 	ier |= (UART_17158_IER_RTSDTR);
85 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_RTSDTR);
86 
87 	/* Turn off auto Xoff flow control */
88 	ier &= ~(UART_17158_IER_XOFF);
89 	efr &= ~(UART_17158_EFR_IXOFF);
90 
91 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
92 	writeb(0, &ch->ch_neo_uart->efr);
93 
94 	/* Turn on UART enhanced bits */
95 	writeb(efr, &ch->ch_neo_uart->efr);
96 
97 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
98 	ch->ch_r_watermark = 4;
99 
100 	writeb(56, &ch->ch_neo_uart->rfifo);
101 	ch->ch_r_tlevel = 56;
102 
103 	writeb(ier, &ch->ch_neo_uart->ier);
104 
105 	/*
106 	 * From the Neo UART spec sheet:
107 	 * The auto RTS/DTR function must be started by asserting
108 	 * RTS/DTR# output pin (MCR bit-0 or 1 to logic 1 after
109 	 * it is enabled.
110 	 */
111 	ch->ch_mostat |= (UART_MCR_RTS);
112 }
113 
114 
115 static void neo_set_ixon_flow_control(struct jsm_channel *ch)
116 {
117 	u8 ier, efr;
118 	ier = readb(&ch->ch_neo_uart->ier);
119 	efr = readb(&ch->ch_neo_uart->efr);
120 
121 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXON FLOW\n");
122 
123 	/* Turn off auto CTS flow control */
124 	ier &= ~(UART_17158_IER_CTSDSR);
125 	efr &= ~(UART_17158_EFR_CTSDSR);
126 
127 	/* Turn on auto Xon flow control */
128 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXON);
129 
130 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
131 	writeb(0, &ch->ch_neo_uart->efr);
132 
133 	/* Turn on UART enhanced bits */
134 	writeb(efr, &ch->ch_neo_uart->efr);
135 
136 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
137 	ch->ch_r_watermark = 4;
138 
139 	writeb(32, &ch->ch_neo_uart->rfifo);
140 	ch->ch_r_tlevel = 32;
141 
142 	/* Tell UART what start/stop chars it should be looking for */
143 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
144 	writeb(0, &ch->ch_neo_uart->xonchar2);
145 
146 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
147 	writeb(0, &ch->ch_neo_uart->xoffchar2);
148 
149 	writeb(ier, &ch->ch_neo_uart->ier);
150 }
151 
152 static void neo_set_ixoff_flow_control(struct jsm_channel *ch)
153 {
154 	u8 ier, efr;
155 	ier = readb(&ch->ch_neo_uart->ier);
156 	efr = readb(&ch->ch_neo_uart->efr);
157 
158 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXOFF FLOW\n");
159 
160 	/* Turn off auto RTS flow control */
161 	ier &= ~(UART_17158_IER_RTSDTR);
162 	efr &= ~(UART_17158_EFR_RTSDTR);
163 
164 	/* Turn on auto Xoff flow control */
165 	ier |= (UART_17158_IER_XOFF);
166 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
167 
168 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
169 	writeb(0, &ch->ch_neo_uart->efr);
170 
171 	/* Turn on UART enhanced bits */
172 	writeb(efr, &ch->ch_neo_uart->efr);
173 
174 	/* Turn on table D, with 8 char hi/low watermarks */
175 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
176 
177 	writeb(8, &ch->ch_neo_uart->tfifo);
178 	ch->ch_t_tlevel = 8;
179 
180 	/* Tell UART what start/stop chars it should be looking for */
181 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
182 	writeb(0, &ch->ch_neo_uart->xonchar2);
183 
184 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
185 	writeb(0, &ch->ch_neo_uart->xoffchar2);
186 
187 	writeb(ier, &ch->ch_neo_uart->ier);
188 }
189 
190 static void neo_set_no_input_flow_control(struct jsm_channel *ch)
191 {
192 	u8 ier, efr;
193 	ier = readb(&ch->ch_neo_uart->ier);
194 	efr = readb(&ch->ch_neo_uart->efr);
195 
196 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Input FLOW\n");
197 
198 	/* Turn off auto RTS flow control */
199 	ier &= ~(UART_17158_IER_RTSDTR);
200 	efr &= ~(UART_17158_EFR_RTSDTR);
201 
202 	/* Turn off auto Xoff flow control */
203 	ier &= ~(UART_17158_IER_XOFF);
204 	if (ch->ch_c_iflag & IXON)
205 		efr &= ~(UART_17158_EFR_IXOFF);
206 	else
207 		efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
208 
209 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
210 	writeb(0, &ch->ch_neo_uart->efr);
211 
212 	/* Turn on UART enhanced bits */
213 	writeb(efr, &ch->ch_neo_uart->efr);
214 
215 	/* Turn on table D, with 8 char hi/low watermarks */
216 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
217 
218 	ch->ch_r_watermark = 0;
219 
220 	writeb(16, &ch->ch_neo_uart->tfifo);
221 	ch->ch_t_tlevel = 16;
222 
223 	writeb(16, &ch->ch_neo_uart->rfifo);
224 	ch->ch_r_tlevel = 16;
225 
226 	writeb(ier, &ch->ch_neo_uart->ier);
227 }
228 
229 static void neo_set_no_output_flow_control(struct jsm_channel *ch)
230 {
231 	u8 ier, efr;
232 	ier = readb(&ch->ch_neo_uart->ier);
233 	efr = readb(&ch->ch_neo_uart->efr);
234 
235 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Output FLOW\n");
236 
237 	/* Turn off auto CTS flow control */
238 	ier &= ~(UART_17158_IER_CTSDSR);
239 	efr &= ~(UART_17158_EFR_CTSDSR);
240 
241 	/* Turn off auto Xon flow control */
242 	if (ch->ch_c_iflag & IXOFF)
243 		efr &= ~(UART_17158_EFR_IXON);
244 	else
245 		efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXON);
246 
247 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
248 	writeb(0, &ch->ch_neo_uart->efr);
249 
250 	/* Turn on UART enhanced bits */
251 	writeb(efr, &ch->ch_neo_uart->efr);
252 
253 	/* Turn on table D, with 8 char hi/low watermarks */
254 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
255 
256 	ch->ch_r_watermark = 0;
257 
258 	writeb(16, &ch->ch_neo_uart->tfifo);
259 	ch->ch_t_tlevel = 16;
260 
261 	writeb(16, &ch->ch_neo_uart->rfifo);
262 	ch->ch_r_tlevel = 16;
263 
264 	writeb(ier, &ch->ch_neo_uart->ier);
265 }
266 
267 static inline void neo_set_new_start_stop_chars(struct jsm_channel *ch)
268 {
269 
270 	/* if hardware flow control is set, then skip this whole thing */
271 	if (ch->ch_c_cflag & CRTSCTS)
272 		return;
273 
274 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "start\n");
275 
276 	/* Tell UART what start/stop chars it should be looking for */
277 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
278 	writeb(0, &ch->ch_neo_uart->xonchar2);
279 
280 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
281 	writeb(0, &ch->ch_neo_uart->xoffchar2);
282 }
283 
284 static void neo_copy_data_from_uart_to_queue(struct jsm_channel *ch)
285 {
286 	int qleft = 0;
287 	u8 linestatus = 0;
288 	u8 error_mask = 0;
289 	int n = 0;
290 	int total = 0;
291 	u16 head;
292 	u16 tail;
293 
294 	if (!ch)
295 		return;
296 
297 	/* cache head and tail of queue */
298 	head = ch->ch_r_head & RQUEUEMASK;
299 	tail = ch->ch_r_tail & RQUEUEMASK;
300 
301 	/* Get our cached LSR */
302 	linestatus = ch->ch_cached_lsr;
303 	ch->ch_cached_lsr = 0;
304 
305 	/* Store how much space we have left in the queue */
306 	if ((qleft = tail - head - 1) < 0)
307 		qleft += RQUEUEMASK + 1;
308 
309 	/*
310 	 * If the UART is not in FIFO mode, force the FIFO copy to
311 	 * NOT be run, by setting total to 0.
312 	 *
313 	 * On the other hand, if the UART IS in FIFO mode, then ask
314 	 * the UART to give us an approximation of data it has RX'ed.
315 	 */
316 	if (!(ch->ch_flags & CH_FIFO_ENABLED))
317 		total = 0;
318 	else {
319 		total = readb(&ch->ch_neo_uart->rfifo);
320 
321 		/*
322 		 * EXAR chip bug - RX FIFO COUNT - Fudge factor.
323 		 *
324 		 * This resolves a problem/bug with the Exar chip that sometimes
325 		 * returns a bogus value in the rfifo register.
326 		 * The count can be any where from 0-3 bytes "off".
327 		 * Bizarre, but true.
328 		 */
329 		total -= 3;
330 	}
331 
332 	/*
333 	 * Finally, bound the copy to make sure we don't overflow
334 	 * our own queue...
335 	 * The byte by byte copy loop below this loop this will
336 	 * deal with the queue overflow possibility.
337 	 */
338 	total = min(total, qleft);
339 
340 	while (total > 0) {
341 		/*
342 		 * Grab the linestatus register, we need to check
343 		 * to see if there are any errors in the FIFO.
344 		 */
345 		linestatus = readb(&ch->ch_neo_uart->lsr);
346 
347 		/*
348 		 * Break out if there is a FIFO error somewhere.
349 		 * This will allow us to go byte by byte down below,
350 		 * finding the exact location of the error.
351 		 */
352 		if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
353 			break;
354 
355 		/* Make sure we don't go over the end of our queue */
356 		n = min(((u32) total), (RQUEUESIZE - (u32) head));
357 
358 		/*
359 		 * Cut down n even further if needed, this is to fix
360 		 * a problem with memcpy_fromio() with the Neo on the
361 		 * IBM pSeries platform.
362 		 * 15 bytes max appears to be the magic number.
363 		 */
364 		n = min((u32) n, (u32) 12);
365 
366 		/*
367 		 * Since we are grabbing the linestatus register, which
368 		 * will reset some bits after our read, we need to ensure
369 		 * we don't miss our TX FIFO emptys.
370 		 */
371 		if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR))
372 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
373 
374 		linestatus = 0;
375 
376 		/* Copy data from uart to the queue */
377 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, n);
378 		/*
379 		 * Since RX_FIFO_DATA_ERROR was 0, we are guaranteed
380 		 * that all the data currently in the FIFO is free of
381 		 * breaks and parity/frame/orun errors.
382 		 */
383 		memset(ch->ch_equeue + head, 0, n);
384 
385 		/* Add to and flip head if needed */
386 		head = (head + n) & RQUEUEMASK;
387 		total -= n;
388 		qleft -= n;
389 		ch->ch_rxcount += n;
390 	}
391 
392 	/*
393 	 * Create a mask to determine whether we should
394 	 * insert the character (if any) into our queue.
395 	 */
396 	if (ch->ch_c_iflag & IGNBRK)
397 		error_mask |= UART_LSR_BI;
398 
399 	/*
400 	 * Now cleanup any leftover bytes still in the UART.
401 	 * Also deal with any possible queue overflow here as well.
402 	 */
403 	while (1) {
404 
405 		/*
406 		 * Its possible we have a linestatus from the loop above
407 		 * this, so we "OR" on any extra bits.
408 		 */
409 		linestatus |= readb(&ch->ch_neo_uart->lsr);
410 
411 		/*
412 		 * If the chip tells us there is no more data pending to
413 		 * be read, we can then leave.
414 		 * But before we do, cache the linestatus, just in case.
415 		 */
416 		if (!(linestatus & UART_LSR_DR)) {
417 			ch->ch_cached_lsr = linestatus;
418 			break;
419 		}
420 
421 		/* No need to store this bit */
422 		linestatus &= ~UART_LSR_DR;
423 
424 		/*
425 		 * Since we are grabbing the linestatus register, which
426 		 * will reset some bits after our read, we need to ensure
427 		 * we don't miss our TX FIFO emptys.
428 		 */
429 		if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR)) {
430 			linestatus &= ~(UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR);
431 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
432 		}
433 
434 		/*
435 		 * Discard character if we are ignoring the error mask.
436 		 */
437 		if (linestatus & error_mask) {
438 			u8 discard;
439 			linestatus = 0;
440 			memcpy_fromio(&discard, &ch->ch_neo_uart->txrxburst, 1);
441 			continue;
442 		}
443 
444 		/*
445 		 * If our queue is full, we have no choice but to drop some data.
446 		 * The assumption is that HWFLOW or SWFLOW should have stopped
447 		 * things way way before we got to this point.
448 		 *
449 		 * I decided that I wanted to ditch the oldest data first,
450 		 * I hope thats okay with everyone? Yes? Good.
451 		 */
452 		while (qleft < 1) {
453 			jsm_dbg(READ, &ch->ch_bd->pci_dev,
454 				"Queue full, dropping DATA:%x LSR:%x\n",
455 				ch->ch_rqueue[tail], ch->ch_equeue[tail]);
456 
457 			ch->ch_r_tail = tail = (tail + 1) & RQUEUEMASK;
458 			ch->ch_err_overrun++;
459 			qleft++;
460 		}
461 
462 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, 1);
463 		ch->ch_equeue[head] = (u8) linestatus;
464 
465 		jsm_dbg(READ, &ch->ch_bd->pci_dev, "DATA/LSR pair: %x %x\n",
466 			ch->ch_rqueue[head], ch->ch_equeue[head]);
467 
468 		/* Ditch any remaining linestatus value. */
469 		linestatus = 0;
470 
471 		/* Add to and flip head if needed */
472 		head = (head + 1) & RQUEUEMASK;
473 
474 		qleft--;
475 		ch->ch_rxcount++;
476 	}
477 
478 	/*
479 	 * Write new final heads to channel structure.
480 	 */
481 	ch->ch_r_head = head & RQUEUEMASK;
482 	ch->ch_e_head = head & EQUEUEMASK;
483 	jsm_input(ch);
484 }
485 
486 static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch)
487 {
488 	u16 head;
489 	u16 tail;
490 	int n;
491 	int s;
492 	int qlen;
493 	u32 len_written = 0;
494 	struct circ_buf *circ;
495 
496 	if (!ch)
497 		return;
498 
499 	circ = &ch->uart_port.state->xmit;
500 
501 	/* No data to write to the UART */
502 	if (uart_circ_empty(circ))
503 		return;
504 
505 	/* If port is "stopped", don't send any data to the UART */
506 	if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
507 		return;
508 	/*
509 	 * If FIFOs are disabled. Send data directly to txrx register
510 	 */
511 	if (!(ch->ch_flags & CH_FIFO_ENABLED)) {
512 		u8 lsrbits = readb(&ch->ch_neo_uart->lsr);
513 
514 		ch->ch_cached_lsr |= lsrbits;
515 		if (ch->ch_cached_lsr & UART_LSR_THRE) {
516 			ch->ch_cached_lsr &= ~(UART_LSR_THRE);
517 
518 			writeb(circ->buf[circ->tail], &ch->ch_neo_uart->txrx);
519 			jsm_dbg(WRITE, &ch->ch_bd->pci_dev,
520 				"Tx data: %x\n", circ->buf[circ->tail]);
521 			circ->tail = (circ->tail + 1) & (UART_XMIT_SIZE - 1);
522 			ch->ch_txcount++;
523 		}
524 		return;
525 	}
526 
527 	/*
528 	 * We have to do it this way, because of the EXAR TXFIFO count bug.
529 	 */
530 	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
531 		return;
532 
533 	n = UART_17158_TX_FIFOSIZE - ch->ch_t_tlevel;
534 
535 	/* cache head and tail of queue */
536 	head = circ->head & (UART_XMIT_SIZE - 1);
537 	tail = circ->tail & (UART_XMIT_SIZE - 1);
538 	qlen = uart_circ_chars_pending(circ);
539 
540 	/* Find minimum of the FIFO space, versus queue length */
541 	n = min(n, qlen);
542 
543 	while (n > 0) {
544 
545 		s = ((head >= tail) ? head : UART_XMIT_SIZE) - tail;
546 		s = min(s, n);
547 
548 		if (s <= 0)
549 			break;
550 
551 		memcpy_toio(&ch->ch_neo_uart->txrxburst, circ->buf + tail, s);
552 		/* Add and flip queue if needed */
553 		tail = (tail + s) & (UART_XMIT_SIZE - 1);
554 		n -= s;
555 		ch->ch_txcount += s;
556 		len_written += s;
557 	}
558 
559 	/* Update the final tail */
560 	circ->tail = tail & (UART_XMIT_SIZE - 1);
561 
562 	if (len_written >= ch->ch_t_tlevel)
563 		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
564 
565 	if (uart_circ_empty(circ))
566 		uart_write_wakeup(&ch->uart_port);
567 }
568 
569 static void neo_parse_modem(struct jsm_channel *ch, u8 signals)
570 {
571 	u8 msignals = signals;
572 
573 	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
574 		"neo_parse_modem: port: %d msignals: %x\n",
575 		ch->ch_portnum, msignals);
576 
577 	/* Scrub off lower bits. They signify delta's, which I don't care about */
578 	/* Keep DDCD and DDSR though */
579 	msignals &= 0xf8;
580 
581 	if (msignals & UART_MSR_DDCD)
582 		uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
583 	if (msignals & UART_MSR_DDSR)
584 		uart_handle_cts_change(&ch->uart_port, msignals & UART_MSR_CTS);
585 	if (msignals & UART_MSR_DCD)
586 		ch->ch_mistat |= UART_MSR_DCD;
587 	else
588 		ch->ch_mistat &= ~UART_MSR_DCD;
589 
590 	if (msignals & UART_MSR_DSR)
591 		ch->ch_mistat |= UART_MSR_DSR;
592 	else
593 		ch->ch_mistat &= ~UART_MSR_DSR;
594 
595 	if (msignals & UART_MSR_RI)
596 		ch->ch_mistat |= UART_MSR_RI;
597 	else
598 		ch->ch_mistat &= ~UART_MSR_RI;
599 
600 	if (msignals & UART_MSR_CTS)
601 		ch->ch_mistat |= UART_MSR_CTS;
602 	else
603 		ch->ch_mistat &= ~UART_MSR_CTS;
604 
605 	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
606 		"Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
607 		ch->ch_portnum,
608 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
609 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
610 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
611 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
612 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
613 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
614 }
615 
616 /* Make the UART raise any of the output signals we want up */
617 static void neo_assert_modem_signals(struct jsm_channel *ch)
618 {
619 	if (!ch)
620 		return;
621 
622 	writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
623 
624 	/* flush write operation */
625 	neo_pci_posting_flush(ch->ch_bd);
626 }
627 
628 /*
629  * Flush the WRITE FIFO on the Neo.
630  *
631  * NOTE: Channel lock MUST be held before calling this function!
632  */
633 static void neo_flush_uart_write(struct jsm_channel *ch)
634 {
635 	u8 tmp = 0;
636 	int i = 0;
637 
638 	if (!ch)
639 		return;
640 
641 	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
642 
643 	for (i = 0; i < 10; i++) {
644 
645 		/* Check to see if the UART feels it completely flushed the FIFO. */
646 		tmp = readb(&ch->ch_neo_uart->isr_fcr);
647 		if (tmp & UART_FCR_CLEAR_XMIT) {
648 			jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
649 				"Still flushing TX UART... i: %d\n", i);
650 			udelay(10);
651 		}
652 		else
653 			break;
654 	}
655 
656 	ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
657 }
658 
659 
660 /*
661  * Flush the READ FIFO on the Neo.
662  *
663  * NOTE: Channel lock MUST be held before calling this function!
664  */
665 static void neo_flush_uart_read(struct jsm_channel *ch)
666 {
667 	u8 tmp = 0;
668 	int i = 0;
669 
670 	if (!ch)
671 		return;
672 
673 	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR), &ch->ch_neo_uart->isr_fcr);
674 
675 	for (i = 0; i < 10; i++) {
676 
677 		/* Check to see if the UART feels it completely flushed the FIFO. */
678 		tmp = readb(&ch->ch_neo_uart->isr_fcr);
679 		if (tmp & 2) {
680 			jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
681 				"Still flushing RX UART... i: %d\n", i);
682 			udelay(10);
683 		}
684 		else
685 			break;
686 	}
687 }
688 
689 /*
690  * No locks are assumed to be held when calling this function.
691  */
692 static void neo_clear_break(struct jsm_channel *ch)
693 {
694 	unsigned long lock_flags;
695 
696 	spin_lock_irqsave(&ch->ch_lock, lock_flags);
697 
698 	/* Turn break off, and unset some variables */
699 	if (ch->ch_flags & CH_BREAK_SENDING) {
700 		u8 temp = readb(&ch->ch_neo_uart->lcr);
701 		writeb((temp & ~UART_LCR_SBC), &ch->ch_neo_uart->lcr);
702 
703 		ch->ch_flags &= ~(CH_BREAK_SENDING);
704 		jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
705 			"clear break Finishing UART_LCR_SBC! finished: %lx\n",
706 			jiffies);
707 
708 		/* flush write operation */
709 		neo_pci_posting_flush(ch->ch_bd);
710 	}
711 	spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
712 }
713 
714 /*
715  * Parse the ISR register.
716  */
717 static void neo_parse_isr(struct jsm_board *brd, u32 port)
718 {
719 	struct jsm_channel *ch;
720 	u8 isr;
721 	u8 cause;
722 	unsigned long lock_flags;
723 
724 	if (!brd)
725 		return;
726 
727 	if (port >= brd->maxports)
728 		return;
729 
730 	ch = brd->channels[port];
731 	if (!ch)
732 		return;
733 
734 	/* Here we try to figure out what caused the interrupt to happen */
735 	while (1) {
736 
737 		isr = readb(&ch->ch_neo_uart->isr_fcr);
738 
739 		/* Bail if no pending interrupt */
740 		if (isr & UART_IIR_NO_INT)
741 			break;
742 
743 		/*
744 		 * Yank off the upper 2 bits, which just show that the FIFO's are enabled.
745 		 */
746 		isr &= ~(UART_17158_IIR_FIFO_ENABLED);
747 
748 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d isr: %x\n",
749 			__FILE__, __LINE__, isr);
750 
751 		if (isr & (UART_17158_IIR_RDI_TIMEOUT | UART_IIR_RDI)) {
752 			/* Read data from uart -> queue */
753 			neo_copy_data_from_uart_to_queue(ch);
754 
755 			/* Call our tty layer to enforce queue flow control if needed. */
756 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
757 			jsm_check_queue_flow_control(ch);
758 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
759 		}
760 
761 		if (isr & UART_IIR_THRI) {
762 			/* Transfer data (if any) from Write Queue -> UART. */
763 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
764 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
765 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
766 			neo_copy_data_from_queue_to_uart(ch);
767 		}
768 
769 		if (isr & UART_17158_IIR_XONXOFF) {
770 			cause = readb(&ch->ch_neo_uart->xoffchar1);
771 
772 			jsm_dbg(INTR, &ch->ch_bd->pci_dev,
773 				"Port %d. Got ISR_XONXOFF: cause:%x\n",
774 				port, cause);
775 
776 			/*
777 			 * Since the UART detected either an XON or
778 			 * XOFF match, we need to figure out which
779 			 * one it was, so we can suspend or resume data flow.
780 			 */
781 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
782 			if (cause == UART_17158_XON_DETECT) {
783 				/* Is output stopped right now, if so, resume it */
784 				if (brd->channels[port]->ch_flags & CH_STOP) {
785 					ch->ch_flags &= ~(CH_STOP);
786 				}
787 				jsm_dbg(INTR, &ch->ch_bd->pci_dev,
788 					"Port %d. XON detected in incoming data\n",
789 					port);
790 			}
791 			else if (cause == UART_17158_XOFF_DETECT) {
792 				if (!(brd->channels[port]->ch_flags & CH_STOP)) {
793 					ch->ch_flags |= CH_STOP;
794 					jsm_dbg(INTR, &ch->ch_bd->pci_dev,
795 						"Setting CH_STOP\n");
796 				}
797 				jsm_dbg(INTR, &ch->ch_bd->pci_dev,
798 					"Port: %d. XOFF detected in incoming data\n",
799 					port);
800 			}
801 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
802 		}
803 
804 		if (isr & UART_17158_IIR_HWFLOW_STATE_CHANGE) {
805 			/*
806 			 * If we get here, this means the hardware is doing auto flow control.
807 			 * Check to see whether RTS/DTR or CTS/DSR caused this interrupt.
808 			 */
809 			cause = readb(&ch->ch_neo_uart->mcr);
810 
811 			/* Which pin is doing auto flow? RTS or DTR? */
812 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
813 			if ((cause & 0x4) == 0) {
814 				if (cause & UART_MCR_RTS)
815 					ch->ch_mostat |= UART_MCR_RTS;
816 				else
817 					ch->ch_mostat &= ~(UART_MCR_RTS);
818 			} else {
819 				if (cause & UART_MCR_DTR)
820 					ch->ch_mostat |= UART_MCR_DTR;
821 				else
822 					ch->ch_mostat &= ~(UART_MCR_DTR);
823 			}
824 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
825 		}
826 
827 		/* Parse any modem signal changes */
828 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
829 			"MOD_STAT: sending to parse_modem_sigs\n");
830 		neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
831 	}
832 }
833 
834 static inline void neo_parse_lsr(struct jsm_board *brd, u32 port)
835 {
836 	struct jsm_channel *ch;
837 	int linestatus;
838 	unsigned long lock_flags;
839 
840 	if (!brd)
841 		return;
842 
843 	if (port >= brd->maxports)
844 		return;
845 
846 	ch = brd->channels[port];
847 	if (!ch)
848 		return;
849 
850 	linestatus = readb(&ch->ch_neo_uart->lsr);
851 
852 	jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d port: %d linestatus: %x\n",
853 		__FILE__, __LINE__, port, linestatus);
854 
855 	ch->ch_cached_lsr |= linestatus;
856 
857 	if (ch->ch_cached_lsr & UART_LSR_DR) {
858 		/* Read data from uart -> queue */
859 		neo_copy_data_from_uart_to_queue(ch);
860 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
861 		jsm_check_queue_flow_control(ch);
862 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
863 	}
864 
865 	/*
866 	 * This is a special flag. It indicates that at least 1
867 	 * RX error (parity, framing, or break) has happened.
868 	 * Mark this in our struct, which will tell me that I have
869 	 *to do the special RX+LSR read for this FIFO load.
870 	 */
871 	if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
872 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
873 			"%s:%d Port: %d Got an RX error, need to parse LSR\n",
874 			__FILE__, __LINE__, port);
875 
876 	/*
877 	 * The next 3 tests should *NOT* happen, as the above test
878 	 * should encapsulate all 3... At least, thats what Exar says.
879 	 */
880 
881 	if (linestatus & UART_LSR_PE) {
882 		ch->ch_err_parity++;
883 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. PAR ERR!\n",
884 			__FILE__, __LINE__, port);
885 	}
886 
887 	if (linestatus & UART_LSR_FE) {
888 		ch->ch_err_frame++;
889 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. FRM ERR!\n",
890 			__FILE__, __LINE__, port);
891 	}
892 
893 	if (linestatus & UART_LSR_BI) {
894 		ch->ch_err_break++;
895 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
896 			"%s:%d Port: %d. BRK INTR!\n",
897 			__FILE__, __LINE__, port);
898 	}
899 
900 	if (linestatus & UART_LSR_OE) {
901 		/*
902 		 * Rx Oruns. Exar says that an orun will NOT corrupt
903 		 * the FIFO. It will just replace the holding register
904 		 * with this new data byte. So basically just ignore this.
905 		 * Probably we should eventually have an orun stat in our driver...
906 		 */
907 		ch->ch_err_overrun++;
908 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
909 			"%s:%d Port: %d. Rx Overrun!\n",
910 			__FILE__, __LINE__, port);
911 	}
912 
913 	if (linestatus & UART_LSR_THRE) {
914 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
915 		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
916 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
917 
918 		/* Transfer data (if any) from Write Queue -> UART. */
919 		neo_copy_data_from_queue_to_uart(ch);
920 	}
921 	else if (linestatus & UART_17158_TX_AND_FIFO_CLR) {
922 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
923 		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
924 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
925 
926 		/* Transfer data (if any) from Write Queue -> UART. */
927 		neo_copy_data_from_queue_to_uart(ch);
928 	}
929 }
930 
931 /*
932  * neo_param()
933  * Send any/all changes to the line to the UART.
934  */
935 static void neo_param(struct jsm_channel *ch)
936 {
937 	u8 lcr = 0;
938 	u8 uart_lcr, ier;
939 	u32 baud;
940 	int quot;
941 	struct jsm_board *bd;
942 
943 	bd = ch->ch_bd;
944 	if (!bd)
945 		return;
946 
947 	/*
948 	 * If baud rate is zero, flush queues, and set mval to drop DTR.
949 	 */
950 	if ((ch->ch_c_cflag & (CBAUD)) == 0) {
951 		ch->ch_r_head = ch->ch_r_tail = 0;
952 		ch->ch_e_head = ch->ch_e_tail = 0;
953 
954 		neo_flush_uart_write(ch);
955 		neo_flush_uart_read(ch);
956 
957 		ch->ch_flags |= (CH_BAUD0);
958 		ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
959 		neo_assert_modem_signals(ch);
960 		return;
961 
962 	} else {
963 		int i;
964 		unsigned int cflag;
965 		static struct {
966 			unsigned int rate;
967 			unsigned int cflag;
968 		} baud_rates[] = {
969 			{ 921600, B921600 },
970 			{ 460800, B460800 },
971 			{ 230400, B230400 },
972 			{ 115200, B115200 },
973 			{  57600, B57600  },
974 			{  38400, B38400  },
975 			{  19200, B19200  },
976 			{   9600, B9600   },
977 			{   4800, B4800   },
978 			{   2400, B2400   },
979 			{   1200, B1200   },
980 			{    600, B600    },
981 			{    300, B300    },
982 			{    200, B200    },
983 			{    150, B150    },
984 			{    134, B134    },
985 			{    110, B110    },
986 			{     75, B75     },
987 			{     50, B50     },
988 		};
989 
990 		cflag = C_BAUD(ch->uart_port.state->port.tty);
991 		baud = 9600;
992 		for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
993 			if (baud_rates[i].cflag == cflag) {
994 				baud = baud_rates[i].rate;
995 				break;
996 			}
997 		}
998 
999 		if (ch->ch_flags & CH_BAUD0)
1000 			ch->ch_flags &= ~(CH_BAUD0);
1001 	}
1002 
1003 	if (ch->ch_c_cflag & PARENB)
1004 		lcr |= UART_LCR_PARITY;
1005 
1006 	if (!(ch->ch_c_cflag & PARODD))
1007 		lcr |= UART_LCR_EPAR;
1008 
1009 	/*
1010 	 * Not all platforms support mark/space parity,
1011 	 * so this will hide behind an ifdef.
1012 	 */
1013 #ifdef CMSPAR
1014 	if (ch->ch_c_cflag & CMSPAR)
1015 		lcr |= UART_LCR_SPAR;
1016 #endif
1017 
1018 	if (ch->ch_c_cflag & CSTOPB)
1019 		lcr |= UART_LCR_STOP;
1020 
1021 	switch (ch->ch_c_cflag & CSIZE) {
1022 	case CS5:
1023 		lcr |= UART_LCR_WLEN5;
1024 		break;
1025 	case CS6:
1026 		lcr |= UART_LCR_WLEN6;
1027 		break;
1028 	case CS7:
1029 		lcr |= UART_LCR_WLEN7;
1030 		break;
1031 	case CS8:
1032 	default:
1033 		lcr |= UART_LCR_WLEN8;
1034 	break;
1035 	}
1036 
1037 	ier = readb(&ch->ch_neo_uart->ier);
1038 	uart_lcr = readb(&ch->ch_neo_uart->lcr);
1039 
1040 	quot = ch->ch_bd->bd_dividend / baud;
1041 
1042 	if (quot != 0) {
1043 		writeb(UART_LCR_DLAB, &ch->ch_neo_uart->lcr);
1044 		writeb((quot & 0xff), &ch->ch_neo_uart->txrx);
1045 		writeb((quot >> 8), &ch->ch_neo_uart->ier);
1046 		writeb(lcr, &ch->ch_neo_uart->lcr);
1047 	}
1048 
1049 	if (uart_lcr != lcr)
1050 		writeb(lcr, &ch->ch_neo_uart->lcr);
1051 
1052 	if (ch->ch_c_cflag & CREAD)
1053 		ier |= (UART_IER_RDI | UART_IER_RLSI);
1054 
1055 	ier |= (UART_IER_THRI | UART_IER_MSI);
1056 
1057 	writeb(ier, &ch->ch_neo_uart->ier);
1058 
1059 	/* Set new start/stop chars */
1060 	neo_set_new_start_stop_chars(ch);
1061 
1062 	if (ch->ch_c_cflag & CRTSCTS)
1063 		neo_set_cts_flow_control(ch);
1064 	else if (ch->ch_c_iflag & IXON) {
1065 		/* If start/stop is set to disable, then we should disable flow control */
1066 		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1067 			neo_set_no_output_flow_control(ch);
1068 		else
1069 			neo_set_ixon_flow_control(ch);
1070 	}
1071 	else
1072 		neo_set_no_output_flow_control(ch);
1073 
1074 	if (ch->ch_c_cflag & CRTSCTS)
1075 		neo_set_rts_flow_control(ch);
1076 	else if (ch->ch_c_iflag & IXOFF) {
1077 		/* If start/stop is set to disable, then we should disable flow control */
1078 		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1079 			neo_set_no_input_flow_control(ch);
1080 		else
1081 			neo_set_ixoff_flow_control(ch);
1082 	}
1083 	else
1084 		neo_set_no_input_flow_control(ch);
1085 	/*
1086 	 * Adjust the RX FIFO Trigger level if baud is less than 9600.
1087 	 * Not exactly elegant, but this is needed because of the Exar chip's
1088 	 * delay on firing off the RX FIFO interrupt on slower baud rates.
1089 	 */
1090 	if (baud < 9600) {
1091 		writeb(1, &ch->ch_neo_uart->rfifo);
1092 		ch->ch_r_tlevel = 1;
1093 	}
1094 
1095 	neo_assert_modem_signals(ch);
1096 
1097 	/* Get current status of the modem signals now */
1098 	neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
1099 	return;
1100 }
1101 
1102 /*
1103  * jsm_neo_intr()
1104  *
1105  * Neo specific interrupt handler.
1106  */
1107 static irqreturn_t neo_intr(int irq, void *voidbrd)
1108 {
1109 	struct jsm_board *brd = voidbrd;
1110 	struct jsm_channel *ch;
1111 	int port = 0;
1112 	int type = 0;
1113 	int current_port;
1114 	u32 tmp;
1115 	u32 uart_poll;
1116 	unsigned long lock_flags;
1117 	unsigned long lock_flags2;
1118 	int outofloop_count = 0;
1119 
1120 	/* Lock out the slow poller from running on this board. */
1121 	spin_lock_irqsave(&brd->bd_intr_lock, lock_flags);
1122 
1123 	/*
1124 	 * Read in "extended" IRQ information from the 32bit Neo register.
1125 	 * Bits 0-7: What port triggered the interrupt.
1126 	 * Bits 8-31: Each 3bits indicate what type of interrupt occurred.
1127 	 */
1128 	uart_poll = readl(brd->re_map_membase + UART_17158_POLL_ADDR_OFFSET);
1129 
1130 	jsm_dbg(INTR, &brd->pci_dev, "%s:%d uart_poll: %x\n",
1131 		__FILE__, __LINE__, uart_poll);
1132 
1133 	if (!uart_poll) {
1134 		jsm_dbg(INTR, &brd->pci_dev,
1135 			"Kernel interrupted to me, but no pending interrupts...\n");
1136 		spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1137 		return IRQ_NONE;
1138 	}
1139 
1140 	/* At this point, we have at least SOMETHING to service, dig further... */
1141 
1142 	current_port = 0;
1143 
1144 	/* Loop on each port */
1145 	while (((uart_poll & 0xff) != 0) && (outofloop_count < 0xff)){
1146 
1147 		tmp = uart_poll;
1148 		outofloop_count++;
1149 
1150 		/* Check current port to see if it has interrupt pending */
1151 		if ((tmp & jsm_offset_table[current_port]) != 0) {
1152 			port = current_port;
1153 			type = tmp >> (8 + (port * 3));
1154 			type &= 0x7;
1155 		} else {
1156 			current_port++;
1157 			continue;
1158 		}
1159 
1160 		jsm_dbg(INTR, &brd->pci_dev, "%s:%d port: %x type: %x\n",
1161 			__FILE__, __LINE__, port, type);
1162 
1163 		/* Remove this port + type from uart_poll */
1164 		uart_poll &= ~(jsm_offset_table[port]);
1165 
1166 		if (!type) {
1167 			/* If no type, just ignore it, and move onto next port */
1168 			jsm_dbg(INTR, &brd->pci_dev,
1169 				"Interrupt with no type! port: %d\n", port);
1170 			continue;
1171 		}
1172 
1173 		/* Switch on type of interrupt we have */
1174 		switch (type) {
1175 
1176 		case UART_17158_RXRDY_TIMEOUT:
1177 			/*
1178 			 * RXRDY Time-out is cleared by reading data in the
1179 			* RX FIFO until it falls below the trigger level.
1180 			 */
1181 
1182 			/* Verify the port is in range. */
1183 			if (port >= brd->nasync)
1184 				continue;
1185 
1186 			ch = brd->channels[port];
1187 			neo_copy_data_from_uart_to_queue(ch);
1188 
1189 			/* Call our tty layer to enforce queue flow control if needed. */
1190 			spin_lock_irqsave(&ch->ch_lock, lock_flags2);
1191 			jsm_check_queue_flow_control(ch);
1192 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags2);
1193 
1194 			continue;
1195 
1196 		case UART_17158_RX_LINE_STATUS:
1197 			/*
1198 			 * RXRDY and RX LINE Status (logic OR of LSR[4:1])
1199 			 */
1200 			neo_parse_lsr(brd, port);
1201 			continue;
1202 
1203 		case UART_17158_TXRDY:
1204 			/*
1205 			 * TXRDY interrupt clears after reading ISR register for the UART channel.
1206 			 */
1207 
1208 			/*
1209 			 * Yes, this is odd...
1210 			 * Why would I check EVERY possibility of type of
1211 			 * interrupt, when we know its TXRDY???
1212 			 * Becuz for some reason, even tho we got triggered for TXRDY,
1213 			 * it seems to be occasionally wrong. Instead of TX, which
1214 			 * it should be, I was getting things like RXDY too. Weird.
1215 			 */
1216 			neo_parse_isr(brd, port);
1217 			continue;
1218 
1219 		case UART_17158_MSR:
1220 			/*
1221 			 * MSR or flow control was seen.
1222 			 */
1223 			neo_parse_isr(brd, port);
1224 			continue;
1225 
1226 		default:
1227 			/*
1228 			 * The UART triggered us with a bogus interrupt type.
1229 			 * It appears the Exar chip, when REALLY bogged down, will throw
1230 			 * these once and awhile.
1231 			 * Its harmless, just ignore it and move on.
1232 			 */
1233 			jsm_dbg(INTR, &brd->pci_dev,
1234 				"%s:%d Unknown Interrupt type: %x\n",
1235 				__FILE__, __LINE__, type);
1236 			continue;
1237 		}
1238 	}
1239 
1240 	spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1241 
1242 	jsm_dbg(INTR, &brd->pci_dev, "finish\n");
1243 	return IRQ_HANDLED;
1244 }
1245 
1246 /*
1247  * Neo specific way of turning off the receiver.
1248  * Used as a way to enforce queue flow control when in
1249  * hardware flow control mode.
1250  */
1251 static void neo_disable_receiver(struct jsm_channel *ch)
1252 {
1253 	u8 tmp = readb(&ch->ch_neo_uart->ier);
1254 	tmp &= ~(UART_IER_RDI);
1255 	writeb(tmp, &ch->ch_neo_uart->ier);
1256 
1257 	/* flush write operation */
1258 	neo_pci_posting_flush(ch->ch_bd);
1259 }
1260 
1261 
1262 /*
1263  * Neo specific way of turning on the receiver.
1264  * Used as a way to un-enforce queue flow control when in
1265  * hardware flow control mode.
1266  */
1267 static void neo_enable_receiver(struct jsm_channel *ch)
1268 {
1269 	u8 tmp = readb(&ch->ch_neo_uart->ier);
1270 	tmp |= (UART_IER_RDI);
1271 	writeb(tmp, &ch->ch_neo_uart->ier);
1272 
1273 	/* flush write operation */
1274 	neo_pci_posting_flush(ch->ch_bd);
1275 }
1276 
1277 static void neo_send_start_character(struct jsm_channel *ch)
1278 {
1279 	if (!ch)
1280 		return;
1281 
1282 	if (ch->ch_startc != __DISABLED_CHAR) {
1283 		ch->ch_xon_sends++;
1284 		writeb(ch->ch_startc, &ch->ch_neo_uart->txrx);
1285 
1286 		/* flush write operation */
1287 		neo_pci_posting_flush(ch->ch_bd);
1288 	}
1289 }
1290 
1291 static void neo_send_stop_character(struct jsm_channel *ch)
1292 {
1293 	if (!ch)
1294 		return;
1295 
1296 	if (ch->ch_stopc != __DISABLED_CHAR) {
1297 		ch->ch_xoff_sends++;
1298 		writeb(ch->ch_stopc, &ch->ch_neo_uart->txrx);
1299 
1300 		/* flush write operation */
1301 		neo_pci_posting_flush(ch->ch_bd);
1302 	}
1303 }
1304 
1305 /*
1306  * neo_uart_init
1307  */
1308 static void neo_uart_init(struct jsm_channel *ch)
1309 {
1310 	writeb(0, &ch->ch_neo_uart->ier);
1311 	writeb(0, &ch->ch_neo_uart->efr);
1312 	writeb(UART_EFR_ECB, &ch->ch_neo_uart->efr);
1313 
1314 	/* Clear out UART and FIFO */
1315 	readb(&ch->ch_neo_uart->txrx);
1316 	writeb((UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
1317 	readb(&ch->ch_neo_uart->lsr);
1318 	readb(&ch->ch_neo_uart->msr);
1319 
1320 	ch->ch_flags |= CH_FIFO_ENABLED;
1321 
1322 	/* Assert any signals we want up */
1323 	writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
1324 }
1325 
1326 /*
1327  * Make the UART completely turn off.
1328  */
1329 static void neo_uart_off(struct jsm_channel *ch)
1330 {
1331 	/* Turn off UART enhanced bits */
1332 	writeb(0, &ch->ch_neo_uart->efr);
1333 
1334 	/* Stop all interrupts from occurring. */
1335 	writeb(0, &ch->ch_neo_uart->ier);
1336 }
1337 
1338 static u32 neo_get_uart_bytes_left(struct jsm_channel *ch)
1339 {
1340 	u8 left = 0;
1341 	u8 lsr = readb(&ch->ch_neo_uart->lsr);
1342 
1343 	/* We must cache the LSR as some of the bits get reset once read... */
1344 	ch->ch_cached_lsr |= lsr;
1345 
1346 	/* Determine whether the Transmitter is empty or not */
1347 	if (!(lsr & UART_LSR_TEMT))
1348 		left = 1;
1349 	else {
1350 		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
1351 		left = 0;
1352 	}
1353 
1354 	return left;
1355 }
1356 
1357 /* Channel lock MUST be held by the calling function! */
1358 static void neo_send_break(struct jsm_channel *ch)
1359 {
1360 	/*
1361 	 * Set the time we should stop sending the break.
1362 	 * If we are already sending a break, toss away the existing
1363 	 * time to stop, and use this new value instead.
1364 	 */
1365 
1366 	/* Tell the UART to start sending the break */
1367 	if (!(ch->ch_flags & CH_BREAK_SENDING)) {
1368 		u8 temp = readb(&ch->ch_neo_uart->lcr);
1369 		writeb((temp | UART_LCR_SBC), &ch->ch_neo_uart->lcr);
1370 		ch->ch_flags |= (CH_BREAK_SENDING);
1371 
1372 		/* flush write operation */
1373 		neo_pci_posting_flush(ch->ch_bd);
1374 	}
1375 }
1376 
1377 /*
1378  * neo_send_immediate_char.
1379  *
1380  * Sends a specific character as soon as possible to the UART,
1381  * jumping over any bytes that might be in the write queue.
1382  *
1383  * The channel lock MUST be held by the calling function.
1384  */
1385 static void neo_send_immediate_char(struct jsm_channel *ch, unsigned char c)
1386 {
1387 	if (!ch)
1388 		return;
1389 
1390 	writeb(c, &ch->ch_neo_uart->txrx);
1391 
1392 	/* flush write operation */
1393 	neo_pci_posting_flush(ch->ch_bd);
1394 }
1395 
1396 struct board_ops jsm_neo_ops = {
1397 	.intr				= neo_intr,
1398 	.uart_init			= neo_uart_init,
1399 	.uart_off			= neo_uart_off,
1400 	.param				= neo_param,
1401 	.assert_modem_signals		= neo_assert_modem_signals,
1402 	.flush_uart_write		= neo_flush_uart_write,
1403 	.flush_uart_read		= neo_flush_uart_read,
1404 	.disable_receiver		= neo_disable_receiver,
1405 	.enable_receiver		= neo_enable_receiver,
1406 	.send_break			= neo_send_break,
1407 	.clear_break			= neo_clear_break,
1408 	.send_start_character		= neo_send_start_character,
1409 	.send_stop_character		= neo_send_stop_character,
1410 	.copy_data_from_queue_to_uart	= neo_copy_data_from_queue_to_uart,
1411 	.get_uart_bytes_left		= neo_get_uart_bytes_left,
1412 	.send_immediate_char		= neo_send_immediate_char
1413 };
1414