xref: /linux/drivers/tty/serial/jsm/jsm_neo.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
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  * Wendy Xiong   <wendyx@us.ibm.com>
10  *
11  ***********************************************************************/
12 #include <linux/delay.h>	/* For udelay */
13 #include <linux/serial_reg.h>	/* For the various UART offsets */
14 #include <linux/tty.h>
15 #include <linux/pci.h>
16 #include <asm/io.h>
17 
18 #include "jsm.h"		/* Driver main header file */
19 
20 static u32 jsm_offset_table[8] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
21 
22 /*
23  * This function allows calls to ensure that all outstanding
24  * PCI writes have been completed, by doing a PCI read against
25  * a non-destructive, read-only location on the Neo card.
26  *
27  * In this case, we are reading the DVID (Read-only Device Identification)
28  * value of the Neo card.
29  */
30 static inline void neo_pci_posting_flush(struct jsm_board *bd)
31 {
32       readb(bd->re_map_membase + 0x8D);
33 }
34 
35 static void neo_set_cts_flow_control(struct jsm_channel *ch)
36 {
37 	u8 ier, efr;
38 	ier = readb(&ch->ch_neo_uart->ier);
39 	efr = readb(&ch->ch_neo_uart->efr);
40 
41 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting CTSFLOW\n");
42 
43 	/* Turn on auto CTS flow control */
44 	ier |= (UART_17158_IER_CTSDSR);
45 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_CTSDSR);
46 
47 	/* Turn off auto Xon flow control */
48 	efr &= ~(UART_17158_EFR_IXON);
49 
50 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
51 	writeb(0, &ch->ch_neo_uart->efr);
52 
53 	/* Turn on UART enhanced bits */
54 	writeb(efr, &ch->ch_neo_uart->efr);
55 
56 	/* Turn on table D, with 8 char hi/low watermarks */
57 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
58 
59 	/* Feed the UART our trigger levels */
60 	writeb(8, &ch->ch_neo_uart->tfifo);
61 	ch->ch_t_tlevel = 8;
62 
63 	writeb(ier, &ch->ch_neo_uart->ier);
64 }
65 
66 static void neo_set_rts_flow_control(struct jsm_channel *ch)
67 {
68 	u8 ier, efr;
69 	ier = readb(&ch->ch_neo_uart->ier);
70 	efr = readb(&ch->ch_neo_uart->efr);
71 
72 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting RTSFLOW\n");
73 
74 	/* Turn on auto RTS flow control */
75 	ier |= (UART_17158_IER_RTSDTR);
76 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_RTSDTR);
77 
78 	/* Turn off auto Xoff flow control */
79 	ier &= ~(UART_17158_IER_XOFF);
80 	efr &= ~(UART_17158_EFR_IXOFF);
81 
82 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
83 	writeb(0, &ch->ch_neo_uart->efr);
84 
85 	/* Turn on UART enhanced bits */
86 	writeb(efr, &ch->ch_neo_uart->efr);
87 
88 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_4DELAY), &ch->ch_neo_uart->fctr);
89 	ch->ch_r_watermark = 4;
90 
91 	writeb(56, &ch->ch_neo_uart->rfifo);
92 	ch->ch_r_tlevel = 56;
93 
94 	writeb(ier, &ch->ch_neo_uart->ier);
95 
96 	/*
97 	 * From the Neo UART spec sheet:
98 	 * The auto RTS/DTR function must be started by asserting
99 	 * RTS/DTR# output pin (MCR bit-0 or 1 to logic 1 after
100 	 * it is enabled.
101 	 */
102 	ch->ch_mostat |= (UART_MCR_RTS);
103 }
104 
105 
106 static void neo_set_ixon_flow_control(struct jsm_channel *ch)
107 {
108 	u8 ier, efr;
109 	ier = readb(&ch->ch_neo_uart->ier);
110 	efr = readb(&ch->ch_neo_uart->efr);
111 
112 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXON FLOW\n");
113 
114 	/* Turn off auto CTS flow control */
115 	ier &= ~(UART_17158_IER_CTSDSR);
116 	efr &= ~(UART_17158_EFR_CTSDSR);
117 
118 	/* Turn on auto Xon flow control */
119 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXON);
120 
121 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
122 	writeb(0, &ch->ch_neo_uart->efr);
123 
124 	/* Turn on UART enhanced bits */
125 	writeb(efr, &ch->ch_neo_uart->efr);
126 
127 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
128 	ch->ch_r_watermark = 4;
129 
130 	writeb(32, &ch->ch_neo_uart->rfifo);
131 	ch->ch_r_tlevel = 32;
132 
133 	/* Tell UART what start/stop chars it should be looking for */
134 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
135 	writeb(0, &ch->ch_neo_uart->xonchar2);
136 
137 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
138 	writeb(0, &ch->ch_neo_uart->xoffchar2);
139 
140 	writeb(ier, &ch->ch_neo_uart->ier);
141 }
142 
143 static void neo_set_ixoff_flow_control(struct jsm_channel *ch)
144 {
145 	u8 ier, efr;
146 	ier = readb(&ch->ch_neo_uart->ier);
147 	efr = readb(&ch->ch_neo_uart->efr);
148 
149 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Setting IXOFF FLOW\n");
150 
151 	/* Turn off auto RTS flow control */
152 	ier &= ~(UART_17158_IER_RTSDTR);
153 	efr &= ~(UART_17158_EFR_RTSDTR);
154 
155 	/* Turn on auto Xoff flow control */
156 	ier |= (UART_17158_IER_XOFF);
157 	efr |= (UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
158 
159 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
160 	writeb(0, &ch->ch_neo_uart->efr);
161 
162 	/* Turn on UART enhanced bits */
163 	writeb(efr, &ch->ch_neo_uart->efr);
164 
165 	/* Turn on table D, with 8 char hi/low watermarks */
166 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
167 
168 	writeb(8, &ch->ch_neo_uart->tfifo);
169 	ch->ch_t_tlevel = 8;
170 
171 	/* Tell UART what start/stop chars it should be looking for */
172 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
173 	writeb(0, &ch->ch_neo_uart->xonchar2);
174 
175 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
176 	writeb(0, &ch->ch_neo_uart->xoffchar2);
177 
178 	writeb(ier, &ch->ch_neo_uart->ier);
179 }
180 
181 static void neo_set_no_input_flow_control(struct jsm_channel *ch)
182 {
183 	u8 ier, efr;
184 	ier = readb(&ch->ch_neo_uart->ier);
185 	efr = readb(&ch->ch_neo_uart->efr);
186 
187 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Input FLOW\n");
188 
189 	/* Turn off auto RTS flow control */
190 	ier &= ~(UART_17158_IER_RTSDTR);
191 	efr &= ~(UART_17158_EFR_RTSDTR);
192 
193 	/* Turn off auto Xoff flow control */
194 	ier &= ~(UART_17158_IER_XOFF);
195 	if (ch->ch_c_iflag & IXON)
196 		efr &= ~(UART_17158_EFR_IXOFF);
197 	else
198 		efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXOFF);
199 
200 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
201 	writeb(0, &ch->ch_neo_uart->efr);
202 
203 	/* Turn on UART enhanced bits */
204 	writeb(efr, &ch->ch_neo_uart->efr);
205 
206 	/* Turn on table D, with 8 char hi/low watermarks */
207 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
208 
209 	ch->ch_r_watermark = 0;
210 
211 	writeb(16, &ch->ch_neo_uart->tfifo);
212 	ch->ch_t_tlevel = 16;
213 
214 	writeb(16, &ch->ch_neo_uart->rfifo);
215 	ch->ch_r_tlevel = 16;
216 
217 	writeb(ier, &ch->ch_neo_uart->ier);
218 }
219 
220 static void neo_set_no_output_flow_control(struct jsm_channel *ch)
221 {
222 	u8 ier, efr;
223 	ier = readb(&ch->ch_neo_uart->ier);
224 	efr = readb(&ch->ch_neo_uart->efr);
225 
226 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "Unsetting Output FLOW\n");
227 
228 	/* Turn off auto CTS flow control */
229 	ier &= ~(UART_17158_IER_CTSDSR);
230 	efr &= ~(UART_17158_EFR_CTSDSR);
231 
232 	/* Turn off auto Xon flow control */
233 	if (ch->ch_c_iflag & IXOFF)
234 		efr &= ~(UART_17158_EFR_IXON);
235 	else
236 		efr &= ~(UART_17158_EFR_ECB | UART_17158_EFR_IXON);
237 
238 	/* Why? Becuz Exar's spec says we have to zero it out before setting it */
239 	writeb(0, &ch->ch_neo_uart->efr);
240 
241 	/* Turn on UART enhanced bits */
242 	writeb(efr, &ch->ch_neo_uart->efr);
243 
244 	/* Turn on table D, with 8 char hi/low watermarks */
245 	writeb((UART_17158_FCTR_TRGD | UART_17158_FCTR_RTS_8DELAY), &ch->ch_neo_uart->fctr);
246 
247 	ch->ch_r_watermark = 0;
248 
249 	writeb(16, &ch->ch_neo_uart->tfifo);
250 	ch->ch_t_tlevel = 16;
251 
252 	writeb(16, &ch->ch_neo_uart->rfifo);
253 	ch->ch_r_tlevel = 16;
254 
255 	writeb(ier, &ch->ch_neo_uart->ier);
256 }
257 
258 static inline void neo_set_new_start_stop_chars(struct jsm_channel *ch)
259 {
260 
261 	/* if hardware flow control is set, then skip this whole thing */
262 	if (ch->ch_c_cflag & CRTSCTS)
263 		return;
264 
265 	jsm_dbg(PARAM, &ch->ch_bd->pci_dev, "start\n");
266 
267 	/* Tell UART what start/stop chars it should be looking for */
268 	writeb(ch->ch_startc, &ch->ch_neo_uart->xonchar1);
269 	writeb(0, &ch->ch_neo_uart->xonchar2);
270 
271 	writeb(ch->ch_stopc, &ch->ch_neo_uart->xoffchar1);
272 	writeb(0, &ch->ch_neo_uart->xoffchar2);
273 }
274 
275 static void neo_copy_data_from_uart_to_queue(struct jsm_channel *ch)
276 {
277 	int qleft = 0;
278 	u8 linestatus = 0;
279 	u8 error_mask = 0;
280 	int n = 0;
281 	int total = 0;
282 	u16 head;
283 	u16 tail;
284 
285 	/* cache head and tail of queue */
286 	head = ch->ch_r_head & RQUEUEMASK;
287 	tail = ch->ch_r_tail & RQUEUEMASK;
288 
289 	/* Get our cached LSR */
290 	linestatus = ch->ch_cached_lsr;
291 	ch->ch_cached_lsr = 0;
292 
293 	/* Store how much space we have left in the queue */
294 	qleft = tail - head - 1;
295 	if (qleft < 0)
296 		qleft += RQUEUEMASK + 1;
297 
298 	/*
299 	 * If the UART is not in FIFO mode, force the FIFO copy to
300 	 * NOT be run, by setting total to 0.
301 	 *
302 	 * On the other hand, if the UART IS in FIFO mode, then ask
303 	 * the UART to give us an approximation of data it has RX'ed.
304 	 */
305 	if (!(ch->ch_flags & CH_FIFO_ENABLED))
306 		total = 0;
307 	else {
308 		total = readb(&ch->ch_neo_uart->rfifo);
309 
310 		/*
311 		 * EXAR chip bug - RX FIFO COUNT - Fudge factor.
312 		 *
313 		 * This resolves a problem/bug with the Exar chip that sometimes
314 		 * returns a bogus value in the rfifo register.
315 		 * The count can be any where from 0-3 bytes "off".
316 		 * Bizarre, but true.
317 		 */
318 		total -= 3;
319 	}
320 
321 	/*
322 	 * Finally, bound the copy to make sure we don't overflow
323 	 * our own queue...
324 	 * The byte by byte copy loop below this loop this will
325 	 * deal with the queue overflow possibility.
326 	 */
327 	total = min(total, qleft);
328 
329 	while (total > 0) {
330 		/*
331 		 * Grab the linestatus register, we need to check
332 		 * to see if there are any errors in the FIFO.
333 		 */
334 		linestatus = readb(&ch->ch_neo_uart->lsr);
335 
336 		/*
337 		 * Break out if there is a FIFO error somewhere.
338 		 * This will allow us to go byte by byte down below,
339 		 * finding the exact location of the error.
340 		 */
341 		if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
342 			break;
343 
344 		/* Make sure we don't go over the end of our queue */
345 		n = min(((u32) total), (RQUEUESIZE - (u32) head));
346 
347 		/*
348 		 * Cut down n even further if needed, this is to fix
349 		 * a problem with memcpy_fromio() with the Neo on the
350 		 * IBM pSeries platform.
351 		 * 15 bytes max appears to be the magic number.
352 		 */
353 		n = min((u32) n, (u32) 12);
354 
355 		/*
356 		 * Since we are grabbing the linestatus register, which
357 		 * will reset some bits after our read, we need to ensure
358 		 * we don't miss our TX FIFO emptys.
359 		 */
360 		if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR))
361 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
362 
363 		linestatus = 0;
364 
365 		/* Copy data from uart to the queue */
366 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, n);
367 		/*
368 		 * Since RX_FIFO_DATA_ERROR was 0, we are guaranteed
369 		 * that all the data currently in the FIFO is free of
370 		 * breaks and parity/frame/orun errors.
371 		 */
372 		memset(ch->ch_equeue + head, 0, n);
373 
374 		/* Add to and flip head if needed */
375 		head = (head + n) & RQUEUEMASK;
376 		total -= n;
377 		qleft -= n;
378 		ch->ch_rxcount += n;
379 	}
380 
381 	/*
382 	 * Create a mask to determine whether we should
383 	 * insert the character (if any) into our queue.
384 	 */
385 	if (ch->ch_c_iflag & IGNBRK)
386 		error_mask |= UART_LSR_BI;
387 
388 	/*
389 	 * Now cleanup any leftover bytes still in the UART.
390 	 * Also deal with any possible queue overflow here as well.
391 	 */
392 	while (1) {
393 
394 		/*
395 		 * Its possible we have a linestatus from the loop above
396 		 * this, so we "OR" on any extra bits.
397 		 */
398 		linestatus |= readb(&ch->ch_neo_uart->lsr);
399 
400 		/*
401 		 * If the chip tells us there is no more data pending to
402 		 * be read, we can then leave.
403 		 * But before we do, cache the linestatus, just in case.
404 		 */
405 		if (!(linestatus & UART_LSR_DR)) {
406 			ch->ch_cached_lsr = linestatus;
407 			break;
408 		}
409 
410 		/* No need to store this bit */
411 		linestatus &= ~UART_LSR_DR;
412 
413 		/*
414 		 * Since we are grabbing the linestatus register, which
415 		 * will reset some bits after our read, we need to ensure
416 		 * we don't miss our TX FIFO emptys.
417 		 */
418 		if (linestatus & (UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR)) {
419 			linestatus &= ~(UART_LSR_THRE | UART_17158_TX_AND_FIFO_CLR);
420 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
421 		}
422 
423 		/*
424 		 * Discard character if we are ignoring the error mask.
425 		 */
426 		if (linestatus & error_mask) {
427 			u8 discard;
428 			linestatus = 0;
429 			memcpy_fromio(&discard, &ch->ch_neo_uart->txrxburst, 1);
430 			continue;
431 		}
432 
433 		/*
434 		 * If our queue is full, we have no choice but to drop some data.
435 		 * The assumption is that HWFLOW or SWFLOW should have stopped
436 		 * things way way before we got to this point.
437 		 *
438 		 * I decided that I wanted to ditch the oldest data first,
439 		 * I hope thats okay with everyone? Yes? Good.
440 		 */
441 		while (qleft < 1) {
442 			jsm_dbg(READ, &ch->ch_bd->pci_dev,
443 				"Queue full, dropping DATA:%x LSR:%x\n",
444 				ch->ch_rqueue[tail], ch->ch_equeue[tail]);
445 
446 			ch->ch_r_tail = tail = (tail + 1) & RQUEUEMASK;
447 			ch->ch_err_overrun++;
448 			qleft++;
449 		}
450 
451 		memcpy_fromio(ch->ch_rqueue + head, &ch->ch_neo_uart->txrxburst, 1);
452 		ch->ch_equeue[head] = (u8) linestatus;
453 
454 		jsm_dbg(READ, &ch->ch_bd->pci_dev, "DATA/LSR pair: %x %x\n",
455 			ch->ch_rqueue[head], ch->ch_equeue[head]);
456 
457 		/* Ditch any remaining linestatus value. */
458 		linestatus = 0;
459 
460 		/* Add to and flip head if needed */
461 		head = (head + 1) & RQUEUEMASK;
462 
463 		qleft--;
464 		ch->ch_rxcount++;
465 	}
466 
467 	/*
468 	 * Write new final heads to channel structure.
469 	 */
470 	ch->ch_r_head = head & RQUEUEMASK;
471 	ch->ch_e_head = head & EQUEUEMASK;
472 	jsm_input(ch);
473 }
474 
475 static void neo_copy_data_from_queue_to_uart(struct jsm_channel *ch)
476 {
477 	struct tty_port *tport;
478 	unsigned char *tail;
479 	unsigned char c;
480 	int n;
481 	int s;
482 	int qlen;
483 	u32 len_written = 0;
484 
485 	if (!ch)
486 		return;
487 
488 	tport = &ch->uart_port.state->port;
489 
490 	/* No data to write to the UART */
491 	if (kfifo_is_empty(&tport->xmit_fifo))
492 		return;
493 
494 	/* If port is "stopped", don't send any data to the UART */
495 	if ((ch->ch_flags & CH_STOP) || (ch->ch_flags & CH_BREAK_SENDING))
496 		return;
497 	/*
498 	 * If FIFOs are disabled. Send data directly to txrx register
499 	 */
500 	if (!(ch->ch_flags & CH_FIFO_ENABLED)) {
501 		u8 lsrbits = readb(&ch->ch_neo_uart->lsr);
502 
503 		ch->ch_cached_lsr |= lsrbits;
504 		if (ch->ch_cached_lsr & UART_LSR_THRE) {
505 			ch->ch_cached_lsr &= ~(UART_LSR_THRE);
506 
507 			WARN_ON_ONCE(!kfifo_get(&tport->xmit_fifo, &c));
508 			writeb(c, &ch->ch_neo_uart->txrx);
509 			jsm_dbg(WRITE, &ch->ch_bd->pci_dev, "Tx data: %x\n", c);
510 			ch->ch_txcount++;
511 		}
512 		return;
513 	}
514 
515 	/*
516 	 * We have to do it this way, because of the EXAR TXFIFO count bug.
517 	 */
518 	if (!(ch->ch_flags & (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM)))
519 		return;
520 
521 	n = UART_17158_TX_FIFOSIZE - ch->ch_t_tlevel;
522 	qlen = kfifo_len(&tport->xmit_fifo);
523 
524 	/* Find minimum of the FIFO space, versus queue length */
525 	n = min(n, qlen);
526 
527 	while (n > 0) {
528 		s = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail, n);
529 		if (s <= 0)
530 			break;
531 
532 		memcpy_toio(&ch->ch_neo_uart->txrxburst, tail, s);
533 		kfifo_skip_count(&tport->xmit_fifo, s);
534 		n -= s;
535 		ch->ch_txcount += s;
536 		len_written += s;
537 	}
538 
539 	if (len_written >= ch->ch_t_tlevel)
540 		ch->ch_flags &= ~(CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
541 
542 	if (kfifo_is_empty(&tport->xmit_fifo))
543 		uart_write_wakeup(&ch->uart_port);
544 }
545 
546 static void neo_parse_modem(struct jsm_channel *ch, u8 signals)
547 {
548 	u8 msignals = signals;
549 
550 	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
551 		"neo_parse_modem: port: %d msignals: %x\n",
552 		ch->ch_portnum, msignals);
553 
554 	/* Scrub off lower bits. They signify delta's, which I don't care about */
555 	/* Keep DDCD and DDSR though */
556 	msignals &= 0xf8;
557 
558 	if (msignals & UART_MSR_DDCD)
559 		uart_handle_dcd_change(&ch->uart_port, msignals & UART_MSR_DCD);
560 	if (msignals & UART_MSR_DDSR)
561 		uart_handle_cts_change(&ch->uart_port, msignals & UART_MSR_CTS);
562 	if (msignals & UART_MSR_DCD)
563 		ch->ch_mistat |= UART_MSR_DCD;
564 	else
565 		ch->ch_mistat &= ~UART_MSR_DCD;
566 
567 	if (msignals & UART_MSR_DSR)
568 		ch->ch_mistat |= UART_MSR_DSR;
569 	else
570 		ch->ch_mistat &= ~UART_MSR_DSR;
571 
572 	if (msignals & UART_MSR_RI)
573 		ch->ch_mistat |= UART_MSR_RI;
574 	else
575 		ch->ch_mistat &= ~UART_MSR_RI;
576 
577 	if (msignals & UART_MSR_CTS)
578 		ch->ch_mistat |= UART_MSR_CTS;
579 	else
580 		ch->ch_mistat &= ~UART_MSR_CTS;
581 
582 	jsm_dbg(MSIGS, &ch->ch_bd->pci_dev,
583 		"Port: %d DTR: %d RTS: %d CTS: %d DSR: %d " "RI: %d CD: %d\n",
584 		ch->ch_portnum,
585 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_DTR),
586 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MCR_RTS),
587 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_CTS),
588 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DSR),
589 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_RI),
590 		!!((ch->ch_mistat | ch->ch_mostat) & UART_MSR_DCD));
591 }
592 
593 /* Make the UART raise any of the output signals we want up */
594 static void neo_assert_modem_signals(struct jsm_channel *ch)
595 {
596 	if (!ch)
597 		return;
598 
599 	writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
600 
601 	/* flush write operation */
602 	neo_pci_posting_flush(ch->ch_bd);
603 }
604 
605 /*
606  * Flush the WRITE FIFO on the Neo.
607  *
608  * NOTE: Channel lock MUST be held before calling this function!
609  */
610 static void neo_flush_uart_write(struct jsm_channel *ch)
611 {
612 	u8 tmp = 0;
613 	int i = 0;
614 
615 	if (!ch)
616 		return;
617 
618 	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
619 
620 	for (i = 0; i < 10; i++) {
621 
622 		/* Check to see if the UART feels it completely flushed the FIFO. */
623 		tmp = readb(&ch->ch_neo_uart->isr_fcr);
624 		if (tmp & UART_FCR_CLEAR_XMIT) {
625 			jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
626 				"Still flushing TX UART... i: %d\n", i);
627 			udelay(10);
628 		}
629 		else
630 			break;
631 	}
632 
633 	ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
634 }
635 
636 
637 /*
638  * Flush the READ FIFO on the Neo.
639  *
640  * NOTE: Channel lock MUST be held before calling this function!
641  */
642 static void neo_flush_uart_read(struct jsm_channel *ch)
643 {
644 	u8 tmp = 0;
645 	int i = 0;
646 
647 	if (!ch)
648 		return;
649 
650 	writeb((UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR), &ch->ch_neo_uart->isr_fcr);
651 
652 	for (i = 0; i < 10; i++) {
653 
654 		/* Check to see if the UART feels it completely flushed the FIFO. */
655 		tmp = readb(&ch->ch_neo_uart->isr_fcr);
656 		if (tmp & 2) {
657 			jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
658 				"Still flushing RX UART... i: %d\n", i);
659 			udelay(10);
660 		}
661 		else
662 			break;
663 	}
664 }
665 
666 /*
667  * No locks are assumed to be held when calling this function.
668  */
669 static void neo_clear_break(struct jsm_channel *ch)
670 {
671 	unsigned long lock_flags;
672 
673 	spin_lock_irqsave(&ch->ch_lock, lock_flags);
674 
675 	/* Turn break off, and unset some variables */
676 	if (ch->ch_flags & CH_BREAK_SENDING) {
677 		u8 temp = readb(&ch->ch_neo_uart->lcr);
678 		writeb((temp & ~UART_LCR_SBC), &ch->ch_neo_uart->lcr);
679 
680 		ch->ch_flags &= ~(CH_BREAK_SENDING);
681 		jsm_dbg(IOCTL, &ch->ch_bd->pci_dev,
682 			"clear break Finishing UART_LCR_SBC! finished: %lx\n",
683 			jiffies);
684 
685 		/* flush write operation */
686 		neo_pci_posting_flush(ch->ch_bd);
687 	}
688 	spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
689 }
690 
691 /*
692  * Parse the ISR register.
693  */
694 static void neo_parse_isr(struct jsm_board *brd, u32 port)
695 {
696 	struct jsm_channel *ch;
697 	u8 isr;
698 	u8 cause;
699 	unsigned long lock_flags;
700 
701 	if (!brd)
702 		return;
703 
704 	if (port >= brd->maxports)
705 		return;
706 
707 	ch = brd->channels[port];
708 	if (!ch)
709 		return;
710 
711 	/* Here we try to figure out what caused the interrupt to happen */
712 	while (1) {
713 
714 		isr = readb(&ch->ch_neo_uart->isr_fcr);
715 
716 		/* Bail if no pending interrupt */
717 		if (isr & UART_IIR_NO_INT)
718 			break;
719 
720 		/*
721 		 * Yank off the upper 2 bits, which just show that the FIFO's are enabled.
722 		 */
723 		isr &= ~(UART_17158_IIR_FIFO_ENABLED);
724 
725 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d isr: %x\n",
726 			__FILE__, __LINE__, isr);
727 
728 		if (isr & (UART_17158_IIR_RDI_TIMEOUT | UART_IIR_RDI)) {
729 			/* Read data from uart -> queue */
730 			neo_copy_data_from_uart_to_queue(ch);
731 
732 			/* Call our tty layer to enforce queue flow control if needed. */
733 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
734 			jsm_check_queue_flow_control(ch);
735 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
736 		}
737 
738 		if (isr & UART_IIR_THRI) {
739 			/* Transfer data (if any) from Write Queue -> UART. */
740 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
741 			ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
742 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
743 			neo_copy_data_from_queue_to_uart(ch);
744 		}
745 
746 		if (isr & UART_17158_IIR_XONXOFF) {
747 			cause = readb(&ch->ch_neo_uart->xoffchar1);
748 
749 			jsm_dbg(INTR, &ch->ch_bd->pci_dev,
750 				"Port %d. Got ISR_XONXOFF: cause:%x\n",
751 				port, cause);
752 
753 			/*
754 			 * Since the UART detected either an XON or
755 			 * XOFF match, we need to figure out which
756 			 * one it was, so we can suspend or resume data flow.
757 			 */
758 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
759 			if (cause == UART_17158_XON_DETECT) {
760 				/* Is output stopped right now, if so, resume it */
761 				if (brd->channels[port]->ch_flags & CH_STOP) {
762 					ch->ch_flags &= ~(CH_STOP);
763 				}
764 				jsm_dbg(INTR, &ch->ch_bd->pci_dev,
765 					"Port %d. XON detected in incoming data\n",
766 					port);
767 			}
768 			else if (cause == UART_17158_XOFF_DETECT) {
769 				if (!(brd->channels[port]->ch_flags & CH_STOP)) {
770 					ch->ch_flags |= CH_STOP;
771 					jsm_dbg(INTR, &ch->ch_bd->pci_dev,
772 						"Setting CH_STOP\n");
773 				}
774 				jsm_dbg(INTR, &ch->ch_bd->pci_dev,
775 					"Port: %d. XOFF detected in incoming data\n",
776 					port);
777 			}
778 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
779 		}
780 
781 		if (isr & UART_17158_IIR_HWFLOW_STATE_CHANGE) {
782 			/*
783 			 * If we get here, this means the hardware is doing auto flow control.
784 			 * Check to see whether RTS/DTR or CTS/DSR caused this interrupt.
785 			 */
786 			cause = readb(&ch->ch_neo_uart->mcr);
787 
788 			/* Which pin is doing auto flow? RTS or DTR? */
789 			spin_lock_irqsave(&ch->ch_lock, lock_flags);
790 			if ((cause & 0x4) == 0) {
791 				if (cause & UART_MCR_RTS)
792 					ch->ch_mostat |= UART_MCR_RTS;
793 				else
794 					ch->ch_mostat &= ~(UART_MCR_RTS);
795 			} else {
796 				if (cause & UART_MCR_DTR)
797 					ch->ch_mostat |= UART_MCR_DTR;
798 				else
799 					ch->ch_mostat &= ~(UART_MCR_DTR);
800 			}
801 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
802 		}
803 
804 		/* Parse any modem signal changes */
805 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
806 			"MOD_STAT: sending to parse_modem_sigs\n");
807 		uart_port_lock_irqsave(&ch->uart_port, &lock_flags);
808 		neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
809 		uart_port_unlock_irqrestore(&ch->uart_port, lock_flags);
810 	}
811 }
812 
813 static inline void neo_parse_lsr(struct jsm_board *brd, u32 port)
814 {
815 	struct jsm_channel *ch;
816 	int linestatus;
817 	unsigned long lock_flags;
818 
819 	if (!brd)
820 		return;
821 
822 	if (port >= brd->maxports)
823 		return;
824 
825 	ch = brd->channels[port];
826 	if (!ch)
827 		return;
828 
829 	linestatus = readb(&ch->ch_neo_uart->lsr);
830 
831 	jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d port: %d linestatus: %x\n",
832 		__FILE__, __LINE__, port, linestatus);
833 
834 	ch->ch_cached_lsr |= linestatus;
835 
836 	if (ch->ch_cached_lsr & UART_LSR_DR) {
837 		/* Read data from uart -> queue */
838 		neo_copy_data_from_uart_to_queue(ch);
839 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
840 		jsm_check_queue_flow_control(ch);
841 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
842 	}
843 
844 	/*
845 	 * This is a special flag. It indicates that at least 1
846 	 * RX error (parity, framing, or break) has happened.
847 	 * Mark this in our struct, which will tell me that I have
848 	 *to do the special RX+LSR read for this FIFO load.
849 	 */
850 	if (linestatus & UART_17158_RX_FIFO_DATA_ERROR)
851 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
852 			"%s:%d Port: %d Got an RX error, need to parse LSR\n",
853 			__FILE__, __LINE__, port);
854 
855 	/*
856 	 * The next 3 tests should *NOT* happen, as the above test
857 	 * should encapsulate all 3... At least, thats what Exar says.
858 	 */
859 
860 	if (linestatus & UART_LSR_PE) {
861 		ch->ch_err_parity++;
862 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. PAR ERR!\n",
863 			__FILE__, __LINE__, port);
864 	}
865 
866 	if (linestatus & UART_LSR_FE) {
867 		ch->ch_err_frame++;
868 		jsm_dbg(INTR, &ch->ch_bd->pci_dev, "%s:%d Port: %d. FRM ERR!\n",
869 			__FILE__, __LINE__, port);
870 	}
871 
872 	if (linestatus & UART_LSR_BI) {
873 		ch->ch_err_break++;
874 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
875 			"%s:%d Port: %d. BRK INTR!\n",
876 			__FILE__, __LINE__, port);
877 	}
878 
879 	if (linestatus & UART_LSR_OE) {
880 		/*
881 		 * Rx Oruns. Exar says that an orun will NOT corrupt
882 		 * the FIFO. It will just replace the holding register
883 		 * with this new data byte. So basically just ignore this.
884 		 * Probably we should eventually have an orun stat in our driver...
885 		 */
886 		ch->ch_err_overrun++;
887 		jsm_dbg(INTR, &ch->ch_bd->pci_dev,
888 			"%s:%d Port: %d. Rx Overrun!\n",
889 			__FILE__, __LINE__, port);
890 	}
891 
892 	if (linestatus & UART_LSR_THRE) {
893 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
894 		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
895 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
896 
897 		/* Transfer data (if any) from Write Queue -> UART. */
898 		neo_copy_data_from_queue_to_uart(ch);
899 	}
900 	else if (linestatus & UART_17158_TX_AND_FIFO_CLR) {
901 		spin_lock_irqsave(&ch->ch_lock, lock_flags);
902 		ch->ch_flags |= (CH_TX_FIFO_EMPTY | CH_TX_FIFO_LWM);
903 		spin_unlock_irqrestore(&ch->ch_lock, lock_flags);
904 
905 		/* Transfer data (if any) from Write Queue -> UART. */
906 		neo_copy_data_from_queue_to_uart(ch);
907 	}
908 }
909 
910 /*
911  * neo_param()
912  * Send any/all changes to the line to the UART.
913  */
914 static void neo_param(struct jsm_channel *ch)
915 {
916 	u8 lcr = 0;
917 	u8 uart_lcr, ier;
918 	u32 baud;
919 	int quot;
920 	struct jsm_board *bd;
921 
922 	bd = ch->ch_bd;
923 	if (!bd)
924 		return;
925 
926 	/*
927 	 * If baud rate is zero, flush queues, and set mval to drop DTR.
928 	 */
929 	if ((ch->ch_c_cflag & CBAUD) == B0) {
930 		ch->ch_r_head = ch->ch_r_tail = 0;
931 		ch->ch_e_head = ch->ch_e_tail = 0;
932 
933 		neo_flush_uart_write(ch);
934 		neo_flush_uart_read(ch);
935 
936 		ch->ch_flags |= (CH_BAUD0);
937 		ch->ch_mostat &= ~(UART_MCR_RTS | UART_MCR_DTR);
938 		neo_assert_modem_signals(ch);
939 		return;
940 
941 	} else {
942 		int i;
943 		unsigned int cflag;
944 		static struct {
945 			unsigned int rate;
946 			unsigned int cflag;
947 		} baud_rates[] = {
948 			{ 921600, B921600 },
949 			{ 460800, B460800 },
950 			{ 230400, B230400 },
951 			{ 115200, B115200 },
952 			{  57600, B57600  },
953 			{  38400, B38400  },
954 			{  19200, B19200  },
955 			{   9600, B9600   },
956 			{   4800, B4800   },
957 			{   2400, B2400   },
958 			{   1200, B1200   },
959 			{    600, B600    },
960 			{    300, B300    },
961 			{    200, B200    },
962 			{    150, B150    },
963 			{    134, B134    },
964 			{    110, B110    },
965 			{     75, B75     },
966 			{     50, B50     },
967 		};
968 
969 		cflag = C_BAUD(ch->uart_port.state->port.tty);
970 		baud = 9600;
971 		for (i = 0; i < ARRAY_SIZE(baud_rates); i++) {
972 			if (baud_rates[i].cflag == cflag) {
973 				baud = baud_rates[i].rate;
974 				break;
975 			}
976 		}
977 
978 		if (ch->ch_flags & CH_BAUD0)
979 			ch->ch_flags &= ~(CH_BAUD0);
980 	}
981 
982 	if (ch->ch_c_cflag & PARENB)
983 		lcr |= UART_LCR_PARITY;
984 
985 	if (!(ch->ch_c_cflag & PARODD))
986 		lcr |= UART_LCR_EPAR;
987 
988 	if (ch->ch_c_cflag & CMSPAR)
989 		lcr |= UART_LCR_SPAR;
990 
991 	if (ch->ch_c_cflag & CSTOPB)
992 		lcr |= UART_LCR_STOP;
993 
994 	lcr |= UART_LCR_WLEN(tty_get_char_size(ch->ch_c_cflag));
995 
996 	ier = readb(&ch->ch_neo_uart->ier);
997 	uart_lcr = readb(&ch->ch_neo_uart->lcr);
998 
999 	quot = ch->ch_bd->bd_dividend / baud;
1000 
1001 	if (quot != 0) {
1002 		writeb(UART_LCR_DLAB, &ch->ch_neo_uart->lcr);
1003 		writeb((quot & 0xff), &ch->ch_neo_uart->txrx);
1004 		writeb((quot >> 8), &ch->ch_neo_uart->ier);
1005 		writeb(lcr, &ch->ch_neo_uart->lcr);
1006 	}
1007 
1008 	if (uart_lcr != lcr)
1009 		writeb(lcr, &ch->ch_neo_uart->lcr);
1010 
1011 	if (ch->ch_c_cflag & CREAD)
1012 		ier |= (UART_IER_RDI | UART_IER_RLSI);
1013 
1014 	ier |= (UART_IER_THRI | UART_IER_MSI);
1015 
1016 	writeb(ier, &ch->ch_neo_uart->ier);
1017 
1018 	/* Set new start/stop chars */
1019 	neo_set_new_start_stop_chars(ch);
1020 
1021 	if (ch->ch_c_cflag & CRTSCTS)
1022 		neo_set_cts_flow_control(ch);
1023 	else if (ch->ch_c_iflag & IXON) {
1024 		/* If start/stop is set to disable, then we should disable flow control */
1025 		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1026 			neo_set_no_output_flow_control(ch);
1027 		else
1028 			neo_set_ixon_flow_control(ch);
1029 	}
1030 	else
1031 		neo_set_no_output_flow_control(ch);
1032 
1033 	if (ch->ch_c_cflag & CRTSCTS)
1034 		neo_set_rts_flow_control(ch);
1035 	else if (ch->ch_c_iflag & IXOFF) {
1036 		/* If start/stop is set to disable, then we should disable flow control */
1037 		if ((ch->ch_startc == __DISABLED_CHAR) || (ch->ch_stopc == __DISABLED_CHAR))
1038 			neo_set_no_input_flow_control(ch);
1039 		else
1040 			neo_set_ixoff_flow_control(ch);
1041 	}
1042 	else
1043 		neo_set_no_input_flow_control(ch);
1044 	/*
1045 	 * Adjust the RX FIFO Trigger level if baud is less than 9600.
1046 	 * Not exactly elegant, but this is needed because of the Exar chip's
1047 	 * delay on firing off the RX FIFO interrupt on slower baud rates.
1048 	 */
1049 	if (baud < 9600) {
1050 		writeb(1, &ch->ch_neo_uart->rfifo);
1051 		ch->ch_r_tlevel = 1;
1052 	}
1053 
1054 	neo_assert_modem_signals(ch);
1055 
1056 	/* Get current status of the modem signals now */
1057 	neo_parse_modem(ch, readb(&ch->ch_neo_uart->msr));
1058 	return;
1059 }
1060 
1061 /*
1062  * jsm_neo_intr()
1063  *
1064  * Neo specific interrupt handler.
1065  */
1066 static irqreturn_t neo_intr(int irq, void *voidbrd)
1067 {
1068 	struct jsm_board *brd = voidbrd;
1069 	struct jsm_channel *ch;
1070 	int port = 0;
1071 	int type = 0;
1072 	int current_port;
1073 	u32 tmp;
1074 	u32 uart_poll;
1075 	unsigned long lock_flags;
1076 	unsigned long lock_flags2;
1077 	int outofloop_count = 0;
1078 
1079 	/* Lock out the slow poller from running on this board. */
1080 	spin_lock_irqsave(&brd->bd_intr_lock, lock_flags);
1081 
1082 	/*
1083 	 * Read in "extended" IRQ information from the 32bit Neo register.
1084 	 * Bits 0-7: What port triggered the interrupt.
1085 	 * Bits 8-31: Each 3bits indicate what type of interrupt occurred.
1086 	 */
1087 	uart_poll = readl(brd->re_map_membase + UART_17158_POLL_ADDR_OFFSET);
1088 
1089 	jsm_dbg(INTR, &brd->pci_dev, "%s:%d uart_poll: %x\n",
1090 		__FILE__, __LINE__, uart_poll);
1091 
1092 	if (!uart_poll) {
1093 		jsm_dbg(INTR, &brd->pci_dev,
1094 			"Kernel interrupted to me, but no pending interrupts...\n");
1095 		spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1096 		return IRQ_NONE;
1097 	}
1098 
1099 	/* At this point, we have at least SOMETHING to service, dig further... */
1100 
1101 	current_port = 0;
1102 
1103 	/* Loop on each port */
1104 	while (((uart_poll & 0xff) != 0) && (outofloop_count < 0xff)){
1105 
1106 		tmp = uart_poll;
1107 		outofloop_count++;
1108 
1109 		/* Check current port to see if it has interrupt pending */
1110 		if ((tmp & jsm_offset_table[current_port]) != 0) {
1111 			port = current_port;
1112 			type = tmp >> (8 + (port * 3));
1113 			type &= 0x7;
1114 		} else {
1115 			current_port++;
1116 			continue;
1117 		}
1118 
1119 		jsm_dbg(INTR, &brd->pci_dev, "%s:%d port: %x type: %x\n",
1120 			__FILE__, __LINE__, port, type);
1121 
1122 		/* Remove this port + type from uart_poll */
1123 		uart_poll &= ~(jsm_offset_table[port]);
1124 
1125 		if (!type) {
1126 			/* If no type, just ignore it, and move onto next port */
1127 			jsm_dbg(INTR, &brd->pci_dev,
1128 				"Interrupt with no type! port: %d\n", port);
1129 			continue;
1130 		}
1131 
1132 		/* Switch on type of interrupt we have */
1133 		switch (type) {
1134 
1135 		case UART_17158_RXRDY_TIMEOUT:
1136 			/*
1137 			 * RXRDY Time-out is cleared by reading data in the
1138 			* RX FIFO until it falls below the trigger level.
1139 			 */
1140 
1141 			/* Verify the port is in range. */
1142 			if (port >= brd->nasync)
1143 				continue;
1144 
1145 			ch = brd->channels[port];
1146 			if (!ch)
1147 				continue;
1148 
1149 			neo_copy_data_from_uart_to_queue(ch);
1150 
1151 			/* Call our tty layer to enforce queue flow control if needed. */
1152 			spin_lock_irqsave(&ch->ch_lock, lock_flags2);
1153 			jsm_check_queue_flow_control(ch);
1154 			spin_unlock_irqrestore(&ch->ch_lock, lock_flags2);
1155 
1156 			continue;
1157 
1158 		case UART_17158_RX_LINE_STATUS:
1159 			/*
1160 			 * RXRDY and RX LINE Status (logic OR of LSR[4:1])
1161 			 */
1162 			neo_parse_lsr(brd, port);
1163 			continue;
1164 
1165 		case UART_17158_TXRDY:
1166 			/*
1167 			 * TXRDY interrupt clears after reading ISR register for the UART channel.
1168 			 */
1169 
1170 			/*
1171 			 * Yes, this is odd...
1172 			 * Why would I check EVERY possibility of type of
1173 			 * interrupt, when we know its TXRDY???
1174 			 * Becuz for some reason, even tho we got triggered for TXRDY,
1175 			 * it seems to be occasionally wrong. Instead of TX, which
1176 			 * it should be, I was getting things like RXDY too. Weird.
1177 			 */
1178 			neo_parse_isr(brd, port);
1179 			continue;
1180 
1181 		case UART_17158_MSR:
1182 			/*
1183 			 * MSR or flow control was seen.
1184 			 */
1185 			neo_parse_isr(brd, port);
1186 			continue;
1187 
1188 		default:
1189 			/*
1190 			 * The UART triggered us with a bogus interrupt type.
1191 			 * It appears the Exar chip, when REALLY bogged down, will throw
1192 			 * these once and awhile.
1193 			 * Its harmless, just ignore it and move on.
1194 			 */
1195 			jsm_dbg(INTR, &brd->pci_dev,
1196 				"%s:%d Unknown Interrupt type: %x\n",
1197 				__FILE__, __LINE__, type);
1198 			continue;
1199 		}
1200 	}
1201 
1202 	spin_unlock_irqrestore(&brd->bd_intr_lock, lock_flags);
1203 
1204 	jsm_dbg(INTR, &brd->pci_dev, "finish\n");
1205 	return IRQ_HANDLED;
1206 }
1207 
1208 /*
1209  * Neo specific way of turning off the receiver.
1210  * Used as a way to enforce queue flow control when in
1211  * hardware flow control mode.
1212  */
1213 static void neo_disable_receiver(struct jsm_channel *ch)
1214 {
1215 	u8 tmp = readb(&ch->ch_neo_uart->ier);
1216 	tmp &= ~(UART_IER_RDI);
1217 	writeb(tmp, &ch->ch_neo_uart->ier);
1218 
1219 	/* flush write operation */
1220 	neo_pci_posting_flush(ch->ch_bd);
1221 }
1222 
1223 
1224 /*
1225  * Neo specific way of turning on the receiver.
1226  * Used as a way to un-enforce queue flow control when in
1227  * hardware flow control mode.
1228  */
1229 static void neo_enable_receiver(struct jsm_channel *ch)
1230 {
1231 	u8 tmp = readb(&ch->ch_neo_uart->ier);
1232 	tmp |= (UART_IER_RDI);
1233 	writeb(tmp, &ch->ch_neo_uart->ier);
1234 
1235 	/* flush write operation */
1236 	neo_pci_posting_flush(ch->ch_bd);
1237 }
1238 
1239 static void neo_send_start_character(struct jsm_channel *ch)
1240 {
1241 	if (!ch)
1242 		return;
1243 
1244 	if (ch->ch_startc != __DISABLED_CHAR) {
1245 		ch->ch_xon_sends++;
1246 		writeb(ch->ch_startc, &ch->ch_neo_uart->txrx);
1247 
1248 		/* flush write operation */
1249 		neo_pci_posting_flush(ch->ch_bd);
1250 	}
1251 }
1252 
1253 static void neo_send_stop_character(struct jsm_channel *ch)
1254 {
1255 	if (!ch)
1256 		return;
1257 
1258 	if (ch->ch_stopc != __DISABLED_CHAR) {
1259 		ch->ch_xoff_sends++;
1260 		writeb(ch->ch_stopc, &ch->ch_neo_uart->txrx);
1261 
1262 		/* flush write operation */
1263 		neo_pci_posting_flush(ch->ch_bd);
1264 	}
1265 }
1266 
1267 /*
1268  * neo_uart_init
1269  */
1270 static void neo_uart_init(struct jsm_channel *ch)
1271 {
1272 	writeb(0, &ch->ch_neo_uart->ier);
1273 	writeb(0, &ch->ch_neo_uart->efr);
1274 	writeb(UART_EFR_ECB, &ch->ch_neo_uart->efr);
1275 
1276 	/* Clear out UART and FIFO */
1277 	readb(&ch->ch_neo_uart->txrx);
1278 	writeb((UART_FCR_ENABLE_FIFO|UART_FCR_CLEAR_RCVR|UART_FCR_CLEAR_XMIT), &ch->ch_neo_uart->isr_fcr);
1279 	readb(&ch->ch_neo_uart->lsr);
1280 	readb(&ch->ch_neo_uart->msr);
1281 
1282 	ch->ch_flags |= CH_FIFO_ENABLED;
1283 
1284 	/* Assert any signals we want up */
1285 	writeb(ch->ch_mostat, &ch->ch_neo_uart->mcr);
1286 }
1287 
1288 /*
1289  * Make the UART completely turn off.
1290  */
1291 static void neo_uart_off(struct jsm_channel *ch)
1292 {
1293 	/* Turn off UART enhanced bits */
1294 	writeb(0, &ch->ch_neo_uart->efr);
1295 
1296 	/* Stop all interrupts from occurring. */
1297 	writeb(0, &ch->ch_neo_uart->ier);
1298 }
1299 
1300 /* Channel lock MUST be held by the calling function! */
1301 static void neo_send_break(struct jsm_channel *ch)
1302 {
1303 	/*
1304 	 * Set the time we should stop sending the break.
1305 	 * If we are already sending a break, toss away the existing
1306 	 * time to stop, and use this new value instead.
1307 	 */
1308 
1309 	/* Tell the UART to start sending the break */
1310 	if (!(ch->ch_flags & CH_BREAK_SENDING)) {
1311 		u8 temp = readb(&ch->ch_neo_uart->lcr);
1312 		writeb((temp | UART_LCR_SBC), &ch->ch_neo_uart->lcr);
1313 		ch->ch_flags |= (CH_BREAK_SENDING);
1314 
1315 		/* flush write operation */
1316 		neo_pci_posting_flush(ch->ch_bd);
1317 	}
1318 }
1319 
1320 struct board_ops jsm_neo_ops = {
1321 	.intr				= neo_intr,
1322 	.uart_init			= neo_uart_init,
1323 	.uart_off			= neo_uart_off,
1324 	.param				= neo_param,
1325 	.assert_modem_signals		= neo_assert_modem_signals,
1326 	.flush_uart_write		= neo_flush_uart_write,
1327 	.flush_uart_read		= neo_flush_uart_read,
1328 	.disable_receiver		= neo_disable_receiver,
1329 	.enable_receiver		= neo_enable_receiver,
1330 	.send_break			= neo_send_break,
1331 	.clear_break			= neo_clear_break,
1332 	.send_start_character		= neo_send_start_character,
1333 	.send_stop_character		= neo_send_stop_character,
1334 	.copy_data_from_queue_to_uart	= neo_copy_data_from_queue_to_uart,
1335 };
1336