xref: /netbsd-src/sys/arch/sun2/dev/zs.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: zs.c,v 1.9 2004/02/13 11:36:19 wiz Exp $	*/
2 
3 /*-
4  * Copyright (c) 1996 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Gordon W. Ross.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Zilog Z8530 Dual UART driver (machine-dependent part)
41  *
42  * Runs two serial lines per chip using slave drivers.
43  * Plain tty/async lines use the zs_async slave.
44  * Sun keyboard/mouse uses the zs_kbd/zs_ms slaves.
45  */
46 
47 #include <sys/cdefs.h>
48 __KERNEL_RCSID(0, "$NetBSD: zs.c,v 1.9 2004/02/13 11:36:19 wiz Exp $");
49 
50 #include "opt_ddb.h"
51 #include "opt_kgdb.h"
52 
53 #include <sys/param.h>
54 #include <sys/systm.h>
55 #include <sys/conf.h>
56 #include <sys/device.h>
57 #include <sys/file.h>
58 #include <sys/ioctl.h>
59 #include <sys/kernel.h>
60 #include <sys/proc.h>
61 #include <sys/tty.h>
62 #include <sys/time.h>
63 #include <sys/syslog.h>
64 
65 #include <machine/autoconf.h>
66 #include <machine/promlib.h>
67 #include <machine/cpu.h>
68 #include <machine/eeprom.h>
69 #include <machine/psl.h>
70 #include <machine/z8530var.h>
71 
72 #include <dev/cons.h>
73 #include <dev/ic/z8530reg.h>
74 #include <dev/sun/kbd_ms_ttyvar.h>
75 #include <ddb/db_output.h>
76 
77 #include <sun2/dev/cons.h>
78 
79 #include "kbd.h"	/* NKBD */
80 #include "ms.h"		/* NMS */
81 
82 /*
83  * Some warts needed by z8530tty.c -
84  * The default parity REALLY needs to be the same as the PROM uses,
85  * or you can not see messages done with printf during boot-up...
86  */
87 int zs_def_cflag = (CREAD | CS8 | HUPCL);
88 
89 /* ZS channel used as the console device (if any) */
90 void *zs_conschan_get, *zs_conschan_put;
91 
92 static u_char zs_init_reg[16] = {
93 	0,	/* 0: CMD (reset, etc.) */
94 	0,	/* 1: No interrupts yet. */
95 #ifdef  ZS_INIT_IVECT
96 	ZS_INIT_IVECT,	/* 2: IVECT */
97 #else
98 	0,	/* 2: IVECT */
99 #endif
100 	ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
101 	ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
102 	ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
103 	0,	/* 6: TXSYNC/SYNCLO */
104 	0,	/* 7: RXSYNC/SYNCHI */
105 	0,	/* 8: alias for data port */
106 #ifdef  ZS_INIT_IVECT
107 	ZSWR9_MASTER_IE,
108 #else
109 	ZSWR9_MASTER_IE | ZSWR9_NO_VECTOR,
110 #endif
111 	0,	/*10: Misc. TX/RX control bits */
112 	ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
113 	((PCLK/32)/9600)-2,	/*12: BAUDLO (default=9600) */
114 	0,			/*13: BAUDHI (default=9600) */
115 	ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK,
116 	ZSWR15_BREAK_IE,
117 };
118 
119 /* Console ops */
120 static int  zscngetc __P((dev_t));
121 static void zscnputc __P((dev_t, int));
122 static void zscnpollc __P((dev_t, int));
123 
124 struct consdev zs_consdev = {
125 	NULL,
126 	NULL,
127 	zscngetc,
128 	zscnputc,
129 	zscnpollc,
130 	NULL,
131 };
132 
133 
134 /****************************************************************
135  * Autoconfig
136  ****************************************************************/
137 
138 static int  zs_print __P((void *, const char *name));
139 
140 extern struct cfdriver zs_cd;
141 
142 /* Interrupt handlers. */
143 int zscheckintr __P((void *));
144 static int zshard __P((void *));
145 static void zssoft __P((void *));
146 
147 static int zs_get_speed __P((struct zs_chanstate *));
148 
149 /*
150  * Attach a found zs.
151  *
152  * USE ROM PROPERTIES port-a-ignore-cd AND port-b-ignore-cd FOR
153  * SOFT CARRIER, AND keyboard PROPERTY FOR KEYBOARD/MOUSE?
154  */
155 void
156 zs_attach(zsc, zsd, pri)
157 	struct zsc_softc *zsc;
158 	struct zsdevice *zsd;
159 	int pri;
160 {
161 	struct zsc_attach_args zsc_args;
162 	struct zs_chanstate *cs;
163 	int s, channel, softpri = IPL_SOFTSERIAL;
164 
165 	if (zsd == NULL) {
166 		printf("configuration incomplete\n");
167 		return;
168 	}
169 
170 	printf(" softpri %d\n", softpri);
171 
172 	/*
173 	 * Initialize software state for each channel.
174 	 */
175 	for (channel = 0; channel < 2; channel++) {
176 		struct zschan *zc;
177 		struct device *child;
178 
179 		zsc_args.channel = channel;
180 		cs = &zsc->zsc_cs_store[channel];
181 		zsc->zsc_cs[channel] = cs;
182 
183 		simple_lock_init(&cs->cs_lock);
184 		cs->cs_channel = channel;
185 		cs->cs_private = NULL;
186 		cs->cs_ops = &zsops_null;
187 		cs->cs_brg_clk = PCLK / 16;
188 
189 		zc = (channel == 0) ? &zsd->zs_chan_a : &zsd->zs_chan_b;
190 
191 		zsc_args.consdev = NULL;
192 		zsc_args.hwflags = zs_console_flags(zsc->zsc_promunit,
193 						    zsc->zsc_node,
194 						    channel);
195 
196 		if (zsc_args.hwflags & ZS_HWFLAG_CONSOLE) {
197 			zsc_args.hwflags |= ZS_HWFLAG_USE_CONSDEV;
198 			zsc_args.consdev = &zs_consdev;
199 		}
200 
201 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
202 			zs_conschan_get = zc;
203 		}
204 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
205 			zs_conschan_put = zc;
206 		}
207 
208 		/* Children need to set cn_dev, etc */
209 		cs->cs_reg_csr  = &zc->zc_csr;
210 		cs->cs_reg_data = &zc->zc_data;
211 
212 		memcpy(cs->cs_creg, zs_init_reg, 16);
213 		memcpy(cs->cs_preg, zs_init_reg, 16);
214 
215 		/* XXX: Consult PROM properties for this?! */
216 		cs->cs_defspeed = zs_get_speed(cs);
217 		cs->cs_defcflag = zs_def_cflag;
218 
219 		/* Make these correspond to cs_defcflag (-crtscts) */
220 		cs->cs_rr0_dcd = ZSRR0_DCD;
221 		cs->cs_rr0_cts = 0;
222 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
223 		cs->cs_wr5_rts = 0;
224 
225 		/*
226 		 * Clear the master interrupt enable.
227 		 * The INTENA is common to both channels,
228 		 * so just do it on the A channel.
229 		 */
230 		if (channel == 0) {
231 			zs_write_reg(cs, 9, 0);
232 		}
233 
234 		/*
235 		 * Look for a child driver for this channel.
236 		 * The child attach will setup the hardware.
237 		 */
238 		if (!(child =
239 		      config_found(&zsc->zsc_dev, (void *)&zsc_args, zs_print))) {
240 			/* No sub-driver.  Just reset it. */
241 			u_char reset = (channel == 0) ?
242 				ZSWR9_A_RESET : ZSWR9_B_RESET;
243 			s = splzs();
244 			zs_write_reg(cs,  9, reset);
245 			splx(s);
246 		}
247 #if (NKBD > 0) || (NMS > 0)
248 		/*
249 		 * If this was a zstty it has a keyboard
250 		 * property on it we need to attach the
251 		 * sunkbd and sunms line disciplines.
252 		 */
253 		if (child
254 		    && (!strcmp(child->dv_cfdata->cf_name,
255 		    		"zstty"))) {
256 			struct kbd_ms_tty_attach_args kma;
257 			struct zstty_softc {
258 				/* The following are the only fields we need here */
259 				struct	device zst_dev;
260 				struct  tty *zst_tty;
261 				struct	zs_chanstate *zst_cs;
262 			} *zst = (struct zstty_softc *)child;
263 			struct tty *tp;
264 
265 			kma.kmta_tp = tp = zst->zst_tty;
266 			if (tp != NULL) {
267 				kma.kmta_dev = tp->t_dev;
268 				kma.kmta_consdev = zsc_args.consdev;
269 
270 				/* Attach 'em if we got 'em. */
271 				switch(zs_peripheral_type(zsc->zsc_promunit,
272 						 	  zsc->zsc_node,
273 						  	  channel)) {
274 				case ZS_PERIPHERAL_SUNKBD:
275 #if (NKBD > 0)
276 					kma.kmta_name = "keyboard";
277 					config_found(child, (void *)&kma, NULL);
278 #endif
279 					break;
280 				case ZS_PERIPHERAL_SUNMS:
281 #if (NMS > 0)
282 					kma.kmta_name = "mouse";
283 					config_found(child, (void *)&kma, NULL);
284 #endif
285 					break;
286 				default:
287 					break;
288 				}
289 			}
290 		}
291 #endif
292 	}
293 
294 	/*
295 	 * Now safe to install interrupt handlers.  Note the arguments
296 	 * to the interrupt handlers aren't used.  Note, we only do this
297 	 * once since both SCCs interrupt at the same level and vector.
298 	 */
299 	bus_intr_establish(zsc->zsc_bustag, pri, IPL_SERIAL, 0, zshard, zsc);
300 	if (!(zsc->zsc_softintr = softintr_establish(softpri, zssoft, zsc)))
301 		panic("zsattach: could not establish soft interrupt");
302 
303 	evcnt_attach_dynamic(&zsc->zsc_intrcnt, EVCNT_TYPE_INTR, NULL,
304 	    zsc->zsc_dev.dv_xname, "intr");
305 
306 
307 	/*
308 	 * Set the master interrupt enable and interrupt vector.
309 	 * (common to both channels, do it on A)
310 	 */
311 	cs = zsc->zsc_cs[0];
312 	s = splhigh();
313 	/* interrupt vector */
314 	zs_write_reg(cs, 2, zs_init_reg[2]);
315 	/* master interrupt control (enable) */
316 	zs_write_reg(cs, 9, zs_init_reg[9]);
317 	splx(s);
318 
319 }
320 
321 static int
322 zs_print(aux, name)
323 	void *aux;
324 	const char *name;
325 {
326 	struct zsc_attach_args *args = aux;
327 
328 	if (name != NULL)
329 		aprint_normal("%s: ", name);
330 
331 	if (args->channel != -1)
332 		aprint_normal(" channel %d", args->channel);
333 
334 	return (UNCONF);
335 }
336 
337 static int
338 zshard(arg)
339 	void *arg;
340 {
341 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
342 	int rr3, rval;
343 
344 	rval = 0;
345 	while ((rr3 = zsc_intr_hard(zsc))) {
346 		/* Count up the interrupts. */
347 		rval |= rr3;
348 		zsc->zsc_intrcnt.ev_count++;
349 	}
350 	if (((zsc->zsc_cs[0] && zsc->zsc_cs[0]->cs_softreq) ||
351 	     (zsc->zsc_cs[1] && zsc->zsc_cs[1]->cs_softreq)) &&
352 	    zsc->zsc_softintr) {
353 		softintr_schedule(zsc->zsc_softintr);
354 	}
355 	return (rval);
356 }
357 
358 int
359 zscheckintr(arg)
360 	void *arg;
361 {
362 	struct zsc_softc *zsc;
363 	int unit, rval;
364 
365 	rval = 0;
366 	for (unit = 0; unit < zs_cd.cd_ndevs; unit++) {
367 
368 		zsc = zs_cd.cd_devs[unit];
369 		if (zsc == NULL)
370 			continue;
371 		rval = (zshard((void *)zsc) || rval);
372 	}
373 	return (rval);
374 }
375 
376 
377 /*
378  * We need this only for TTY_DEBUG purposes.
379  */
380 static void
381 zssoft(arg)
382 	void *arg;
383 {
384 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
385 	int s;
386 
387 	/* Make sure we call the tty layer at spltty. */
388 	s = spltty();
389 	(void)zsc_intr_soft(zsc);
390 #ifdef TTY_DEBUG
391 	{
392 		struct zstty_softc *zst0 = zsc->zsc_cs[0]->cs_private;
393 		struct zstty_softc *zst1 = zsc->zsc_cs[1]->cs_private;
394 		if (zst0->zst_overflows || zst1->zst_overflows ) {
395 			struct trapframe *frame = (struct trapframe *)arg;
396 
397 			printf("zs silo overflow from %p\n",
398 			       (long)frame->tf_pc);
399 		}
400 	}
401 #endif
402 	splx(s);
403 }
404 
405 
406 /*
407  * Compute the current baud rate given a ZS channel.
408  */
409 static int
410 zs_get_speed(cs)
411 	struct zs_chanstate *cs;
412 {
413 	int tconst;
414 
415 	tconst = zs_read_reg(cs, 12);
416 	tconst |= zs_read_reg(cs, 13) << 8;
417 	return (TCONST_TO_BPS(cs->cs_brg_clk, tconst));
418 }
419 
420 /*
421  * MD functions for setting the baud rate and control modes.
422  */
423 int
424 zs_set_speed(cs, bps)
425 	struct zs_chanstate *cs;
426 	int bps;	/* bits per second */
427 {
428 	int tconst, real_bps;
429 
430 	if (bps == 0)
431 		return (0);
432 
433 #ifdef	DIAGNOSTIC
434 	if (cs->cs_brg_clk == 0)
435 		panic("zs_set_speed");
436 #endif
437 
438 	tconst = BPS_TO_TCONST(cs->cs_brg_clk, bps);
439 	if (tconst < 0)
440 		return (EINVAL);
441 
442 	/* Convert back to make sure we can do it. */
443 	real_bps = TCONST_TO_BPS(cs->cs_brg_clk, tconst);
444 
445 	/* XXX - Allow some tolerance here? */
446 	if (real_bps != bps)
447 		return (EINVAL);
448 
449 	cs->cs_preg[12] = tconst;
450 	cs->cs_preg[13] = tconst >> 8;
451 
452 	/* Caller will stuff the pending registers. */
453 	return (0);
454 }
455 
456 int
457 zs_set_modes(cs, cflag)
458 	struct zs_chanstate *cs;
459 	int cflag;	/* bits per second */
460 {
461 	int s;
462 
463 	/*
464 	 * Output hardware flow control on the chip is horrendous:
465 	 * if carrier detect drops, the receiver is disabled, and if
466 	 * CTS drops, the transmitter is stoped IN MID CHARACTER!
467 	 * Therefore, NEVER set the HFC bit, and instead use the
468 	 * status interrupt to detect CTS changes.
469 	 */
470 	s = splzs();
471 	cs->cs_rr0_pps = 0;
472 	if ((cflag & (CLOCAL | MDMBUF)) != 0) {
473 		cs->cs_rr0_dcd = 0;
474 		if ((cflag & MDMBUF) == 0)
475 			cs->cs_rr0_pps = ZSRR0_DCD;
476 	} else
477 		cs->cs_rr0_dcd = ZSRR0_DCD;
478 	if ((cflag & CRTSCTS) != 0) {
479 		cs->cs_wr5_dtr = ZSWR5_DTR;
480 		cs->cs_wr5_rts = ZSWR5_RTS;
481 		cs->cs_rr0_cts = ZSRR0_CTS;
482 	} else if ((cflag & CDTRCTS) != 0) {
483 		cs->cs_wr5_dtr = 0;
484 		cs->cs_wr5_rts = ZSWR5_DTR;
485 		cs->cs_rr0_cts = ZSRR0_CTS;
486 	} else if ((cflag & MDMBUF) != 0) {
487 		cs->cs_wr5_dtr = 0;
488 		cs->cs_wr5_rts = ZSWR5_DTR;
489 		cs->cs_rr0_cts = ZSRR0_DCD;
490 	} else {
491 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
492 		cs->cs_wr5_rts = 0;
493 		cs->cs_rr0_cts = 0;
494 	}
495 	splx(s);
496 
497 	/* Caller will stuff the pending registers. */
498 	return (0);
499 }
500 
501 
502 /*
503  * Read or write the chip with suitable delays.
504  */
505 
506 u_char
507 zs_read_reg(cs, reg)
508 	struct zs_chanstate *cs;
509 	u_char reg;
510 {
511 	u_char val;
512 
513 	*cs->cs_reg_csr = reg;
514 	ZS_DELAY();
515 	val = *cs->cs_reg_csr;
516 	ZS_DELAY();
517 	return (val);
518 }
519 
520 void
521 zs_write_reg(cs, reg, val)
522 	struct zs_chanstate *cs;
523 	u_char reg, val;
524 {
525 	*cs->cs_reg_csr = reg;
526 	ZS_DELAY();
527 	*cs->cs_reg_csr = val;
528 	ZS_DELAY();
529 }
530 
531 u_char
532 zs_read_csr(cs)
533 	struct zs_chanstate *cs;
534 {
535 	u_char val;
536 
537 	val = *cs->cs_reg_csr;
538 	ZS_DELAY();
539 	return (val);
540 }
541 
542 void  zs_write_csr(cs, val)
543 	struct zs_chanstate *cs;
544 	u_char val;
545 {
546 	*cs->cs_reg_csr = val;
547 	ZS_DELAY();
548 }
549 
550 u_char zs_read_data(cs)
551 	struct zs_chanstate *cs;
552 {
553 	u_char val;
554 
555 	val = *cs->cs_reg_data;
556 	ZS_DELAY();
557 	return (val);
558 }
559 
560 void  zs_write_data(cs, val)
561 	struct zs_chanstate *cs;
562 	u_char val;
563 {
564 	*cs->cs_reg_data = val;
565 	ZS_DELAY();
566 }
567 
568 /****************************************************************
569  * Console support functions (Sun specific!)
570  * Note: this code is allowed to know about the layout of
571  * the chip registers, and uses that to keep things simple.
572  * XXX - I think I like the mvme167 code better. -gwr
573  ****************************************************************/
574 
575 extern void Debugger __P((void));
576 
577 /*
578  * Handle user request to enter kernel debugger.
579  */
580 void
581 zs_abort(cs)
582 	struct zs_chanstate *cs;
583 {
584 	volatile struct zschan *zc = zs_conschan_get;
585 	int rr0;
586 
587 	/* Wait for end of break to avoid PROM abort. */
588 	/* XXX - Limit the wait? */
589 	do {
590 		rr0 = zc->zc_csr;
591 		ZS_DELAY();
592 	} while (rr0 & ZSRR0_BREAK);
593 
594 #if defined(KGDB)
595 	zskgdb(cs);
596 #elif defined(DDB)
597 	{
598 		extern int db_active;
599 
600 		if (!db_active)
601 			Debugger();
602 		else
603 			/* Debugger is probably hozed */
604 			callrom();
605 	}
606 #else
607 	printf("stopping on keyboard abort\n");
608 	callrom();
609 #endif
610 }
611 
612 
613 /*
614  * Polled input char.
615  */
616 int
617 zs_getc(arg)
618 	void *arg;
619 {
620 	volatile struct zschan *zc = arg;
621 	int s, c, rr0;
622 
623 	s = splhigh();
624 	/* Wait for a character to arrive. */
625 	do {
626 		rr0 = zc->zc_csr;
627 		ZS_DELAY();
628 	} while ((rr0 & ZSRR0_RX_READY) == 0);
629 
630 	c = zc->zc_data;
631 	ZS_DELAY();
632 	splx(s);
633 
634 	/*
635 	 * This is used by the kd driver to read scan codes,
636 	 * so don't translate '\r' ==> '\n' here...
637 	 */
638 	return (c);
639 }
640 
641 /*
642  * Polled output char.
643  */
644 void
645 zs_putc(arg, c)
646 	void *arg;
647 	int c;
648 {
649 	volatile struct zschan *zc = arg;
650 	int s, rr0;
651 
652 	s = splhigh();
653 
654 	/* Wait for transmitter to become ready. */
655 	do {
656 		rr0 = zc->zc_csr;
657 		ZS_DELAY();
658 	} while ((rr0 & ZSRR0_TX_READY) == 0);
659 
660 	/*
661 	 * Send the next character.
662 	 * Now you'd think that this could be followed by a ZS_DELAY()
663 	 * just like all the other chip accesses, but it turns out that
664 	 * the `transmit-ready' interrupt isn't de-asserted until
665 	 * some period of time after the register write completes
666 	 * (more than a couple instructions).  So to avoid stray
667 	 * interrupts we put in the 2us delay regardless of CPU model.
668 	 */
669 	zc->zc_data = c;
670 	delay(2);
671 
672 	splx(s);
673 }
674 
675 /*****************************************************************/
676 
677 
678 
679 
680 /*
681  * Polled console input putchar.
682  */
683 static int
684 zscngetc(dev)
685 	dev_t dev;
686 {
687 	return (zs_getc(zs_conschan_get));
688 }
689 
690 /*
691  * Polled console output putchar.
692  */
693 static void
694 zscnputc(dev, c)
695 	dev_t dev;
696 	int c;
697 {
698 	zs_putc(zs_conschan_put, c);
699 }
700 
701 int swallow_zsintrs;
702 
703 static void
704 zscnpollc(dev, on)
705 	dev_t dev;
706 	int on;
707 {
708 	/*
709 	 * Need to tell zs driver to acknowledge all interrupts or we get
710 	 * annoying spurious interrupt messages.  This is because mucking
711 	 * with spl() levels during polling does not prevent interrupts from
712 	 * being generated.
713 	 */
714 
715 	if (on) swallow_zsintrs++;
716 	else swallow_zsintrs--;
717 }
718 
719