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zs.c revision 1.16
      1 /*	$NetBSD: zs.c,v 1.16 2007/12/04 15:12:07 tsutsui 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 1.16 2007/12/04 15:12:07 tsutsui 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 #include <sys/intr.h>
     65 
     66 #include <machine/autoconf.h>
     67 #include <machine/promlib.h>
     68 #include <machine/cpu.h>
     69 #include <machine/eeprom.h>
     70 #include <machine/psl.h>
     71 #include <machine/z8530var.h>
     72 
     73 #include <dev/cons.h>
     74 #include <dev/ic/z8530reg.h>
     75 #include <dev/sun/kbd_ms_ttyvar.h>
     76 #include <ddb/db_output.h>
     77 
     78 #include <sun2/dev/cons.h>
     79 
     80 #include "kbd.h"	/* NKBD */
     81 #include "ms.h"		/* NMS */
     82 
     83 /*
     84  * Some warts needed by z8530tty.c -
     85  * The default parity REALLY needs to be the same as the PROM uses,
     86  * or you can not see messages done with printf during boot-up...
     87  */
     88 int zs_def_cflag = (CREAD | CS8 | HUPCL);
     89 
     90 /* ZS channel used as the console device (if any) */
     91 void *zs_conschan_get, *zs_conschan_put;
     92 
     93 static u_char zs_init_reg[16] = {
     94 	0,	/* 0: CMD (reset, etc.) */
     95 	0,	/* 1: No interrupts yet. */
     96 #ifdef  ZS_INIT_IVECT
     97 	ZS_INIT_IVECT,	/* 2: IVECT */
     98 #else
     99 	0,	/* 2: IVECT */
    100 #endif
    101 	ZSWR3_RX_8 | ZSWR3_RX_ENABLE,
    102 	ZSWR4_CLK_X16 | ZSWR4_ONESB | ZSWR4_EVENP,
    103 	ZSWR5_TX_8 | ZSWR5_TX_ENABLE,
    104 	0,	/* 6: TXSYNC/SYNCLO */
    105 	0,	/* 7: RXSYNC/SYNCHI */
    106 	0,	/* 8: alias for data port */
    107 #ifdef  ZS_INIT_IVECT
    108 	ZSWR9_MASTER_IE,
    109 #else
    110 	ZSWR9_MASTER_IE | ZSWR9_NO_VECTOR,
    111 #endif
    112 	0,	/*10: Misc. TX/RX control bits */
    113 	ZSWR11_TXCLK_BAUD | ZSWR11_RXCLK_BAUD,
    114 	((PCLK/32)/9600)-2,	/*12: BAUDLO (default=9600) */
    115 	0,			/*13: BAUDHI (default=9600) */
    116 	ZSWR14_BAUD_ENA | ZSWR14_BAUD_FROM_PCLK,
    117 	ZSWR15_BREAK_IE,
    118 };
    119 
    120 /* Console ops */
    121 static int  zscngetc(dev_t);
    122 static void zscnputc(dev_t, int);
    123 static void zscnpollc(dev_t, int);
    124 
    125 struct consdev zs_consdev = {
    126 	NULL,
    127 	NULL,
    128 	zscngetc,
    129 	zscnputc,
    130 	zscnpollc,
    131 	NULL,
    132 };
    133 
    134 
    135 /****************************************************************
    136  * Autoconfig
    137  ****************************************************************/
    138 
    139 static int  zs_print(void *, const char *name);
    140 
    141 extern struct cfdriver zs_cd;
    142 
    143 /* Interrupt handlers. */
    144 int zscheckintr(void *);
    145 static int zshard(void *);
    146 static void zssoft(void *);
    147 
    148 static int zs_get_speed(struct zs_chanstate *);
    149 
    150 /*
    151  * Attach a found zs.
    152  *
    153  * USE ROM PROPERTIES port-a-ignore-cd AND port-b-ignore-cd FOR
    154  * SOFT CARRIER, AND keyboard PROPERTY FOR KEYBOARD/MOUSE?
    155  */
    156 void
    157 zs_attach(struct zsc_softc *zsc, struct zsdevice *zsd, int pri)
    158 {
    159 	struct zsc_attach_args zsc_args;
    160 	struct zs_chanstate *cs;
    161 	int s, channel;
    162 
    163 	if (zsd == NULL) {
    164 		printf("configuration incomplete\n");
    165 		return;
    166 	}
    167 
    168 #if 0
    169 	/* we should use ipl2si(softpri) but it isn't exported */
    170 	printf(" softpri %d\n", _IPL_SOFT_LEVEL3);
    171 #else
    172 	printf("\n");
    173 #endif
    174 
    175 	/*
    176 	 * Initialize software state for each channel.
    177 	 */
    178 	for (channel = 0; channel < 2; channel++) {
    179 		struct zschan *zc;
    180 		struct device *child;
    181 
    182 		zsc_args.channel = channel;
    183 		cs = &zsc->zsc_cs_store[channel];
    184 		zsc->zsc_cs[channel] = cs;
    185 
    186 		zs_lock_init(cs);
    187 		cs->cs_channel = channel;
    188 		cs->cs_private = NULL;
    189 		cs->cs_ops = &zsops_null;
    190 		cs->cs_brg_clk = PCLK / 16;
    191 
    192 		zc = (channel == 0) ? &zsd->zs_chan_a : &zsd->zs_chan_b;
    193 
    194 		zsc_args.consdev = NULL;
    195 		zsc_args.hwflags = zs_console_flags(zsc->zsc_promunit,
    196 						    zsc->zsc_node,
    197 						    channel);
    198 
    199 		if (zsc_args.hwflags & ZS_HWFLAG_CONSOLE) {
    200 			zsc_args.hwflags |= ZS_HWFLAG_USE_CONSDEV;
    201 			zsc_args.consdev = &zs_consdev;
    202 		}
    203 
    204 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_INPUT) != 0) {
    205 			zs_conschan_get = zc;
    206 		}
    207 		if ((zsc_args.hwflags & ZS_HWFLAG_CONSOLE_OUTPUT) != 0) {
    208 			zs_conschan_put = zc;
    209 		}
    210 
    211 		/* Children need to set cn_dev, etc */
    212 		cs->cs_reg_csr  = &zc->zc_csr;
    213 		cs->cs_reg_data = &zc->zc_data;
    214 
    215 		memcpy(cs->cs_creg, zs_init_reg, 16);
    216 		memcpy(cs->cs_preg, zs_init_reg, 16);
    217 
    218 		/* XXX: Consult PROM properties for this?! */
    219 		cs->cs_defspeed = zs_get_speed(cs);
    220 		cs->cs_defcflag = zs_def_cflag;
    221 
    222 		/* Make these correspond to cs_defcflag (-crtscts) */
    223 		cs->cs_rr0_dcd = ZSRR0_DCD;
    224 		cs->cs_rr0_cts = 0;
    225 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
    226 		cs->cs_wr5_rts = 0;
    227 
    228 		/*
    229 		 * Clear the master interrupt enable.
    230 		 * The INTENA is common to both channels,
    231 		 * so just do it on the A channel.
    232 		 */
    233 		if (channel == 0) {
    234 			zs_write_reg(cs, 9, 0);
    235 		}
    236 
    237 		/*
    238 		 * Look for a child driver for this channel.
    239 		 * The child attach will setup the hardware.
    240 		 */
    241 		if (!(child =
    242 		      config_found(&zsc->zsc_dev, (void *)&zsc_args, zs_print))) {
    243 			/* No sub-driver.  Just reset it. */
    244 			u_char reset = (channel == 0) ?
    245 				ZSWR9_A_RESET : ZSWR9_B_RESET;
    246 			s = splzs();
    247 			zs_write_reg(cs,  9, reset);
    248 			splx(s);
    249 		}
    250 #if (NKBD > 0) || (NMS > 0)
    251 		/*
    252 		 * If this was a zstty it has a keyboard
    253 		 * property on it we need to attach the
    254 		 * sunkbd and sunms line disciplines.
    255 		 */
    256 		if (child
    257 		    && device_is_a(child, "zstty")) {
    258 			struct kbd_ms_tty_attach_args kma;
    259 			struct zstty_softc {
    260 				/* The following are the only fields we need here */
    261 				struct	device zst_dev;
    262 				struct  tty *zst_tty;
    263 				struct	zs_chanstate *zst_cs;
    264 			} *zst = (struct zstty_softc *)child;
    265 			struct tty *tp;
    266 
    267 			kma.kmta_tp = tp = zst->zst_tty;
    268 			if (tp != NULL) {
    269 				kma.kmta_dev = tp->t_dev;
    270 				kma.kmta_consdev = zsc_args.consdev;
    271 
    272 				/* Attach 'em if we got 'em. */
    273 				switch(zs_peripheral_type(zsc->zsc_promunit,
    274 						 	  zsc->zsc_node,
    275 						  	  channel)) {
    276 				case ZS_PERIPHERAL_SUNKBD:
    277 #if (NKBD > 0)
    278 					kma.kmta_name = "keyboard";
    279 					config_found(child, (void *)&kma, NULL);
    280 #endif
    281 					break;
    282 				case ZS_PERIPHERAL_SUNMS:
    283 #if (NMS > 0)
    284 					kma.kmta_name = "mouse";
    285 					config_found(child, (void *)&kma, NULL);
    286 #endif
    287 					break;
    288 				default:
    289 					break;
    290 				}
    291 			}
    292 		}
    293 #endif
    294 	}
    295 
    296 	/*
    297 	 * Now safe to install interrupt handlers.
    298 	 */
    299 	bus_intr_establish(zsc->zsc_bustag, pri, IPL_SERIAL, 0, zshard, zsc);
    300 	if (!(zsc->zsc_softintr = softint_establish(SOFTINT_SERIAL,
    301 	    zssoft, zsc)))
    302 		panic("zsattach: could not establish soft interrupt");
    303 
    304 	evcnt_attach_dynamic(&zsc->zsc_intrcnt, EVCNT_TYPE_INTR, NULL,
    305 	    zsc->zsc_dev.dv_xname, "intr");
    306 
    307 
    308 	/*
    309 	 * Set the master interrupt enable and interrupt vector.
    310 	 * (common to both channels, do it on A)
    311 	 */
    312 	cs = zsc->zsc_cs[0];
    313 	s = splhigh();
    314 	/* interrupt vector */
    315 	zs_write_reg(cs, 2, zs_init_reg[2]);
    316 	/* master interrupt control (enable) */
    317 	zs_write_reg(cs, 9, zs_init_reg[9]);
    318 	splx(s);
    319 
    320 }
    321 
    322 static int
    323 zs_print(void *aux, const char *name)
    324 {
    325 	struct zsc_attach_args *args = aux;
    326 
    327 	if (name != NULL)
    328 		aprint_normal("%s: ", name);
    329 
    330 	if (args->channel != -1)
    331 		aprint_normal(" channel %d", args->channel);
    332 
    333 	return (UNCONF);
    334 }
    335 
    336 static int
    337 zshard(void *arg)
    338 {
    339 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
    340 	int rr3, rval;
    341 
    342 	rval = 0;
    343 	while ((rr3 = zsc_intr_hard(zsc))) {
    344 		/* Count up the interrupts. */
    345 		rval |= rr3;
    346 		zsc->zsc_intrcnt.ev_count++;
    347 	}
    348 	if (((zsc->zsc_cs[0] && zsc->zsc_cs[0]->cs_softreq) ||
    349 	     (zsc->zsc_cs[1] && zsc->zsc_cs[1]->cs_softreq)) &&
    350 	    zsc->zsc_softintr) {
    351 		softint_schedule(zsc->zsc_softintr);
    352 	}
    353 	return (rval);
    354 }
    355 
    356 int
    357 zscheckintr(void *arg)
    358 {
    359 	struct zsc_softc *zsc;
    360 	int unit, rval;
    361 
    362 	rval = 0;
    363 	for (unit = 0; unit < zs_cd.cd_ndevs; unit++) {
    364 
    365 		zsc = zs_cd.cd_devs[unit];
    366 		if (zsc == NULL)
    367 			continue;
    368 		rval = (zshard((void *)zsc) || rval);
    369 	}
    370 	return (rval);
    371 }
    372 
    373 
    374 /*
    375  * We need this only for TTY_DEBUG purposes.
    376  */
    377 static void
    378 zssoft(void *arg)
    379 {
    380 	struct zsc_softc *zsc = (struct zsc_softc *)arg;
    381 	int s;
    382 
    383 	/* Make sure we call the tty layer at spltty. */
    384 	s = spltty();
    385 	(void)zsc_intr_soft(zsc);
    386 #ifdef TTY_DEBUG
    387 	{
    388 		struct zstty_softc *zst0 = zsc->zsc_cs[0]->cs_private;
    389 		struct zstty_softc *zst1 = zsc->zsc_cs[1]->cs_private;
    390 		if (zst0->zst_overflows || zst1->zst_overflows ) {
    391 			struct trapframe *frame = (struct trapframe *)arg;
    392 
    393 			printf("zs silo overflow from %p\n",
    394 			       (long)frame->tf_pc);
    395 		}
    396 	}
    397 #endif
    398 	splx(s);
    399 }
    400 
    401 
    402 /*
    403  * Compute the current baud rate given a ZS channel.
    404  */
    405 static int
    406 zs_get_speed(struct zs_chanstate *cs)
    407 {
    408 	int tconst;
    409 
    410 	tconst = zs_read_reg(cs, 12);
    411 	tconst |= zs_read_reg(cs, 13) << 8;
    412 	return (TCONST_TO_BPS(cs->cs_brg_clk, tconst));
    413 }
    414 
    415 /*
    416  * MD functions for setting the baud rate and control modes.
    417  */
    418 int
    419 zs_set_speed(struct zs_chanstate *cs, int bps)
    420 {
    421 	int tconst, real_bps;
    422 
    423 	if (bps == 0)
    424 		return (0);
    425 
    426 #ifdef	DIAGNOSTIC
    427 	if (cs->cs_brg_clk == 0)
    428 		panic("zs_set_speed");
    429 #endif
    430 
    431 	tconst = BPS_TO_TCONST(cs->cs_brg_clk, bps);
    432 	if (tconst < 0)
    433 		return (EINVAL);
    434 
    435 	/* Convert back to make sure we can do it. */
    436 	real_bps = TCONST_TO_BPS(cs->cs_brg_clk, tconst);
    437 
    438 	/* XXX - Allow some tolerance here? */
    439 	if (real_bps != bps)
    440 		return (EINVAL);
    441 
    442 	cs->cs_preg[12] = tconst;
    443 	cs->cs_preg[13] = tconst >> 8;
    444 
    445 	/* Caller will stuff the pending registers. */
    446 	return (0);
    447 }
    448 
    449 int
    450 zs_set_modes(struct zs_chanstate *cs, int cflag	/* bits per second */)
    451 {
    452 	int s;
    453 
    454 	/*
    455 	 * Output hardware flow control on the chip is horrendous:
    456 	 * if carrier detect drops, the receiver is disabled, and if
    457 	 * CTS drops, the transmitter is stoped IN MID CHARACTER!
    458 	 * Therefore, NEVER set the HFC bit, and instead use the
    459 	 * status interrupt to detect CTS changes.
    460 	 */
    461 	s = splzs();
    462 	cs->cs_rr0_pps = 0;
    463 	if ((cflag & (CLOCAL | MDMBUF)) != 0) {
    464 		cs->cs_rr0_dcd = 0;
    465 		if ((cflag & MDMBUF) == 0)
    466 			cs->cs_rr0_pps = ZSRR0_DCD;
    467 	} else
    468 		cs->cs_rr0_dcd = ZSRR0_DCD;
    469 	if ((cflag & CRTSCTS) != 0) {
    470 		cs->cs_wr5_dtr = ZSWR5_DTR;
    471 		cs->cs_wr5_rts = ZSWR5_RTS;
    472 		cs->cs_rr0_cts = ZSRR0_CTS;
    473 	} else if ((cflag & CDTRCTS) != 0) {
    474 		cs->cs_wr5_dtr = 0;
    475 		cs->cs_wr5_rts = ZSWR5_DTR;
    476 		cs->cs_rr0_cts = ZSRR0_CTS;
    477 	} else if ((cflag & MDMBUF) != 0) {
    478 		cs->cs_wr5_dtr = 0;
    479 		cs->cs_wr5_rts = ZSWR5_DTR;
    480 		cs->cs_rr0_cts = ZSRR0_DCD;
    481 	} else {
    482 		cs->cs_wr5_dtr = ZSWR5_DTR | ZSWR5_RTS;
    483 		cs->cs_wr5_rts = 0;
    484 		cs->cs_rr0_cts = 0;
    485 	}
    486 	splx(s);
    487 
    488 	/* Caller will stuff the pending registers. */
    489 	return (0);
    490 }
    491 
    492 
    493 /*
    494  * Read or write the chip with suitable delays.
    495  */
    496 
    497 u_char
    498 zs_read_reg(struct zs_chanstate *cs, u_char reg)
    499 {
    500 	u_char val;
    501 
    502 	*cs->cs_reg_csr = reg;
    503 	ZS_DELAY();
    504 	val = *cs->cs_reg_csr;
    505 	ZS_DELAY();
    506 	return (val);
    507 }
    508 
    509 void
    510 zs_write_reg(struct zs_chanstate *cs, u_char reg, u_char val)
    511 {
    512 	*cs->cs_reg_csr = reg;
    513 	ZS_DELAY();
    514 	*cs->cs_reg_csr = val;
    515 	ZS_DELAY();
    516 }
    517 
    518 u_char
    519 zs_read_csr(struct zs_chanstate *cs)
    520 {
    521 	u_char val;
    522 
    523 	val = *cs->cs_reg_csr;
    524 	ZS_DELAY();
    525 	return (val);
    526 }
    527 
    528 void
    529 zs_write_csr(struct zs_chanstate *cs, u_char val)
    530 {
    531 	*cs->cs_reg_csr = val;
    532 	ZS_DELAY();
    533 }
    534 
    535 u_char
    536 zs_read_data(struct zs_chanstate *cs)
    537 {
    538 	u_char val;
    539 
    540 	val = *cs->cs_reg_data;
    541 	ZS_DELAY();
    542 	return (val);
    543 }
    544 
    545 void
    546 zs_write_data(struct zs_chanstate *cs, u_char val)
    547 {
    548 	*cs->cs_reg_data = val;
    549 	ZS_DELAY();
    550 }
    551 
    552 /****************************************************************
    553  * Console support functions (Sun specific!)
    554  * Note: this code is allowed to know about the layout of
    555  * the chip registers, and uses that to keep things simple.
    556  * XXX - I think I like the mvme167 code better. -gwr
    557  ****************************************************************/
    558 
    559 extern void Debugger(void);
    560 
    561 /*
    562  * Handle user request to enter kernel debugger.
    563  */
    564 void
    565 zs_abort(struct zs_chanstate *cs)
    566 {
    567 	volatile struct zschan *zc = zs_conschan_get;
    568 	int rr0;
    569 
    570 	/* Wait for end of break to avoid PROM abort. */
    571 	/* XXX - Limit the wait? */
    572 	do {
    573 		rr0 = zc->zc_csr;
    574 		ZS_DELAY();
    575 	} while (rr0 & ZSRR0_BREAK);
    576 
    577 #if defined(KGDB)
    578 	zskgdb(cs);
    579 #elif defined(DDB)
    580 	{
    581 		extern int db_active;
    582 
    583 		if (!db_active)
    584 			Debugger();
    585 		else
    586 			/* Debugger is probably hozed */
    587 			callrom();
    588 	}
    589 #else
    590 	printf("stopping on keyboard abort\n");
    591 	callrom();
    592 #endif
    593 }
    594 
    595 
    596 /*
    597  * Polled input char.
    598  */
    599 int
    600 zs_getc(void *arg)
    601 {
    602 	volatile struct zschan *zc = arg;
    603 	int s, c, rr0;
    604 
    605 	s = splhigh();
    606 	/* Wait for a character to arrive. */
    607 	do {
    608 		rr0 = zc->zc_csr;
    609 		ZS_DELAY();
    610 	} while ((rr0 & ZSRR0_RX_READY) == 0);
    611 
    612 	c = zc->zc_data;
    613 	ZS_DELAY();
    614 	splx(s);
    615 
    616 	/*
    617 	 * This is used by the kd driver to read scan codes,
    618 	 * so don't translate '\r' ==> '\n' here...
    619 	 */
    620 	return (c);
    621 }
    622 
    623 /*
    624  * Polled output char.
    625  */
    626 void
    627 zs_putc(void *arg, int c)
    628 {
    629 	volatile struct zschan *zc = arg;
    630 	int s, rr0;
    631 
    632 	s = splhigh();
    633 
    634 	/* Wait for transmitter to become ready. */
    635 	do {
    636 		rr0 = zc->zc_csr;
    637 		ZS_DELAY();
    638 	} while ((rr0 & ZSRR0_TX_READY) == 0);
    639 
    640 	/*
    641 	 * Send the next character.
    642 	 * Now you'd think that this could be followed by a ZS_DELAY()
    643 	 * just like all the other chip accesses, but it turns out that
    644 	 * the `transmit-ready' interrupt isn't de-asserted until
    645 	 * some period of time after the register write completes
    646 	 * (more than a couple instructions).  So to avoid stray
    647 	 * interrupts we put in the 2us delay regardless of CPU model.
    648 	 */
    649 	zc->zc_data = c;
    650 	delay(2);
    651 
    652 	splx(s);
    653 }
    654 
    655 /*****************************************************************/
    656 
    657 
    658 
    659 
    660 /*
    661  * Polled console input putchar.
    662  */
    663 static int
    664 zscngetc(dev_t dev)
    665 {
    666 	return (zs_getc(zs_conschan_get));
    667 }
    668 
    669 /*
    670  * Polled console output putchar.
    671  */
    672 static void
    673 zscnputc(dev_t dev, int c)
    674 {
    675 	zs_putc(zs_conschan_put, c);
    676 }
    677 
    678 int swallow_zsintrs;
    679 
    680 static void
    681 zscnpollc(dev_t dev, int on)
    682 {
    683 	/*
    684 	 * Need to tell zs driver to acknowledge all interrupts or we get
    685 	 * annoying spurious interrupt messages.  This is because mucking
    686 	 * with spl() levels during polling does not prevent interrupts from
    687 	 * being generated.
    688 	 */
    689 
    690 	if (on) swallow_zsintrs++;
    691 	else swallow_zsintrs--;
    692 }
    693 
    694