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com.c revision 1.387
      1 /* $NetBSD: com.c,v 1.387 2025/02/09 10:27:29 skrll Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1998, 1999, 2004, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Charles M. Hannum.
      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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Copyright (c) 1991 The Regents of the University of California.
     34  * All rights reserved.
     35  *
     36  * Redistribution and use in source and binary forms, with or without
     37  * modification, are permitted provided that the following conditions
     38  * are met:
     39  * 1. Redistributions of source code must retain the above copyright
     40  *    notice, this list of conditions and the following disclaimer.
     41  * 2. Redistributions in binary form must reproduce the above copyright
     42  *    notice, this list of conditions and the following disclaimer in the
     43  *    documentation and/or other materials provided with the distribution.
     44  * 3. Neither the name of the University nor the names of its contributors
     45  *    may be used to endorse or promote products derived from this software
     46  *    without specific prior written permission.
     47  *
     48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     58  * SUCH DAMAGE.
     59  *
     60  *	@(#)com.c	7.5 (Berkeley) 5/16/91
     61  */
     62 
     63 /*
     64  * COM driver, uses National Semiconductor NS16450/NS16550AF UART
     65  * Supports automatic hardware flow control on StarTech ST16C650A UART
     66  *
     67  * Lock order:
     68  *	ttylock (IPL_VM)
     69  *	-> sc->sc_lock (IPL_HIGH)
     70  *	-> timecounter_lock (IPL_HIGH)
     71  */
     72 
     73 #include <sys/cdefs.h>
     74 __KERNEL_RCSID(0, "$NetBSD: com.c,v 1.387 2025/02/09 10:27:29 skrll Exp $");
     75 
     76 #include "opt_com.h"
     77 #include "opt_ddb.h"
     78 #include "opt_kgdb.h"
     79 #include "opt_lockdebug.h"
     80 #include "opt_multiprocessor.h"
     81 #include "opt_ntp.h"
     82 
     83 /* The COM16650 option was renamed to COM_16650. */
     84 #ifdef COM16650
     85 #error Obsolete COM16650 option; use COM_16650 instead.
     86 #endif
     87 
     88 /*
     89  * Override cnmagic(9) macro before including <sys/systm.h>.
     90  * We need to know if cn_check_magic triggered debugger, so set a flag.
     91  * Callers of cn_check_magic must declare int cn_trapped = 0;
     92  * XXX: this is *ugly*!
     93  */
     94 #define cn_trap()				\
     95 	do {					\
     96 		console_debugger();		\
     97 		cn_trapped = 1;			\
     98 		(void)cn_trapped;		\
     99 	} while (/* CONSTCOND */ 0)
    100 
    101 #include <sys/param.h>
    102 #include <sys/systm.h>
    103 #include <sys/ioctl.h>
    104 #include <sys/select.h>
    105 #include <sys/poll.h>
    106 #include <sys/tty.h>
    107 #include <sys/proc.h>
    108 #include <sys/conf.h>
    109 #include <sys/file.h>
    110 #include <sys/uio.h>
    111 #include <sys/kernel.h>
    112 #include <sys/syslog.h>
    113 #include <sys/device.h>
    114 #include <sys/malloc.h>
    115 #include <sys/timepps.h>
    116 #include <sys/vnode.h>
    117 #include <sys/kauth.h>
    118 #include <sys/intr.h>
    119 #ifdef RND_COM
    120 #include <sys/rndsource.h>
    121 #endif
    122 
    123 #include <sys/bus.h>
    124 
    125 #include <ddb/db_active.h>
    126 
    127 #include <dev/ic/comreg.h>
    128 #include <dev/ic/comvar.h>
    129 #include <dev/ic/ns16550reg.h>
    130 #include <dev/ic/st16650reg.h>
    131 #include <dev/ic/hayespreg.h>
    132 #define	com_lcr	com_cfcr
    133 #include <dev/cons.h>
    134 
    135 #include "ioconf.h"
    136 
    137 #define	CSR_READ_1(r, o)	\
    138 	(r)->cr_read((r), (r)->cr_map[o])
    139 #define	CSR_WRITE_1(r, o, v)	\
    140 	(r)->cr_write((r), (r)->cr_map[o], (v))
    141 #define	CSR_WRITE_MULTI(r, o, p, n)	\
    142 	(r)->cr_write_multi((r), (r)->cr_map[o], (p), (n))
    143 
    144 /*
    145  * XXX COM_TYPE_AU1x00 specific
    146  */
    147 #define	CSR_WRITE_2(r, o, v)	\
    148 	bus_space_write_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o], v)
    149 #define	CSR_READ_2(r, o)	\
    150 	bus_space_read_2((r)->cr_iot, (r)->cr_ioh, (r)->cr_map[o])
    151 
    152 static void com_enable_debugport(struct com_softc *);
    153 
    154 void	com_config(struct com_softc *);
    155 void	com_shutdown(struct com_softc *);
    156 int	comspeed(long, long, int);
    157 static	u_char	cflag2lcr(tcflag_t);
    158 int	comparam(struct tty *, struct termios *);
    159 void	comstart(struct tty *);
    160 int	comhwiflow(struct tty *, int);
    161 
    162 void	com_loadchannelregs(struct com_softc *);
    163 void	com_hwiflow(struct com_softc *);
    164 void	com_break(struct com_softc *, int);
    165 void	com_modem(struct com_softc *, int);
    166 void	tiocm_to_com(struct com_softc *, u_long, int);
    167 int	com_to_tiocm(struct com_softc *);
    168 void	com_iflush(struct com_softc *);
    169 
    170 int	com_common_getc(dev_t, struct com_regs *);
    171 static void	com_common_putc(dev_t, struct com_regs *, int, int);
    172 
    173 int	cominit(struct com_regs *, int, int, int, tcflag_t);
    174 
    175 static int comcnreattach(void);
    176 
    177 int	comcngetc(dev_t);
    178 void	comcnputc(dev_t, int);
    179 void	comcnpollc(dev_t, int);
    180 
    181 void	comsoft(void *);
    182 static inline void com_rxsoft(struct com_softc *, struct tty *);
    183 static inline void com_txsoft(struct com_softc *, struct tty *);
    184 static inline void com_stsoft(struct com_softc *, struct tty *);
    185 static inline void com_schedrx(struct com_softc *);
    186 void	comdiag(void *);
    187 
    188 dev_type_open(comopen);
    189 dev_type_close(comclose);
    190 dev_type_read(comread);
    191 dev_type_write(comwrite);
    192 dev_type_ioctl(comioctl);
    193 dev_type_stop(comstop);
    194 dev_type_tty(comtty);
    195 dev_type_poll(compoll);
    196 
    197 static struct comcons_info comcons_info;
    198 
    199 /*
    200  * Following are all routines needed for COM to act as console
    201  */
    202 static struct consdev comcons = {
    203 	.cn_getc = comcngetc,
    204 	.cn_putc = comcnputc,
    205 	.cn_pollc = comcnpollc,
    206 	.cn_dev = NODEV,
    207 	.cn_pri = CN_NORMAL
    208 };
    209 
    210 
    211 const struct cdevsw com_cdevsw = {
    212 	.d_open = comopen,
    213 	.d_close = comclose,
    214 	.d_read = comread,
    215 	.d_write = comwrite,
    216 	.d_ioctl = comioctl,
    217 	.d_stop = comstop,
    218 	.d_tty = comtty,
    219 	.d_poll = compoll,
    220 	.d_mmap = nommap,
    221 	.d_kqfilter = ttykqfilter,
    222 	.d_discard = nodiscard,
    223 	.d_flag = D_TTY
    224 };
    225 
    226 /*
    227  * Make this an option variable one can patch.
    228  * But be warned:  this must be a power of 2!
    229  */
    230 u_int com_rbuf_size = COM_RING_SIZE;
    231 
    232 /* Stop input when 3/4 of the ring is full; restart when only 1/4 is full. */
    233 u_int com_rbuf_hiwat = (COM_RING_SIZE * 1) / 4;
    234 u_int com_rbuf_lowat = (COM_RING_SIZE * 3) / 4;
    235 
    236 static int comconsattached;
    237 static struct cnm_state com_cnm_state;
    238 
    239 #ifdef KGDB
    240 #include <sys/kgdb.h>
    241 
    242 static struct com_regs comkgdbregs;
    243 static int com_kgdb_attached;
    244 
    245 int	com_kgdb_getc(void *);
    246 void	com_kgdb_putc(void *, int);
    247 #endif /* KGDB */
    248 
    249 /* initializer for typical 16550-ish hardware */
    250 static const bus_size_t com_std_map[COM_REGMAP_NENTRIES] = {
    251 	[COM_REG_RXDATA]	=	com_data,
    252 	[COM_REG_TXDATA]	=	com_data,
    253 	[COM_REG_DLBL]		=	com_dlbl,
    254 	[COM_REG_DLBH]		=	com_dlbh,
    255 	[COM_REG_IER]		=	com_ier,
    256 	[COM_REG_IIR]		=	com_iir,
    257 	[COM_REG_FIFO]		=	com_fifo,
    258 	[COM_REG_TCR]		=	com_fifo,
    259 	[COM_REG_EFR]		=	com_efr,
    260 	[COM_REG_TLR]		=	com_efr,
    261 	[COM_REG_LCR]		=	com_lcr,
    262 	[COM_REG_MCR]		=	com_mcr,
    263 	[COM_REG_LSR]		=	com_lsr,
    264 	[COM_REG_MSR]		=	com_msr,
    265 	[COM_REG_USR]		=	com_usr,
    266 	[COM_REG_TFL]		=	com_tfl,
    267 	[COM_REG_RFL]		=	com_rfl,
    268 	[COM_REG_HALT]		=	com_halt,
    269 	[COM_REG_MDR1]		=	com_mdr1,
    270 };
    271 
    272 #define	COMDIALOUT_MASK	TTDIALOUT_MASK
    273 
    274 #define	COMUNIT(x)	TTUNIT(x)
    275 #define	COMDIALOUT(x)	TTDIALOUT(x)
    276 
    277 #define	COM_ISALIVE(sc)	((sc)->enabled != 0 && \
    278 			 device_is_active((sc)->sc_dev))
    279 
    280 #define	BR	BUS_SPACE_BARRIER_READ
    281 #define	BW	BUS_SPACE_BARRIER_WRITE
    282 #define COM_BARRIER(r, f) \
    283 	bus_space_barrier((r)->cr_iot, (r)->cr_ioh, 0, (r)->cr_nports, (f))
    284 
    285 /*
    286  * com_read_1 --
    287  *	Default register read callback using single byte accesses.
    288  */
    289 static uint8_t
    290 com_read_1(struct com_regs *regs, u_int reg)
    291 {
    292 	return bus_space_read_1(regs->cr_iot, regs->cr_ioh, reg);
    293 }
    294 
    295 /*
    296  * com_write_1 --
    297  *	Default register write callback using single byte accesses.
    298  */
    299 static void
    300 com_write_1(struct com_regs *regs, u_int reg, uint8_t val)
    301 {
    302 	bus_space_write_1(regs->cr_iot, regs->cr_ioh, reg, val);
    303 }
    304 
    305 /*
    306  * com_write_multi_1 --
    307  *	Default register multi write callback using single byte accesses.
    308  */
    309 static void
    310 com_write_multi_1(struct com_regs *regs, u_int reg, const uint8_t *datap,
    311     bus_size_t count)
    312 {
    313 	bus_space_write_multi_1(regs->cr_iot, regs->cr_ioh, reg, datap, count);
    314 }
    315 
    316 /*
    317  * com_read_4 --
    318  *	Default register read callback using dword accesses.
    319  */
    320 static uint8_t
    321 com_read_4(struct com_regs *regs, u_int reg)
    322 {
    323 	return bus_space_read_4(regs->cr_iot, regs->cr_ioh, reg) & 0xff;
    324 }
    325 
    326 /*
    327  * com_write_4 --
    328  *	Default register write callback using dword accesses.
    329  */
    330 static void
    331 com_write_4(struct com_regs *regs, u_int reg, uint8_t val)
    332 {
    333 	bus_space_write_4(regs->cr_iot, regs->cr_ioh, reg, val);
    334 }
    335 
    336 /*
    337  * com_write_multi_4 --
    338  *	Default register multi write callback using dword accesses.
    339  */
    340 static void
    341 com_write_multi_4(struct com_regs *regs, u_int reg, const uint8_t *datap,
    342     bus_size_t count)
    343 {
    344 	while (count-- > 0) {
    345 		bus_space_write_4(regs->cr_iot, regs->cr_ioh, reg, *datap++);
    346 	}
    347 }
    348 
    349 /*
    350  * com_init_regs --
    351  *	Driver front-ends use this to initialize our register map
    352  *	in the standard fashion.  They may then tailor the map to
    353  *	their own particular requirements.
    354  */
    355 void
    356 com_init_regs(struct com_regs *regs, bus_space_tag_t st, bus_space_handle_t sh,
    357 	      bus_addr_t addr)
    358 {
    359 
    360 	memset(regs, 0, sizeof(*regs));
    361 	regs->cr_iot = st;
    362 	regs->cr_ioh = sh;
    363 	regs->cr_iobase = addr;
    364 	regs->cr_nports = COM_NPORTS;
    365 	regs->cr_read = com_read_1;
    366 	regs->cr_write = com_write_1;
    367 	regs->cr_write_multi = com_write_multi_1;
    368 	memcpy(regs->cr_map, com_std_map, sizeof(regs->cr_map));
    369 }
    370 
    371 /*
    372  * com_init_regs_stride --
    373  *	Convenience function for front-ends that have a stride between
    374  *	registers.
    375  */
    376 void
    377 com_init_regs_stride(struct com_regs *regs, bus_space_tag_t st,
    378 		     bus_space_handle_t sh, bus_addr_t addr, u_int regshift)
    379 {
    380 
    381 	com_init_regs(regs, st, sh, addr);
    382 	for (size_t i = 0; i < __arraycount(regs->cr_map); i++) {
    383 		regs->cr_map[i] <<= regshift;
    384 	}
    385 	regs->cr_nports <<= regshift;
    386 }
    387 
    388 /*
    389  * com_init_regs_stride_width --
    390  *	Convenience function for front-ends that have a stride between
    391  *	registers and specific I/O width requirements.
    392  */
    393 void
    394 com_init_regs_stride_width(struct com_regs *regs, bus_space_tag_t st,
    395 			   bus_space_handle_t sh, bus_addr_t addr,
    396 			   u_int regshift, u_int width)
    397 {
    398 
    399 	com_init_regs(regs, st, sh, addr);
    400 	for (size_t i = 0; i < __arraycount(regs->cr_map); i++) {
    401 		regs->cr_map[i] <<= regshift;
    402 	}
    403 	regs->cr_nports <<= regshift;
    404 
    405 	switch (width) {
    406 	case 1:
    407 		/* Already set by com_init_regs */
    408 		break;
    409 	case 4:
    410 		regs->cr_read = com_read_4;
    411 		regs->cr_write = com_write_4;
    412 		regs->cr_write_multi = com_write_multi_4;
    413 		break;
    414 	default:
    415 		panic("com: unsupported I/O width %d", width);
    416 	}
    417 }
    418 
    419 /*ARGSUSED*/
    420 int
    421 comspeed(long speed, long frequency, int type)
    422 {
    423 #define	divrnd(n, q)	(((n)*2/(q)+1)/2)	/* divide and round off */
    424 
    425 	int x, err;
    426 	int divisor = 16;
    427 
    428 	if ((type == COM_TYPE_OMAP) && (speed > 230400)) {
    429 	    divisor = 13;
    430 	}
    431 
    432 	if (speed == 0)
    433 		return (0);
    434 	if (speed < 0)
    435 		return (-1);
    436 	x = divrnd(frequency / divisor, speed);
    437 	if (x <= 0)
    438 		return (-1);
    439 	err = divrnd(((quad_t)frequency) * 1000 / divisor, speed * x) - 1000;
    440 	if (err < 0)
    441 		err = -err;
    442 	if (err > COM_TOLERANCE)
    443 		return (-1);
    444 	return (x);
    445 
    446 #undef	divrnd
    447 }
    448 
    449 #ifdef COM_DEBUG
    450 int	com_debug = 0;
    451 
    452 void comstatus(struct com_softc *, const char *);
    453 void
    454 comstatus(struct com_softc *sc, const char *str)
    455 {
    456 	struct tty *tp = sc->sc_tty;
    457 
    458 	aprint_normal_dev(sc->sc_dev,
    459 	    "%s %cclocal  %cdcd %cts_carr_on %cdtr %ctx_stopped\n",
    460 	    str,
    461 	    ISSET(tp->t_cflag, CLOCAL) ? '+' : '-',
    462 	    ISSET(sc->sc_msr, MSR_DCD) ? '+' : '-',
    463 	    ISSET(tp->t_state, TS_CARR_ON) ? '+' : '-',
    464 	    ISSET(sc->sc_mcr, MCR_DTR) ? '+' : '-',
    465 	    sc->sc_tx_stopped ? '+' : '-');
    466 
    467 	aprint_normal_dev(sc->sc_dev,
    468 	    "%s %ccrtscts %ccts %cts_ttstop  %crts rx_flags=0x%x\n",
    469 	    str,
    470 	    ISSET(tp->t_cflag, CRTSCTS) ? '+' : '-',
    471 	    ISSET(sc->sc_msr, MSR_CTS) ? '+' : '-',
    472 	    ISSET(tp->t_state, TS_TTSTOP) ? '+' : '-',
    473 	    ISSET(sc->sc_mcr, MCR_RTS) ? '+' : '-',
    474 	    sc->sc_rx_flags);
    475 }
    476 #endif
    477 
    478 int
    479 com_probe_subr(struct com_regs *regs)
    480 {
    481 
    482 	/* force access to id reg */
    483 	CSR_WRITE_1(regs, COM_REG_LCR, LCR_8BITS);
    484 	CSR_WRITE_1(regs, COM_REG_IIR, 0);
    485 	if ((CSR_READ_1(regs, COM_REG_LCR) != LCR_8BITS) ||
    486 	    (CSR_READ_1(regs, COM_REG_IIR) & 0x38))
    487 		return (0);
    488 
    489 	return (1);
    490 }
    491 
    492 int
    493 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
    494 {
    495 	struct com_regs	regs;
    496 
    497 	com_init_regs(&regs, iot, ioh, 0/*XXX*/);
    498 
    499 	return com_probe_subr(&regs);
    500 }
    501 
    502 /*
    503  * No locking in this routine; it is only called during attach,
    504  * or with the port already locked.
    505  */
    506 static void
    507 com_enable_debugport(struct com_softc *sc)
    508 {
    509 
    510 	/* Turn on line break interrupt, set carrier. */
    511 	sc->sc_ier = IER_ERLS;
    512 	if (sc->sc_type == COM_TYPE_PXA2x0)
    513 		sc->sc_ier |= IER_EUART | IER_ERXTOUT;
    514 	if (sc->sc_type == COM_TYPE_INGENIC ||
    515 	    sc->sc_type == COM_TYPE_TEGRA)
    516 		sc->sc_ier |= IER_ERXTOUT;
    517 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
    518 	SET(sc->sc_mcr, MCR_DTR | MCR_RTS);
    519 	CSR_WRITE_1(&sc->sc_regs, COM_REG_MCR, sc->sc_mcr);
    520 }
    521 
    522 static void
    523 com_intr_poll(void *arg)
    524 {
    525 	struct com_softc * const sc = arg;
    526 
    527 	comintr(sc);
    528 
    529 	callout_schedule(&sc->sc_poll_callout, sc->sc_poll_ticks);
    530 }
    531 
    532 void
    533 com_attach_subr(struct com_softc *sc)
    534 {
    535 	struct com_regs *regsp = &sc->sc_regs;
    536 	struct tty *tp;
    537 	uint32_t cpr;
    538 	uint8_t lcr;
    539 	const char *fifo_msg = NULL;
    540 	prop_dictionary_t dict;
    541 	bool is_console = true;
    542 	bool force_console = false;
    543 
    544 	aprint_naive("\n");
    545 
    546 	dict = device_properties(sc->sc_dev);
    547 	prop_dictionary_get_bool(dict, "is_console", &is_console);
    548 	prop_dictionary_get_bool(dict, "force_console", &force_console);
    549 	callout_init(&sc->sc_diag_callout, 0);
    550 	callout_init(&sc->sc_poll_callout, 0);
    551 	callout_setfunc(&sc->sc_poll_callout, com_intr_poll, sc);
    552 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_HIGH);
    553 
    554 #if defined(COM_16650)
    555 	sc->sc_type = COM_TYPE_16650;
    556 #elif defined(COM_16750)
    557 	sc->sc_type = COM_TYPE_16750;
    558 #elif defined(COM_HAYESP)
    559 	sc->sc_type = COM_TYPE_HAYESP;
    560 #elif defined(COM_PXA2X0)
    561 	sc->sc_type = COM_TYPE_PXA2x0;
    562 #endif
    563 
    564 	/* Disable interrupts before configuring the device. */
    565 	if (sc->sc_type == COM_TYPE_PXA2x0)
    566 		sc->sc_ier = IER_EUART;
    567 	else
    568 		sc->sc_ier = 0;
    569 
    570 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
    571 
    572 	if ((bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
    573 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) || force_console) {
    574 		comconsattached = 1;
    575 
    576 		if (force_console)
    577 			memcpy(regsp, &comcons_info.regs, sizeof(*regsp));
    578 
    579 		if (cn_tab == NULL && comcnreattach() != 0) {
    580 			printf("can't re-init serial console @%lx\n",
    581 			    (u_long)comcons_info.regs.cr_iobase);
    582 		}
    583 
    584 		switch (sc->sc_type) {
    585 		case COM_TYPE_16750:
    586 		case COM_TYPE_DW_APB:
    587 			/* Use in comintr(). */
    588  			sc->sc_lcr = cflag2lcr(comcons_info.cflag);
    589 			break;
    590 		}
    591 
    592 		/* Make sure the console is always "hardwired". */
    593 		delay(10000);			/* wait for output to finish */
    594 		if (is_console) {
    595 			SET(sc->sc_hwflags, COM_HW_CONSOLE);
    596 		}
    597 
    598 		SET(sc->sc_swflags, TIOCFLAG_SOFTCAR);
    599 	}
    600 
    601 	/* Probe for FIFO */
    602 	switch (sc->sc_type) {
    603 	case COM_TYPE_HAYESP:
    604 		goto fifodone;
    605 
    606 	case COM_TYPE_AU1x00:
    607 		sc->sc_fifolen = 16;
    608 		fifo_msg = "Au1X00 UART";
    609 		SET(sc->sc_hwflags, COM_HW_FIFO);
    610 		goto fifodelay;
    611 
    612 	case COM_TYPE_16550_NOERS:
    613 		sc->sc_fifolen = 16;
    614 		fifo_msg = "ns16650, no ERS";
    615 		SET(sc->sc_hwflags, COM_HW_FIFO);
    616 		goto fifodelay;
    617 
    618 	case COM_TYPE_OMAP:
    619 		sc->sc_fifolen = 64;
    620 		fifo_msg = "OMAP UART";
    621 		SET(sc->sc_hwflags, COM_HW_FIFO);
    622 		goto fifodelay;
    623 
    624 	case COM_TYPE_INGENIC:
    625 		sc->sc_fifolen = 16;
    626 		fifo_msg = "Ingenic UART";
    627 		SET(sc->sc_hwflags, COM_HW_FIFO);
    628 		SET(sc->sc_hwflags, COM_HW_NOIEN);
    629 		goto fifodelay;
    630 
    631 	case COM_TYPE_TEGRA:
    632 		sc->sc_fifolen = 8;
    633 		fifo_msg = "Tegra UART";
    634 		SET(sc->sc_hwflags, COM_HW_FIFO);
    635 		CSR_WRITE_1(regsp, COM_REG_FIFO,
    636 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
    637 		goto fifodelay;
    638 
    639 	case COM_TYPE_BCMAUXUART:
    640 		sc->sc_fifolen = 1;
    641 		fifo_msg = "BCM AUX UART";
    642 		SET(sc->sc_hwflags, COM_HW_FIFO);
    643 		CSR_WRITE_1(regsp, COM_REG_FIFO,
    644 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
    645 		goto fifodelay;
    646 
    647 	case COM_TYPE_DW_APB:
    648 		if (!prop_dictionary_get_uint(dict, "fifolen", &sc->sc_fifolen)) {
    649 			cpr = bus_space_read_4(sc->sc_regs.cr_iot,
    650 			    sc->sc_regs.cr_ioh, DW_APB_UART_CPR);
    651 			sc->sc_fifolen = __SHIFTOUT(cpr, UART_CPR_FIFO_MODE) * 16;
    652 		}
    653 		if (sc->sc_fifolen == 0) {
    654 			sc->sc_fifolen = 1;
    655 			fifo_msg = "DesignWare APB UART, no fifo";
    656 			CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
    657 		} else {
    658 			fifo_msg = "DesignWare APB UART";
    659 			SET(sc->sc_hwflags, COM_HW_FIFO);
    660 			CSR_WRITE_1(regsp, COM_REG_FIFO,
    661 			    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_1);
    662 		}
    663 		goto fifodelay;
    664 	}
    665 
    666 	sc->sc_fifolen = 1;
    667 	/* look for a NS 16550AF UART with FIFOs */
    668 	if (sc->sc_type == COM_TYPE_INGENIC) {
    669 		CSR_WRITE_1(regsp, COM_REG_FIFO,
    670 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
    671 		    FIFO_TRIGGER_14 | FIFO_UART_ON);
    672 	} else
    673 		CSR_WRITE_1(regsp, COM_REG_FIFO,
    674 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST | FIFO_TRIGGER_14);
    675 	delay(100);
    676 	if (ISSET(CSR_READ_1(regsp, COM_REG_IIR), IIR_FIFO_MASK)
    677 	    == IIR_FIFO_MASK)
    678 		if (ISSET(CSR_READ_1(regsp, COM_REG_FIFO), FIFO_TRIGGER_14)
    679 		    == FIFO_TRIGGER_14) {
    680 			SET(sc->sc_hwflags, COM_HW_FIFO);
    681 
    682 			fifo_msg = "ns16550a";
    683 			sc->sc_fifolen = 16;
    684 
    685 			/*
    686 			 * IIR changes into the EFR if LCR is set to LCR_EERS
    687 			 * on 16650s. We also know IIR != 0 at this point.
    688 			 * Write 0 into the EFR, and read it. If the result
    689 			 * is 0, we have a 16650.
    690 			 *
    691 			 * Older 16650s were broken; the test to detect them
    692 			 * is taken from the Linux driver. Apparently
    693 			 * setting DLAB enable gives access to the EFR on
    694 			 * these chips.
    695 			 */
    696 			if (sc->sc_type == COM_TYPE_16650) {
    697 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
    698 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
    699 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
    700 				if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
    701 					CSR_WRITE_1(regsp, COM_REG_LCR,
    702 					    lcr | LCR_DLAB);
    703 					if (CSR_READ_1(regsp, COM_REG_EFR) == 0) {
    704 						CLR(sc->sc_hwflags, COM_HW_FIFO);
    705 						sc->sc_fifolen = 0;
    706 					} else {
    707 						SET(sc->sc_hwflags, COM_HW_FLOW);
    708 						sc->sc_fifolen = 32;
    709 					}
    710 				} else
    711 					sc->sc_fifolen = 16;
    712 
    713 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
    714 				if (sc->sc_fifolen == 0)
    715 					fifo_msg = "st16650, broken fifo";
    716 				else if (sc->sc_fifolen == 32)
    717 					fifo_msg = "st16650a";
    718 				else
    719 					fifo_msg = "ns16550a";
    720 			}
    721 
    722 			/*
    723 			 * TL16C750 can enable 64byte FIFO, only when DLAB
    724 			 * is 1.  However, some 16750 may always enable.  For
    725 			 * example, restrictions according to DLAB in a data
    726 			 * sheet for SC16C750 were not described.
    727 			 * Please enable 'options COM_16650', supposing you
    728 			 * use SC16C750.  Probably 32 bytes of FIFO and HW FLOW
    729 			 * should become effective.
    730 			 */
    731 			if (sc->sc_type == COM_TYPE_16750) {
    732 				uint8_t iir1, iir2;
    733 				uint8_t fcr = FIFO_ENABLE | FIFO_TRIGGER_14;
    734 
    735 				lcr = CSR_READ_1(regsp, COM_REG_LCR);
    736 				CSR_WRITE_1(regsp, COM_REG_LCR,
    737 				    lcr & ~LCR_DLAB);
    738 				CSR_WRITE_1(regsp, COM_REG_FIFO,
    739 				    fcr | FIFO_64B_ENABLE);
    740 				iir1 = CSR_READ_1(regsp, COM_REG_IIR);
    741 				CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
    742 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr | LCR_DLAB);
    743 				CSR_WRITE_1(regsp, COM_REG_FIFO,
    744 				    fcr | FIFO_64B_ENABLE);
    745 				iir2 = CSR_READ_1(regsp, COM_REG_IIR);
    746 
    747 				CSR_WRITE_1(regsp, COM_REG_LCR, lcr);
    748 
    749 				if (!ISSET(iir1, IIR_64B_FIFO) &&
    750 				    ISSET(iir2, IIR_64B_FIFO)) {
    751 					/* It is TL16C750. */
    752 					sc->sc_fifolen = 64;
    753 					SET(sc->sc_hwflags, COM_HW_AFE);
    754 				} else
    755 					CSR_WRITE_1(regsp, COM_REG_FIFO, fcr);
    756 
    757 				if (sc->sc_fifolen == 64)
    758 					fifo_msg = "tl16c750";
    759 				else
    760 					fifo_msg = "ns16750";
    761 			}
    762 		} else
    763 			fifo_msg = "ns16550, broken fifo";
    764 	else
    765 		fifo_msg = "ns8250 or ns16450, no fifo";
    766 	CSR_WRITE_1(regsp, COM_REG_FIFO, 0);
    767 
    768 fifodelay:
    769 	/*
    770 	 * Some chips will clear down both Tx and Rx FIFOs when zero is
    771 	 * written to com_fifo. If this chip is the console, writing zero
    772 	 * results in some of the chip/FIFO description being lost, so delay
    773 	 * printing it until now.
    774 	 */
    775 	delay(10);
    776 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
    777 		aprint_normal(": %s, %d-byte FIFO\n", fifo_msg, sc->sc_fifolen);
    778 	} else {
    779 		aprint_normal(": %s\n", fifo_msg);
    780 	}
    781 	if (ISSET(sc->sc_hwflags, COM_HW_TXFIFO_DISABLE)) {
    782 		sc->sc_fifolen = 1;
    783 		aprint_normal_dev(sc->sc_dev, "txfifo disabled\n");
    784 	}
    785 
    786 fifodone:
    787 
    788 	tp = tty_alloc();
    789 	tp->t_oproc = comstart;
    790 	tp->t_param = comparam;
    791 	tp->t_hwiflow = comhwiflow;
    792 	tp->t_softc = sc;
    793 
    794 	sc->sc_tty = tp;
    795 	sc->sc_rbuf = malloc(com_rbuf_size << 1, M_DEVBUF, M_WAITOK);
    796 	sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
    797 	sc->sc_rbavail = com_rbuf_size;
    798 	sc->sc_ebuf = sc->sc_rbuf + (com_rbuf_size << 1);
    799 
    800 	tty_attach(tp);
    801 
    802 	if (!ISSET(sc->sc_hwflags, COM_HW_NOIEN))
    803 		SET(sc->sc_mcr, MCR_IENABLE);
    804 
    805 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
    806 		int maj;
    807 
    808 		/* locate the major number */
    809 		maj = cdevsw_lookup_major(&com_cdevsw);
    810 
    811 		tp->t_dev = cn_tab->cn_dev = makedev(maj,
    812 						     device_unit(sc->sc_dev));
    813 
    814 		aprint_normal_dev(sc->sc_dev, "console\n");
    815 	}
    816 
    817 #ifdef KGDB
    818 	/*
    819 	 * Allow kgdb to "take over" this port.  If this is
    820 	 * not the console and is the kgdb device, it has
    821 	 * exclusive use.  If it's the console _and_ the
    822 	 * kgdb device, it doesn't.
    823 	 */
    824 	if (bus_space_is_equal(regsp->cr_iot, comkgdbregs.cr_iot) &&
    825 	    regsp->cr_iobase == comkgdbregs.cr_iobase) {
    826 		if (!ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
    827 			com_kgdb_attached = 1;
    828 
    829 			SET(sc->sc_hwflags, COM_HW_KGDB);
    830 		}
    831 		aprint_normal_dev(sc->sc_dev, "kgdb\n");
    832 	}
    833 #endif
    834 
    835 	sc->sc_si = softint_establish(SOFTINT_SERIAL, comsoft, sc);
    836 
    837 #ifdef RND_COM
    838 	rnd_attach_source(&sc->rnd_source, device_xname(sc->sc_dev),
    839 			  RND_TYPE_TTY, RND_FLAG_DEFAULT);
    840 #endif
    841 
    842 	/* if there are no enable/disable functions, assume the device
    843 	   is always enabled */
    844 	if (!sc->enable)
    845 		sc->enabled = 1;
    846 
    847 	com_config(sc);
    848 
    849 	SET(sc->sc_hwflags, COM_HW_DEV_OK);
    850 
    851 	if (sc->sc_poll_ticks != 0)
    852 		callout_schedule(&sc->sc_poll_callout, sc->sc_poll_ticks);
    853 }
    854 
    855 void
    856 com_config(struct com_softc *sc)
    857 {
    858 	struct com_regs *regsp = &sc->sc_regs;
    859 
    860 	/* Disable interrupts before configuring the device. */
    861 	if (sc->sc_type == COM_TYPE_PXA2x0)
    862 		sc->sc_ier = IER_EUART;
    863 	else
    864 		sc->sc_ier = 0;
    865 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
    866 	(void) CSR_READ_1(regsp, COM_REG_IIR);
    867 
    868 	/* Look for a Hayes ESP board. */
    869 	if (sc->sc_type == COM_TYPE_HAYESP) {
    870 
    871 		/* Set 16550 compatibility mode */
    872 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
    873 				  HAYESP_SETMODE);
    874 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    875 				  HAYESP_MODE_FIFO|HAYESP_MODE_RTS|
    876 				  HAYESP_MODE_SCALE);
    877 
    878 		/* Set RTS/CTS flow control */
    879 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
    880 				  HAYESP_SETFLOWTYPE);
    881 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    882 				  HAYESP_FLOW_RTS);
    883 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    884 				  HAYESP_FLOW_CTS);
    885 
    886 		/* Set flow control levels */
    887 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
    888 				  HAYESP_SETRXFLOW);
    889 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    890 				  HAYESP_HIBYTE(HAYESP_RXHIWMARK));
    891 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    892 				  HAYESP_LOBYTE(HAYESP_RXHIWMARK));
    893 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    894 				  HAYESP_HIBYTE(HAYESP_RXLOWMARK));
    895 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
    896 				  HAYESP_LOBYTE(HAYESP_RXLOWMARK));
    897 	}
    898 
    899 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE|COM_HW_KGDB))
    900 		com_enable_debugport(sc);
    901 }
    902 
    903 int
    904 com_detach(device_t self, int flags)
    905 {
    906 	struct com_softc *sc = device_private(self);
    907 	int maj, mn;
    908 
    909 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
    910 		return EBUSY;
    911 
    912 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE) &&
    913 	    (flags & DETACH_SHUTDOWN) != 0)
    914 		return EBUSY;
    915 
    916 	if (sc->disable != NULL && sc->enabled != 0) {
    917 		(*sc->disable)(sc);
    918 		sc->enabled = 0;
    919 	}
    920 
    921 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
    922 		comconsattached = 0;
    923 		cn_tab = NULL;
    924 	}
    925 
    926 	/* locate the major number */
    927 	maj = cdevsw_lookup_major(&com_cdevsw);
    928 
    929 	/* Nuke the vnodes for any open instances. */
    930 	mn = device_unit(self);
    931 	vdevgone(maj, mn, mn, VCHR);
    932 
    933 	mn |= COMDIALOUT_MASK;
    934 	vdevgone(maj, mn, mn, VCHR);
    935 
    936 	if (sc->sc_rbuf == NULL) {
    937 		/*
    938 		 * Ring buffer allocation failed in the com_attach_subr,
    939 		 * only the tty is allocated, and nothing else.
    940 		 */
    941 		tty_free(sc->sc_tty);
    942 		return 0;
    943 	}
    944 
    945 	/* Free the receive buffer. */
    946 	free(sc->sc_rbuf, M_DEVBUF);
    947 
    948 	/* Detach and free the tty. */
    949 	tty_detach(sc->sc_tty);
    950 	tty_free(sc->sc_tty);
    951 
    952 	/* Unhook the soft interrupt handler. */
    953 	softint_disestablish(sc->sc_si);
    954 
    955 #ifdef RND_COM
    956 	/* Unhook the entropy source. */
    957 	rnd_detach_source(&sc->rnd_source);
    958 #endif
    959 	callout_destroy(&sc->sc_diag_callout);
    960 
    961 	/* Destroy the lock. */
    962 	mutex_destroy(&sc->sc_lock);
    963 
    964 	return (0);
    965 }
    966 
    967 void
    968 com_shutdown(struct com_softc *sc)
    969 {
    970 	struct tty *tp = sc->sc_tty;
    971 
    972 	mutex_spin_enter(&sc->sc_lock);
    973 
    974 	/* If we were asserting flow control, then deassert it. */
    975 	SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
    976 	com_hwiflow(sc);
    977 
    978 	/* Clear any break condition set with TIOCSBRK. */
    979 	com_break(sc, 0);
    980 
    981 	/*
    982 	 * Hang up if necessary.  Record when we hung up, so if we
    983 	 * immediately open the port again, we will wait a bit until
    984 	 * the other side has had time to notice that we hung up.
    985 	 */
    986 	if (ISSET(tp->t_cflag, HUPCL)) {
    987 		com_modem(sc, 0);
    988 		microuptime(&sc->sc_hup_pending);
    989 		sc->sc_hup_pending.tv_sec++;
    990 	}
    991 
    992 	/* Turn off interrupts. */
    993 	if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
    994 		sc->sc_ier = IER_ERLS; /* interrupt on line break */
    995 		if ((sc->sc_type == COM_TYPE_PXA2x0) ||
    996 		    (sc->sc_type == COM_TYPE_INGENIC) ||
    997 		    (sc->sc_type == COM_TYPE_TEGRA))
    998 			sc->sc_ier |= IER_ERXTOUT;
    999 	} else
   1000 		sc->sc_ier = 0;
   1001 
   1002 	if (sc->sc_type == COM_TYPE_PXA2x0)
   1003 		sc->sc_ier |= IER_EUART;
   1004 
   1005 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
   1006 
   1007 	mutex_spin_exit(&sc->sc_lock);
   1008 
   1009 	if (sc->disable) {
   1010 #ifdef DIAGNOSTIC
   1011 		if (!sc->enabled)
   1012 			panic("com_shutdown: not enabled?");
   1013 #endif
   1014 		(*sc->disable)(sc);
   1015 		sc->enabled = 0;
   1016 	}
   1017 }
   1018 
   1019 int
   1020 comopen(dev_t dev, int flag, int mode, struct lwp *l)
   1021 {
   1022 	struct com_softc *sc;
   1023 	struct tty *tp;
   1024 	int s;
   1025 	int error;
   1026 
   1027 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
   1028 	if (sc == NULL || !ISSET(sc->sc_hwflags, COM_HW_DEV_OK) ||
   1029 		sc->sc_rbuf == NULL)
   1030 		return (ENXIO);
   1031 
   1032 	if (!device_is_active(sc->sc_dev))
   1033 		return (ENXIO);
   1034 
   1035 #ifdef KGDB
   1036 	/*
   1037 	 * If this is the kgdb port, no other use is permitted.
   1038 	 */
   1039 	if (ISSET(sc->sc_hwflags, COM_HW_KGDB))
   1040 		return (EBUSY);
   1041 #endif
   1042 
   1043 	tp = sc->sc_tty;
   1044 
   1045 	/*
   1046 	 * If the device is exclusively for kernel use, deny userland
   1047 	 * open.
   1048 	 */
   1049 	if (ISSET(tp->t_state, TS_KERN_ONLY))
   1050 		return (EBUSY);
   1051 
   1052 	if (kauth_authorize_device_tty(l->l_cred, KAUTH_DEVICE_TTY_OPEN, tp))
   1053 		return (EBUSY);
   1054 
   1055 	s = spltty();
   1056 
   1057 	/*
   1058 	 * Do the following iff this is a first open.
   1059 	 */
   1060 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
   1061 		struct termios t;
   1062 		struct timeval now, diff;
   1063 
   1064 		tp->t_dev = dev;
   1065 
   1066 		if (sc->enable) {
   1067 			if ((*sc->enable)(sc)) {
   1068 				splx(s);
   1069 				aprint_error_dev(sc->sc_dev,
   1070 				    "device enable failed\n");
   1071 				return (EIO);
   1072 			}
   1073 			mutex_spin_enter(&sc->sc_lock);
   1074 			sc->enabled = 1;
   1075 			com_config(sc);
   1076 		} else {
   1077 			mutex_spin_enter(&sc->sc_lock);
   1078 		}
   1079 
   1080 		if (timerisset(&sc->sc_hup_pending)) {
   1081 			microuptime(&now);
   1082 			while (timercmp(&now, &sc->sc_hup_pending, <)) {
   1083 				timersub(&sc->sc_hup_pending, &now, &diff);
   1084 				const int ms = diff.tv_sec * 1000 +
   1085 				    diff.tv_usec / 1000;
   1086 				kpause(ttclos, false, uimax(mstohz(ms), 1),
   1087 				    &sc->sc_lock);
   1088 				microuptime(&now);
   1089 			}
   1090 			timerclear(&sc->sc_hup_pending);
   1091 		}
   1092 
   1093 		/* Turn on interrupts. */
   1094 		sc->sc_ier = IER_ERXRDY | IER_ERLS;
   1095 		if (!ISSET(tp->t_cflag, CLOCAL))
   1096 			sc->sc_ier |= IER_EMSC;
   1097 
   1098 		if (sc->sc_type == COM_TYPE_PXA2x0)
   1099 			sc->sc_ier |= IER_EUART | IER_ERXTOUT;
   1100 		else if (sc->sc_type == COM_TYPE_INGENIC ||
   1101 			 sc->sc_type == COM_TYPE_TEGRA)
   1102 			sc->sc_ier |= IER_ERXTOUT;
   1103 		CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, sc->sc_ier);
   1104 
   1105 		/* Fetch the current modem control status, needed later. */
   1106 		sc->sc_msr = CSR_READ_1(&sc->sc_regs, COM_REG_MSR);
   1107 
   1108 		/* Clear PPS capture state on first open. */
   1109 		mutex_spin_enter(&timecounter_lock);
   1110 		memset(&sc->sc_pps_state, 0, sizeof(sc->sc_pps_state));
   1111 		sc->sc_pps_state.ppscap = PPS_CAPTUREASSERT | PPS_CAPTURECLEAR;
   1112 		pps_init(&sc->sc_pps_state);
   1113 		mutex_spin_exit(&timecounter_lock);
   1114 
   1115 		mutex_spin_exit(&sc->sc_lock);
   1116 
   1117 		/*
   1118 		 * Initialize the termios status to the defaults.  Add in the
   1119 		 * sticky bits from TIOCSFLAGS.
   1120 		 */
   1121 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
   1122 			t.c_ospeed = comcons_info.rate;
   1123 			t.c_cflag = comcons_info.cflag;
   1124 		} else {
   1125 			t.c_ospeed = TTYDEF_SPEED;
   1126 			t.c_cflag = TTYDEF_CFLAG;
   1127 		}
   1128 		t.c_ispeed = t.c_ospeed;
   1129 		if (ISSET(sc->sc_swflags, TIOCFLAG_CLOCAL))
   1130 			SET(t.c_cflag, CLOCAL);
   1131 		if (ISSET(sc->sc_swflags, TIOCFLAG_CRTSCTS))
   1132 			SET(t.c_cflag, CRTSCTS);
   1133 		if (ISSET(sc->sc_swflags, TIOCFLAG_MDMBUF))
   1134 			SET(t.c_cflag, MDMBUF);
   1135 		/* Make sure comparam() will do something. */
   1136 		tp->t_ospeed = 0;
   1137 		(void) comparam(tp, &t);
   1138 		tp->t_iflag = TTYDEF_IFLAG;
   1139 		tp->t_oflag = TTYDEF_OFLAG;
   1140 		tp->t_lflag = TTYDEF_LFLAG;
   1141 		ttychars(tp);
   1142 		ttsetwater(tp);
   1143 
   1144 		mutex_spin_enter(&sc->sc_lock);
   1145 
   1146 		/*
   1147 		 * Turn on DTR.  We must always do this, even if carrier is not
   1148 		 * present, because otherwise we'd have to use TIOCSDTR
   1149 		 * immediately after setting CLOCAL, which applications do not
   1150 		 * expect.  We always assert DTR while the device is open
   1151 		 * unless explicitly requested to deassert it.
   1152 		 */
   1153 		com_modem(sc, 1);
   1154 
   1155 		/* Clear the input ring, and unblock. */
   1156 		sc->sc_rbput = sc->sc_rbget = sc->sc_rbuf;
   1157 		sc->sc_rbavail = com_rbuf_size;
   1158 		com_iflush(sc);
   1159 		CLR(sc->sc_rx_flags, RX_ANY_BLOCK);
   1160 		com_hwiflow(sc);
   1161 
   1162 #ifdef COM_DEBUG
   1163 		if (com_debug)
   1164 			comstatus(sc, "comopen  ");
   1165 #endif
   1166 
   1167 		mutex_spin_exit(&sc->sc_lock);
   1168 	}
   1169 
   1170 	splx(s);
   1171 
   1172 	error = ttyopen(tp, COMDIALOUT(dev), ISSET(flag, O_NONBLOCK));
   1173 	if (error)
   1174 		goto bad;
   1175 
   1176 	error = (*tp->t_linesw->l_open)(dev, tp);
   1177 	if (error)
   1178 		goto bad;
   1179 
   1180 	return (0);
   1181 
   1182 bad:
   1183 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
   1184 		/*
   1185 		 * We failed to open the device, and nobody else had it opened.
   1186 		 * Clean up the state as appropriate.
   1187 		 */
   1188 		com_shutdown(sc);
   1189 	}
   1190 
   1191 	return (error);
   1192 }
   1193 
   1194 int
   1195 comclose(dev_t dev, int flag, int mode, struct lwp *l)
   1196 {
   1197 	struct com_softc *sc =
   1198 	    device_lookup_private(&com_cd, COMUNIT(dev));
   1199 	struct tty *tp = sc->sc_tty;
   1200 
   1201 	/* XXX This is for cons.c. */
   1202 	if (!ISSET(tp->t_state, TS_ISOPEN))
   1203 		return (0);
   1204 	/*
   1205 	 * If the device is exclusively for kernel use, deny userland
   1206 	 * close.
   1207 	 */
   1208 	if (ISSET(tp->t_state, TS_KERN_ONLY))
   1209 		return (0);
   1210 
   1211 	(*tp->t_linesw->l_close)(tp, flag);
   1212 	ttyclose(tp);
   1213 
   1214 	if (COM_ISALIVE(sc) == 0)
   1215 		return (0);
   1216 
   1217 	if (!ISSET(tp->t_state, TS_ISOPEN) && tp->t_wopen == 0) {
   1218 		/*
   1219 		 * Although we got a last close, the device may still be in
   1220 		 * use; e.g. if this was the dialout node, and there are still
   1221 		 * processes waiting for carrier on the non-dialout node.
   1222 		 */
   1223 		com_shutdown(sc);
   1224 	}
   1225 
   1226 	return (0);
   1227 }
   1228 
   1229 int
   1230 comread(dev_t dev, struct uio *uio, int flag)
   1231 {
   1232 	struct com_softc *sc =
   1233 	    device_lookup_private(&com_cd, COMUNIT(dev));
   1234 	struct tty *tp = sc->sc_tty;
   1235 
   1236 	if (COM_ISALIVE(sc) == 0)
   1237 		return (EIO);
   1238 
   1239 	return ((*tp->t_linesw->l_read)(tp, uio, flag));
   1240 }
   1241 
   1242 int
   1243 comwrite(dev_t dev, struct uio *uio, int flag)
   1244 {
   1245 	struct com_softc *sc =
   1246 	    device_lookup_private(&com_cd, COMUNIT(dev));
   1247 	struct tty *tp = sc->sc_tty;
   1248 
   1249 	if (COM_ISALIVE(sc) == 0)
   1250 		return (EIO);
   1251 
   1252 	return ((*tp->t_linesw->l_write)(tp, uio, flag));
   1253 }
   1254 
   1255 int
   1256 compoll(dev_t dev, int events, struct lwp *l)
   1257 {
   1258 	struct com_softc *sc =
   1259 	    device_lookup_private(&com_cd, COMUNIT(dev));
   1260 	struct tty *tp = sc->sc_tty;
   1261 
   1262 	if (COM_ISALIVE(sc) == 0)
   1263 		return (POLLHUP);
   1264 
   1265 	return ((*tp->t_linesw->l_poll)(tp, events, l));
   1266 }
   1267 
   1268 struct tty *
   1269 comtty(dev_t dev)
   1270 {
   1271 	struct com_softc *sc =
   1272 	    device_lookup_private(&com_cd, COMUNIT(dev));
   1273 	struct tty *tp = sc->sc_tty;
   1274 
   1275 	return (tp);
   1276 }
   1277 
   1278 int
   1279 comioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
   1280 {
   1281 	struct com_softc *sc;
   1282 	struct tty *tp;
   1283 	int error;
   1284 
   1285 	sc = device_lookup_private(&com_cd, COMUNIT(dev));
   1286 	if (sc == NULL)
   1287 		return ENXIO;
   1288 	if (COM_ISALIVE(sc) == 0)
   1289 		return (EIO);
   1290 
   1291 	tp = sc->sc_tty;
   1292 
   1293 	error = (*tp->t_linesw->l_ioctl)(tp, cmd, data, flag, l);
   1294 	if (error != EPASSTHROUGH)
   1295 		return (error);
   1296 
   1297 	error = ttioctl(tp, cmd, data, flag, l);
   1298 	if (error != EPASSTHROUGH)
   1299 		return (error);
   1300 
   1301 	error = 0;
   1302 	switch (cmd) {
   1303 	case TIOCSFLAGS:
   1304 		error = kauth_authorize_device_tty(l->l_cred,
   1305 		    KAUTH_DEVICE_TTY_PRIVSET, tp);
   1306 		break;
   1307 	default:
   1308 		/* nothing */
   1309 		break;
   1310 	}
   1311 	if (error) {
   1312 		return error;
   1313 	}
   1314 
   1315 	mutex_spin_enter(&sc->sc_lock);
   1316 
   1317 	switch (cmd) {
   1318 	case TIOCSBRK:
   1319 		com_break(sc, 1);
   1320 		break;
   1321 
   1322 	case TIOCCBRK:
   1323 		com_break(sc, 0);
   1324 		break;
   1325 
   1326 	case TIOCSDTR:
   1327 		com_modem(sc, 1);
   1328 		break;
   1329 
   1330 	case TIOCCDTR:
   1331 		com_modem(sc, 0);
   1332 		break;
   1333 
   1334 	case TIOCGFLAGS:
   1335 		*(int *)data = sc->sc_swflags;
   1336 		break;
   1337 
   1338 	case TIOCSFLAGS:
   1339 		sc->sc_swflags = *(int *)data;
   1340 		break;
   1341 
   1342 	case TIOCMSET:
   1343 	case TIOCMBIS:
   1344 	case TIOCMBIC:
   1345 		tiocm_to_com(sc, cmd, *(int *)data);
   1346 		break;
   1347 
   1348 	case TIOCMGET:
   1349 		*(int *)data = com_to_tiocm(sc);
   1350 		break;
   1351 
   1352 	case PPS_IOC_CREATE:
   1353 	case PPS_IOC_DESTROY:
   1354 	case PPS_IOC_GETPARAMS:
   1355 	case PPS_IOC_SETPARAMS:
   1356 	case PPS_IOC_GETCAP:
   1357 	case PPS_IOC_FETCH:
   1358 #ifdef PPS_SYNC
   1359 	case PPS_IOC_KCBIND:
   1360 #endif
   1361 		mutex_spin_enter(&timecounter_lock);
   1362 		error = pps_ioctl(cmd, data, &sc->sc_pps_state);
   1363 		mutex_spin_exit(&timecounter_lock);
   1364 		break;
   1365 
   1366 	case TIOCDCDTIMESTAMP:	/* XXX old, overloaded  API used by xntpd v3 */
   1367 		mutex_spin_enter(&timecounter_lock);
   1368 #ifndef PPS_TRAILING_EDGE
   1369 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
   1370 		    &sc->sc_pps_state.ppsinfo.assert_timestamp);
   1371 #else
   1372 		TIMESPEC_TO_TIMEVAL((struct timeval *)data,
   1373 		    &sc->sc_pps_state.ppsinfo.clear_timestamp);
   1374 #endif
   1375 		mutex_spin_exit(&timecounter_lock);
   1376 		break;
   1377 
   1378 	default:
   1379 		error = EPASSTHROUGH;
   1380 		break;
   1381 	}
   1382 
   1383 	mutex_spin_exit(&sc->sc_lock);
   1384 
   1385 #ifdef COM_DEBUG
   1386 	if (com_debug)
   1387 		comstatus(sc, "comioctl ");
   1388 #endif
   1389 
   1390 	return (error);
   1391 }
   1392 
   1393 static inline void
   1394 com_schedrx(struct com_softc *sc)
   1395 {
   1396 
   1397 	sc->sc_rx_ready = 1;
   1398 
   1399 	/* Wake up the poller. */
   1400 	softint_schedule(sc->sc_si);
   1401 }
   1402 
   1403 void
   1404 com_break(struct com_softc *sc, int onoff)
   1405 {
   1406 
   1407 	if (onoff)
   1408 		SET(sc->sc_lcr, LCR_SBREAK);
   1409 	else
   1410 		CLR(sc->sc_lcr, LCR_SBREAK);
   1411 
   1412 	if (!sc->sc_heldchange) {
   1413 		if (sc->sc_tx_busy) {
   1414 			sc->sc_heldtbc = sc->sc_tbc;
   1415 			sc->sc_tbc = 0;
   1416 			sc->sc_heldchange = 1;
   1417 		} else
   1418 			com_loadchannelregs(sc);
   1419 	}
   1420 }
   1421 
   1422 void
   1423 com_modem(struct com_softc *sc, int onoff)
   1424 {
   1425 
   1426 	if (sc->sc_mcr_dtr == 0)
   1427 		return;
   1428 
   1429 	if (onoff)
   1430 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
   1431 	else
   1432 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
   1433 
   1434 	if (!sc->sc_heldchange) {
   1435 		if (sc->sc_tx_busy) {
   1436 			sc->sc_heldtbc = sc->sc_tbc;
   1437 			sc->sc_tbc = 0;
   1438 			sc->sc_heldchange = 1;
   1439 		} else
   1440 			com_loadchannelregs(sc);
   1441 	}
   1442 }
   1443 
   1444 void
   1445 tiocm_to_com(struct com_softc *sc, u_long how, int ttybits)
   1446 {
   1447 	u_char combits;
   1448 
   1449 	combits = 0;
   1450 	if (ISSET(ttybits, TIOCM_DTR))
   1451 		SET(combits, MCR_DTR);
   1452 	if (ISSET(ttybits, TIOCM_RTS))
   1453 		SET(combits, MCR_RTS);
   1454 
   1455 	switch (how) {
   1456 	case TIOCMBIC:
   1457 		CLR(sc->sc_mcr, combits);
   1458 		break;
   1459 
   1460 	case TIOCMBIS:
   1461 		SET(sc->sc_mcr, combits);
   1462 		break;
   1463 
   1464 	case TIOCMSET:
   1465 		CLR(sc->sc_mcr, MCR_DTR | MCR_RTS);
   1466 		SET(sc->sc_mcr, combits);
   1467 		break;
   1468 	}
   1469 
   1470 	if (!sc->sc_heldchange) {
   1471 		if (sc->sc_tx_busy) {
   1472 			sc->sc_heldtbc = sc->sc_tbc;
   1473 			sc->sc_tbc = 0;
   1474 			sc->sc_heldchange = 1;
   1475 		} else
   1476 			com_loadchannelregs(sc);
   1477 	}
   1478 }
   1479 
   1480 int
   1481 com_to_tiocm(struct com_softc *sc)
   1482 {
   1483 	u_char combits;
   1484 	int ttybits = 0;
   1485 
   1486 	combits = sc->sc_mcr;
   1487 	if (ISSET(combits, MCR_DTR))
   1488 		SET(ttybits, TIOCM_DTR);
   1489 	if (ISSET(combits, MCR_RTS))
   1490 		SET(ttybits, TIOCM_RTS);
   1491 
   1492 	combits = sc->sc_msr;
   1493 	if (sc->sc_type == COM_TYPE_INGENIC) {
   1494 		SET(ttybits, TIOCM_CD);
   1495 	} else {
   1496 		if (ISSET(combits, MSR_DCD))
   1497 			SET(ttybits, TIOCM_CD);
   1498 	}
   1499 	if (ISSET(combits, MSR_CTS))
   1500 		SET(ttybits, TIOCM_CTS);
   1501 	if (ISSET(combits, MSR_DSR))
   1502 		SET(ttybits, TIOCM_DSR);
   1503 	if (ISSET(combits, MSR_RI | MSR_TERI))
   1504 		SET(ttybits, TIOCM_RI);
   1505 
   1506 	if (ISSET(sc->sc_ier, IER_ERXRDY | IER_ETXRDY | IER_ERLS | IER_EMSC))
   1507 		SET(ttybits, TIOCM_LE);
   1508 
   1509 	return (ttybits);
   1510 }
   1511 
   1512 static u_char
   1513 cflag2lcr(tcflag_t cflag)
   1514 {
   1515 	u_char lcr = 0;
   1516 
   1517 	switch (ISSET(cflag, CSIZE)) {
   1518 	case CS5:
   1519 		SET(lcr, LCR_5BITS);
   1520 		break;
   1521 	case CS6:
   1522 		SET(lcr, LCR_6BITS);
   1523 		break;
   1524 	case CS7:
   1525 		SET(lcr, LCR_7BITS);
   1526 		break;
   1527 	case CS8:
   1528 		SET(lcr, LCR_8BITS);
   1529 		break;
   1530 	}
   1531 	if (ISSET(cflag, PARENB)) {
   1532 		SET(lcr, LCR_PENAB);
   1533 		if (!ISSET(cflag, PARODD))
   1534 			SET(lcr, LCR_PEVEN);
   1535 	}
   1536 	if (ISSET(cflag, CSTOPB))
   1537 		SET(lcr, LCR_STOPB);
   1538 
   1539 	return (lcr);
   1540 }
   1541 
   1542 int
   1543 comparam(struct tty *tp, struct termios *t)
   1544 {
   1545 	struct com_softc *sc =
   1546 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
   1547 	int ospeed;
   1548 	u_char lcr;
   1549 
   1550 	if (COM_ISALIVE(sc) == 0)
   1551 		return (EIO);
   1552 
   1553 	if (sc->sc_type == COM_TYPE_HAYESP) {
   1554 		int prescaler, speed;
   1555 
   1556 		/*
   1557 		 * Calculate UART clock prescaler.  It should be in
   1558 		 * range of 0 .. 3.
   1559 		 */
   1560 		for (prescaler = 0, speed = t->c_ospeed; prescaler < 4;
   1561 		    prescaler++, speed /= 2)
   1562 			if ((ospeed = comspeed(speed, sc->sc_frequency,
   1563 					       sc->sc_type)) > 0)
   1564 				break;
   1565 
   1566 		if (prescaler == 4)
   1567 			return (EINVAL);
   1568 		sc->sc_prescaler = prescaler;
   1569 	} else
   1570 		ospeed = comspeed(t->c_ospeed, sc->sc_frequency, sc->sc_type);
   1571 
   1572 	/* Check requested parameters. */
   1573 	if (ospeed < 0)
   1574 		return (EINVAL);
   1575 	if (t->c_ispeed && t->c_ispeed != t->c_ospeed)
   1576 		return (EINVAL);
   1577 
   1578 	/*
   1579 	 * For the console, always force CLOCAL and !HUPCL, so that the port
   1580 	 * is always active.
   1581 	 */
   1582 	if (ISSET(sc->sc_swflags, TIOCFLAG_SOFTCAR) ||
   1583 	    ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
   1584 		SET(t->c_cflag, CLOCAL);
   1585 		CLR(t->c_cflag, HUPCL);
   1586 	}
   1587 
   1588 	/*
   1589 	 * If there were no changes, don't do anything.  This avoids dropping
   1590 	 * input and improves performance when all we did was frob things like
   1591 	 * VMIN and VTIME.
   1592 	 */
   1593 	if (tp->t_ospeed == t->c_ospeed &&
   1594 	    tp->t_cflag == t->c_cflag)
   1595 		return (0);
   1596 
   1597 	lcr = ISSET(sc->sc_lcr, LCR_SBREAK) | cflag2lcr(t->c_cflag);
   1598 
   1599 	mutex_spin_enter(&sc->sc_lock);
   1600 
   1601 	sc->sc_lcr = lcr;
   1602 
   1603 	/*
   1604 	 * If we're not in a mode that assumes a connection is present, then
   1605 	 * ignore carrier changes.
   1606 	 */
   1607 	if (ISSET(t->c_cflag, CLOCAL | MDMBUF))
   1608 		sc->sc_msr_dcd = 0;
   1609 	else
   1610 		sc->sc_msr_dcd = MSR_DCD;
   1611 	/*
   1612 	 * Set the flow control pins depending on the current flow control
   1613 	 * mode.
   1614 	 */
   1615 	if (ISSET(t->c_cflag, CRTSCTS)) {
   1616 		sc->sc_mcr_dtr = MCR_DTR;
   1617 		sc->sc_mcr_rts = MCR_RTS;
   1618 		sc->sc_msr_cts = MSR_CTS;
   1619 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
   1620 			SET(sc->sc_mcr, MCR_AFE);
   1621 		} else {
   1622 			sc->sc_efr = EFR_AUTORTS | EFR_AUTOCTS;
   1623 		}
   1624 	} else if (ISSET(t->c_cflag, MDMBUF)) {
   1625 		/*
   1626 		 * For DTR/DCD flow control, make sure we don't toggle DTR for
   1627 		 * carrier detection.
   1628 		 */
   1629 		sc->sc_mcr_dtr = 0;
   1630 		sc->sc_mcr_rts = MCR_DTR;
   1631 		sc->sc_msr_cts = MSR_DCD;
   1632 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
   1633 			CLR(sc->sc_mcr, MCR_AFE);
   1634 		} else {
   1635 			sc->sc_efr = 0;
   1636 		}
   1637 	} else {
   1638 		/*
   1639 		 * If no flow control, then always set RTS.  This will make
   1640 		 * the other side happy if it mistakenly thinks we're doing
   1641 		 * RTS/CTS flow control.
   1642 		 */
   1643 		sc->sc_mcr_dtr = MCR_DTR | MCR_RTS;
   1644 		sc->sc_mcr_rts = 0;
   1645 		sc->sc_msr_cts = 0;
   1646 		if (ISSET(sc->sc_hwflags, COM_HW_AFE)) {
   1647 			CLR(sc->sc_mcr, MCR_AFE);
   1648 		} else {
   1649 			sc->sc_efr = 0;
   1650 		}
   1651 		if (ISSET(sc->sc_mcr, MCR_DTR))
   1652 			SET(sc->sc_mcr, MCR_RTS);
   1653 		else
   1654 			CLR(sc->sc_mcr, MCR_RTS);
   1655 	}
   1656 	sc->sc_msr_mask = sc->sc_msr_cts | sc->sc_msr_dcd;
   1657 
   1658 	if (t->c_ospeed == 0 && tp->t_ospeed != 0)
   1659 		CLR(sc->sc_mcr, sc->sc_mcr_dtr);
   1660 	else if (t->c_ospeed != 0 && tp->t_ospeed == 0)
   1661 		SET(sc->sc_mcr, sc->sc_mcr_dtr);
   1662 
   1663 	sc->sc_dlbl = ospeed;
   1664 	sc->sc_dlbh = ospeed >> 8;
   1665 
   1666 	/*
   1667 	 * Set the FIFO threshold based on the receive speed.
   1668 	 *
   1669 	 *  * If it's a low speed, it's probably a mouse or some other
   1670 	 *    interactive device, so set the threshold low.
   1671 	 *  * If it's a high speed, trim the trigger level down to prevent
   1672 	 *    overflows.
   1673 	 *  * Otherwise set it a bit higher.
   1674 	 */
   1675 	if (sc->sc_type == COM_TYPE_HAYESP) {
   1676 		sc->sc_fifo = FIFO_DMA_MODE | FIFO_ENABLE | FIFO_TRIGGER_8;
   1677 	} else if (sc->sc_type == COM_TYPE_TEGRA) {
   1678 		sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
   1679 	} else if (ISSET(sc->sc_hwflags, COM_HW_FIFO)) {
   1680 		if (t->c_ospeed <= 1200)
   1681 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_1;
   1682 		else if (t->c_ospeed <= 38400)
   1683 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_8;
   1684 		else
   1685 			sc->sc_fifo = FIFO_ENABLE | FIFO_TRIGGER_4;
   1686 	} else {
   1687 		sc->sc_fifo = 0;
   1688 	}
   1689 
   1690 	if (sc->sc_type == COM_TYPE_INGENIC)
   1691 		sc->sc_fifo |= FIFO_UART_ON;
   1692 
   1693 	/* And copy to tty. */
   1694 	tp->t_ispeed = t->c_ospeed;
   1695 	tp->t_ospeed = t->c_ospeed;
   1696 	tp->t_cflag = t->c_cflag;
   1697 
   1698 	if (!sc->sc_heldchange) {
   1699 		if (sc->sc_tx_busy) {
   1700 			sc->sc_heldtbc = sc->sc_tbc;
   1701 			sc->sc_tbc = 0;
   1702 			sc->sc_heldchange = 1;
   1703 		} else
   1704 			com_loadchannelregs(sc);
   1705 	}
   1706 
   1707 	if (!ISSET(t->c_cflag, CHWFLOW)) {
   1708 		/* Disable the high water mark. */
   1709 		sc->sc_r_hiwat = 0;
   1710 		sc->sc_r_lowat = 0;
   1711 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
   1712 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
   1713 			com_schedrx(sc);
   1714 		}
   1715 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED)) {
   1716 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED|RX_IBUF_BLOCKED);
   1717 			com_hwiflow(sc);
   1718 		}
   1719 	} else {
   1720 		sc->sc_r_hiwat = com_rbuf_hiwat;
   1721 		sc->sc_r_lowat = com_rbuf_lowat;
   1722 	}
   1723 
   1724 	mutex_spin_exit(&sc->sc_lock);
   1725 
   1726 	/*
   1727 	 * Update the tty layer's idea of the carrier bit, in case we changed
   1728 	 * CLOCAL or MDMBUF.  We don't hang up here; we only do that by
   1729 	 * explicit request.
   1730 	 */
   1731 	if (sc->sc_type == COM_TYPE_INGENIC) {
   1732 		/* no DCD here */
   1733 		(void) (*tp->t_linesw->l_modem)(tp, 1);
   1734 	} else
   1735 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(sc->sc_msr, MSR_DCD));
   1736 
   1737 #ifdef COM_DEBUG
   1738 	if (com_debug)
   1739 		comstatus(sc, "comparam ");
   1740 #endif
   1741 
   1742 	if (!ISSET(t->c_cflag, CHWFLOW)) {
   1743 		if (sc->sc_tx_stopped) {
   1744 			sc->sc_tx_stopped = 0;
   1745 			comstart(tp);
   1746 		}
   1747 	}
   1748 
   1749 	return (0);
   1750 }
   1751 
   1752 void
   1753 com_iflush(struct com_softc *sc)
   1754 {
   1755 	struct com_regs	*regsp = &sc->sc_regs;
   1756 	uint8_t fifo;
   1757 #ifdef DIAGNOSTIC
   1758 	int reg;
   1759 #endif
   1760 	int timo;
   1761 
   1762 #ifdef DIAGNOSTIC
   1763 	reg = 0xffff;
   1764 #endif
   1765 	timo = 50000;
   1766 	/* flush any pending I/O */
   1767 	while (ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)
   1768 	    && --timo)
   1769 #ifdef DIAGNOSTIC
   1770 		reg =
   1771 #else
   1772 		    (void)
   1773 #endif
   1774 		    CSR_READ_1(regsp, COM_REG_RXDATA);
   1775 #ifdef DIAGNOSTIC
   1776 	if (!timo)
   1777 		aprint_error_dev(sc->sc_dev, "com_iflush timeout %02x\n", reg);
   1778 #endif
   1779 
   1780 	switch (sc->sc_type) {
   1781 	case COM_TYPE_16750:
   1782 	case COM_TYPE_DW_APB:
   1783 		/*
   1784 		 * Reset all Rx/Tx FIFO, preserve current FIFO length.
   1785 		 * This should prevent triggering busy interrupt while
   1786 		 * manipulating divisors.
   1787 		 */
   1788 		fifo = CSR_READ_1(regsp, COM_REG_FIFO) & (FIFO_TRIGGER_1 |
   1789 		    FIFO_TRIGGER_4 | FIFO_TRIGGER_8 | FIFO_TRIGGER_14);
   1790 		CSR_WRITE_1(regsp, COM_REG_FIFO,
   1791 		    fifo | FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST);
   1792 		delay(100);
   1793 		break;
   1794 	}
   1795 }
   1796 
   1797 void
   1798 com_loadchannelregs(struct com_softc *sc)
   1799 {
   1800 	struct com_regs *regsp = &sc->sc_regs;
   1801 
   1802 	/* XXXXX necessary? */
   1803 	com_iflush(sc);
   1804 
   1805 	if (sc->sc_type == COM_TYPE_PXA2x0)
   1806 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
   1807 	else
   1808 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
   1809 
   1810 	if (sc->sc_type == COM_TYPE_OMAP) {
   1811 		/* disable before changing settings */
   1812 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
   1813 	}
   1814 
   1815 	if (ISSET(sc->sc_hwflags, COM_HW_FLOW)) {
   1816 		KASSERT(sc->sc_type != COM_TYPE_AU1x00);
   1817 		KASSERT(sc->sc_type != COM_TYPE_16550_NOERS);
   1818 		/* no EFR on alchemy */
   1819 		CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
   1820 		CSR_WRITE_1(regsp, COM_REG_EFR, sc->sc_efr);
   1821 	}
   1822 	if (sc->sc_type == COM_TYPE_AU1x00) {
   1823 		/* alchemy has single separate 16-bit clock divisor register */
   1824 		CSR_WRITE_2(regsp, COM_REG_DLBL, sc->sc_dlbl +
   1825 		    (sc->sc_dlbh << 8));
   1826 	} else {
   1827 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
   1828 		CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
   1829 		CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
   1830 	}
   1831 	CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
   1832 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active = sc->sc_mcr);
   1833 	CSR_WRITE_1(regsp, COM_REG_FIFO, sc->sc_fifo);
   1834 	if (sc->sc_type == COM_TYPE_HAYESP) {
   1835 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD1,
   1836 		    HAYESP_SETPRESCALER);
   1837 		bus_space_write_1(regsp->cr_iot, sc->sc_hayespioh, HAYESP_CMD2,
   1838 		    sc->sc_prescaler);
   1839 	}
   1840 	if (sc->sc_type == COM_TYPE_OMAP) {
   1841 		/* setup the fifos.  the FCR value is not used as long
   1842 		   as SCR[6] and SCR[7] are 0, which they are at reset
   1843 		   and we never touch the SCR register */
   1844 		uint8_t rx_fifo_trig = 40;
   1845 		uint8_t tx_fifo_trig = 60;
   1846 		uint8_t rx_start = 8;
   1847 		uint8_t rx_halt = 60;
   1848 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
   1849 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
   1850 
   1851 		/* enable access to TCR & TLR */
   1852 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr | MCR_TCR_TLR);
   1853 
   1854 		/* write tcr and tlr values */
   1855 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
   1856 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
   1857 
   1858 		/* disable access to TCR & TLR */
   1859 		CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr);
   1860 
   1861 		/* enable again, but mode is based on speed */
   1862 		if (sc->sc_tty->t_termios.c_ospeed > 230400) {
   1863 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
   1864 		} else {
   1865 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
   1866 		}
   1867 	}
   1868 
   1869 	CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
   1870 }
   1871 
   1872 int
   1873 comhwiflow(struct tty *tp, int block)
   1874 {
   1875 	struct com_softc *sc =
   1876 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
   1877 
   1878 	if (COM_ISALIVE(sc) == 0)
   1879 		return (0);
   1880 
   1881 	if (sc->sc_mcr_rts == 0)
   1882 		return (0);
   1883 
   1884 	mutex_spin_enter(&sc->sc_lock);
   1885 
   1886 	if (block) {
   1887 		if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
   1888 			SET(sc->sc_rx_flags, RX_TTY_BLOCKED);
   1889 			com_hwiflow(sc);
   1890 		}
   1891 	} else {
   1892 		if (ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED)) {
   1893 			CLR(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
   1894 			com_schedrx(sc);
   1895 		}
   1896 		if (ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
   1897 			CLR(sc->sc_rx_flags, RX_TTY_BLOCKED);
   1898 			com_hwiflow(sc);
   1899 		}
   1900 	}
   1901 
   1902 	mutex_spin_exit(&sc->sc_lock);
   1903 	return (1);
   1904 }
   1905 
   1906 /*
   1907  * (un)block input via hw flowcontrol
   1908  */
   1909 void
   1910 com_hwiflow(struct com_softc *sc)
   1911 {
   1912 	struct com_regs *regsp= &sc->sc_regs;
   1913 
   1914 	if (sc->sc_mcr_rts == 0)
   1915 		return;
   1916 
   1917 	if (ISSET(sc->sc_rx_flags, RX_ANY_BLOCK)) {
   1918 		CLR(sc->sc_mcr, sc->sc_mcr_rts);
   1919 		CLR(sc->sc_mcr_active, sc->sc_mcr_rts);
   1920 	} else {
   1921 		SET(sc->sc_mcr, sc->sc_mcr_rts);
   1922 		SET(sc->sc_mcr_active, sc->sc_mcr_rts);
   1923 	}
   1924 	CSR_WRITE_1(regsp, COM_REG_MCR, sc->sc_mcr_active);
   1925 }
   1926 
   1927 
   1928 void
   1929 comstart(struct tty *tp)
   1930 {
   1931 	struct com_softc *sc =
   1932 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
   1933 	struct com_regs *regsp = &sc->sc_regs;
   1934 
   1935 	if (COM_ISALIVE(sc) == 0)
   1936 		return;
   1937 
   1938 	if (ISSET(tp->t_state, TS_BUSY | TS_TIMEOUT | TS_TTSTOP))
   1939 		return;
   1940 	if (sc->sc_tx_stopped)
   1941 		return;
   1942 	if (!ttypull(tp))
   1943 		return;
   1944 
   1945 	/* Grab the first contiguous region of buffer space. */
   1946 	{
   1947 		u_char *tba;
   1948 		int tbc;
   1949 
   1950 		tba = tp->t_outq.c_cf;
   1951 		tbc = ndqb(&tp->t_outq, 0);
   1952 
   1953 		mutex_spin_enter(&sc->sc_lock);
   1954 
   1955 		sc->sc_tba = tba;
   1956 		sc->sc_tbc = tbc;
   1957 	}
   1958 
   1959 	SET(tp->t_state, TS_BUSY);
   1960 	sc->sc_tx_busy = 1;
   1961 
   1962 	/* Enable transmit completion interrupts if necessary. */
   1963 	if (!ISSET(sc->sc_ier, IER_ETXRDY)) {
   1964 		SET(sc->sc_ier, IER_ETXRDY);
   1965 		CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
   1966 	}
   1967 
   1968 	/* Output the first chunk of the contiguous buffer. */
   1969 	if (!ISSET(sc->sc_hwflags, COM_HW_NO_TXPRELOAD)) {
   1970 		u_int n;
   1971 
   1972 		n = sc->sc_tbc;
   1973 		if (n > sc->sc_fifolen)
   1974 			n = sc->sc_fifolen;
   1975 		CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
   1976 		sc->sc_tbc -= n;
   1977 		sc->sc_tba += n;
   1978 	}
   1979 
   1980 	mutex_spin_exit(&sc->sc_lock);
   1981 }
   1982 
   1983 /*
   1984  * Stop output on a line.
   1985  */
   1986 void
   1987 comstop(struct tty *tp, int flag)
   1988 {
   1989 	struct com_softc *sc =
   1990 	    device_lookup_private(&com_cd, COMUNIT(tp->t_dev));
   1991 
   1992 	mutex_spin_enter(&sc->sc_lock);
   1993 	if (ISSET(tp->t_state, TS_BUSY)) {
   1994 		/* Stop transmitting at the next chunk. */
   1995 		sc->sc_tbc = 0;
   1996 		sc->sc_heldtbc = 0;
   1997 		if (!ISSET(tp->t_state, TS_TTSTOP))
   1998 			SET(tp->t_state, TS_FLUSH);
   1999 	}
   2000 	mutex_spin_exit(&sc->sc_lock);
   2001 }
   2002 
   2003 void
   2004 comdiag(void *arg)
   2005 {
   2006 	struct com_softc *sc = arg;
   2007 	int overflows, floods;
   2008 
   2009 	mutex_spin_enter(&sc->sc_lock);
   2010 	overflows = sc->sc_overflows;
   2011 	sc->sc_overflows = 0;
   2012 	floods = sc->sc_floods;
   2013 	sc->sc_floods = 0;
   2014 	sc->sc_errors = 0;
   2015 	mutex_spin_exit(&sc->sc_lock);
   2016 
   2017 	log(LOG_WARNING, "%s: %d silo overflow%s, %d ibuf flood%s\n",
   2018 	    device_xname(sc->sc_dev),
   2019 	    overflows, overflows == 1 ? "" : "s",
   2020 	    floods, floods == 1 ? "" : "s");
   2021 }
   2022 
   2023 static inline void
   2024 com_rxsoft(struct com_softc *sc, struct tty *tp)
   2025 {
   2026 	int (*rint)(int, struct tty *) = tp->t_linesw->l_rint;
   2027 	u_char *get, *end;
   2028 	u_int cc, scc;
   2029 	u_char lsr;
   2030 	int code;
   2031 
   2032 	end = sc->sc_ebuf;
   2033 	get = sc->sc_rbget;
   2034 	scc = cc = com_rbuf_size - sc->sc_rbavail;
   2035 
   2036 	if (cc == com_rbuf_size) {
   2037 		sc->sc_floods++;
   2038 		if (sc->sc_errors++ == 0)
   2039 			callout_reset(&sc->sc_diag_callout, 60 * hz,
   2040 			    comdiag, sc);
   2041 	}
   2042 
   2043 	/* If not yet open, drop the entire buffer content here */
   2044 	if (!ISSET(tp->t_state, TS_ISOPEN)) {
   2045 		get += cc << 1;
   2046 		if (get >= end)
   2047 			get -= com_rbuf_size << 1;
   2048 		cc = 0;
   2049 	}
   2050 	while (cc) {
   2051 		code = get[0];
   2052 		lsr = get[1];
   2053 		if (ISSET(lsr, LSR_OE | LSR_BI | LSR_FE | LSR_PE)) {
   2054 			if (ISSET(lsr, LSR_OE)) {
   2055 				sc->sc_overflows++;
   2056 				if (sc->sc_errors++ == 0)
   2057 					callout_reset(&sc->sc_diag_callout,
   2058 					    60 * hz, comdiag, sc);
   2059 			}
   2060 			if (ISSET(lsr, LSR_BI | LSR_FE))
   2061 				SET(code, TTY_FE);
   2062 			if (ISSET(lsr, LSR_PE))
   2063 				SET(code, TTY_PE);
   2064 		}
   2065 		if ((*rint)(code, tp) == -1) {
   2066 			/*
   2067 			 * The line discipline's buffer is out of space.
   2068 			 */
   2069 			if (!ISSET(sc->sc_rx_flags, RX_TTY_BLOCKED)) {
   2070 				/*
   2071 				 * We're either not using flow control, or the
   2072 				 * line discipline didn't tell us to block for
   2073 				 * some reason.  Either way, we have no way to
   2074 				 * know when there's more space available, so
   2075 				 * just drop the rest of the data.
   2076 				 */
   2077 				get += cc << 1;
   2078 				if (get >= end)
   2079 					get -= com_rbuf_size << 1;
   2080 				cc = 0;
   2081 			} else {
   2082 				/*
   2083 				 * Don't schedule any more receive processing
   2084 				 * until the line discipline tells us there's
   2085 				 * space available (through comhwiflow()).
   2086 				 * Leave the rest of the data in the input
   2087 				 * buffer.
   2088 				 */
   2089 				SET(sc->sc_rx_flags, RX_TTY_OVERFLOWED);
   2090 			}
   2091 			break;
   2092 		}
   2093 		get += 2;
   2094 		if (get >= end)
   2095 			get = sc->sc_rbuf;
   2096 		cc--;
   2097 	}
   2098 
   2099 	if (cc != scc) {
   2100 		sc->sc_rbget = get;
   2101 		mutex_spin_enter(&sc->sc_lock);
   2102 
   2103 		cc = sc->sc_rbavail += scc - cc;
   2104 		/* Buffers should be ok again, release possible block. */
   2105 		if (cc >= sc->sc_r_lowat) {
   2106 			if (ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
   2107 				CLR(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
   2108 				SET(sc->sc_ier, IER_ERXRDY);
   2109 				if (sc->sc_type == COM_TYPE_PXA2x0)
   2110 					SET(sc->sc_ier, IER_ERXTOUT);
   2111 				if (sc->sc_type == COM_TYPE_INGENIC ||
   2112 				    sc->sc_type == COM_TYPE_TEGRA)
   2113 					SET(sc->sc_ier, IER_ERXTOUT);
   2114 
   2115 				CSR_WRITE_1(&sc->sc_regs, COM_REG_IER,
   2116 				    sc->sc_ier);
   2117 			}
   2118 			if (ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED)) {
   2119 				CLR(sc->sc_rx_flags, RX_IBUF_BLOCKED);
   2120 				com_hwiflow(sc);
   2121 			}
   2122 		}
   2123 		mutex_spin_exit(&sc->sc_lock);
   2124 	}
   2125 }
   2126 
   2127 static inline void
   2128 com_txsoft(struct com_softc *sc, struct tty *tp)
   2129 {
   2130 
   2131 	CLR(tp->t_state, TS_BUSY);
   2132 	if (ISSET(tp->t_state, TS_FLUSH))
   2133 		CLR(tp->t_state, TS_FLUSH);
   2134 	else
   2135 		ndflush(&tp->t_outq, (int)(sc->sc_tba - tp->t_outq.c_cf));
   2136 	(*tp->t_linesw->l_start)(tp);
   2137 }
   2138 
   2139 static inline void
   2140 com_stsoft(struct com_softc *sc, struct tty *tp)
   2141 {
   2142 	u_char msr, delta;
   2143 
   2144 	mutex_spin_enter(&sc->sc_lock);
   2145 	msr = sc->sc_msr;
   2146 	delta = sc->sc_msr_delta;
   2147 	sc->sc_msr_delta = 0;
   2148 	mutex_spin_exit(&sc->sc_lock);
   2149 
   2150 	if (ISSET(delta, sc->sc_msr_dcd)) {
   2151 		/*
   2152 		 * Inform the tty layer that carrier detect changed.
   2153 		 */
   2154 		(void) (*tp->t_linesw->l_modem)(tp, ISSET(msr, MSR_DCD));
   2155 	}
   2156 
   2157 	if (ISSET(delta, sc->sc_msr_cts)) {
   2158 		/* Block or unblock output according to flow control. */
   2159 		if (ISSET(msr, sc->sc_msr_cts)) {
   2160 			sc->sc_tx_stopped = 0;
   2161 			(*tp->t_linesw->l_start)(tp);
   2162 		} else {
   2163 			sc->sc_tx_stopped = 1;
   2164 		}
   2165 	}
   2166 
   2167 #ifdef COM_DEBUG
   2168 	if (com_debug)
   2169 		comstatus(sc, "com_stsoft");
   2170 #endif
   2171 }
   2172 
   2173 void
   2174 comsoft(void *arg)
   2175 {
   2176 	struct com_softc *sc = arg;
   2177 	struct tty *tp;
   2178 
   2179 	if (COM_ISALIVE(sc) == 0)
   2180 		return;
   2181 
   2182 	tp = sc->sc_tty;
   2183 
   2184 	if (sc->sc_rx_ready) {
   2185 		sc->sc_rx_ready = 0;
   2186 		com_rxsoft(sc, tp);
   2187 	}
   2188 
   2189 	if (sc->sc_st_check) {
   2190 		sc->sc_st_check = 0;
   2191 		com_stsoft(sc, tp);
   2192 	}
   2193 
   2194 	if (sc->sc_tx_done) {
   2195 		sc->sc_tx_done = 0;
   2196 		com_txsoft(sc, tp);
   2197 	}
   2198 }
   2199 
   2200 int
   2201 comintr(void *arg)
   2202 {
   2203 	struct com_softc *sc = arg;
   2204 	struct com_regs *regsp = &sc->sc_regs;
   2205 
   2206 	u_char *put, *end;
   2207 	u_int cc;
   2208 	u_char lsr, iir;
   2209 
   2210 	if (COM_ISALIVE(sc) == 0)
   2211 		return (0);
   2212 
   2213 	KASSERT(regsp != NULL);
   2214 
   2215 	mutex_spin_enter(&sc->sc_lock);
   2216 	iir = CSR_READ_1(regsp, COM_REG_IIR);
   2217 
   2218 	/* Handle ns16750-specific busy interrupt. */
   2219 	if (sc->sc_type == COM_TYPE_16750 &&
   2220 	    (iir & IIR_BUSY) == IIR_BUSY) {
   2221 		for (int timeout = 10000;
   2222 		    (CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0; timeout--)
   2223 			if (timeout <= 0) {
   2224 				aprint_error_dev(sc->sc_dev,
   2225 				    "timeout while waiting for BUSY interrupt "
   2226 				    "acknowledge\n");
   2227 				mutex_spin_exit(&sc->sc_lock);
   2228 				return (0);
   2229 			}
   2230 
   2231 		CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
   2232 		iir = CSR_READ_1(regsp, COM_REG_IIR);
   2233 	}
   2234 
   2235 	/* DesignWare APB UART BUSY interrupt */
   2236 	if (sc->sc_type == COM_TYPE_DW_APB &&
   2237 	    (iir & IIR_BUSY) == IIR_BUSY) {
   2238 		if (ISSET(sc->sc_hwflags, COM_HW_CONSOLE)) {
   2239 			(void)CSR_READ_1(regsp, COM_REG_USR);
   2240 		} else if ((CSR_READ_1(regsp, COM_REG_USR) & 0x1) != 0) {
   2241 			CSR_WRITE_1(regsp, COM_REG_HALT, HALT_CHCFG_EN);
   2242 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
   2243 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
   2244 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
   2245 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
   2246 			CSR_WRITE_1(regsp, COM_REG_HALT,
   2247 			    HALT_CHCFG_EN | HALT_CHCFG_UD);
   2248 			for (int timeout = 10000000;
   2249 			    (CSR_READ_1(regsp, COM_REG_HALT) & HALT_CHCFG_UD) != 0;
   2250 			    timeout--) {
   2251 				if (timeout <= 0) {
   2252 					aprint_error_dev(sc->sc_dev,
   2253 					    "timeout while waiting for HALT "
   2254 					    "update acknowledge 0x%x 0x%x\n",
   2255 					    CSR_READ_1(regsp, COM_REG_HALT),
   2256 					    CSR_READ_1(regsp, COM_REG_USR));
   2257 					break;
   2258 				}
   2259 			}
   2260 			CSR_WRITE_1(regsp, COM_REG_HALT, 0);
   2261 			(void)CSR_READ_1(regsp, COM_REG_USR);
   2262 		} else {
   2263 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr | LCR_DLAB);
   2264 			CSR_WRITE_1(regsp, COM_REG_DLBL, sc->sc_dlbl);
   2265 			CSR_WRITE_1(regsp, COM_REG_DLBH, sc->sc_dlbh);
   2266 			CSR_WRITE_1(regsp, COM_REG_LCR, sc->sc_lcr);
   2267 		}
   2268 	}
   2269 
   2270 	end = sc->sc_ebuf;
   2271 	put = sc->sc_rbput;
   2272 	cc = sc->sc_rbavail;
   2273 
   2274 	if (ISSET(iir, IIR_NOPEND)) {
   2275 		if (ISSET(sc->sc_hwflags, COM_HW_BROKEN_ETXRDY))
   2276 			goto do_tx;
   2277 		mutex_spin_exit(&sc->sc_lock);
   2278 		return (0);
   2279 	}
   2280 
   2281 again:	do {
   2282 		u_char	msr, delta;
   2283 
   2284 		lsr = CSR_READ_1(regsp, COM_REG_LSR);
   2285 		if (ISSET(lsr, LSR_BI)) {
   2286 			int cn_trapped = 0; /* see above: cn_trap() */
   2287 
   2288 			cn_check_magic(sc->sc_tty->t_dev,
   2289 				       CNC_BREAK, com_cnm_state);
   2290 			if (cn_trapped)
   2291 				continue;
   2292 #if defined(KGDB) && !defined(DDB)
   2293 			if (ISSET(sc->sc_hwflags, COM_HW_KGDB)) {
   2294 				kgdb_connect(1);
   2295 				continue;
   2296 			}
   2297 #endif
   2298 		}
   2299 
   2300 		if (sc->sc_type == COM_TYPE_BCMAUXUART && ISSET(iir, IIR_RXRDY))
   2301 			lsr |= LSR_RXRDY;
   2302 
   2303 		if (ISSET(lsr, LSR_RCV_MASK) &&
   2304 		    !ISSET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED)) {
   2305 			while (cc > 0) {
   2306 				int cn_trapped = 0;
   2307 				put[0] = CSR_READ_1(regsp, COM_REG_RXDATA);
   2308 				put[1] = lsr;
   2309 				cn_check_magic(sc->sc_tty->t_dev,
   2310 					       put[0], com_cnm_state);
   2311 				if (cn_trapped)
   2312 					goto next;
   2313 				put += 2;
   2314 				if (put >= end)
   2315 					put = sc->sc_rbuf;
   2316 				cc--;
   2317 			next:
   2318 				lsr = CSR_READ_1(regsp, COM_REG_LSR);
   2319 				if (!ISSET(lsr, LSR_RCV_MASK))
   2320 					break;
   2321 			}
   2322 
   2323 			/*
   2324 			 * Current string of incoming characters ended because
   2325 			 * no more data was available or we ran out of space.
   2326 			 * Schedule a receive event if any data was received.
   2327 			 * If we're out of space, turn off receive interrupts.
   2328 			 */
   2329 			sc->sc_rbput = put;
   2330 			sc->sc_rbavail = cc;
   2331 			if (!ISSET(sc->sc_rx_flags, RX_TTY_OVERFLOWED))
   2332 				sc->sc_rx_ready = 1;
   2333 
   2334 			/*
   2335 			 * See if we are in danger of overflowing a buffer. If
   2336 			 * so, use hardware flow control to ease the pressure.
   2337 			 */
   2338 			if (!ISSET(sc->sc_rx_flags, RX_IBUF_BLOCKED) &&
   2339 			    cc < sc->sc_r_hiwat) {
   2340 				SET(sc->sc_rx_flags, RX_IBUF_BLOCKED);
   2341 				com_hwiflow(sc);
   2342 			}
   2343 
   2344 			/*
   2345 			 * If we're out of space, disable receive interrupts
   2346 			 * until the queue has drained a bit.
   2347 			 */
   2348 			if (!cc) {
   2349 				SET(sc->sc_rx_flags, RX_IBUF_OVERFLOWED);
   2350 				switch (sc->sc_type) {
   2351 				case COM_TYPE_PXA2x0:
   2352 					CLR(sc->sc_ier, IER_ERXRDY|IER_ERXTOUT);
   2353 					break;
   2354 				case COM_TYPE_INGENIC:
   2355 				case COM_TYPE_TEGRA:
   2356 					CLR(sc->sc_ier,
   2357 					    IER_ERXRDY | IER_ERXTOUT);
   2358 					break;
   2359 				default:
   2360 					CLR(sc->sc_ier, IER_ERXRDY);
   2361 					break;
   2362 				}
   2363 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
   2364 			}
   2365 		} else {
   2366 			if ((iir & (IIR_RXRDY|IIR_TXRDY)) == IIR_RXRDY) {
   2367 				(void) CSR_READ_1(regsp, COM_REG_RXDATA);
   2368 				continue;
   2369 			}
   2370 		}
   2371 
   2372 		msr = CSR_READ_1(regsp, COM_REG_MSR);
   2373 		delta = msr ^ sc->sc_msr;
   2374 		sc->sc_msr = msr;
   2375 		if ((sc->sc_pps_state.ppsparam.mode & PPS_CAPTUREBOTH) &&
   2376 		    (delta & MSR_DCD)) {
   2377 			mutex_spin_enter(&timecounter_lock);
   2378 			pps_capture(&sc->sc_pps_state);
   2379 			pps_event(&sc->sc_pps_state,
   2380 			    (msr & MSR_DCD) ?
   2381 			    PPS_CAPTUREASSERT :
   2382 			    PPS_CAPTURECLEAR);
   2383 			mutex_spin_exit(&timecounter_lock);
   2384 		}
   2385 
   2386 		/*
   2387 		 * Process normal status changes
   2388 		 */
   2389 		if (ISSET(delta, sc->sc_msr_mask)) {
   2390 			SET(sc->sc_msr_delta, delta);
   2391 
   2392 			/*
   2393 			 * Stop output immediately if we lose the output
   2394 			 * flow control signal or carrier detect.
   2395 			 */
   2396 			if (ISSET(~msr, sc->sc_msr_mask)) {
   2397 				sc->sc_tbc = 0;
   2398 				sc->sc_heldtbc = 0;
   2399 #ifdef COM_DEBUG
   2400 				if (com_debug)
   2401 					comstatus(sc, "comintr  ");
   2402 #endif
   2403 			}
   2404 
   2405 			sc->sc_st_check = 1;
   2406 		}
   2407 	} while (!ISSET((iir =
   2408 	    CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND) &&
   2409 	    /*
   2410 	     * Since some device (e.g., ST16C1550) doesn't clear IIR_TXRDY
   2411 	     * by IIR read, so we can't do this way: `process all interrupts,
   2412 	     * then do TX if possible'.
   2413 	     */
   2414 	    (iir & IIR_IMASK) != IIR_TXRDY);
   2415 
   2416 do_tx:
   2417 	/*
   2418 	 * Read LSR again, since there may be an interrupt between
   2419 	 * the last LSR read and IIR read above.
   2420 	 */
   2421 	lsr = CSR_READ_1(regsp, COM_REG_LSR);
   2422 
   2423 	/*
   2424 	 * See if data can be transmitted as well.
   2425 	 * Schedule tx done event if no data left
   2426 	 * and tty was marked busy.
   2427 	 */
   2428 	if (ISSET(lsr, LSR_TXRDY)) {
   2429 		/*
   2430 		 * If we've delayed a parameter change, do it now, and restart
   2431 		 * output.
   2432 		 */
   2433 		if (sc->sc_heldchange) {
   2434 			com_loadchannelregs(sc);
   2435 			sc->sc_heldchange = 0;
   2436 			sc->sc_tbc = sc->sc_heldtbc;
   2437 			sc->sc_heldtbc = 0;
   2438 		}
   2439 
   2440 		/* Output the next chunk of the contiguous buffer, if any. */
   2441 		if (sc->sc_tbc > 0) {
   2442 			u_int n;
   2443 
   2444 			n = sc->sc_tbc;
   2445 			if (n > sc->sc_fifolen)
   2446 				n = sc->sc_fifolen;
   2447 			CSR_WRITE_MULTI(regsp, COM_REG_TXDATA, sc->sc_tba, n);
   2448 			sc->sc_tbc -= n;
   2449 			sc->sc_tba += n;
   2450 		} else {
   2451 			/* Disable transmit completion interrupts if necessary. */
   2452 			if (ISSET(sc->sc_ier, IER_ETXRDY)) {
   2453 				CLR(sc->sc_ier, IER_ETXRDY);
   2454 				CSR_WRITE_1(regsp, COM_REG_IER, sc->sc_ier);
   2455 			}
   2456 			if (sc->sc_tx_busy) {
   2457 				sc->sc_tx_busy = 0;
   2458 				sc->sc_tx_done = 1;
   2459 			}
   2460 		}
   2461 	}
   2462 
   2463 	if (!ISSET((iir = CSR_READ_1(regsp, COM_REG_IIR)), IIR_NOPEND))
   2464 		goto again;
   2465 
   2466 	mutex_spin_exit(&sc->sc_lock);
   2467 
   2468 	/* Wake up the poller. */
   2469 	if ((sc->sc_rx_ready | sc->sc_st_check | sc->sc_tx_done) != 0)
   2470 		softint_schedule(sc->sc_si);
   2471 
   2472 #ifdef RND_COM
   2473 	rnd_add_uint32(&sc->rnd_source, iir | lsr);
   2474 #endif
   2475 
   2476 	return (1);
   2477 }
   2478 
   2479 /*
   2480  * The following functions are polled getc and putc routines, shared
   2481  * by the console and kgdb glue.
   2482  *
   2483  * The read-ahead code is so that you can detect pending in-band
   2484  * cn_magic in polled mode while doing output rather than having to
   2485  * wait until the kernel decides it needs input.
   2486  */
   2487 
   2488 #define MAX_READAHEAD	20
   2489 static int com_readahead[MAX_READAHEAD];
   2490 static int com_readaheadcount = 0;
   2491 
   2492 int
   2493 com_common_getc(dev_t dev, struct com_regs *regsp)
   2494 {
   2495 	int s = splserial();
   2496 	u_char stat, c;
   2497 
   2498 	/* got a character from reading things earlier */
   2499 	if (com_readaheadcount > 0) {
   2500 		int i;
   2501 
   2502 		c = com_readahead[0];
   2503 		for (i = 1; i < com_readaheadcount; i++) {
   2504 			com_readahead[i-1] = com_readahead[i];
   2505 		}
   2506 		com_readaheadcount--;
   2507 		splx(s);
   2508 		return (c);
   2509 	}
   2510 
   2511 	/* don't block until a character becomes available */
   2512 	if (!ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
   2513 		splx(s);
   2514 		return -1;
   2515 	}
   2516 
   2517 	c = CSR_READ_1(regsp, COM_REG_RXDATA);
   2518 	stat = CSR_READ_1(regsp, COM_REG_IIR);
   2519 	{
   2520 		int cn_trapped = 0;	/* required by cn_trap, see above */
   2521 		if (!db_active)
   2522 			cn_check_magic(dev, c, com_cnm_state);
   2523 	}
   2524 	splx(s);
   2525 	return (c);
   2526 }
   2527 
   2528 static void
   2529 com_common_putc(dev_t dev, struct com_regs *regsp, int c, int with_readahead)
   2530 {
   2531 	int s = splserial();
   2532 	int cin, stat, timo;
   2533 
   2534 	if (with_readahead && com_readaheadcount < MAX_READAHEAD
   2535 	     && ISSET(stat = CSR_READ_1(regsp, COM_REG_LSR), LSR_RXRDY)) {
   2536 		int cn_trapped = 0;
   2537 		cin = CSR_READ_1(regsp, COM_REG_RXDATA);
   2538 		stat = CSR_READ_1(regsp, COM_REG_IIR);
   2539 		cn_check_magic(dev, cin, com_cnm_state);
   2540 		com_readahead[com_readaheadcount++] = cin;
   2541 	}
   2542 
   2543 	/* wait for any pending transmission to finish */
   2544 	timo = 150000;
   2545 	while (!ISSET(CSR_READ_1(regsp, COM_REG_LSR), LSR_TXRDY) && --timo)
   2546 		continue;
   2547 
   2548 	CSR_WRITE_1(regsp, COM_REG_TXDATA, c);
   2549 	COM_BARRIER(regsp, BR | BW);
   2550 
   2551 	splx(s);
   2552 }
   2553 
   2554 /*
   2555  * Initialize UART for use as console or KGDB line.
   2556  */
   2557 int
   2558 cominit(struct com_regs *regsp, int rate, int frequency, int type,
   2559     tcflag_t cflag)
   2560 {
   2561 
   2562 	if (bus_space_map(regsp->cr_iot, regsp->cr_iobase, regsp->cr_nports, 0,
   2563 		&regsp->cr_ioh))
   2564 		return (ENOMEM); /* ??? */
   2565 
   2566 	if (type == COM_TYPE_OMAP) {
   2567 		/* disable before changing settings */
   2568 		CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_DISABLE);
   2569 	}
   2570 
   2571 	rate = comspeed(rate, frequency, type);
   2572 	if (rate != -1) {
   2573 		if (type == COM_TYPE_AU1x00) {
   2574 			/* no EFR on alchemy */
   2575 			CSR_WRITE_2(regsp, COM_REG_DLBL, rate);
   2576 		} else {
   2577 			if ((type != COM_TYPE_16550_NOERS) &&
   2578 			    (type != COM_TYPE_INGENIC)) {
   2579 				CSR_WRITE_1(regsp, COM_REG_LCR, LCR_EERS);
   2580 				CSR_WRITE_1(regsp, COM_REG_EFR, 0);
   2581 			}
   2582 			CSR_WRITE_1(regsp, COM_REG_LCR, LCR_DLAB);
   2583 			CSR_WRITE_1(regsp, COM_REG_DLBL, rate & 0xff);
   2584 			CSR_WRITE_1(regsp, COM_REG_DLBH, rate >> 8);
   2585 		}
   2586 	}
   2587 	CSR_WRITE_1(regsp, COM_REG_LCR, cflag2lcr(cflag));
   2588 	CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
   2589 
   2590 	if (type == COM_TYPE_INGENIC) {
   2591 		CSR_WRITE_1(regsp, COM_REG_FIFO,
   2592 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
   2593 		    FIFO_TRIGGER_1 | FIFO_UART_ON);
   2594 	} else {
   2595 		CSR_WRITE_1(regsp, COM_REG_FIFO,
   2596 		    FIFO_ENABLE | FIFO_RCV_RST | FIFO_XMT_RST |
   2597 		    FIFO_TRIGGER_1);
   2598 	}
   2599 
   2600 	if (type == COM_TYPE_OMAP) {
   2601 		/* setup the fifos.  the FCR value is not used as long
   2602 		   as SCR[6] and SCR[7] are 0, which they are at reset
   2603 		   and we never touch the SCR register */
   2604 		uint8_t rx_fifo_trig = 40;
   2605 		uint8_t tx_fifo_trig = 60;
   2606 		uint8_t rx_start = 8;
   2607 		uint8_t rx_halt = 60;
   2608 		uint8_t tlr_value = ((rx_fifo_trig>>2) << 4) | (tx_fifo_trig>>2);
   2609 		uint8_t tcr_value = ((rx_start>>2) << 4) | (rx_halt>>2);
   2610 
   2611 		/* enable access to TCR & TLR */
   2612 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS | MCR_TCR_TLR);
   2613 
   2614 		/* write tcr and tlr values */
   2615 		CSR_WRITE_1(regsp, COM_REG_TLR, tlr_value);
   2616 		CSR_WRITE_1(regsp, COM_REG_TCR, tcr_value);
   2617 
   2618 		/* disable access to TCR & TLR */
   2619 		CSR_WRITE_1(regsp, COM_REG_MCR, MCR_DTR | MCR_RTS);
   2620 
   2621 		/* enable again, but mode is based on speed */
   2622 		if (rate > 230400) {
   2623 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_13X);
   2624 		} else {
   2625 			CSR_WRITE_1(regsp, COM_REG_MDR1, MDR1_MODE_UART_16X);
   2626 		}
   2627 	}
   2628 
   2629 	if (type == COM_TYPE_PXA2x0)
   2630 		CSR_WRITE_1(regsp, COM_REG_IER, IER_EUART);
   2631 	else
   2632 		CSR_WRITE_1(regsp, COM_REG_IER, 0);
   2633 
   2634 	return (0);
   2635 }
   2636 
   2637 int
   2638 comcnattach1(struct com_regs *regsp, int rate, int frequency, int type,
   2639     tcflag_t cflag)
   2640 {
   2641 	int res;
   2642 
   2643 	comcons_info.regs = *regsp;
   2644 
   2645 	res = cominit(&comcons_info.regs, rate, frequency, type, cflag);
   2646 	if (res)
   2647 		return (res);
   2648 
   2649 	cn_tab = &comcons;
   2650 	cn_init_magic(&com_cnm_state);
   2651 	cn_set_magic("\047\001"); /* default magic is BREAK */
   2652 
   2653 	comcons_info.frequency = frequency;
   2654 	comcons_info.type = type;
   2655 	comcons_info.rate = rate;
   2656 	comcons_info.cflag = cflag;
   2657 
   2658 	return (0);
   2659 }
   2660 
   2661 int
   2662 comcnattach(bus_space_tag_t iot, bus_addr_t iobase, int rate, int frequency,
   2663     int type, tcflag_t cflag)
   2664 {
   2665 	struct com_regs	regs;
   2666 
   2667 	/*XXX*/
   2668 	bus_space_handle_t dummy_bsh;
   2669 	memset(&dummy_bsh, 0, sizeof(dummy_bsh));
   2670 
   2671 	/*
   2672 	 * dummy_bsh required because com_init_regs() wants it.  A
   2673 	 * real bus_space_handle will be filled in by cominit() later.
   2674 	 * XXXJRT Detangle this mess eventually, plz.
   2675 	 */
   2676 	com_init_regs(&regs, iot, dummy_bsh/*XXX*/, iobase);
   2677 
   2678 	return comcnattach1(&regs, rate, frequency, type, cflag);
   2679 }
   2680 
   2681 static int
   2682 comcnreattach(void)
   2683 {
   2684 	return comcnattach1(&comcons_info.regs, comcons_info.rate,
   2685 	    comcons_info.frequency, comcons_info.type, comcons_info.cflag);
   2686 }
   2687 
   2688 int
   2689 comcngetc(dev_t dev)
   2690 {
   2691 
   2692 	return (com_common_getc(dev, &comcons_info.regs));
   2693 }
   2694 
   2695 /*
   2696  * Console kernel output character routine.
   2697  */
   2698 void
   2699 comcnputc(dev_t dev, int c)
   2700 {
   2701 
   2702 	com_common_putc(dev, &comcons_info.regs, c, cold);
   2703 }
   2704 
   2705 void
   2706 comcnpollc(dev_t dev, int on)
   2707 {
   2708 
   2709 	com_readaheadcount = 0;
   2710 }
   2711 
   2712 #ifdef KGDB
   2713 int
   2714 com_kgdb_attach1(struct com_regs *regsp, int rate, int frequency, int type,
   2715     tcflag_t cflag)
   2716 {
   2717 	int res;
   2718 
   2719 	if (bus_space_is_equal(regsp->cr_iot, comcons_info.regs.cr_iot) &&
   2720 	    regsp->cr_iobase == comcons_info.regs.cr_iobase) {
   2721 #if !defined(DDB)
   2722 		return (EBUSY); /* cannot share with console */
   2723 #else
   2724 		comkgdbregs = *regsp;
   2725 		comkgdbregs.cr_ioh = comcons_info.regs.cr_ioh;
   2726 #endif
   2727 	} else {
   2728 		comkgdbregs = *regsp;
   2729 		res = cominit(&comkgdbregs, rate, frequency, type, cflag);
   2730 		if (res)
   2731 			return (res);
   2732 
   2733 		/*
   2734 		 * XXXfvdl this shouldn't be needed, but the cn_magic goo
   2735 		 * expects this to be initialized
   2736 		 */
   2737 		cn_init_magic(&com_cnm_state);
   2738 		cn_set_magic("\047\001");
   2739 	}
   2740 
   2741 	kgdb_attach(com_kgdb_getc, com_kgdb_putc, NULL);
   2742 	kgdb_dev = 123; /* unneeded, only to satisfy some tests */
   2743 
   2744 	return (0);
   2745 }
   2746 
   2747 int
   2748 com_kgdb_attach(bus_space_tag_t iot, bus_addr_t iobase, int rate,
   2749     int frequency, int type, tcflag_t cflag)
   2750 {
   2751 	struct com_regs regs;
   2752 
   2753 	com_init_regs(&regs, iot, (bus_space_handle_t)0/*XXX*/, iobase);
   2754 
   2755 	return com_kgdb_attach1(&regs, rate, frequency, type, cflag);
   2756 }
   2757 
   2758 /* ARGSUSED */
   2759 int
   2760 com_kgdb_getc(void *arg)
   2761 {
   2762 
   2763 	return (com_common_getc(NODEV, &comkgdbregs));
   2764 }
   2765 
   2766 /* ARGSUSED */
   2767 void
   2768 com_kgdb_putc(void *arg, int c)
   2769 {
   2770 
   2771 	com_common_putc(NODEV, &comkgdbregs, c, 0);
   2772 }
   2773 #endif /* KGDB */
   2774 
   2775 /*
   2776  * helper function to identify the com ports used by
   2777  * console or KGDB (and not yet autoconf attached)
   2778  */
   2779 int
   2780 com_is_console(bus_space_tag_t iot, bus_addr_t iobase, bus_space_handle_t *ioh)
   2781 {
   2782 	bus_space_handle_t help;
   2783 
   2784 	if (!comconsattached &&
   2785 	    bus_space_is_equal(iot, comcons_info.regs.cr_iot) &&
   2786 	    iobase == comcons_info.regs.cr_iobase)
   2787 		help = comcons_info.regs.cr_ioh;
   2788 #ifdef KGDB
   2789 	else if (!com_kgdb_attached &&
   2790 	    bus_space_is_equal(iot, comkgdbregs.cr_iot) &&
   2791 	    iobase == comkgdbregs.cr_iobase)
   2792 		help = comkgdbregs.cr_ioh;
   2793 #endif
   2794 	else
   2795 		return (0);
   2796 
   2797 	if (ioh)
   2798 		*ioh = help;
   2799 	return (1);
   2800 }
   2801 
   2802 /*
   2803  * this routine exists to serve as a shutdown hook for systems that
   2804  * have firmware which doesn't interact properly with a com device in
   2805  * FIFO mode.
   2806  */
   2807 bool
   2808 com_cleanup(device_t self, int how)
   2809 {
   2810 	struct com_softc *sc = device_private(self);
   2811 
   2812 	if (ISSET(sc->sc_hwflags, COM_HW_FIFO))
   2813 		CSR_WRITE_1(&sc->sc_regs, COM_REG_FIFO, 0);
   2814 
   2815 	return true;
   2816 }
   2817 
   2818 bool
   2819 com_suspend(device_t self, const pmf_qual_t *qual)
   2820 {
   2821 	struct com_softc *sc = device_private(self);
   2822 
   2823 	CSR_WRITE_1(&sc->sc_regs, COM_REG_IER, 0);
   2824 	(void)CSR_READ_1(&sc->sc_regs, COM_REG_IIR);
   2825 
   2826 	return true;
   2827 }
   2828 
   2829 bool
   2830 com_resume(device_t self, const pmf_qual_t *qual)
   2831 {
   2832 	struct com_softc *sc = device_private(self);
   2833 
   2834 	mutex_spin_enter(&sc->sc_lock);
   2835 	com_loadchannelregs(sc);
   2836 	mutex_spin_exit(&sc->sc_lock);
   2837 
   2838 	return true;
   2839 }
   2840