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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/dev/uart/uart_dev_sab82532.c |
/*-
* Copyright (c) 2003 Marcel Moolenaar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/dev/uart/uart_dev_sab82532.c 168281 2007-04-02 22:00:22Z marcel $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <machine/bus.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_cpu.h>
#include <dev/uart/uart_bus.h>
#include <dev/ic/sab82532.h>
#include "uart_if.h"
#define DEFAULT_RCLK 29491200
/*
* NOTE: To allow us to read the baudrate divisor from the chip, we
* copy the value written to the write-only BGR register to an unused
* read-write register. We use TCR for that.
*/
static int
sab82532_delay(struct uart_bas *bas)
{
int divisor, m, n;
uint8_t bgr, ccr2;
bgr = uart_getreg(bas, SAB_TCR);
ccr2 = uart_getreg(bas, SAB_CCR2);
n = (bgr & 0x3f) + 1;
m = (bgr >> 6) | ((ccr2 >> 4) & 0xC);
divisor = n * (1<<m);
/* 1/10th the time to transmit 1 character (estimate). */
return (16000000 * divisor / bas->rclk);
}
static int
sab82532_divisor(int rclk, int baudrate)
{
int act_baud, act_div, divisor;
int error, m, n;
if (baudrate == 0)
return (0);
divisor = (rclk / (baudrate << 3) + 1) >> 1;
if (divisor < 2 || divisor >= 1048576)
return (0);
/* Find the best (N+1,M) pair. */
for (m = 1; m < 15; m++) {
n = divisor / (1<<m);
if (n < 1 || n > 63)
continue;
act_div = n * (1<<m);
act_baud = rclk / (act_div << 4);
/* 10 times error in percent: */
error = ((act_baud - baudrate) * 2000 / baudrate + 1) >> 1;
/* 3.0% maximum error tolerance: */
if (error < -30 || error > 30)
continue;
/* Got it. */
return ((n - 1) | (m << 6));
}
return (0);
}
static void
sab82532_flush(struct uart_bas *bas, int what)
{
if (what & UART_FLUSH_TRANSMITTER) {
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_XRES);
uart_barrier(bas);
}
if (what & UART_FLUSH_RECEIVER) {
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_RRES);
uart_barrier(bas);
}
}
static int
sab82532_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
int divisor;
uint8_t ccr2, dafo;
if (databits >= 8)
dafo = SAB_DAFO_CHL_CS8;
else if (databits == 7)
dafo = SAB_DAFO_CHL_CS7;
else if (databits == 6)
dafo = SAB_DAFO_CHL_CS6;
else
dafo = SAB_DAFO_CHL_CS5;
if (stopbits > 1)
dafo |= SAB_DAFO_STOP;
switch (parity) {
case UART_PARITY_EVEN: dafo |= SAB_DAFO_PAR_EVEN; break;
case UART_PARITY_MARK: dafo |= SAB_DAFO_PAR_MARK; break;
case UART_PARITY_NONE: dafo |= SAB_DAFO_PAR_NONE; break;
case UART_PARITY_ODD: dafo |= SAB_DAFO_PAR_ODD; break;
case UART_PARITY_SPACE: dafo |= SAB_DAFO_PAR_SPACE; break;
default: return (EINVAL);
}
/* Set baudrate. */
if (baudrate > 0) {
divisor = sab82532_divisor(bas->rclk, baudrate);
if (divisor == 0)
return (EINVAL);
uart_setreg(bas, SAB_BGR, divisor & 0xff);
uart_barrier(bas);
/* Allow reading the (n-1,m) tuple from the chip. */
uart_setreg(bas, SAB_TCR, divisor & 0xff);
uart_barrier(bas);
ccr2 = uart_getreg(bas, SAB_CCR2);
ccr2 &= ~(SAB_CCR2_BR9 | SAB_CCR2_BR8);
ccr2 |= (divisor >> 2) & (SAB_CCR2_BR9 | SAB_CCR2_BR8);
uart_setreg(bas, SAB_CCR2, ccr2);
uart_barrier(bas);
}
uart_setreg(bas, SAB_DAFO, dafo);
uart_barrier(bas);
return (0);
}
/*
* Low-level UART interface.
*/
static int sab82532_probe(struct uart_bas *bas);
static void sab82532_init(struct uart_bas *bas, int, int, int, int);
static void sab82532_term(struct uart_bas *bas);
static void sab82532_putc(struct uart_bas *bas, int);
static int sab82532_rxready(struct uart_bas *bas);
static int sab82532_getc(struct uart_bas *bas, struct mtx *);
static struct uart_ops uart_sab82532_ops = {
.probe = sab82532_probe,
.init = sab82532_init,
.term = sab82532_term,
.putc = sab82532_putc,
.rxready = sab82532_rxready,
.getc = sab82532_getc,
};
static int
sab82532_probe(struct uart_bas *bas)
{
return (0);
}
static void
sab82532_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
uint8_t ccr0, pvr;
if (bas->rclk == 0)
bas->rclk = DEFAULT_RCLK;
/*
* Set all pins, except the DTR pins (pin 1 and 2) to be inputs.
* Pin 4 is magical, meaning that I don't know what it does, but
* it too has to be set to output.
*/
uart_setreg(bas, SAB_PCR,
~(SAB_PVR_DTR_A|SAB_PVR_DTR_B|SAB_PVR_MAGIC));
uart_barrier(bas);
/* Disable port interrupts. */
uart_setreg(bas, SAB_PIM, 0xff);
uart_barrier(bas);
/* Interrupts are active low. */
uart_setreg(bas, SAB_IPC, SAB_IPC_ICPL);
uart_barrier(bas);
/* Set DTR. */
pvr = uart_getreg(bas, SAB_PVR);
switch (bas->chan) {
case 1:
pvr &= ~SAB_PVR_DTR_A;
break;
case 2:
pvr &= ~SAB_PVR_DTR_B;
break;
}
uart_setreg(bas, SAB_PVR, pvr | SAB_PVR_MAGIC);
uart_barrier(bas);
/* power down */
uart_setreg(bas, SAB_CCR0, 0);
uart_barrier(bas);
/* set basic configuration */
ccr0 = SAB_CCR0_MCE|SAB_CCR0_SC_NRZ|SAB_CCR0_SM_ASYNC;
uart_setreg(bas, SAB_CCR0, ccr0);
uart_barrier(bas);
uart_setreg(bas, SAB_CCR1, SAB_CCR1_ODS|SAB_CCR1_BCR|SAB_CCR1_CM_7);
uart_barrier(bas);
uart_setreg(bas, SAB_CCR2, SAB_CCR2_BDF|SAB_CCR2_SSEL|SAB_CCR2_TOE);
uart_barrier(bas);
uart_setreg(bas, SAB_CCR3, 0);
uart_barrier(bas);
uart_setreg(bas, SAB_CCR4, SAB_CCR4_MCK4|SAB_CCR4_EBRG|SAB_CCR4_ICD);
uart_barrier(bas);
uart_setreg(bas, SAB_MODE, SAB_MODE_FCTS|SAB_MODE_RTS|SAB_MODE_RAC);
uart_barrier(bas);
uart_setreg(bas, SAB_RFC, SAB_RFC_DPS|SAB_RFC_RFDF|
SAB_RFC_RFTH_32CHAR);
uart_barrier(bas);
sab82532_param(bas, baudrate, databits, stopbits, parity);
/* Clear interrupts. */
uart_setreg(bas, SAB_IMR0, (unsigned char)~SAB_IMR0_TCD);
uart_setreg(bas, SAB_IMR1, 0xff);
uart_barrier(bas);
uart_getreg(bas, SAB_ISR0);
uart_getreg(bas, SAB_ISR1);
uart_barrier(bas);
sab82532_flush(bas, UART_FLUSH_TRANSMITTER|UART_FLUSH_RECEIVER);
/* Power up. */
uart_setreg(bas, SAB_CCR0, ccr0|SAB_CCR0_PU);
uart_barrier(bas);
}
static void
sab82532_term(struct uart_bas *bas)
{
uint8_t pvr;
pvr = uart_getreg(bas, SAB_PVR);
switch (bas->chan) {
case 1:
pvr |= SAB_PVR_DTR_A;
break;
case 2:
pvr |= SAB_PVR_DTR_B;
break;
}
uart_setreg(bas, SAB_PVR, pvr);
uart_barrier(bas);
}
static void
sab82532_putc(struct uart_bas *bas, int c)
{
int delay, limit;
/* 1/10th the time to transmit 1 character (estimate). */
delay = sab82532_delay(bas);
limit = 20;
while ((uart_getreg(bas, SAB_STAR) & SAB_STAR_TEC) && --limit)
DELAY(delay);
uart_setreg(bas, SAB_TIC, c);
limit = 20;
while ((uart_getreg(bas, SAB_STAR) & SAB_STAR_TEC) && --limit)
DELAY(delay);
}
static int
sab82532_rxready(struct uart_bas *bas)
{
return ((uart_getreg(bas, SAB_STAR) & SAB_STAR_RFNE) != 0 ? 1 : 0);
}
static int
sab82532_getc(struct uart_bas *bas, struct mtx *hwmtx)
{
int c, delay;
uart_lock(hwmtx);
/* 1/10th the time to transmit 1 character (estimate). */
delay = sab82532_delay(bas);
while (!(uart_getreg(bas, SAB_STAR) & SAB_STAR_RFNE)) {
uart_unlock(hwmtx);
DELAY(delay);
uart_lock(hwmtx);
}
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_RFRD);
uart_barrier(bas);
while (!(uart_getreg(bas, SAB_ISR0) & SAB_ISR0_TCD))
DELAY(delay);
c = uart_getreg(bas, SAB_RFIFO);
uart_barrier(bas);
/* Blow away everything left in the FIFO... */
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_RMC);
uart_barrier(bas);
uart_unlock(hwmtx);
return (c);
}
/*
* High-level UART interface.
*/
struct sab82532_softc {
struct uart_softc base;
};
static int sab82532_bus_attach(struct uart_softc *);
static int sab82532_bus_detach(struct uart_softc *);
static int sab82532_bus_flush(struct uart_softc *, int);
static int sab82532_bus_getsig(struct uart_softc *);
static int sab82532_bus_ioctl(struct uart_softc *, int, intptr_t);
static int sab82532_bus_ipend(struct uart_softc *);
static int sab82532_bus_param(struct uart_softc *, int, int, int, int);
static int sab82532_bus_probe(struct uart_softc *);
static int sab82532_bus_receive(struct uart_softc *);
static int sab82532_bus_setsig(struct uart_softc *, int);
static int sab82532_bus_transmit(struct uart_softc *);
static kobj_method_t sab82532_methods[] = {
KOBJMETHOD(uart_attach, sab82532_bus_attach),
KOBJMETHOD(uart_detach, sab82532_bus_detach),
KOBJMETHOD(uart_flush, sab82532_bus_flush),
KOBJMETHOD(uart_getsig, sab82532_bus_getsig),
KOBJMETHOD(uart_ioctl, sab82532_bus_ioctl),
KOBJMETHOD(uart_ipend, sab82532_bus_ipend),
KOBJMETHOD(uart_param, sab82532_bus_param),
KOBJMETHOD(uart_probe, sab82532_bus_probe),
KOBJMETHOD(uart_receive, sab82532_bus_receive),
KOBJMETHOD(uart_setsig, sab82532_bus_setsig),
KOBJMETHOD(uart_transmit, sab82532_bus_transmit),
{ 0, 0 }
};
struct uart_class uart_sab82532_class = {
"sab82532",
sab82532_methods,
sizeof(struct sab82532_softc),
.uc_ops = &uart_sab82532_ops,
.uc_range = 64,
.uc_rclk = DEFAULT_RCLK
};
#define SIGCHG(c, i, s, d) \
if (c) { \
i |= (i & s) ? s : s | d; \
} else { \
i = (i & s) ? (i & ~s) | d : i; \
}
static int
sab82532_bus_attach(struct uart_softc *sc)
{
struct uart_bas *bas;
uint8_t imr0, imr1;
bas = &sc->sc_bas;
if (sc->sc_sysdev == NULL)
sab82532_init(bas, 9600, 8, 1, UART_PARITY_NONE);
sc->sc_rxfifosz = 32;
sc->sc_txfifosz = 32;
imr0 = SAB_IMR0_TCD|SAB_IMR0_TIME|SAB_IMR0_CDSC|SAB_IMR0_RFO|
SAB_IMR0_RPF;
uart_setreg(bas, SAB_IMR0, 0xff & ~imr0);
imr1 = SAB_IMR1_BRKT|SAB_IMR1_ALLS|SAB_IMR1_CSC;
uart_setreg(bas, SAB_IMR1, 0xff & ~imr1);
uart_barrier(bas);
if (sc->sc_sysdev == NULL)
sab82532_bus_setsig(sc, SER_DDTR|SER_DRTS);
(void)sab82532_bus_getsig(sc);
return (0);
}
static int
sab82532_bus_detach(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
uart_setreg(bas, SAB_IMR0, 0xff);
uart_setreg(bas, SAB_IMR1, 0xff);
uart_barrier(bas);
uart_getreg(bas, SAB_ISR0);
uart_getreg(bas, SAB_ISR1);
uart_barrier(bas);
uart_setreg(bas, SAB_CCR0, 0);
uart_barrier(bas);
return (0);
}
static int
sab82532_bus_flush(struct uart_softc *sc, int what)
{
uart_lock(sc->sc_hwmtx);
sab82532_flush(&sc->sc_bas, what);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
sab82532_bus_getsig(struct uart_softc *sc)
{
struct uart_bas *bas;
uint32_t new, old, sig;
uint8_t pvr, star, vstr;
bas = &sc->sc_bas;
do {
old = sc->sc_hwsig;
sig = old;
uart_lock(sc->sc_hwmtx);
star = uart_getreg(bas, SAB_STAR);
SIGCHG(star & SAB_STAR_CTS, sig, SER_CTS, SER_DCTS);
vstr = uart_getreg(bas, SAB_VSTR);
SIGCHG(vstr & SAB_VSTR_CD, sig, SER_DCD, SER_DDCD);
pvr = ~uart_getreg(bas, SAB_PVR);
switch (bas->chan) {
case 1:
pvr &= SAB_PVR_DSR_A;
break;
case 2:
pvr &= SAB_PVR_DSR_B;
break;
}
SIGCHG(pvr, sig, SER_DSR, SER_DDSR);
uart_unlock(sc->sc_hwmtx);
new = sig & ~SER_MASK_DELTA;
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
return (sig);
}
static int
sab82532_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
{
struct uart_bas *bas;
uint8_t dafo, mode;
int error;
bas = &sc->sc_bas;
error = 0;
uart_lock(sc->sc_hwmtx);
switch (request) {
case UART_IOCTL_BREAK:
dafo = uart_getreg(bas, SAB_DAFO);
if (data)
dafo |= SAB_DAFO_XBRK;
else
dafo &= ~SAB_DAFO_XBRK;
uart_setreg(bas, SAB_DAFO, dafo);
uart_barrier(bas);
break;
case UART_IOCTL_IFLOW:
mode = uart_getreg(bas, SAB_MODE);
if (data) {
mode &= ~SAB_MODE_RTS;
mode |= SAB_MODE_FRTS;
} else {
mode |= SAB_MODE_RTS;
mode &= ~SAB_MODE_FRTS;
}
uart_setreg(bas, SAB_MODE, mode);
uart_barrier(bas);
break;
case UART_IOCTL_OFLOW:
mode = uart_getreg(bas, SAB_MODE);
if (data)
mode &= ~SAB_MODE_FCTS;
else
mode |= SAB_MODE_FCTS;
uart_setreg(bas, SAB_MODE, mode);
uart_barrier(bas);
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
sab82532_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
int ipend;
uint8_t isr0, isr1;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
isr0 = uart_getreg(bas, SAB_ISR0);
isr1 = uart_getreg(bas, SAB_ISR1);
uart_barrier(bas);
if (isr0 & SAB_ISR0_TIME) {
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_RFRD);
uart_barrier(bas);
}
uart_unlock(sc->sc_hwmtx);
ipend = 0;
if (isr1 & SAB_ISR1_BRKT)
ipend |= SER_INT_BREAK;
if (isr0 & SAB_ISR0_RFO)
ipend |= SER_INT_OVERRUN;
if (isr0 & (SAB_ISR0_TCD|SAB_ISR0_RPF))
ipend |= SER_INT_RXREADY;
if ((isr0 & SAB_ISR0_CDSC) || (isr1 & SAB_ISR1_CSC))
ipend |= SER_INT_SIGCHG;
if (isr1 & SAB_ISR1_ALLS)
ipend |= SER_INT_TXIDLE;
return (ipend);
}
static int
sab82532_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
error = sab82532_param(bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
sab82532_bus_probe(struct uart_softc *sc)
{
char buf[80];
const char *vstr;
int error;
char ch;
error = sab82532_probe(&sc->sc_bas);
if (error)
return (error);
ch = sc->sc_bas.chan - 1 + 'A';
switch (uart_getreg(&sc->sc_bas, SAB_VSTR) & SAB_VSTR_VMASK) {
case SAB_VSTR_V_1:
vstr = "v1";
break;
case SAB_VSTR_V_2:
vstr = "v2";
break;
case SAB_VSTR_V_32:
vstr = "v3.2";
sc->sc_hwiflow = 0; /* CTS doesn't work with RFC:RFDF. */
sc->sc_hwoflow = 1;
break;
default:
vstr = "v4?";
break;
}
snprintf(buf, sizeof(buf), "SAB 82532 %s, channel %c", vstr, ch);
device_set_desc_copy(sc->sc_dev, buf);
return (0);
}
static int
sab82532_bus_receive(struct uart_softc *sc)
{
struct uart_bas *bas;
int i, rbcl, xc;
uint8_t s;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
if (uart_getreg(bas, SAB_STAR) & SAB_STAR_RFNE) {
rbcl = uart_getreg(bas, SAB_RBCL) & 31;
if (rbcl == 0)
rbcl = 32;
for (i = 0; i < rbcl; i += 2) {
if (uart_rx_full(sc)) {
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
xc = uart_getreg(bas, SAB_RFIFO);
s = uart_getreg(bas, SAB_RFIFO + 1);
if (s & SAB_RSTAT_FE)
xc |= UART_STAT_FRAMERR;
if (s & SAB_RSTAT_PE)
xc |= UART_STAT_PARERR;
uart_rx_put(sc, xc);
}
}
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_RMC);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
sab82532_bus_setsig(struct uart_softc *sc, int sig)
{
struct uart_bas *bas;
uint32_t new, old;
uint8_t mode, pvr;
bas = &sc->sc_bas;
do {
old = sc->sc_hwsig;
new = old;
if (sig & SER_DDTR) {
SIGCHG(sig & SER_DTR, new, SER_DTR,
SER_DDTR);
}
if (sig & SER_DRTS) {
SIGCHG(sig & SER_RTS, new, SER_RTS,
SER_DRTS);
}
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
uart_lock(sc->sc_hwmtx);
/* Set DTR pin. */
pvr = uart_getreg(bas, SAB_PVR);
switch (bas->chan) {
case 1:
if (new & SER_DTR)
pvr &= ~SAB_PVR_DTR_A;
else
pvr |= SAB_PVR_DTR_A;
break;
case 2:
if (new & SER_DTR)
pvr &= ~SAB_PVR_DTR_B;
else
pvr |= SAB_PVR_DTR_B;
break;
}
uart_setreg(bas, SAB_PVR, pvr);
/* Set RTS pin. */
mode = uart_getreg(bas, SAB_MODE);
if (new & SER_RTS)
mode &= ~SAB_MODE_FRTS;
else
mode |= SAB_MODE_FRTS;
uart_setreg(bas, SAB_MODE, mode);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
sab82532_bus_transmit(struct uart_softc *sc)
{
struct uart_bas *bas;
int i;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
while (!(uart_getreg(bas, SAB_STAR) & SAB_STAR_XFW))
;
for (i = 0; i < sc->sc_txdatasz; i++)
uart_setreg(bas, SAB_XFIFO + i, sc->sc_txbuf[i]);
uart_barrier(bas);
while (uart_getreg(bas, SAB_STAR) & SAB_STAR_CEC)
;
uart_setreg(bas, SAB_CMDR, SAB_CMDR_XF);
sc->sc_txbusy = 1;
uart_unlock(sc->sc_hwmtx);
return (0);
}