d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
83e4b6172e
freebsd-skq/sys/mips/octeon1/uart_dev_oct16550.c

827 lines
21 KiB
C
Raw Blame History

/*-
* 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.
*/
/*
* uart_dev_oct16550.c
*
* Derived from uart_dev_ns8250.c
*
* 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <machine/bus.h>
#include <machine/pcpu.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_cpu.h>
#include <dev/uart/uart_bus.h>
#include <dev/ic/ns16550.h>
#include "uart_if.h"
/*
* Clear pending interrupts. THRE is cleared by reading IIR. Data
* that may have been received gets lost here.
*/
static void
oct16550_clrint (struct uart_bas *bas)
{
uint8_t iir;
iir = uart_getreg(bas, REG_IIR);
while ((iir & IIR_NOPEND) == 0) {
iir &= IIR_IMASK;
if (iir == IIR_RLS)
(void)uart_getreg(bas, REG_LSR);
else if (iir == IIR_RXRDY || iir == IIR_RXTOUT)
(void)uart_getreg(bas, REG_DATA);
else if (iir == IIR_MLSC)
(void)uart_getreg(bas, REG_MSR);
else if (iir == IIR_BUSY)
(void) uart_getreg(bas, REG_USR);
uart_barrier(bas);
iir = uart_getreg(bas, REG_IIR);
}
}
static int delay_changed = 1;
static int
oct16550_delay (struct uart_bas *bas)
{
int divisor;
u_char lcr;
static int delay = 0;
if (!delay_changed) return delay;
delay_changed = 0;
lcr = uart_getreg(bas, REG_LCR);
uart_setreg(bas, REG_LCR, lcr | LCR_DLAB);
uart_barrier(bas);
divisor = uart_getreg(bas, REG_DLL) | (uart_getreg(bas, REG_DLH) << 8);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
if(!bas->rclk)
return 10; /* return an approx delay value */
/* 1/10th the time to transmit 1 character (estimate). */
if (divisor <= 134)
return (16000000 * divisor / bas->rclk);
return (16000 * divisor / (bas->rclk / 1000));
}
static int
oct16550_divisor (int rclk, int baudrate)
{
int actual_baud, divisor;
int error;
if (baudrate == 0)
return (0);
divisor = (rclk / (baudrate << 3) + 1) >> 1;
if (divisor == 0 || divisor >= 65536)
return (0);
actual_baud = rclk / (divisor << 4);
/* 10 times error in percent: */
error = ((actual_baud - baudrate) * 2000 / baudrate + 1) >> 1;
/* 3.0% maximum error tolerance: */
if (error < -30 || error > 30)
return (0);
return (divisor);
}
static int
oct16550_drain (struct uart_bas *bas, int what)
{
int delay, limit;
delay = oct16550_delay(bas);
if (what & UART_DRAIN_TRANSMITTER) {
/*
* Pick an arbitrary high limit to avoid getting stuck in
* an infinite loop when the hardware is broken. Make the
* limit high enough to handle large FIFOs.
*/
limit = 10*10*10*1024;
while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0 && --limit)
DELAY(delay);
if (limit == 0) {
/* printf("oct16550: transmitter appears stuck... "); */
return (0);
}
}
if (what & UART_DRAIN_RECEIVER) {
/*
* Pick an arbitrary high limit to avoid getting stuck in
* an infinite loop when the hardware is broken. Make the
* limit high enough to handle large FIFOs and integrated
* UARTs. The HP rx2600 for example has 3 UARTs on the
* management board that tend to get a lot of data send
* to it when the UART is first activated.
*/
limit=10*4096;
while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) && --limit) {
(void)uart_getreg(bas, REG_DATA);
uart_barrier(bas);
DELAY(delay << 2);
}
if (limit == 0) {
/* printf("oct16550: receiver appears broken... "); */
return (EIO);
}
}
return (0);
}
/*
* We can only flush UARTs with FIFOs. UARTs without FIFOs should be
* drained. WARNING: this function clobbers the FIFO setting!
*/
static void
oct16550_flush (struct uart_bas *bas, int what)
{
uint8_t fcr;
fcr = FCR_ENABLE;
if (what & UART_FLUSH_TRANSMITTER)
fcr |= FCR_XMT_RST;
if (what & UART_FLUSH_RECEIVER)
fcr |= FCR_RCV_RST;
uart_setreg(bas, REG_FCR, fcr);
uart_barrier(bas);
}
static int
oct16550_param (struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
int divisor;
uint8_t lcr;
lcr = 0;
if (databits >= 8)
lcr |= LCR_8BITS;
else if (databits == 7)
lcr |= LCR_7BITS;
else if (databits == 6)
lcr |= LCR_6BITS;
else
lcr |= LCR_5BITS;
if (stopbits > 1)
lcr |= LCR_STOPB;
lcr |= parity << 3;
/* Set baudrate. */
if (baudrate > 0) {
divisor = oct16550_divisor(bas->rclk, baudrate);
if (divisor == 0)
return (EINVAL);
uart_setreg(bas, REG_LCR, lcr | LCR_DLAB);
uart_barrier(bas);
uart_setreg(bas, REG_DLL, divisor & 0xff);
uart_setreg(bas, REG_DLH, (divisor >> 8) & 0xff);
uart_barrier(bas);
delay_changed = 1;
}
/* Set LCR and clear DLAB. */
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
return (0);
}
/*
* Low-level UART interface.
*/
static int oct16550_probe(struct uart_bas *bas);
static void oct16550_init(struct uart_bas *bas, int, int, int, int);
static void oct16550_term(struct uart_bas *bas);
static void oct16550_putc(struct uart_bas *bas, int);
static int oct16550_rxready(struct uart_bas *bas);
static int oct16550_getc(struct uart_bas *bas, struct mtx *);
struct uart_ops uart_oct16550_ops = {
.probe = oct16550_probe,
.init = oct16550_init,
.term = oct16550_term,
.putc = oct16550_putc,
.rxready = oct16550_rxready,
.getc = oct16550_getc,
};
static int
oct16550_probe (struct uart_bas *bas)
{
u_char val;
/* Check known 0 bits that don't depend on DLAB. */
val = uart_getreg(bas, REG_IIR);
if (val & 0x30)
return (ENXIO);
val = uart_getreg(bas, REG_MCR);
if (val & 0xc0)
return (ENXIO);
val = uart_getreg(bas, REG_USR);
if (val & 0xe0)
return (ENXIO);
return (0);
}
static void
oct16550_init (struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
u_char ier;
oct16550_param(bas, baudrate, databits, stopbits, parity);
/* Disable all interrupt sources. */
ier = uart_getreg(bas, REG_IER) & 0x0;
uart_setreg(bas, REG_IER, ier);
uart_barrier(bas);
/* Disable the FIFO (if present). */
// uart_setreg(bas, REG_FCR, 0);
uart_barrier(bas);
/* Set RTS & DTR. */
uart_setreg(bas, REG_MCR, MCR_RTS | MCR_DTR);
uart_barrier(bas);
oct16550_clrint(bas);
}
static void
oct16550_term (struct uart_bas *bas)
{
/* Clear RTS & DTR. */
uart_setreg(bas, REG_MCR, 0);
uart_barrier(bas);
}
static inline void oct16550_wait_txhr_empty (struct uart_bas *bas, int limit, int delay)
{
while (((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0) &&
((uart_getreg(bas, REG_USR) & USR_TXFIFO_NOTFULL) == 0))
DELAY(delay);
}
static void
oct16550_putc (struct uart_bas *bas, int c)
{
int delay;
/* 1/10th the time to transmit 1 character (estimate). */
delay = oct16550_delay(bas);
oct16550_wait_txhr_empty(bas, 100, delay);
uart_setreg(bas, REG_DATA, c);
uart_barrier(bas);
oct16550_wait_txhr_empty(bas, 100, delay);
}
static int
oct16550_rxready (struct uart_bas *bas)
{
return ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) != 0 ? 1 : 0);
}
static int
oct16550_getc (struct uart_bas *bas, struct mtx *hwmtx)
{
int c, delay;
uart_lock(hwmtx);
/* 1/10th the time to transmit 1 character (estimate). */
delay = oct16550_delay(bas);
while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0) {
uart_unlock(hwmtx);
DELAY(delay);
uart_lock(hwmtx);
}
c = uart_getreg(bas, REG_DATA);
uart_unlock(hwmtx);
return (c);
}
/*
* High-level UART interface.
*/
struct oct16550_softc {
struct uart_softc base;
uint8_t fcr;
uint8_t ier;
uint8_t mcr;
};
static int oct16550_bus_attach(struct uart_softc *);
static int oct16550_bus_detach(struct uart_softc *);
static int oct16550_bus_flush(struct uart_softc *, int);
static int oct16550_bus_getsig(struct uart_softc *);
static int oct16550_bus_ioctl(struct uart_softc *, int, intptr_t);
static int oct16550_bus_ipend(struct uart_softc *);
static int oct16550_bus_param(struct uart_softc *, int, int, int, int);
static int oct16550_bus_probe(struct uart_softc *);
static int oct16550_bus_receive(struct uart_softc *);
static int oct16550_bus_setsig(struct uart_softc *, int);
static int oct16550_bus_transmit(struct uart_softc *);
static kobj_method_t oct16550_methods[] = {
KOBJMETHOD(uart_attach, oct16550_bus_attach),
KOBJMETHOD(uart_detach, oct16550_bus_detach),
KOBJMETHOD(uart_flush, oct16550_bus_flush),
KOBJMETHOD(uart_getsig, oct16550_bus_getsig),
KOBJMETHOD(uart_ioctl, oct16550_bus_ioctl),
KOBJMETHOD(uart_ipend, oct16550_bus_ipend),
KOBJMETHOD(uart_param, oct16550_bus_param),
KOBJMETHOD(uart_probe, oct16550_bus_probe),
KOBJMETHOD(uart_receive, oct16550_bus_receive),
KOBJMETHOD(uart_setsig, oct16550_bus_setsig),
KOBJMETHOD(uart_transmit, oct16550_bus_transmit),
{ 0, 0 }
};
struct uart_class uart_oct16550_class = {
"oct16550 class",
oct16550_methods,
sizeof(struct oct16550_softc),
.uc_ops = &uart_oct16550_ops,
.uc_range = 8,
.uc_rclk = 0
};
#define SIGCHG(c, i, s, d) \
if (c) { \
i |= (i & s) ? s : s | d; \
} else { \
i = (i & s) ? (i & ~s) | d : i; \
}
static int
oct16550_bus_attach (struct uart_softc *sc)
{
struct oct16550_softc *oct16550 = (struct oct16550_softc*)sc;
struct uart_bas *bas;
int unit;
unit = device_get_unit(sc->sc_dev);
bas = &sc->sc_bas;
oct16550_drain(bas, UART_DRAIN_TRANSMITTER);
oct16550->mcr = uart_getreg(bas, REG_MCR);
oct16550->fcr = FCR_ENABLE | FCR_RX_HIGH;
uart_setreg(bas, REG_FCR, oct16550->fcr);
uart_barrier(bas);
oct16550_bus_flush(sc, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER);
if (oct16550->mcr & MCR_DTR)
sc->sc_hwsig |= SER_DTR;
if (oct16550->mcr & MCR_RTS)
sc->sc_hwsig |= SER_RTS;
oct16550_bus_getsig(sc);
oct16550_clrint(bas);
oct16550->ier = uart_getreg(bas, REG_IER) & 0xf0;
oct16550->ier |= IER_EMSC | IER_ERLS | IER_ERXRDY;
uart_setreg(bas, REG_IER, oct16550->ier);
uart_barrier(bas);
uint32_t status_bits = mips_rd_status();
mips_wr_status(status_bits & ~MIPS_SR_INT_IE);
/*
* Enable the interrupt in CIU. // UART-x2 @ IP2
*/
ciu_enable_interrupts(0, CIU_INT_0, CIU_EN_0,
(!unit) ? CIU_UART_BITS_UART0 : CIU_UART_BITS_UART1, CIU_MIPS_IP2);
return (0);
}
static int
oct16550_bus_detach (struct uart_softc *sc)
{
struct uart_bas *bas;
u_char ier;
bas = &sc->sc_bas;
ier = uart_getreg(bas, REG_IER) & 0xf0;
uart_setreg(bas, REG_IER, ier);
uart_barrier(bas);
oct16550_clrint(bas);
return (0);
}
static int
oct16550_bus_flush (struct uart_softc *sc, int what)
{
struct oct16550_softc *oct16550 = (struct oct16550_softc*)sc;
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
if (sc->sc_rxfifosz > 1) {
oct16550_flush(bas, what);
uart_setreg(bas, REG_FCR, oct16550->fcr);
uart_barrier(bas);
error = 0;
} else
error = oct16550_drain(bas, what);
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
oct16550_bus_getsig (struct uart_softc *sc)
{
uint32_t new, old, sig;
uint8_t msr;
do {
old = sc->sc_hwsig;
sig = old;
uart_lock(sc->sc_hwmtx);
msr = uart_getreg(&sc->sc_bas, REG_MSR);
uart_unlock(sc->sc_hwmtx);
SIGCHG(msr & MSR_DSR, sig, SER_DSR, SER_DDSR);
SIGCHG(msr & MSR_CTS, sig, SER_CTS, SER_DCTS);
SIGCHG(msr & MSR_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(msr & MSR_RI, sig, SER_RI, SER_DRI);
new = sig & ~SER_MASK_DELTA;
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
return (sig);
}
static int
oct16550_bus_ioctl (struct uart_softc *sc, int request, intptr_t data)
{
struct uart_bas *bas;
int baudrate, divisor, error;
uint8_t efr, lcr;
bas = &sc->sc_bas;
error = 0;
uart_lock(sc->sc_hwmtx);
switch (request) {
case UART_IOCTL_BREAK:
lcr = uart_getreg(bas, REG_LCR);
if (data)
lcr |= LCR_SBREAK;
else
lcr &= ~LCR_SBREAK;
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
break;
case UART_IOCTL_IFLOW:
lcr = uart_getreg(bas, REG_LCR);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, 0xbf);
uart_barrier(bas);
efr = uart_getreg(bas, REG_EFR);
if (data)
efr |= EFR_RTS;
else
efr &= ~EFR_RTS;
uart_setreg(bas, REG_EFR, efr);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
break;
case UART_IOCTL_OFLOW:
lcr = uart_getreg(bas, REG_LCR);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, 0xbf);
uart_barrier(bas);
efr = uart_getreg(bas, REG_EFR);
if (data)
efr |= EFR_CTS;
else
efr &= ~EFR_CTS;
uart_setreg(bas, REG_EFR, efr);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
break;
case UART_IOCTL_BAUD:
lcr = uart_getreg(bas, REG_LCR);
uart_setreg(bas, REG_LCR, lcr | LCR_DLAB);
uart_barrier(bas);
divisor = uart_getreg(bas, REG_DLL) |
(uart_getreg(bas, REG_DLH) << 8);
uart_barrier(bas);
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
baudrate = (divisor > 0) ? bas->rclk / divisor / 16 : 0;
delay_changed = 1;
if (baudrate > 0)
*(int*)data = baudrate;
else
error = ENXIO;
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
oct16550_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
int ipend = 0;
uint8_t iir, lsr;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
iir = uart_getreg(bas, REG_IIR) & IIR_IMASK;
if (iir != IIR_NOPEND) {
if (iir == IIR_RLS) {
lsr = uart_getreg(bas, REG_LSR);
if (lsr & LSR_OE)
ipend |= SER_INT_OVERRUN;
if (lsr & LSR_BI)
ipend |= SER_INT_BREAK;
if (lsr & LSR_RXRDY)
ipend |= SER_INT_RXREADY;
} else if (iir == IIR_RXRDY) {
ipend |= SER_INT_RXREADY;
} else if (iir == IIR_RXTOUT) {
ipend |= SER_INT_RXREADY;
} else if (iir == IIR_TXRDY) {
ipend |= SER_INT_TXIDLE;
} else if (iir == IIR_MLSC) {
ipend |= SER_INT_SIGCHG;
} else if (iir == IIR_BUSY) {
(void) uart_getreg(bas, REG_USR);
}
}
uart_unlock(sc->sc_hwmtx);
//#define OCTEON_VISUAL_UART 1
#ifdef OCTEON_VISUAL_UART
static int where1 = 0;
if (ipend) octeon_led_run_wheel(&where1, 6 + device_get_unit(sc->sc_dev));
#endif
return ((sc->sc_leaving) ? 0 : ipend);
}
static int
oct16550_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 = oct16550_param(bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
oct16550_bus_probe (struct uart_softc *sc)
{
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
bas->rclk = uart_oct16550_class.uc_rclk = octeon_cpu_clock;
error = oct16550_probe(bas);
if (error) {
return (error);
}
uart_setreg(bas, REG_MCR, (MCR_DTR | MCR_RTS));
/*
* Enable FIFOs. And check that the UART has them. If not, we're
* done. Since this is the first time we enable the FIFOs, we reset
* them.
*/
oct16550_drain(bas, UART_DRAIN_TRANSMITTER);
#define ENABLE_OCTEON_FIFO 1
#ifdef ENABLE_OCTEON_FIFO
uart_setreg(bas, REG_FCR, FCR_ENABLE | FCR_XMT_RST | FCR_RCV_RST);
#endif
uart_barrier(bas);
oct16550_flush(bas, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER);
if (device_get_unit(sc->sc_dev)) {
device_set_desc(sc->sc_dev, "Octeon-16550 channel 1");
} else {
device_set_desc(sc->sc_dev, "Octeon-16550 channel 0");
}
#ifdef ENABLE_OCTEON_FIFO
sc->sc_rxfifosz = 64;
sc->sc_txfifosz = 64;
#else
sc->sc_rxfifosz = 1;
sc->sc_txfifosz = 1;
#endif
#if 0
/*
* XXX there are some issues related to hardware flow control and
* it's likely that uart(4) is the cause. This basicly needs more
* investigation, but we avoid using for hardware flow control
* until then.
*/
/* 16650s or higher have automatic flow control. */
if (sc->sc_rxfifosz > 16) {
sc->sc_hwiflow = 1;
sc->sc_hwoflow = 1;
}
#endif
return (0);
}
static int
oct16550_bus_receive (struct uart_softc *sc)
{
struct uart_bas *bas;
int xc;
uint8_t lsr;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
lsr = uart_getreg(bas, REG_LSR);
while (lsr & LSR_RXRDY) {
if (uart_rx_full(sc)) {
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
xc = uart_getreg(bas, REG_DATA);
if (lsr & LSR_FE)
xc |= UART_STAT_FRAMERR;
if (lsr & LSR_PE)
xc |= UART_STAT_PARERR;
uart_rx_put(sc, xc);
lsr = uart_getreg(bas, REG_LSR);
}
/* Discard everything left in the Rx FIFO. */
/*
* First do a dummy read/discard anyway, in case the UART was lying to us.
* This problem was seen on board, when IIR said RBR, but LSR said no RXRDY
* Results in a stuck ipend loop.
*/
(void)uart_getreg(bas, REG_DATA);
while (lsr & LSR_RXRDY) {
(void)uart_getreg(bas, REG_DATA);
uart_barrier(bas);
lsr = uart_getreg(bas, REG_LSR);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
oct16550_bus_setsig (struct uart_softc *sc, int sig)
{
struct oct16550_softc *oct16550 = (struct oct16550_softc*)sc;
struct uart_bas *bas;
uint32_t new, old;
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);
oct16550->mcr &= ~(MCR_DTR|MCR_RTS);
if (new & SER_DTR)
oct16550->mcr |= MCR_DTR;
if (new & SER_RTS)
oct16550->mcr |= MCR_RTS;
uart_setreg(bas, REG_MCR, oct16550->mcr);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
oct16550_bus_transmit (struct uart_softc *sc)
{
struct oct16550_softc *oct16550 = (struct oct16550_softc*)sc;
struct uart_bas *bas;
int i;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
#ifdef NO_UART_INTERRUPTS
for (i = 0; i < sc->sc_txdatasz; i++) {
oct16550_putc(bas, sc->sc_txbuf[i]);
}
#else
oct16550_wait_txhr_empty(bas, 100, oct16550_delay(bas));
uart_setreg(bas, REG_IER, oct16550->ier | IER_ETXRDY);
uart_barrier(bas);
for (i = 0; i < sc->sc_txdatasz; i++) {
uart_setreg(bas, REG_DATA, sc->sc_txbuf[i]);
uart_barrier(bas);
}
sc->sc_txbusy = 1;
#endif
uart_unlock(sc->sc_hwmtx);
return (0);
}
Reference in New Issue View Git Blame Copy Permalink