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freebsd-skq/sys/dev/uart/uart_dev_z8530.c
Marcel Moolenaar ca83142fc3 Make the Z8530 more reliable as low-level console by making use of the 
fact that access to RR0 does not need a prior write to the register
index because the index always reverts to 0 after the indexed register
has been accessed.

Typically when a RR or WR is to accessed, one programs the index (which
is a write to the control register), followed by a read or write to the
actual indexed register (a read pr write to the same control register).
When this non-atomic sequence is interrupted after having written the
index and low-level console I/O is done in that situation, the write to
program the index will actually write to the indexed register and nuke
state. This almost always yields a wedge.

By not programming the index register and instead just reading from RR0,
the worst case scenario is non-fatal. For if we don't actually read from
RR0 but some other register we get an invalid status, which may lead us
to conclude that the transit data register is empty when it's not or that
the receive data register contains data when it doesn't. Hence, we may
lose an output character or get a sporadic input character, but given
the situation this is a non-issue.

Full serialization is not possible due to the fact that this code needs
to work from DDB and before mutex initialization has happened.

In collaboration with: kris@, marius@
Tested by: kris@
MFC after: 1 day
X-MFC: 5.4-RELEASE candidate
2005-04-27 21:57:51 +00:00

593 lines
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/*-
* 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("$FreeBSD$");
#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/z8530.h>
#include "uart_if.h"
#define DEFAULT_RCLK 307200
/* Multiplexed I/O. */
static __inline void
uart_setmreg(struct uart_bas *bas, int reg, int val)
{
uart_setreg(bas, REG_CTRL, reg);
uart_barrier(bas);
uart_setreg(bas, REG_CTRL, val);
}
static __inline uint8_t
uart_getmreg(struct uart_bas *bas, int reg)
{
uart_setreg(bas, REG_CTRL, reg);
uart_barrier(bas);
return (uart_getreg(bas, REG_CTRL));
}
static int
z8530_divisor(int rclk, int baudrate)
{
int act_baud, divisor, error;
if (baudrate == 0)
return (0);
divisor = (rclk + baudrate) / (baudrate << 1) - 2;
if (divisor >= 65536)
return (0);
act_baud = rclk / 2 / (divisor + 2);
/* 10 times error in percent: */
error = ((act_baud - baudrate) * 2000 / baudrate + 1) >> 1;
/* 3.0% maximum error tolerance: */
if (error < -30 || error > 30)
return (0);
return (divisor);
}
static int
z8530_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity, uint8_t *tpcp)
{
int divisor;
uint8_t mpm, rpc, tpc;
rpc = RPC_RXE;
mpm = MPM_CM16;
tpc = TPC_TXE | (*tpcp & (TPC_DTR | TPC_RTS));
if (databits >= 8) {
rpc |= RPC_RB8;
tpc |= TPC_TB8;
} else if (databits == 7) {
rpc |= RPC_RB7;
tpc |= TPC_TB7;
} else if (databits == 6) {
rpc |= RPC_RB6;
tpc |= TPC_TB6;
} else {
rpc |= RPC_RB5;
tpc |= TPC_TB5;
}
mpm |= (stopbits > 1) ? MPM_SB2 : MPM_SB1;
switch (parity) {
case UART_PARITY_EVEN: mpm |= MPM_PE | MPM_EVEN; break;
case UART_PARITY_NONE: break;
case UART_PARITY_ODD: mpm |= MPM_PE; break;
default: return (EINVAL);
}
/* Set baudrate. */
if (baudrate > 0) {
divisor = z8530_divisor(bas->rclk, baudrate);
if (divisor == 0)
return (EINVAL);
uart_setmreg(bas, WR_TCL, divisor & 0xff);
uart_barrier(bas);
uart_setmreg(bas, WR_TCH, (divisor >> 8) & 0xff);
uart_barrier(bas);
}
uart_setmreg(bas, WR_RPC, rpc);
uart_barrier(bas);
uart_setmreg(bas, WR_MPM, mpm);
uart_barrier(bas);
uart_setmreg(bas, WR_TPC, tpc);
uart_barrier(bas);
*tpcp = tpc;
return (0);
}
static int
z8530_setup(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
uint8_t tpc;
if (bas->rclk == 0)
bas->rclk = DEFAULT_RCLK;
/* Assume we don't need to perform a full hardware reset. */
switch (bas->chan) {
case 1:
uart_setmreg(bas, WR_MIC, MIC_NV | MIC_CRA);
break;
case 2:
uart_setmreg(bas, WR_MIC, MIC_NV | MIC_CRB);
break;
}
uart_barrier(bas);
/* Set clock sources and enable BRG. */
uart_setmreg(bas, WR_CMC, CMC_RC_BRG | CMC_TC_BRG);
uart_setmreg(bas, WR_MCB2, MCB2_PCLK | MCB2_BRGE);
uart_barrier(bas);
/* Set data encoding. */
uart_setmreg(bas, WR_MCB1, MCB1_NRZ);
uart_barrier(bas);
tpc = TPC_DTR | TPC_RTS;
z8530_param(bas, baudrate, databits, stopbits, parity, &tpc);
return (int)tpc;
}
/*
* Low-level UART interface.
*/
static int z8530_probe(struct uart_bas *bas);
static void z8530_init(struct uart_bas *bas, int, int, int, int);
static void z8530_term(struct uart_bas *bas);
static void z8530_putc(struct uart_bas *bas, int);
static int z8530_poll(struct uart_bas *bas);
static int z8530_getc(struct uart_bas *bas);
struct uart_ops uart_z8530_ops = {
.probe = z8530_probe,
.init = z8530_init,
.term = z8530_term,
.putc = z8530_putc,
.poll = z8530_poll,
.getc = z8530_getc,
};
static int
z8530_probe(struct uart_bas *bas)
{
return (0);
}
static void
z8530_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
z8530_setup(bas, baudrate, databits, stopbits, parity);
}
static void
z8530_term(struct uart_bas *bas)
{
}
static void
z8530_putc(struct uart_bas *bas, int c)
{
while (!(uart_getreg(bas, REG_CTRL) & BES_TXE))
;
uart_setreg(bas, REG_DATA, c);
uart_barrier(bas);
}
static int
z8530_poll(struct uart_bas *bas)
{
if (!(uart_getreg(bas, REG_CTRL) & BES_RXA))
return (-1);
return (uart_getreg(bas, REG_DATA));
}
static int
z8530_getc(struct uart_bas *bas)
{
while (!(uart_getreg(bas, REG_CTRL) & BES_RXA))
;
return (uart_getreg(bas, REG_DATA));
}
/*
* High-level UART interface.
*/
struct z8530_softc {
struct uart_softc base;
uint8_t tpc;
uint8_t txidle;
};
static int z8530_bus_attach(struct uart_softc *);
static int z8530_bus_detach(struct uart_softc *);
static int z8530_bus_flush(struct uart_softc *, int);
static int z8530_bus_getsig(struct uart_softc *);
static int z8530_bus_ioctl(struct uart_softc *, int, intptr_t);
static int z8530_bus_ipend(struct uart_softc *);
static int z8530_bus_param(struct uart_softc *, int, int, int, int);
static int z8530_bus_probe(struct uart_softc *);
static int z8530_bus_receive(struct uart_softc *);
static int z8530_bus_setsig(struct uart_softc *, int);
static int z8530_bus_transmit(struct uart_softc *);
static kobj_method_t z8530_methods[] = {
KOBJMETHOD(uart_attach, z8530_bus_attach),
KOBJMETHOD(uart_detach, z8530_bus_detach),
KOBJMETHOD(uart_flush, z8530_bus_flush),
KOBJMETHOD(uart_getsig, z8530_bus_getsig),
KOBJMETHOD(uart_ioctl, z8530_bus_ioctl),
KOBJMETHOD(uart_ipend, z8530_bus_ipend),
KOBJMETHOD(uart_param, z8530_bus_param),
KOBJMETHOD(uart_probe, z8530_bus_probe),
KOBJMETHOD(uart_receive, z8530_bus_receive),
KOBJMETHOD(uart_setsig, z8530_bus_setsig),
KOBJMETHOD(uart_transmit, z8530_bus_transmit),
{ 0, 0 }
};
struct uart_class uart_z8530_class = {
"z8530 class",
z8530_methods,
sizeof(struct z8530_softc),
.uc_range = 2,
.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
z8530_bus_attach(struct uart_softc *sc)
{
struct z8530_softc *z8530 = (struct z8530_softc*)sc;
struct uart_bas *bas;
struct uart_devinfo *di;
bas = &sc->sc_bas;
if (sc->sc_sysdev != NULL) {
di = sc->sc_sysdev;
z8530->tpc = TPC_DTR|TPC_RTS;
z8530_param(bas, di->baudrate, di->databits, di->stopbits,
di->parity, &z8530->tpc);
} else {
z8530->tpc = z8530_setup(bas, 9600, 8, 1, UART_PARITY_NONE);
z8530->tpc &= ~(TPC_DTR|TPC_RTS);
}
z8530->txidle = 1; /* Report UART_IPEND_TXIDLE. */
sc->sc_rxfifosz = 3;
sc->sc_txfifosz = 1;
(void)z8530_bus_getsig(sc);
uart_setmreg(bas, WR_IC, IC_BRK | IC_CTS | IC_DCD);
uart_barrier(bas);
uart_setmreg(bas, WR_IDT, IDT_XIE | IDT_TIE | IDT_RIA);
uart_barrier(bas);
uart_setmreg(bas, WR_IV, 0);
uart_barrier(bas);
uart_setmreg(bas, WR_TPC, z8530->tpc);
uart_barrier(bas);
uart_setmreg(bas, WR_MIC, MIC_NV | MIC_MIE);
uart_barrier(bas);
return (0);
}
static int
z8530_bus_detach(struct uart_softc *sc)
{
return (0);
}
static int
z8530_bus_flush(struct uart_softc *sc, int what)
{
return (0);
}
static int
z8530_bus_getsig(struct uart_softc *sc)
{
uint32_t new, old, sig;
uint8_t bes;
do {
old = sc->sc_hwsig;
sig = old;
mtx_lock_spin(&sc->sc_hwmtx);
bes = uart_getmreg(&sc->sc_bas, RR_BES);
mtx_unlock_spin(&sc->sc_hwmtx);
SIGCHG(bes & BES_CTS, sig, SER_CTS, SER_DCTS);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);
new = sig & ~UART_SIGMASK_DELTA;
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
return (sig);
}
static int
z8530_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
{
struct z8530_softc *z8530 = (struct z8530_softc*)sc;
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
error = 0;
mtx_lock_spin(&sc->sc_hwmtx);
switch (request) {
case UART_IOCTL_BREAK:
if (data)
z8530->tpc |= TPC_BRK;
else
z8530->tpc &= ~TPC_BRK;
uart_setmreg(bas, WR_TPC, z8530->tpc);
uart_barrier(bas);
break;
default:
error = EINVAL;
break;
}
mtx_unlock_spin(&sc->sc_hwmtx);
return (error);
}
static int
z8530_bus_ipend(struct uart_softc *sc)
{
struct z8530_softc *z8530 = (struct z8530_softc*)sc;
struct uart_bas *bas;
int ipend;
uint32_t sig;
uint8_t bes, ip, iv, src;
bas = &sc->sc_bas;
ipend = 0;
mtx_lock_spin(&sc->sc_hwmtx);
switch (bas->chan) {
case 1:
ip = uart_getmreg(bas, RR_IP);
break;
case 2: /* XXX hack!!! */
iv = uart_getmreg(bas, RR_IV) & 0x0E;
switch (iv) {
case IV_TEB: ip = IP_TIA; break;
case IV_XSB: ip = IP_SIA; break;
case IV_RAB: ip = IP_RIA; break;
default: ip = 0; break;
}
break;
default:
ip = 0;
break;
}
if (ip & IP_RIA)
ipend |= UART_IPEND_RXREADY;
if (ip & IP_TIA) {
uart_setreg(bas, REG_CTRL, CR_RSTTXI);
uart_barrier(bas);
if (z8530->txidle) {
ipend |= UART_IPEND_TXIDLE;
z8530->txidle = 0; /* Mask UART_IPEND_TXIDLE. */
}
}
if (ip & IP_SIA) {
uart_setreg(bas, REG_CTRL, CR_RSTXSI);
uart_barrier(bas);
bes = uart_getmreg(bas, RR_BES);
if (bes & BES_BRK)
ipend |= UART_IPEND_BREAK;
sig = sc->sc_hwsig;
SIGCHG(bes & BES_CTS, sig, SER_CTS, SER_DCTS);
SIGCHG(bes & BES_DCD, sig, SER_DCD, SER_DDCD);
SIGCHG(bes & BES_SYNC, sig, SER_DSR, SER_DDSR);
if (sig & UART_SIGMASK_DELTA)
ipend |= UART_IPEND_SIGCHG;
src = uart_getmreg(bas, RR_SRC);
if (src & SRC_OVR) {
uart_setreg(bas, REG_CTRL, CR_RSTERR);
uart_barrier(bas);
ipend |= UART_IPEND_OVERRUN;
}
}
if (ipend) {
uart_setreg(bas, REG_CTRL, CR_RSTIUS);
uart_barrier(bas);
}
mtx_unlock_spin(&sc->sc_hwmtx);
return (ipend);
}
static int
z8530_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
struct z8530_softc *z8530 = (struct z8530_softc*)sc;
int error;
mtx_lock_spin(&sc->sc_hwmtx);
error = z8530_param(&sc->sc_bas, baudrate, databits, stopbits, parity,
&z8530->tpc);
mtx_unlock_spin(&sc->sc_hwmtx);
return (error);
}
static int
z8530_bus_probe(struct uart_softc *sc)
{
char buf[80];
int error;
char ch;
error = z8530_probe(&sc->sc_bas);
if (error)
return (error);
ch = sc->sc_bas.chan - 1 + 'A';
snprintf(buf, sizeof(buf), "z8530, channel %c", ch);
device_set_desc_copy(sc->sc_dev, buf);
return (0);
}
static int
z8530_bus_receive(struct uart_softc *sc)
{
struct uart_bas *bas;
int xc;
uint8_t bes, src;
bas = &sc->sc_bas;
mtx_lock_spin(&sc->sc_hwmtx);
bes = uart_getmreg(bas, RR_BES);
while (bes & BES_RXA) {
if (uart_rx_full(sc)) {
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
xc = uart_getreg(bas, REG_DATA);
uart_barrier(bas);
src = uart_getmreg(bas, RR_SRC);
if (src & SRC_FE)
xc |= UART_STAT_FRAMERR;
if (src & SRC_PE)
xc |= UART_STAT_PARERR;
if (src & SRC_OVR)
xc |= UART_STAT_OVERRUN;
uart_rx_put(sc, xc);
if (src & (SRC_FE | SRC_PE | SRC_OVR)) {
uart_setreg(bas, REG_CTRL, CR_RSTERR);
uart_barrier(bas);
}
bes = uart_getmreg(bas, RR_BES);
}
/* Discard everything left in the Rx FIFO. */
while (bes & BES_RXA) {
(void)uart_getreg(bas, REG_DATA);
uart_barrier(bas);
src = uart_getmreg(bas, RR_SRC);
if (src & (SRC_FE | SRC_PE | SRC_OVR)) {
uart_setreg(bas, REG_CTRL, CR_RSTERR);
uart_barrier(bas);
}
bes = uart_getmreg(bas, RR_BES);
}
mtx_unlock_spin(&sc->sc_hwmtx);
return (0);
}
static int
z8530_bus_setsig(struct uart_softc *sc, int sig)
{
struct z8530_softc *z8530 = (struct z8530_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));
mtx_lock_spin(&sc->sc_hwmtx);
if (new & SER_DTR)
z8530->tpc |= TPC_DTR;
else
z8530->tpc &= ~TPC_DTR;
if (new & SER_RTS)
z8530->tpc |= TPC_RTS;
else
z8530->tpc &= ~TPC_RTS;
uart_setmreg(bas, WR_TPC, z8530->tpc);
uart_barrier(bas);
mtx_unlock_spin(&sc->sc_hwmtx);
return (0);
}
static int
z8530_bus_transmit(struct uart_softc *sc)
{
struct z8530_softc *z8530 = (struct z8530_softc*)sc;
struct uart_bas *bas;
bas = &sc->sc_bas;
mtx_lock_spin(&sc->sc_hwmtx);
while (!(uart_getmreg(bas, RR_BES) & BES_TXE))
;
uart_setreg(bas, REG_DATA, sc->sc_txbuf[0]);
uart_barrier(bas);
sc->sc_txbusy = 1;
z8530->txidle = 1; /* Report UART_IPEND_TXIDLE again. */
mtx_unlock_spin(&sc->sc_hwmtx);
return (0);
}
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