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freebsd-skq/sys/dev/uart/uart_dev_ns8250.c
ganbold 07edb9e327 Add support for A10 uart. 
A10 uart is derived from Synopsys DesignWare uart and requires
to read Uart Status Register when IIR_BUSY has detected.
Also this change includes FDT check, where it checks device
specific properties defined in dts and sets the busy_detect variable.
broken_txfifo is also needed to be set in order to make it work for
A10 uart case.

Reviewed by: marcel@
Approved by: gonzo@
2013-03-01 01:42:31 +00:00

914 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 "opt_platform.h"
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <machine/bus.h>
#ifdef FDT
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif
#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"
#define DEFAULT_RCLK 1843200
static int broken_txfifo = 0;
SYSCTL_INT(_hw, OID_AUTO, broken_txfifo, CTLFLAG_RW | CTLFLAG_TUN,
&broken_txfifo, 0, "UART FIFO has QEMU emulation bug");
TUNABLE_INT("hw.broken_txfifo", &broken_txfifo);
/*
* Clear pending interrupts. THRE is cleared by reading IIR. Data
* that may have been received gets lost here.
*/
static void
ns8250_clrint(struct uart_bas *bas)
{
uint8_t iir, lsr;
iir = uart_getreg(bas, REG_IIR);
while ((iir & IIR_NOPEND) == 0) {
iir &= IIR_IMASK;
if (iir == IIR_RLS) {
lsr = uart_getreg(bas, REG_LSR);
if (lsr & (LSR_BI|LSR_FE|LSR_PE))
(void)uart_getreg(bas, REG_DATA);
} 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);
uart_barrier(bas);
iir = uart_getreg(bas, REG_IIR);
}
}
static int
ns8250_delay(struct uart_bas *bas)
{
int divisor;
u_char lcr;
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);
/* 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
ns8250_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
ns8250_drain(struct uart_bas *bas, int what)
{
int delay, limit;
delay = ns8250_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*1024;
while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0 && --limit)
DELAY(delay);
if (limit == 0) {
/* printf("ns8250: transmitter appears stuck... "); */
return (EIO);
}
}
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("ns8250: 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
ns8250_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
ns8250_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 = ns8250_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);
}
/* Set LCR and clear DLAB. */
uart_setreg(bas, REG_LCR, lcr);
uart_barrier(bas);
return (0);
}
/*
* Low-level UART interface.
*/
static int ns8250_probe(struct uart_bas *bas);
static void ns8250_init(struct uart_bas *bas, int, int, int, int);
static void ns8250_term(struct uart_bas *bas);
static void ns8250_putc(struct uart_bas *bas, int);
static int ns8250_rxready(struct uart_bas *bas);
static int ns8250_getc(struct uart_bas *bas, struct mtx *);
static struct uart_ops uart_ns8250_ops = {
.probe = ns8250_probe,
.init = ns8250_init,
.term = ns8250_term,
.putc = ns8250_putc,
.rxready = ns8250_rxready,
.getc = ns8250_getc,
};
static int
ns8250_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);
/*
* Bit 6 of the MCR (= 0x40) appears to be 1 for the Sun1699
* chip, but otherwise doesn't seem to have a function. In
* other words, uart(4) works regardless. Ignore that bit so
* the probe succeeds.
*/
val = uart_getreg(bas, REG_MCR);
if (val & 0xa0)
return (ENXIO);
return (0);
}
static void
ns8250_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
u_char ier;
if (bas->rclk == 0)
bas->rclk = DEFAULT_RCLK;
ns8250_param(bas, baudrate, databits, stopbits, parity);
/* Disable all interrupt sources. */
/*
* We use 0xe0 instead of 0xf0 as the mask because the XScale PXA
* UARTs split the receive time-out interrupt bit out separately as
* 0x10. This gets handled by ier_mask and ier_rxbits below.
*/
ier = uart_getreg(bas, REG_IER) & 0xe0;
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_IE | MCR_RTS | MCR_DTR);
uart_barrier(bas);
ns8250_clrint(bas);
}
static void
ns8250_term(struct uart_bas *bas)
{
/* Clear RTS & DTR. */
uart_setreg(bas, REG_MCR, MCR_IE);
uart_barrier(bas);
}
static void
ns8250_putc(struct uart_bas *bas, int c)
{
int limit;
limit = 250000;
while ((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0 && --limit)
DELAY(4);
uart_setreg(bas, REG_DATA, c);
uart_barrier(bas);
limit = 250000;
while ((uart_getreg(bas, REG_LSR) & LSR_TEMT) == 0 && --limit)
DELAY(4);
}
static int
ns8250_rxready(struct uart_bas *bas)
{
return ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) != 0 ? 1 : 0);
}
static int
ns8250_getc(struct uart_bas *bas, struct mtx *hwmtx)
{
int c;
uart_lock(hwmtx);
while ((uart_getreg(bas, REG_LSR) & LSR_RXRDY) == 0) {
uart_unlock(hwmtx);
DELAY(4);
uart_lock(hwmtx);
}
c = uart_getreg(bas, REG_DATA);
uart_unlock(hwmtx);
return (c);
}
/*
* High-level UART interface.
*/
struct ns8250_softc {
struct uart_softc base;
uint8_t fcr;
uint8_t ier;
uint8_t mcr;
uint8_t ier_mask;
uint8_t ier_rxbits;
uint8_t busy_detect;
};
static int ns8250_bus_attach(struct uart_softc *);
static int ns8250_bus_detach(struct uart_softc *);
static int ns8250_bus_flush(struct uart_softc *, int);
static int ns8250_bus_getsig(struct uart_softc *);
static int ns8250_bus_ioctl(struct uart_softc *, int, intptr_t);
static int ns8250_bus_ipend(struct uart_softc *);
static int ns8250_bus_param(struct uart_softc *, int, int, int, int);
static int ns8250_bus_probe(struct uart_softc *);
static int ns8250_bus_receive(struct uart_softc *);
static int ns8250_bus_setsig(struct uart_softc *, int);
static int ns8250_bus_transmit(struct uart_softc *);
static kobj_method_t ns8250_methods[] = {
KOBJMETHOD(uart_attach, ns8250_bus_attach),
KOBJMETHOD(uart_detach, ns8250_bus_detach),
KOBJMETHOD(uart_flush, ns8250_bus_flush),
KOBJMETHOD(uart_getsig, ns8250_bus_getsig),
KOBJMETHOD(uart_ioctl, ns8250_bus_ioctl),
KOBJMETHOD(uart_ipend, ns8250_bus_ipend),
KOBJMETHOD(uart_param, ns8250_bus_param),
KOBJMETHOD(uart_probe, ns8250_bus_probe),
KOBJMETHOD(uart_receive, ns8250_bus_receive),
KOBJMETHOD(uart_setsig, ns8250_bus_setsig),
KOBJMETHOD(uart_transmit, ns8250_bus_transmit),
{ 0, 0 }
};
struct uart_class uart_ns8250_class = {
"ns8250",
ns8250_methods,
sizeof(struct ns8250_softc),
.uc_ops = &uart_ns8250_ops,
.uc_range = 8,
.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
ns8250_bus_attach(struct uart_softc *sc)
{
struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
struct uart_bas *bas;
unsigned int ivar;
#ifdef FDT
phandle_t node;
pcell_t cell;
#endif
ns8250->busy_detect = 0;
#ifdef FDT
/*
* Check whether uart requires to read USR reg when IIR_BUSY and
* has broken txfifo.
*/
node = ofw_bus_get_node(sc->sc_dev);
if ((OF_getprop(node, "busy-detect", &cell, sizeof(cell))) > 0)
ns8250->busy_detect = 1;
if ((OF_getprop(node, "broken-txfifo", &cell, sizeof(cell))) > 0)
broken_txfifo = 1;
#endif
bas = &sc->sc_bas;
ns8250->mcr = uart_getreg(bas, REG_MCR);
ns8250->fcr = FCR_ENABLE;
if (!resource_int_value("uart", device_get_unit(sc->sc_dev), "flags",
&ivar)) {
if (UART_FLAGS_FCR_RX_LOW(ivar))
ns8250->fcr |= FCR_RX_LOW;
else if (UART_FLAGS_FCR_RX_MEDL(ivar))
ns8250->fcr |= FCR_RX_MEDL;
else if (UART_FLAGS_FCR_RX_HIGH(ivar))
ns8250->fcr |= FCR_RX_HIGH;
else
ns8250->fcr |= FCR_RX_MEDH;
} else
ns8250->fcr |= FCR_RX_MEDH;
/* Get IER mask */
ivar = 0xf0;
resource_int_value("uart", device_get_unit(sc->sc_dev), "ier_mask",
&ivar);
ns8250->ier_mask = (uint8_t)(ivar & 0xff);
/* Get IER RX interrupt bits */
ivar = IER_EMSC | IER_ERLS | IER_ERXRDY;
resource_int_value("uart", device_get_unit(sc->sc_dev), "ier_rxbits",
&ivar);
ns8250->ier_rxbits = (uint8_t)(ivar & 0xff);
uart_setreg(bas, REG_FCR, ns8250->fcr);
uart_barrier(bas);
ns8250_bus_flush(sc, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER);
if (ns8250->mcr & MCR_DTR)
sc->sc_hwsig |= SER_DTR;
if (ns8250->mcr & MCR_RTS)
sc->sc_hwsig |= SER_RTS;
ns8250_bus_getsig(sc);
ns8250_clrint(bas);
ns8250->ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask;
ns8250->ier |= ns8250->ier_rxbits;
uart_setreg(bas, REG_IER, ns8250->ier);
uart_barrier(bas);
return (0);
}
static int
ns8250_bus_detach(struct uart_softc *sc)
{
struct ns8250_softc *ns8250;
struct uart_bas *bas;
u_char ier;
ns8250 = (struct ns8250_softc *)sc;
bas = &sc->sc_bas;
ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask;
uart_setreg(bas, REG_IER, ier);
uart_barrier(bas);
ns8250_clrint(bas);
return (0);
}
static int
ns8250_bus_flush(struct uart_softc *sc, int what)
{
struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
if (sc->sc_rxfifosz > 1) {
ns8250_flush(bas, what);
uart_setreg(bas, REG_FCR, ns8250->fcr);
uart_barrier(bas);
error = 0;
} else
error = ns8250_drain(bas, what);
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
ns8250_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
ns8250_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;
if (baudrate > 0)
*(int*)data = baudrate;
else
error = ENXIO;
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
ns8250_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
struct ns8250_softc *ns8250;
int ipend;
uint8_t iir, lsr;
ns8250 = (struct ns8250_softc *)sc;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
iir = uart_getreg(bas, REG_IIR);
if (ns8250->busy_detect && (iir & IIR_BUSY) == IIR_BUSY) {
(void)uart_getreg(bas, DW_REG_USR);
uart_unlock(sc->sc_hwmtx);
return (0);
}
if (iir & IIR_NOPEND) {
uart_unlock(sc->sc_hwmtx);
return (0);
}
ipend = 0;
if (iir & IIR_RXRDY) {
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_TXRDY) {
ipend |= SER_INT_TXIDLE;
uart_setreg(bas, REG_IER, ns8250->ier);
} else
ipend |= SER_INT_SIGCHG;
}
if (ipend == 0)
ns8250_clrint(bas);
uart_unlock(sc->sc_hwmtx);
return (ipend);
}
static int
ns8250_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 = ns8250_param(bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
ns8250_bus_probe(struct uart_softc *sc)
{
struct ns8250_softc *ns8250;
struct uart_bas *bas;
int count, delay, error, limit;
uint8_t lsr, mcr, ier;
ns8250 = (struct ns8250_softc *)sc;
bas = &sc->sc_bas;
error = ns8250_probe(bas);
if (error)
return (error);
mcr = MCR_IE;
if (sc->sc_sysdev == NULL) {
/* By using ns8250_init() we also set DTR and RTS. */
ns8250_init(bas, 115200, 8, 1, UART_PARITY_NONE);
} else
mcr |= MCR_DTR | MCR_RTS;
error = ns8250_drain(bas, UART_DRAIN_TRANSMITTER);
if (error)
return (error);
/*
* Set loopback mode. This avoids having garbage on the wire and
* also allows us send and receive data. We set DTR and RTS to
* avoid the possibility that automatic flow-control prevents
* any data from being sent.
*/
uart_setreg(bas, REG_MCR, MCR_LOOPBACK | MCR_IE | MCR_DTR | MCR_RTS);
uart_barrier(bas);
/*
* 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.
*/
uart_setreg(bas, REG_FCR, FCR_ENABLE);
uart_barrier(bas);
if (!(uart_getreg(bas, REG_IIR) & IIR_FIFO_MASK)) {
/*
* NS16450 or INS8250. We don't bother to differentiate
* between them. They're too old to be interesting.
*/
uart_setreg(bas, REG_MCR, mcr);
uart_barrier(bas);
sc->sc_rxfifosz = sc->sc_txfifosz = 1;
device_set_desc(sc->sc_dev, "8250 or 16450 or compatible");
return (0);
}
uart_setreg(bas, REG_FCR, FCR_ENABLE | FCR_XMT_RST | FCR_RCV_RST);
uart_barrier(bas);
count = 0;
delay = ns8250_delay(bas);
/* We have FIFOs. Drain the transmitter and receiver. */
error = ns8250_drain(bas, UART_DRAIN_RECEIVER|UART_DRAIN_TRANSMITTER);
if (error) {
uart_setreg(bas, REG_MCR, mcr);
uart_setreg(bas, REG_FCR, 0);
uart_barrier(bas);
goto describe;
}
/*
* We should have a sufficiently clean "pipe" to determine the
* size of the FIFOs. We send as much characters as is reasonable
* and wait for the overflow bit in the LSR register to be
* asserted, counting the characters as we send them. Based on
* that count we know the FIFO size.
*/
do {
uart_setreg(bas, REG_DATA, 0);
uart_barrier(bas);
count++;
limit = 30;
lsr = 0;
/*
* LSR bits are cleared upon read, so we must accumulate
* them to be able to test LSR_OE below.
*/
while (((lsr |= uart_getreg(bas, REG_LSR)) & LSR_TEMT) == 0 &&
--limit)
DELAY(delay);
if (limit == 0) {
ier = uart_getreg(bas, REG_IER) & ns8250->ier_mask;
uart_setreg(bas, REG_IER, ier);
uart_setreg(bas, REG_MCR, mcr);
uart_setreg(bas, REG_FCR, 0);
uart_barrier(bas);
count = 0;
goto describe;
}
} while ((lsr & LSR_OE) == 0 && count < 130);
count--;
uart_setreg(bas, REG_MCR, mcr);
/* Reset FIFOs. */
ns8250_flush(bas, UART_FLUSH_RECEIVER|UART_FLUSH_TRANSMITTER);
describe:
if (count >= 14 && count <= 16) {
sc->sc_rxfifosz = 16;
device_set_desc(sc->sc_dev, "16550 or compatible");
} else if (count >= 28 && count <= 32) {
sc->sc_rxfifosz = 32;
device_set_desc(sc->sc_dev, "16650 or compatible");
} else if (count >= 56 && count <= 64) {
sc->sc_rxfifosz = 64;
device_set_desc(sc->sc_dev, "16750 or compatible");
} else if (count >= 112 && count <= 128) {
sc->sc_rxfifosz = 128;
device_set_desc(sc->sc_dev, "16950 or compatible");
} else {
sc->sc_rxfifosz = 16;
device_set_desc(sc->sc_dev,
"Non-standard ns8250 class UART with FIFOs");
}
/*
* Force the Tx FIFO size to 16 bytes for now. We don't program the
* Tx trigger. Also, we assume that all data has been sent when the
* interrupt happens.
*/
sc->sc_txfifosz = 16;
#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
ns8250_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. */
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
ns8250_bus_setsig(struct uart_softc *sc, int sig)
{
struct ns8250_softc *ns8250 = (struct ns8250_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);
ns8250->mcr &= ~(MCR_DTR|MCR_RTS);
if (new & SER_DTR)
ns8250->mcr |= MCR_DTR;
if (new & SER_RTS)
ns8250->mcr |= MCR_RTS;
uart_setreg(bas, REG_MCR, ns8250->mcr);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
ns8250_bus_transmit(struct uart_softc *sc)
{
struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
struct uart_bas *bas;
int i;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
while ((uart_getreg(bas, REG_LSR) & LSR_THRE) == 0)
;
uart_setreg(bas, REG_IER, ns8250->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);
}
if (broken_txfifo)
ns8250_drain(bas, UART_DRAIN_TRANSMITTER);
else
sc->sc_txbusy = 1;
uart_unlock(sc->sc_hwmtx);
if (broken_txfifo)
uart_sched_softih(sc, SER_INT_TXIDLE);
return (0);
}
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