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freebsd-skq/sys/dev/uart/uart_dev_ns8250.c
mav 25326dab4e Relax TX draining in ns8250_bus_transmit(). 
Since TX interrupt is generated when THRE is set, wait for TEMT set means
wait for full character transmission time.  At low speeds that may take
awhile, burning CPU time while holding sc_hwmtx lock, also congested.

This is partial revert of r317659.

PR:		240121
MFC after:	2 weeks
2019-09-15 23:56:39 +00:00

1083 lines
28 KiB
C
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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_acpi.h"
#include "opt_platform.h"
#include "opt_uart.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>
#ifdef FDT
#include <dev/uart/uart_cpu_fdt.h>
#endif
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_dev_ns8250.h>
#include <dev/uart/uart_ppstypes.h>
#ifdef DEV_ACPI
#include <dev/uart/uart_cpu_acpi.h>
#endif
#include <dev/ic/ns16550.h>
#include "uart_if.h"
#define DEFAULT_RCLK 1843200
/*
* Set the default baudrate tolerance to 3.0%.
*
* Some embedded boards have odd reference clocks (eg 25MHz)
* and we need to handle higher variances in the target baud rate.
*/
#ifndef UART_DEV_TOLERANCE_PCT
#define UART_DEV_TOLERANCE_PCT 30
#endif /* UART_DEV_TOLERANCE_PCT */
static int broken_txfifo = 0;
SYSCTL_INT(_hw, OID_AUTO, broken_txfifo, CTLFLAG_RWTUN,
&broken_txfifo, 0, "UART FIFO has QEMU emulation bug");
/*
* 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;
/* enforce maximum error tolerance: */
if (error < -UART_DEV_TOLERANCE_PCT || error > UART_DEV_TOLERANCE_PCT)
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;
#ifdef CPU_XBURST
fcr |= FCR_UART_ON;
#endif
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 *);
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;
#ifdef CPU_XBURST
uart_setreg(bas, REG_FCR, FCR_UART_ON);
#endif
/* 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, val;
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). */
val = 0;
#ifdef CPU_XBURST
val |= FCR_UART_ON;
#endif
uart_setreg(bas, REG_FCR, val);
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);
}
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);
}
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),
KOBJMETHOD(uart_grab, ns8250_bus_grab),
KOBJMETHOD(uart_ungrab, ns8250_bus_ungrab),
{ 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,
.uc_rshift = 0
};
/*
* XXX -- refactor out ACPI and FDT ifdefs
*/
#ifdef DEV_ACPI
static struct acpi_uart_compat_data acpi_compat_data[] = {
{"AMD0020", &uart_ns8250_class, 0, 2, 0, 48000000, UART_F_BUSY_DETECT, "AMD / Synopsys Designware UART"},
{"AMDI0020", &uart_ns8250_class, 0, 2, 0, 48000000, UART_F_BUSY_DETECT, "AMD / Synopsys Designware UART"},
{"MRVL0001", &uart_ns8250_class, 0, 2, 0, 200000000, UART_F_BUSY_DETECT, "Marvell / Synopsys Designware UART"},
{"SCX0006", &uart_ns8250_class, 0, 2, 0, 62500000, UART_F_BUSY_DETECT, "SynQuacer / Synopsys Designware UART"},
{"HISI0031", &uart_ns8250_class, 0, 2, 0, 200000000, UART_F_BUSY_DETECT, "HiSilicon / Synopsys Designware UART"},
{"PNP0500", &uart_ns8250_class, 0, 0, 0, 0, 0, "Standard PC COM port"},
{"PNP0501", &uart_ns8250_class, 0, 0, 0, 0, 0, "16550A-compatible COM port"},
{"PNP0502", &uart_ns8250_class, 0, 0, 0, 0, 0, "Multiport serial device (non-intelligent 16550)"},
{"PNP0510", &uart_ns8250_class, 0, 0, 0, 0, 0, "Generic IRDA-compatible device"},
{"PNP0511", &uart_ns8250_class, 0, 0, 0, 0, 0, "Generic IRDA-compatible device"},
{"WACF004", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet PC Screen"},
{"WACF00E", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet PC Screen 00e"},
{"FUJ02E5", &uart_ns8250_class, 0, 0, 0, 0, 0, "Wacom Tablet at FuS Lifebook T"},
{NULL, NULL, 0, 0 , 0, 0, 0, NULL},
};
UART_ACPI_CLASS_AND_DEVICE(acpi_compat_data);
#endif
#ifdef FDT
static struct ofw_compat_data compat_data[] = {
{"ns16550", (uintptr_t)&uart_ns8250_class},
{"ns16550a", (uintptr_t)&uart_ns8250_class},
{NULL, (uintptr_t)NULL},
};
UART_FDT_CLASS_AND_DEVICE(compat_data);
#endif
/* Use token-pasting to form SER_ and MSR_ named constants. */
#define SER(sig) SER_##sig
#define SERD(sig) SER_D##sig
#define MSR(sig) MSR_##sig
#define MSRD(sig) MSR_D##sig
/*
* Detect signal changes using software delta detection. The previous state of
* the signals is in 'var' the new hardware state is in 'msr', and 'sig' is the
* short name (DCD, CTS, etc) of the signal bit being processed; 'var' gets the
* new state of both the signal and the delta bits.
*/
#define SIGCHGSW(var, msr, sig) \
if ((msr) & MSR(sig)) { \
if ((var & SER(sig)) == 0) \
var |= SERD(sig) | SER(sig); \
} else { \
if ((var & SER(sig)) != 0) \
var = SERD(sig) | (var & ~SER(sig)); \
}
/*
* Detect signal changes using the hardware msr delta bits. This is currently
* used only when PPS timing information is being captured using the "narrow
* pulse" option. With a narrow PPS pulse the signal may not still be asserted
* by time the interrupt handler is invoked. The hardware will latch the fact
* that it changed in the delta bits.
*/
#define SIGCHGHW(var, msr, sig) \
if ((msr) & MSRD(sig)) { \
if (((msr) & MSR(sig)) != 0) \
var |= SERD(sig) | SER(sig); \
else \
var = SERD(sig) | (var & ~SER(sig)); \
}
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
#ifdef FDT
/* Check whether uart has a broken txfifo. */
node = ofw_bus_get_node(sc->sc_dev);
if ((OF_getencprop(node, "broken-txfifo", &cell, sizeof(cell))) > 0)
broken_txfifo = cell ? 1 : 0;
#endif
bas = &sc->sc_bas;
ns8250->busy_detect = bas->busy_detect;
ns8250->mcr = uart_getreg(bas, REG_MCR);
ns8250->fcr = FCR_ENABLE;
#ifdef CPU_XBURST
ns8250->fcr |= FCR_UART_ON;
#endif
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);
/*
* Timing of the H/W access was changed with r253161 of uart_core.c
* It has been observed that an ITE IT8513E would signal a break
* condition with pretty much every character it received, unless
* it had enough time to settle between ns8250_bus_attach() and
* ns8250_bus_ipend() -- which it accidentally had before r253161.
* It's not understood why the UART chip behaves this way and it
* could very well be that the DELAY make the H/W work in the same
* accidental manner as before. More analysis is warranted, but
* at least now we fixed a known regression.
*/
DELAY(200);
return (0);
}
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);
}
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);
}
int
ns8250_bus_getsig(struct uart_softc *sc)
{
uint32_t old, sig;
uint8_t msr;
/*
* The delta bits are reputed to be broken on some hardware, so use
* software delta detection by default. Use the hardware delta bits
* when capturing PPS pulses which are too narrow for software detection
* to see the edges. Hardware delta for RI doesn't work like the
* others, so always use software for it. Other threads may be changing
* other (non-MSR) bits in sc_hwsig, so loop until it can successfully
* update without other changes happening. Note that the SIGCHGxx()
* macros carefully preserve the delta bits when we have to loop several
* times and a signal transitions between iterations.
*/
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);
if (sc->sc_pps_mode & UART_PPS_NARROW_PULSE) {
SIGCHGHW(sig, msr, DSR);
SIGCHGHW(sig, msr, CTS);
SIGCHGHW(sig, msr, DCD);
} else {
SIGCHGSW(sig, msr, DSR);
SIGCHGSW(sig, msr, CTS);
SIGCHGSW(sig, msr, DCD);
}
SIGCHGSW(sig, msr, RI);
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, sig & ~SER_MASK_DELTA));
return (sig);
}
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);
}
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);
uart_barrier(bas);
} else
ipend |= SER_INT_SIGCHG;
}
if (ipend == 0)
ns8250_clrint(bas);
uart_unlock(sc->sc_hwmtx);
return (ipend);
}
int
ns8250_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
struct ns8250_softc *ns8250;
struct uart_bas *bas;
int error, limit;
ns8250 = (struct ns8250_softc*)sc;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
/*
* When using DW UART with BUSY detection it is necessary to wait
* until all serial transfers are finished before manipulating the
* line control. LCR will not be affected when UART is busy.
*/
if (ns8250->busy_detect != 0) {
/*
* Pick an arbitrary high limit to avoid getting stuck in
* an infinite loop in case when the hardware is broken.
*/
limit = 10 * 1024;
while (((uart_getreg(bas, DW_REG_USR) & USR_BUSY) != 0) &&
--limit)
DELAY(4);
if (limit <= 0) {
/* UART appears to be stuck */
uart_unlock(sc->sc_hwmtx);
return (EIO);
}
}
error = ns8250_param(bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (error);
}
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;
uint8_t val;
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.
*/
val = FCR_ENABLE;
#ifdef CPU_XBURST
val |= FCR_UART_ON;
#endif
uart_setreg(bas, REG_FCR, val);
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);
}
val = FCR_ENABLE | FCR_XMT_RST | FCR_RCV_RST;
#ifdef CPU_XBURST
val |= FCR_UART_ON;
#endif
uart_setreg(bas, REG_FCR, val);
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);
val = 0;
#ifdef CPU_XBURST
val |= FCR_UART_ON;
#endif
uart_setreg(bas, REG_FCR, val);
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);
val = 0;
#ifdef CPU_XBURST
val |= FCR_UART_ON;
#endif
uart_setreg(bas, REG_FCR, val);
uart_barrier(bas);
count = 0;
goto describe;
}
} while ((lsr & LSR_OE) == 0 && count < 260);
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 if (count >= 224 && count <= 256) {
sc->sc_rxfifosz = 256;
device_set_desc(sc->sc_dev, "16x50 with 256 byte FIFO");
} 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 basically 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);
}
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);
}
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) {
new = (new & ~SER_DTR) | (sig & (SER_DTR | SER_DDTR));
}
if (sig & SER_DRTS) {
new = (new & ~SER_RTS) | (sig & (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);
}
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)
DELAY(4);
for (i = 0; i < sc->sc_txdatasz; i++) {
uart_setreg(bas, REG_DATA, sc->sc_txbuf[i]);
uart_barrier(bas);
}
uart_setreg(bas, REG_IER, ns8250->ier | IER_ETXRDY);
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);
}
void
ns8250_bus_grab(struct uart_softc *sc)
{
struct uart_bas *bas = &sc->sc_bas;
struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
u_char ier;
/*
* turn off all interrupts to enter polling mode. Leave the
* saved mask alone. We'll restore whatever it was in ungrab.
* All pending interrupt signals are reset when IER is set to 0.
*/
uart_lock(sc->sc_hwmtx);
ier = uart_getreg(bas, REG_IER);
uart_setreg(bas, REG_IER, ier & ns8250->ier_mask);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
}
void
ns8250_bus_ungrab(struct uart_softc *sc)
{
struct ns8250_softc *ns8250 = (struct ns8250_softc*)sc;
struct uart_bas *bas = &sc->sc_bas;
/*
* Restore previous interrupt mask
*/
uart_lock(sc->sc_hwmtx);
uart_setreg(bas, REG_IER, ns8250->ier);
uart_barrier(bas);
uart_unlock(sc->sc_hwmtx);
}
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