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freebsd-dev/sys/dev/uart/uart_dev_pl011.c
Warner Losh d76a1ef4e1 Introduce grab and ungrab upcalls. When the kernel desires to grab the 
console, it calls the grab functions. These functions should turn off
the RX interrupts, and any others that interfere. This makes mountroot
prompt work again. If there's more generalized need other than
prompting, many of these routines should be expanded to do those new
things.

Should have been part of r260889, but waasn't due to command line typo.

Reviewed by:	bde (with reservations)
2014-01-19 19:39:13 +00:00

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/*-
* Copyright (c) 2012 Semihalf.
* 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/kernel.h>
#include <sys/bus.h>
#include <machine/bus.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_cpu.h>
#include <dev/uart/uart_bus.h>
#include "uart_if.h"
#include <sys/kdb.h>
/* PL011 UART registers and masks*/
#define UART_DR 0x00 /* Data register */
#define DR_FE (1 << 8) /* Framing error */
#define DR_PE (1 << 9) /* Parity error */
#define DR_BE (1 << 10) /* Break error */
#define DR_OE (1 << 11) /* Overrun error */
#define UART_FR 0x06 /* Flag register */
#define FR_RXFF (1 << 6) /* Receive FIFO/reg full */
#define FR_TXFE (1 << 7) /* Transmit FIFO/reg empty */
#define UART_IBRD 0x09 /* Integer baud rate register */
#define IBRD_BDIVINT 0xffff /* Significant part of int. divisor value */
#define UART_FBRD 0x0a /* Fractional baud rate register */
#define FBRD_BDIVFRAC 0x3f /* Significant part of frac. divisor value */
#define UART_LCR_H 0x0b /* Line control register */
#define LCR_H_WLEN8 (0x3 << 5)
#define LCR_H_WLEN7 (0x2 << 5)
#define LCR_H_WLEN6 (0x1 << 5)
#define LCR_H_FEN (1 << 4) /* FIFO mode enable */
#define LCR_H_STP2 (1 << 3) /* 2 stop frames at the end */
#define LCR_H_EPS (1 << 2) /* Even parity select */
#define LCR_H_PEN (1 << 1) /* Parity enable */
#define UART_CR 0x0c /* Control register */
#define CR_RXE (1 << 9) /* Receive enable */
#define CR_TXE (1 << 8) /* Transmit enable */
#define CR_UARTEN (1 << 0) /* UART enable */
#define UART_IMSC 0x0e /* Interrupt mask set/clear register */
#define IMSC_MASK_ALL 0x7ff /* Mask all interrupts */
#define UART_RIS 0x0f /* Raw interrupt status register */
#define UART_RXREADY (1 << 4) /* RX buffer full */
#define UART_TXEMPTY (1 << 5) /* TX buffer empty */
#define RIS_FE (1 << 7) /* Framing error interrupt status */
#define RIS_PE (1 << 8) /* Parity error interrupt status */
#define RIS_BE (1 << 9) /* Break error interrupt status */
#define RIS_OE (1 << 10) /* Overrun interrupt status */
#define UART_MIS 0x10 /* Masked interrupt status register */
#define UART_ICR 0x11 /* Interrupt clear register */
/*
* FIXME: actual register size is SoC-dependent, we need to handle it
*/
#define __uart_getreg(bas, reg) \
bus_space_read_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg))
#define __uart_setreg(bas, reg, value) \
bus_space_write_4((bas)->bst, (bas)->bsh, uart_regofs(bas, reg), value)
/*
* Low-level UART interface.
*/
static int uart_pl011_probe(struct uart_bas *bas);
static void uart_pl011_init(struct uart_bas *bas, int, int, int, int);
static void uart_pl011_term(struct uart_bas *bas);
static void uart_pl011_putc(struct uart_bas *bas, int);
static int uart_pl011_rxready(struct uart_bas *bas);
static int uart_pl011_getc(struct uart_bas *bas, struct mtx *);
static struct uart_ops uart_pl011_ops = {
.probe = uart_pl011_probe,
.init = uart_pl011_init,
.term = uart_pl011_term,
.putc = uart_pl011_putc,
.rxready = uart_pl011_rxready,
.getc = uart_pl011_getc,
};
static int
uart_pl011_probe(struct uart_bas *bas)
{
return (0);
}
static void
uart_pl011_param(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
uint32_t ctrl, line;
uint32_t baud;
/*
* Zero all settings to make sure
* UART is disabled and not configured
*/
ctrl = line = 0x0;
__uart_setreg(bas, UART_CR, ctrl);
/* As we know UART is disabled we may setup the line */
switch (databits) {
case 7:
line |= LCR_H_WLEN7;
break;
case 6:
line |= LCR_H_WLEN6;
break;
case 8:
default:
line |= LCR_H_WLEN8;
break;
}
if (stopbits == 2)
line |= LCR_H_STP2;
else
line &= ~LCR_H_STP2;
if (parity)
line |= LCR_H_PEN;
else
line &= ~LCR_H_PEN;
/* Configure the rest */
line &= ~LCR_H_FEN;
ctrl |= (CR_RXE | CR_TXE | CR_UARTEN);
if (bas->rclk != 0 && baudrate != 0) {
baud = bas->rclk * 4 / baudrate;
__uart_setreg(bas, UART_IBRD, ((uint32_t)(baud >> 6)) & IBRD_BDIVINT);
__uart_setreg(bas, UART_FBRD, (uint32_t)(baud & 0x3F) & FBRD_BDIVFRAC);
}
/* Add config. to line before reenabling UART */
__uart_setreg(bas, UART_LCR_H, (__uart_getreg(bas, UART_LCR_H) &
~0xff) | line);
__uart_setreg(bas, UART_CR, ctrl);
}
static void
uart_pl011_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
/* Mask all interrupts */
__uart_setreg(bas, UART_IMSC, __uart_getreg(bas, UART_IMSC) &
~IMSC_MASK_ALL);
uart_pl011_param(bas, baudrate, databits, stopbits, parity);
}
static void
uart_pl011_term(struct uart_bas *bas)
{
}
static void
uart_pl011_putc(struct uart_bas *bas, int c)
{
while (!(__uart_getreg(bas, UART_FR) & FR_TXFE))
;
__uart_setreg(bas, UART_DR, c & 0xff);
}
static int
uart_pl011_rxready(struct uart_bas *bas)
{
return (__uart_getreg(bas, UART_FR) & FR_RXFF);
}
static int
uart_pl011_getc(struct uart_bas *bas, struct mtx *hwmtx)
{
int c;
while (!uart_pl011_rxready(bas))
;
c = __uart_getreg(bas, UART_DR) & 0xff;
return (c);
}
/*
* High-level UART interface.
*/
struct uart_pl011_softc {
struct uart_softc base;
uint8_t fcr;
uint8_t ier;
uint8_t mcr;
uint8_t ier_mask;
uint8_t ier_rxbits;
};
static int uart_pl011_bus_attach(struct uart_softc *);
static int uart_pl011_bus_detach(struct uart_softc *);
static int uart_pl011_bus_flush(struct uart_softc *, int);
static int uart_pl011_bus_getsig(struct uart_softc *);
static int uart_pl011_bus_ioctl(struct uart_softc *, int, intptr_t);
static int uart_pl011_bus_ipend(struct uart_softc *);
static int uart_pl011_bus_param(struct uart_softc *, int, int, int, int);
static int uart_pl011_bus_probe(struct uart_softc *);
static int uart_pl011_bus_receive(struct uart_softc *);
static int uart_pl011_bus_setsig(struct uart_softc *, int);
static int uart_pl011_bus_transmit(struct uart_softc *);
static void uart_pl011_bus_grab(struct uart_softc *);
static void uart_pl011_bus_ungrab(struct uart_softc *);
static kobj_method_t uart_pl011_methods[] = {
KOBJMETHOD(uart_attach, uart_pl011_bus_attach),
KOBJMETHOD(uart_detach, uart_pl011_bus_detach),
KOBJMETHOD(uart_flush, uart_pl011_bus_flush),
KOBJMETHOD(uart_getsig, uart_pl011_bus_getsig),
KOBJMETHOD(uart_ioctl, uart_pl011_bus_ioctl),
KOBJMETHOD(uart_ipend, uart_pl011_bus_ipend),
KOBJMETHOD(uart_param, uart_pl011_bus_param),
KOBJMETHOD(uart_probe, uart_pl011_bus_probe),
KOBJMETHOD(uart_receive, uart_pl011_bus_receive),
KOBJMETHOD(uart_setsig, uart_pl011_bus_setsig),
KOBJMETHOD(uart_transmit, uart_pl011_bus_transmit),
KOBJMETHOD(uart_grab, uart_pl011_bus_grab),
KOBJMETHOD(uart_ungrab, uart_pl011_bus_ungrab),
{ 0, 0 }
};
struct uart_class uart_pl011_class = {
"uart_pl011",
uart_pl011_methods,
sizeof(struct uart_pl011_softc),
.uc_ops = &uart_pl011_ops,
.uc_range = 0x48,
.uc_rclk = 0
};
static int
uart_pl011_bus_attach(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
/* Enable RX & TX interrupts */
__uart_setreg(bas, UART_IMSC, (UART_RXREADY | UART_TXEMPTY));
/* Clear RX & TX interrupts */
__uart_setreg(bas, UART_ICR, IMSC_MASK_ALL);
return (0);
}
static int
uart_pl011_bus_detach(struct uart_softc *sc)
{
return (0);
}
static int
uart_pl011_bus_flush(struct uart_softc *sc, int what)
{
return (0);
}
static int
uart_pl011_bus_getsig(struct uart_softc *sc)
{
return (0);
}
static int
uart_pl011_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
{
struct uart_bas *bas;
int error;
bas = &sc->sc_bas;
error = 0;
uart_lock(sc->sc_hwmtx);
switch (request) {
case UART_IOCTL_BREAK:
break;
case UART_IOCTL_BAUD:
*(int*)data = 115200;
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
uart_pl011_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
int ipend;
uint32_t ints;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
ints = __uart_getreg(bas, UART_MIS);
ipend = 0;
if (ints & UART_RXREADY)
ipend |= SER_INT_RXREADY;
if (ints & RIS_BE)
ipend |= SER_INT_BREAK;
if (ints & RIS_OE)
ipend |= SER_INT_OVERRUN;
if (ints & UART_TXEMPTY) {
if (sc->sc_txbusy)
ipend |= SER_INT_TXIDLE;
__uart_setreg(bas, UART_IMSC, UART_RXREADY);
}
uart_unlock(sc->sc_hwmtx);
return (ipend);
}
static int
uart_pl011_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
uart_lock(sc->sc_hwmtx);
uart_pl011_param(&sc->sc_bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
uart_pl011_bus_probe(struct uart_softc *sc)
{
device_set_desc(sc->sc_dev, "PrimeCell UART (PL011)");
sc->sc_rxfifosz = 1;
sc->sc_txfifosz = 1;
return (0);
}
static int
uart_pl011_bus_receive(struct uart_softc *sc)
{
struct uart_bas *bas;
int rx;
uint32_t ints, xc;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
ints = __uart_getreg(bas, UART_MIS);
while (ints & UART_RXREADY) {
if (uart_rx_full(sc)) {
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
xc = __uart_getreg(bas, UART_DR);
rx = xc & 0xff;
if (xc & DR_FE)
rx |= UART_STAT_FRAMERR;
if (xc & DR_PE)
rx |= UART_STAT_PARERR;
__uart_setreg(bas, UART_ICR, UART_RXREADY);
uart_rx_put(sc, rx);
ints = __uart_getreg(bas, UART_MIS);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
uart_pl011_bus_setsig(struct uart_softc *sc, int sig)
{
return (0);
}
static int
uart_pl011_bus_transmit(struct uart_softc *sc)
{
struct uart_bas *bas;
int i;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
for (i = 0; i < sc->sc_txdatasz; i++) {
__uart_setreg(bas, UART_DR, sc->sc_txbuf[i]);
uart_barrier(bas);
}
sc->sc_txbusy = 1;
__uart_setreg(bas, UART_IMSC, (UART_RXREADY | UART_TXEMPTY));
uart_unlock(sc->sc_hwmtx);
return (0);
}
static void
uart_pl011_bus_grab(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
__uart_setreg(bas, UART_IMSC, /* Switch to RX polling while grabbed */
~UART_RXREADY & __uart_getreg(bas, UART_IMSC));
uart_unlock(sc->sc_hwmtx);
}
static void
uart_pl011_bus_ungrab(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
__uart_setreg(bas, UART_IMSC, /* Switch to RX interrupts while not grabbed */
UART_RXREADY | __uart_getreg(bas, UART_IMSC));
uart_unlock(sc->sc_hwmtx);
}
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