freebsd-dev/sys/dev/uart/uart_dev_lowrisc.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2018 Ruslan Bukin <br@bsdpad.com>
* All rights reserved.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory (Department of Computer Science and
* Technology) under DARPA contract HR0011-18-C-0016 ("ECATS"), as part of the
* DARPA SSITH research programme.
*
* 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 "opt_ddb.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/conf.h>
#include <sys/kdb.h>
#include <machine/bus.h>
#include <machine/sbi.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_cpu.h>
#include <dev/uart/uart_cpu_fdt.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_dev_lowrisc.h>
#include "uart_if.h"
#define DEFAULT_BAUD_RATE 115200
/*
* Low-level UART interface.
*/
static int lowrisc_uart_probe(struct uart_bas *bas);
static void lowrisc_uart_init(struct uart_bas *bas, int, int, int, int);
static void lowrisc_uart_term(struct uart_bas *bas);
static void lowrisc_uart_putc(struct uart_bas *bas, int);
static int lowrisc_uart_rxready(struct uart_bas *bas);
static int lowrisc_uart_getc(struct uart_bas *bas, struct mtx *);
static struct uart_ops uart_lowrisc_uart_ops = {
.probe = lowrisc_uart_probe,
.init = lowrisc_uart_init,
.term = lowrisc_uart_term,
.putc = lowrisc_uart_putc,
.rxready = lowrisc_uart_rxready,
.getc = lowrisc_uart_getc,
};
static int
lowrisc_uart_probe(struct uart_bas *bas)
{
return (0);
}
static u_int
lowrisc_uart_getbaud(struct uart_bas *bas)
{
return (DEFAULT_BAUD_RATE);
}
static void
lowrisc_uart_init(struct uart_bas *bas, int baudrate, int databits,
int stopbits, int parity)
{
/* TODO */
}
static void
lowrisc_uart_term(struct uart_bas *bas)
{
/* TODO */
}
static void
lowrisc_uart_putc(struct uart_bas *bas, int c)
{
while (GETREG(bas, UART_DR) & DR_TX_FIFO_FULL)
;
SETREG(bas, UART_DR, c);
}
static int
lowrisc_uart_rxready(struct uart_bas *bas)
{
if (GETREG(bas, UART_DR) & DR_RX_FIFO_EMPTY)
return (0);
return (1);
}
static int
lowrisc_uart_getc(struct uart_bas *bas, struct mtx *hwmtx)
{
uint32_t reg;
uart_lock(hwmtx);
SETREG(bas, UART_INT_STATUS, INT_STATUS_ACK);
reg = GETREG(bas, UART_DR);
uart_unlock(hwmtx);
return (reg & 0xff);
}
/*
* High-level UART interface.
*/
struct lowrisc_uart_softc {
struct uart_softc base;
};
static int lowrisc_uart_bus_attach(struct uart_softc *);
static int lowrisc_uart_bus_detach(struct uart_softc *);
static int lowrisc_uart_bus_flush(struct uart_softc *, int);
static int lowrisc_uart_bus_getsig(struct uart_softc *);
static int lowrisc_uart_bus_ioctl(struct uart_softc *, int, intptr_t);
static int lowrisc_uart_bus_ipend(struct uart_softc *);
static int lowrisc_uart_bus_param(struct uart_softc *, int, int, int, int);
static int lowrisc_uart_bus_probe(struct uart_softc *);
static int lowrisc_uart_bus_receive(struct uart_softc *);
static int lowrisc_uart_bus_setsig(struct uart_softc *, int);
static int lowrisc_uart_bus_transmit(struct uart_softc *);
static void lowrisc_uart_bus_grab(struct uart_softc *);
static void lowrisc_uart_bus_ungrab(struct uart_softc *);
static kobj_method_t lowrisc_uart_methods[] = {
KOBJMETHOD(uart_attach, lowrisc_uart_bus_attach),
KOBJMETHOD(uart_detach, lowrisc_uart_bus_detach),
KOBJMETHOD(uart_flush, lowrisc_uart_bus_flush),
KOBJMETHOD(uart_getsig, lowrisc_uart_bus_getsig),
KOBJMETHOD(uart_ioctl, lowrisc_uart_bus_ioctl),
KOBJMETHOD(uart_ipend, lowrisc_uart_bus_ipend),
KOBJMETHOD(uart_param, lowrisc_uart_bus_param),
KOBJMETHOD(uart_probe, lowrisc_uart_bus_probe),
KOBJMETHOD(uart_receive, lowrisc_uart_bus_receive),
KOBJMETHOD(uart_setsig, lowrisc_uart_bus_setsig),
KOBJMETHOD(uart_transmit, lowrisc_uart_bus_transmit),
KOBJMETHOD(uart_grab, lowrisc_uart_bus_grab),
KOBJMETHOD(uart_ungrab, lowrisc_uart_bus_ungrab),
{ 0, 0 }
};
static struct uart_class uart_lowrisc_class = {
"lowrisc",
lowrisc_uart_methods,
sizeof(struct lowrisc_uart_softc),
.uc_ops = &uart_lowrisc_uart_ops,
.uc_range = 0x100,
.uc_rclk = 12500000, /* TODO: get value from clock manager */
.uc_rshift = 0
};
static struct ofw_compat_data compat_data[] = {
{"lowrisc-fake", (uintptr_t)&uart_lowrisc_class},
{NULL, (uintptr_t)NULL},
};
UART_FDT_CLASS_AND_DEVICE(compat_data);
static int
lowrisc_uart_bus_attach(struct uart_softc *sc)
{
struct uart_bas *bas;
struct uart_devinfo *di;
bas = &sc->sc_bas;
if (sc->sc_sysdev != NULL) {
di = sc->sc_sysdev;
lowrisc_uart_init(bas, di->baudrate, di->databits, di->stopbits,
di->parity);
} else
lowrisc_uart_init(bas, DEFAULT_BAUD_RATE, 8, 1, 0);
(void)lowrisc_uart_bus_getsig(sc);
/* TODO: clear all pending interrupts. */
return (0);
}
static int
lowrisc_uart_bus_detach(struct uart_softc *sc)
{
/* TODO */
return (0);
}
static int
lowrisc_uart_bus_flush(struct uart_softc *sc, int what)
{
/* TODO */
return (0);
}
static int
lowrisc_uart_bus_getsig(struct uart_softc *sc)
{
/* TODO */
return (0);
}
static int
lowrisc_uart_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:
/* TODO */
break;
case UART_IOCTL_BAUD:
*(u_int*)data = lowrisc_uart_getbaud(bas);
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
lowrisc_uart_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
int ipend;
bas = &sc->sc_bas;
ipend = 0;
uart_lock(sc->sc_hwmtx);
if ((GETREG(bas, UART_DR) & DR_RX_FIFO_EMPTY) == 0)
ipend |= SER_INT_RXREADY;
SETREG(bas, UART_INT_STATUS, INT_STATUS_ACK);
uart_unlock(sc->sc_hwmtx);
return (ipend);
}
static int
lowrisc_uart_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
uart_lock(sc->sc_hwmtx);
lowrisc_uart_init(&sc->sc_bas, baudrate, databits, stopbits, parity);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
lowrisc_uart_bus_probe(struct uart_softc *sc)
{
int error;
error = lowrisc_uart_probe(&sc->sc_bas);
if (error)
return (error);
/*
* On input we can read up to the full fifo size at once. On output, we
* want to write only as much as the programmed tx low water level,
* because that's all we can be certain we have room for in the fifo
* when we get a tx-ready interrupt.
*/
sc->sc_rxfifosz = 2048;
sc->sc_txfifosz = 2048;
device_set_desc(sc->sc_dev, "lowRISC UART");
return (0);
}
static int
lowrisc_uart_bus_receive(struct uart_softc *sc)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
do {
if (uart_rx_full(sc)) {
/* No space left in the input buffer */
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
reg = GETREG(bas, UART_DR);
SETREG(bas, UART_INT_STATUS, INT_STATUS_ACK);
uart_rx_put(sc, reg & 0xff);
} while ((reg & DR_RX_FIFO_EMPTY) == 0);
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
lowrisc_uart_bus_setsig(struct uart_softc *sc, int sig)
{
return (0);
}
static int
lowrisc_uart_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++) {
while (GETREG(bas, UART_DR) & DR_TX_FIFO_FULL)
;
SETREG(bas, UART_DR, sc->sc_txbuf[i] & 0xff);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
static void
lowrisc_uart_bus_grab(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
/* TODO */
uart_unlock(sc->sc_hwmtx);
}
static void
lowrisc_uart_bus_ungrab(struct uart_softc *sc)
{
struct uart_bas *bas;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
/* TODO */
uart_unlock(sc->sc_hwmtx);
}