freebsd-dev/sys/riscv/sifive/sifive_uart.c
Kristof Provost 76c6e771bc sifive: Fix incorrect tx/rx ctrl defines
Happily these were never used, but they should be correct anyway.

Reported by:	Nicholas O'Brien <nickisobrien_gmail.com>
Sponsored by:	Axiado
2020-01-07 09:02:14 +00:00

544 lines
12 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 Axiado Corporation
* All rights reserved.
*
* This software was developed in part by Kristof Provost under contract for
* Axiado Corporation.
*
* 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/bus.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/rman.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <dev/extres/clk/clk.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_cpu.h>
#include <dev/uart/uart_cpu_fdt.h>
#include "uart_if.h"
#define SFUART_TXDATA 0x00
#define SFUART_TXDATA_FULL (1 << 31)
#define SFUART_RXDATA 0x04
#define SFUART_RXDATA_EMPTY (1 << 31)
#define SFUART_TXCTRL 0x08
#define SFUART_TXCTRL_ENABLE 0x01
#define SFUART_TXCTRL_NSTOP 0x02
#define SFUART_TXCTRL_TXCNT 0x70000
#define SFUART_TXCTRL_TXCNT_SHIFT 16
#define SFUART_RXCTRL 0x0c
#define SFUART_RXCTRL_ENABLE 0x01
#define SFUART_RXCTRL_RXCNT 0x70000
#define SFUART_RXCTRL_RXCNT_SHIFT 16
#define SFUART_IRQ_ENABLE 0x10
#define SFUART_IRQ_ENABLE_TXWM 0x01
#define SFUART_IRQ_ENABLE_RXWM 0x02
#define SFUART_IRQ_PENDING 0x14
#define SFUART_IRQ_PENDING_TXWM 0x01
#define SFUART_IRQ_PENDING_RXQM 0x02
#define SFUART_DIV 0x18
#define SFUART_REGS_SIZE 0x1c
#define SFUART_RX_FIFO_DEPTH 8
#define SFUART_TX_FIFO_DEPTH 8
struct sfuart_softc {
struct uart_softc uart_softc;
clk_t clk;
};
static int
sfuart_probe(struct uart_bas *bas)
{
bas->regiowidth = 4;
return (0);
}
static void
sfuart_init(struct uart_bas *bas, int baudrate, int databits, int stopbits,
int parity)
{
uint32_t reg;
uart_setreg(bas, SFUART_IRQ_ENABLE, 0);
/* Enable RX and configure the watermark so that we get an interrupt
* when a single character arrives (if interrupts are enabled). */
reg = SFUART_RXCTRL_ENABLE;
reg |= (0 << SFUART_RXCTRL_RXCNT_SHIFT);
uart_setreg(bas, SFUART_RXCTRL, reg);
/* Enable TX and configure the watermark so that we get an interrupt
* when there's room for one more character in the TX fifo (if
* interrupts are enabled). */
reg = SFUART_TXCTRL_ENABLE;
reg |= (1 << SFUART_TXCTRL_TXCNT_SHIFT);
if (stopbits == 2)
reg |= SFUART_TXCTRL_NSTOP;
uart_setreg(bas, SFUART_TXCTRL, reg);
/* Don't touch DIV. Assume that's set correctly until we can
* reconfigure. */
}
static void
sfuart_putc(struct uart_bas *bas, int c)
{
while ((uart_getreg(bas, SFUART_TXDATA) & SFUART_TXDATA_FULL)
!= 0)
cpu_spinwait();
uart_setreg(bas, SFUART_TXDATA, c);
}
static int
sfuart_rxready(struct uart_bas *bas)
{
return ((uart_getreg(bas, SFUART_RXDATA) &
SFUART_RXDATA_EMPTY) == 0);
}
static int
sfuart_getc(struct uart_bas *bas, struct mtx *hwmtx)
{
int c;
uart_lock(hwmtx);
while (((c = uart_getreg(bas, SFUART_RXDATA)) &
SFUART_RXDATA_EMPTY) != 0) {
uart_unlock(hwmtx);
DELAY(4);
uart_lock(hwmtx);
}
uart_unlock(hwmtx);
return (c & 0xff);
}
static int
sfuart_bus_probe(struct uart_softc *sc)
{
int error;
error = sfuart_probe(&sc->sc_bas);
if (error)
return (error);
sc->sc_rxfifosz = SFUART_RX_FIFO_DEPTH;
sc->sc_txfifosz = SFUART_TX_FIFO_DEPTH;
sc->sc_hwiflow = 0;
sc->sc_hwoflow = 0;
device_set_desc(sc->sc_dev, "SiFive UART");
return (0);
}
static int
sfuart_bus_attach(struct uart_softc *sc)
{
struct uart_bas *bas;
struct sfuart_softc *sfsc;
uint64_t freq;
uint32_t reg;
int error;
sfsc = (struct sfuart_softc *)sc;
bas = &sc->sc_bas;
error = clk_get_by_ofw_index(sc->sc_dev, 0, 0, &sfsc->clk);
if (error) {
device_printf(sc->sc_dev, "couldn't allocate clock\n");
return (ENXIO);
}
error = clk_enable(sfsc->clk);
if (error) {
device_printf(sc->sc_dev, "couldn't enable clock\n");
return (ENXIO);
}
error = clk_get_freq(sfsc->clk, &freq);
if (error || freq == 0) {
clk_disable(sfsc->clk);
device_printf(sc->sc_dev, "couldn't get clock frequency\n");
return (ENXIO);
}
bas->rclk = freq;
/* Enable RX/RX */
reg = SFUART_RXCTRL_ENABLE;
reg |= (0 << SFUART_RXCTRL_RXCNT_SHIFT);
uart_setreg(bas, SFUART_RXCTRL, reg);
reg = SFUART_TXCTRL_ENABLE;
reg |= (1 << SFUART_TXCTRL_TXCNT_SHIFT);
uart_setreg(bas, SFUART_TXCTRL, reg);
/* Enable RX interrupt */
uart_setreg(bas, SFUART_IRQ_ENABLE, SFUART_IRQ_ENABLE_RXWM);
return (0);
}
static int
sfuart_bus_detach(struct uart_softc *sc)
{
struct sfuart_softc *sfsc;
struct uart_bas *bas;
sfsc = (struct sfuart_softc *)sc;
bas = &sc->sc_bas;
/* Disable RX/TX */
uart_setreg(bas, SFUART_RXCTRL, 0);
uart_setreg(bas, SFUART_TXCTRL, 0);
/* Disable interrupts */
uart_setreg(bas, SFUART_IRQ_ENABLE, 0);
clk_disable(sfsc->clk);
return (0);
}
static int
sfuart_bus_flush(struct uart_softc *sc, int what)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
if (what & UART_FLUSH_TRANSMITTER) {
do {
reg = uart_getreg(bas, SFUART_TXDATA);
} while ((reg & SFUART_TXDATA_FULL) != 0);
}
if (what & UART_FLUSH_RECEIVER) {
do {
reg = uart_getreg(bas, SFUART_RXDATA);
} while ((reg & SFUART_RXDATA_EMPTY) == 0);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
#define SIGCHG(c, i, s, d) \
do { \
if (c) \
i |= ((i) & (s)) ? (s) : (s) | (d); \
else \
i = ((i) & (s)) ? (i) & ~(s) | (d) : (i); \
} while (0)
static int
sfuart_bus_getsig(struct uart_softc *sc)
{
uint32_t new, old, sig;
do {
old = sc->sc_hwsig;
sig = old;
SIGCHG(1, sig, SER_DSR, SER_DDSR);
SIGCHG(1, sig, SER_DCD, SER_DDCD);
SIGCHG(1, sig, SER_CTS, SER_DCTS);
new = sig & ~SER_MASK_DELTA;
} while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
return (sig);
}
static int
sfuart_bus_setsig(struct uart_softc *sc, int sig)
{
uint32_t new, old;
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));
return (0);
}
static int
sfuart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
{
struct uart_bas *bas;
uint32_t reg;
int error;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
switch (request) {
case UART_IOCTL_BAUD:
reg = uart_getreg(bas, SFUART_DIV);
if (reg == 0) {
/* Possible if the divisor hasn't been set up yet. */
error = ENXIO;
break;
}
*(int*)data = bas->rclk / (reg + 1);
error = 0;
break;
default:
error = EINVAL;
break;
}
uart_unlock(sc->sc_hwmtx);
return (error);
}
static int
sfuart_bus_ipend(struct uart_softc *sc)
{
struct uart_bas *bas;
int ipend;
uint32_t reg, ie;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
ipend = 0;
reg = uart_getreg(bas, SFUART_IRQ_PENDING);
ie = uart_getreg(bas, SFUART_IRQ_ENABLE);
if ((reg & SFUART_IRQ_PENDING_TXWM) != 0 &&
(ie & SFUART_IRQ_ENABLE_TXWM) != 0) {
ipend |= SER_INT_TXIDLE;
/* Disable TX interrupt */
ie &= ~(SFUART_IRQ_ENABLE_TXWM);
uart_setreg(bas, SFUART_IRQ_ENABLE, ie);
}
if ((reg & SFUART_IRQ_PENDING_RXQM) != 0)
ipend |= SER_INT_RXREADY;
uart_unlock(sc->sc_hwmtx);
return (ipend);
}
static int
sfuart_bus_param(struct uart_softc *sc, int baudrate, int databits,
int stopbits, int parity)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
if (databits != 8)
return (EINVAL);
if (parity != UART_PARITY_NONE)
return (EINVAL);
uart_lock(sc->sc_hwmtx);
reg = uart_getreg(bas, SFUART_TXCTRL);
if (stopbits == 2) {
reg |= SFUART_TXCTRL_NSTOP;
} else if (stopbits == 1) {
reg &= ~SFUART_TXCTRL_NSTOP;
} else {
uart_unlock(sc->sc_hwmtx);
return (EINVAL);
}
if (baudrate > 0 && bas->rclk != 0) {
reg = (bas->rclk / baudrate) - 1;
uart_setreg(bas, SFUART_DIV, reg);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
sfuart_bus_receive(struct uart_softc *sc)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
reg = uart_getreg(bas, SFUART_RXDATA);
while ((reg & SFUART_RXDATA_EMPTY) == 0) {
if (uart_rx_full(sc)) {
sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
break;
}
uart_rx_put(sc, reg & 0xff);
reg = uart_getreg(bas, SFUART_RXDATA);
}
uart_unlock(sc->sc_hwmtx);
return (0);
}
static int
sfuart_bus_transmit(struct uart_softc *sc)
{
struct uart_bas *bas;
int i;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
reg = uart_getreg(bas, SFUART_IRQ_ENABLE);
reg |= SFUART_IRQ_ENABLE_TXWM;
uart_setreg(bas, SFUART_IRQ_ENABLE, reg);
for (i = 0; i < sc->sc_txdatasz; i++)
sfuart_putc(bas, sc->sc_txbuf[i]);
sc->sc_txbusy = 1;
uart_unlock(sc->sc_hwmtx);
return (0);
}
static void
sfuart_bus_grab(struct uart_softc *sc)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
reg = uart_getreg(bas, SFUART_IRQ_ENABLE);
reg &= ~(SFUART_IRQ_ENABLE_TXWM | SFUART_IRQ_PENDING_RXQM);
uart_setreg(bas, SFUART_IRQ_ENABLE, reg);
uart_unlock(sc->sc_hwmtx);
}
static void
sfuart_bus_ungrab(struct uart_softc *sc)
{
struct uart_bas *bas;
uint32_t reg;
bas = &sc->sc_bas;
uart_lock(sc->sc_hwmtx);
reg = uart_getreg(bas, SFUART_IRQ_ENABLE);
reg |= SFUART_IRQ_ENABLE_TXWM | SFUART_IRQ_PENDING_RXQM;
uart_setreg(bas, SFUART_IRQ_ENABLE, reg);
uart_unlock(sc->sc_hwmtx);
}
static kobj_method_t sfuart_methods[] = {
KOBJMETHOD(uart_probe, sfuart_bus_probe),
KOBJMETHOD(uart_attach, sfuart_bus_attach),
KOBJMETHOD(uart_detach, sfuart_bus_detach),
KOBJMETHOD(uart_flush, sfuart_bus_flush),
KOBJMETHOD(uart_getsig, sfuart_bus_getsig),
KOBJMETHOD(uart_setsig, sfuart_bus_setsig),
KOBJMETHOD(uart_ioctl, sfuart_bus_ioctl),
KOBJMETHOD(uart_ipend, sfuart_bus_ipend),
KOBJMETHOD(uart_param, sfuart_bus_param),
KOBJMETHOD(uart_receive, sfuart_bus_receive),
KOBJMETHOD(uart_transmit, sfuart_bus_transmit),
KOBJMETHOD(uart_grab, sfuart_bus_grab),
KOBJMETHOD(uart_ungrab, sfuart_bus_ungrab),
KOBJMETHOD_END
};
static struct uart_ops sfuart_ops = {
.probe = sfuart_probe,
.init = sfuart_init,
.term = NULL,
.putc = sfuart_putc,
.rxready = sfuart_rxready,
.getc = sfuart_getc,
};
struct uart_class sfuart_class = {
"sifiveuart",
sfuart_methods,
sizeof(struct sfuart_softc),
.uc_ops = &sfuart_ops,
.uc_range = SFUART_REGS_SIZE,
.uc_rclk = 0,
.uc_rshift = 0
};
static struct ofw_compat_data compat_data[] = {
{ "sifive,uart0", (uintptr_t)&sfuart_class },
{ NULL, (uintptr_t)NULL }
};
UART_FDT_CLASS_AND_DEVICE(compat_data);