freebsd-skq/sys/dev/uart/uart_dev_snps.c
br 69f1ecb8f8 Allow setting access-width for UART registers.
This is required for FDT's standard "reg-io-width" property
(similar to "reg-shift" property) found in many DTS files.

This fixes operation on Altera Arria 10 SOC Development Kit,
where standard ns8250 uart allows 4-byte access only.

Reviewed by:	kan, marcel
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D9785
2017-02-27 20:08:42 +00:00

286 lines
6.9 KiB
C

/*-
* Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
* 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.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <machine/bus.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_cpu_fdt.h>
#include <dev/uart/uart_dev_ns8250.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#ifdef EXT_RESOURCES
#include <dev/extres/clk/clk.h>
#include <dev/extres/hwreset/hwreset.h>
#endif
#include "uart_if.h"
struct snps_softc {
struct ns8250_softc ns8250;
#ifdef EXT_RESOURCES
clk_t baudclk;
clk_t apb_pclk;
hwreset_t reset;
#endif
};
static int
snps_uart_attach(struct uart_softc *uart_sc)
{
struct snps_softc *sc;
sc = (struct snps_softc *)uart_sc;
/* UART requires to read USR reg when IIR_BUSY */
sc->ns8250.busy_detect = 1;
return (ns8250_bus_attach(uart_sc));
}
static kobj_method_t snps_methods[] = {
KOBJMETHOD(uart_probe, ns8250_bus_probe),
KOBJMETHOD(uart_attach, snps_uart_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_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),
KOBJMETHOD_END
};
struct uart_class uart_snps_class = {
"snps",
snps_methods,
sizeof(struct snps_softc),
.uc_ops = &uart_ns8250_ops,
.uc_range = 8,
.uc_rclk = 0,
};
static struct ofw_compat_data compat_data[] = {
{ "snps,dw-apb-uart", (uintptr_t)&uart_snps_class },
{ NULL, (uintptr_t)NULL }
};
UART_FDT_CLASS(compat_data);
#ifdef EXT_RESOURCES
static int
snps_get_clocks(device_t dev, clk_t *baudclk, clk_t *apb_pclk)
{
struct snps_softc *sc;
sc = device_get_softc(dev);
*baudclk = NULL;
*apb_pclk = NULL;
/* Baud clock is either named "baudclk", or there is a single
* unnamed clock.
*/
if (clk_get_by_ofw_name(dev, 0, "baudclk", baudclk) != 0 &&
clk_get_by_ofw_index(dev, 0, 0, baudclk) != 0)
return (ENOENT);
/* APB peripheral clock is optional */
(void)clk_get_by_ofw_name(dev, 0, "apb_pclk", apb_pclk);
return (0);
}
#endif
static int
snps_probe(device_t dev)
{
struct snps_softc *sc;
struct uart_class *uart_class;
phandle_t node;
uint32_t shift, iowidth, clock;
uint64_t freq;
int error;
#ifdef EXT_RESOURCES
clk_t baudclk, apb_pclk;
hwreset_t reset;
#endif
if (!ofw_bus_status_okay(dev))
return (ENXIO);
uart_class = (struct uart_class *)ofw_bus_search_compatible(dev,
compat_data)->ocd_data;
if (uart_class == NULL)
return (ENXIO);
freq = 0;
sc = device_get_softc(dev);
sc->ns8250.base.sc_class = uart_class;
node = ofw_bus_get_node(dev);
if (OF_getencprop(node, "reg-shift", &shift, sizeof(shift)) <= 0)
shift = 0;
if (OF_getencprop(node, "reg-io-width", &iowidth, sizeof(iowidth)) <= 0)
iowidth = 1;
if (OF_getencprop(node, "clock-frequency", &clock, sizeof(clock)) <= 0)
clock = 0;
#ifdef EXT_RESOURCES
if (hwreset_get_by_ofw_idx(dev, 0, 0, &reset) == 0) {
error = hwreset_deassert(reset);
if (error != 0) {
device_printf(dev, "cannot de-assert reset\n");
return (error);
}
}
if (snps_get_clocks(dev, &baudclk, &apb_pclk) == 0) {
error = clk_enable(baudclk);
if (error != 0) {
device_printf(dev, "cannot enable baud clock\n");
return (error);
}
if (apb_pclk != NULL) {
error = clk_enable(apb_pclk);
if (error != 0) {
device_printf(dev,
"cannot enable peripheral clock\n");
return (error);
}
}
if (clock == 0) {
error = clk_get_freq(baudclk, &freq);
if (error != 0) {
device_printf(dev, "cannot get frequency\n");
return (error);
}
clock = (uint32_t)freq;
}
}
#endif
if (bootverbose && clock == 0)
device_printf(dev, "could not determine frequency\n");
error = uart_bus_probe(dev, (int)shift, (int)iowidth, (int)clock, 0, 0);
if (error != 0)
return (error);
#ifdef EXT_RESOURCES
/* XXX uart_bus_probe has changed the softc, so refresh it */
sc = device_get_softc(dev);
/* Store clock and reset handles for detach */
sc->baudclk = baudclk;
sc->apb_pclk = apb_pclk;
sc->reset = reset;
#endif
return (0);
}
static int
snps_detach(device_t dev)
{
#ifdef EXT_RESOURCES
struct snps_softc *sc;
clk_t baudclk, apb_pclk;
hwreset_t reset;
#endif
int error;
#ifdef EXT_RESOURCES
sc = device_get_softc(dev);
baudclk = sc->baudclk;
apb_pclk = sc->apb_pclk;
reset = sc->reset;
#endif
error = uart_bus_detach(dev);
if (error != 0)
return (error);
#ifdef EXT_RESOURCES
if (reset != NULL) {
error = hwreset_assert(reset);
if (error != 0) {
device_printf(dev, "cannot assert reset\n");
return (error);
}
hwreset_release(reset);
}
if (apb_pclk != NULL) {
error = clk_release(apb_pclk);
if (error != 0) {
device_printf(dev, "cannot release peripheral clock\n");
return (error);
}
}
if (baudclk != NULL) {
error = clk_release(baudclk);
if (error != 0) {
device_printf(dev, "cannot release baud clock\n");
return (error);
}
}
#endif
return (0);
}
static device_method_t snps_bus_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, snps_probe),
DEVMETHOD(device_attach, uart_bus_attach),
DEVMETHOD(device_detach, snps_detach),
DEVMETHOD_END
};
static driver_t snps_uart_driver = {
uart_driver_name,
snps_bus_methods,
sizeof(struct snps_softc)
};
DRIVER_MODULE(uart_snps, simplebus, snps_uart_driver, uart_devclass, 0, 0);