freebsd-dev/sys/dev/uart/uart_bus_fdt.c
Marcel Moolenaar 3470949a74 Check the environment for system devices before using the FDT.
This allows overriding the FDT, and allows specifying a debug
port.
2011-01-17 23:34:36 +00:00

204 lines
5.1 KiB
C

/*-
* Copyright (c) 2009-2010 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Semihalf under sponsorship from
* the FreeBSD Foundation.
*
* 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/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <machine/bus.h>
#include <machine/fdt.h>
#include <dev/fdt/fdt_common.h>
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/uart/uart.h>
#include <dev/uart/uart_bus.h>
#include <dev/uart/uart_cpu.h>
static int uart_fdt_probe(device_t);
static device_method_t uart_fdt_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, uart_fdt_probe),
DEVMETHOD(device_attach, uart_bus_attach),
DEVMETHOD(device_detach, uart_bus_detach),
{ 0, 0 }
};
static driver_t uart_fdt_driver = {
uart_driver_name,
uart_fdt_methods,
sizeof(struct uart_softc),
};
static int
uart_fdt_get_clock(phandle_t node, pcell_t *cell)
{
pcell_t clock;
if ((OF_getprop(node, "clock-frequency", &clock,
sizeof(clock))) <= 0)
return (ENXIO);
if (clock == 0)
/* Try to retrieve parent 'bus-frequency' */
/* XXX this should go to simple-bus fixup or so */
if ((OF_getprop(OF_parent(node), "bus-frequency", &clock,
sizeof(clock))) <= 0)
clock = 0;
*cell = fdt32_to_cpu(clock);
return (0);
}
static int
uart_fdt_get_shift(phandle_t node, pcell_t *cell)
{
pcell_t shift;
if ((OF_getprop(node, "reg-shift", &shift, sizeof(shift))) <= 0)
shift = 0;
*cell = fdt32_to_cpu(shift);
return (0);
}
static int
uart_fdt_probe(device_t dev)
{
struct uart_softc *sc;
phandle_t node;
pcell_t clock, shift;
int err;
if (!ofw_bus_is_compatible(dev, "ns16550"))
return (ENXIO);
sc = device_get_softc(dev);
sc->sc_class = &uart_ns8250_class;
node = ofw_bus_get_node(dev);
if ((err = uart_fdt_get_clock(node, &clock)) != 0)
return (err);
uart_fdt_get_shift(node, &shift);
return (uart_bus_probe(dev, (int)shift, (int)clock, 0, 0));
}
DRIVER_MODULE(uart, simplebus, uart_fdt_driver, uart_devclass, 0, 0);
/*
* UART console routines.
*/
bus_space_tag_t uart_bus_space_io;
bus_space_tag_t uart_bus_space_mem;
int
uart_cpu_eqres(struct uart_bas *b1, struct uart_bas *b2)
{
return ((b1->bsh == b2->bsh && b1->bst == b2->bst) ? 1 : 0);
}
int
uart_cpu_getdev(int devtype, struct uart_devinfo *di)
{
char buf[64];
struct uart_class *class;
phandle_t node, chosen;
pcell_t shift, br, rclk;
u_long start, size;
int err;
uart_bus_space_mem = fdtbus_bs_tag;
uart_bus_space_io = NULL;
/* Allow overriding the FDT uning the environment. */
class = &uart_ns8250_class;
err = uart_getenv(devtype, di, class);
if (!err)
return (0);
if (devtype != UART_DEV_CONSOLE)
return (ENXIO);
/*
* Retrieve /chosen/std{in,out}.
*/
if ((chosen = OF_finddevice("/chosen")) == 0)
return (ENXIO);
if (OF_getprop(chosen, "stdin", buf, sizeof(buf)) <= 0)
return (ENXIO);
if ((node = OF_finddevice(buf)) == 0)
return (ENXIO);
if (OF_getprop(chosen, "stdout", buf, sizeof(buf)) <= 0)
return (ENXIO);
if (OF_finddevice(buf) != node)
/* Only stdin == stdout is supported. */
return (ENXIO);
/*
* Retrieve serial attributes.
*/
uart_fdt_get_shift(node, &shift);
if (OF_getprop(node, "current-speed", &br, sizeof(br)) <= 0)
br = 0;
br = fdt32_to_cpu(br);
if ((err = uart_fdt_get_clock(node, &rclk)) != 0)
return (err);
/*
* Finalize configuration.
*/
class = &uart_quicc_class;
if (fdt_is_compatible(node, "ns16550"))
class = &uart_ns8250_class;
di->bas.chan = 0;
di->bas.regshft = (u_int)shift;
di->baudrate = 0;
di->bas.rclk = (u_int)rclk;
di->ops = uart_getops(class);
di->databits = 8;
di->stopbits = 1;
di->parity = UART_PARITY_NONE;
di->bas.bst = uart_bus_space_mem;
err = fdt_regsize(node, &start, &size);
if (err)
return (ENXIO);
start += fdt_immr_va;
return (bus_space_map(di->bas.bst, start, size, 0, &di->bas.bsh));
}