uart_bus_fdt.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2009-2010 The FreeBSD Foundation
5 * All rights reserved.
6 *
7 * This software was developed by Semihalf under sponsorship from
8 * the FreeBSD Foundation.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/sys/dev/uart/uart_bus_fdt.c 330897 2018-03-14 03:19:51Z eadler $");
34
35#include "opt_platform.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/bus.h>
40#include <sys/kernel.h>
41#include <sys/module.h>
42
43#include <machine/bus.h>
44
45#include <dev/fdt/fdt_common.h>
46#include <dev/ofw/ofw_bus.h>
47#include <dev/ofw/ofw_bus_subr.h>
48#include <dev/uart/uart.h>
49#include <dev/uart/uart_bus.h>
50#include <dev/uart/uart_cpu.h>
51#include <dev/uart/uart_cpu_fdt.h>
52
53static int uart_fdt_probe(device_t);
54
55static device_method_t uart_fdt_methods[] = {
56	/* Device interface */
57	DEVMETHOD(device_probe,		uart_fdt_probe),
58	DEVMETHOD(device_attach,	uart_bus_attach),
59	DEVMETHOD(device_detach,	uart_bus_detach),
60	{ 0, 0 }
61};
62
63static driver_t uart_fdt_driver = {
64	uart_driver_name,
65	uart_fdt_methods,
66	sizeof(struct uart_softc),
67};
68
69int
70uart_fdt_get_clock(phandle_t node, pcell_t *cell)
71{
72
73	/* clock-frequency is a FreeBSD-only extension. */
74	if ((OF_getencprop(node, "clock-frequency", cell,
75	    sizeof(*cell))) <= 0) {
76		/* Try to retrieve parent 'bus-frequency' */
77		/* XXX this should go to simple-bus fixup or so */
78		if ((OF_getencprop(OF_parent(node), "bus-frequency", cell,
79		    sizeof(*cell))) <= 0)
80			*cell = 0;
81	}
82
83	return (0);
84}
85
86int
87uart_fdt_get_shift(phandle_t node, pcell_t *cell)
88{
89
90	if ((OF_getencprop(node, "reg-shift", cell, sizeof(*cell))) <= 0)
91		return (-1);
92	return (0);
93}
94
95static uintptr_t
96uart_fdt_find_device(device_t dev)
97{
98	struct ofw_compat_data **cd;
99	const struct ofw_compat_data *ocd;
100
101	SET_FOREACH(cd, uart_fdt_class_and_device_set) {
102		ocd = ofw_bus_search_compatible(dev, *cd);
103		if (ocd->ocd_data != 0)
104			return (ocd->ocd_data);
105	}
106	return (0);
107}
108
109static int
110uart_fdt_probe(device_t dev)
111{
112	struct uart_softc *sc;
113	phandle_t node;
114	pcell_t clock, shift;
115	int err;
116
117	sc = device_get_softc(dev);
118
119	if (!ofw_bus_status_okay(dev))
120		return (ENXIO);
121
122	sc->sc_class = (struct uart_class *)uart_fdt_find_device(dev);
123	if (sc->sc_class == NULL)
124		return (ENXIO);
125
126	node = ofw_bus_get_node(dev);
127
128	if ((err = uart_fdt_get_clock(node, &clock)) != 0)
129		return (err);
130	if (uart_fdt_get_shift(node, &shift) != 0)
131		shift = uart_getregshift(sc->sc_class);
132
133	return (uart_bus_probe(dev, (int)shift, (int)clock, 0, 0));
134}
135
136DRIVER_MODULE(uart, simplebus, uart_fdt_driver, uart_devclass, 0, 0);
137DRIVER_MODULE(uart, ofwbus, uart_fdt_driver, uart_devclass, 0, 0);
138