xref: /freebsd/sys/dev/uart/uart_bus_fdt.c (revision 26a222dc0c048fc071b548eadad7b80405a1b126)
1 /*-
2  * Copyright (c) 2009-2010 The FreeBSD Foundation
3  * All rights reserved.
4  *
5  * This software was developed by Semihalf under sponsorship from
6  * the FreeBSD Foundation.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include "opt_platform.h"
34 
35 #include <sys/param.h>
36 #include <sys/bus.h>
37 #include <sys/kernel.h>
38 #include <sys/module.h>
39 
40 #include <machine/bus.h>
41 
42 #include <dev/fdt/fdt_common.h>
43 #include <dev/ofw/ofw_bus.h>
44 #include <dev/ofw/ofw_bus_subr.h>
45 #include <dev/uart/uart.h>
46 #include <dev/uart/uart_bus.h>
47 #include <dev/uart/uart_cpu.h>
48 #include <dev/uart/uart_cpu_fdt.h>
49 
50 static int uart_fdt_probe(device_t);
51 
52 static device_method_t uart_fdt_methods[] = {
53 	/* Device interface */
54 	DEVMETHOD(device_probe,		uart_fdt_probe),
55 	DEVMETHOD(device_attach,	uart_bus_attach),
56 	DEVMETHOD(device_detach,	uart_bus_detach),
57 	{ 0, 0 }
58 };
59 
60 static driver_t uart_fdt_driver = {
61 	uart_driver_name,
62 	uart_fdt_methods,
63 	sizeof(struct uart_softc),
64 };
65 
66 static int
67 uart_fdt_get_clock(phandle_t node, pcell_t *cell)
68 {
69 	pcell_t clock;
70 
71 	/*
72 	 * clock-frequency is a FreeBSD-specific hack. Make its presence optional.
73 	 */
74 	if ((OF_getprop(node, "clock-frequency", &clock,
75 	    sizeof(clock))) <= 0)
76 		clock = 0;
77 
78 	if (clock == 0)
79 		/* Try to retrieve parent 'bus-frequency' */
80 		/* XXX this should go to simple-bus fixup or so */
81 		if ((OF_getprop(OF_parent(node), "bus-frequency", &clock,
82 		    sizeof(clock))) <= 0)
83 			clock = 0;
84 
85 	*cell = fdt32_to_cpu(clock);
86 	return (0);
87 }
88 
89 static int
90 uart_fdt_get_shift(phandle_t node, pcell_t *cell)
91 {
92 	pcell_t shift;
93 
94 	if ((OF_getprop(node, "reg-shift", &shift, sizeof(shift))) <= 0)
95 		shift = 0;
96 	*cell = fdt32_to_cpu(shift);
97 	return (0);
98 }
99 
100 static uintptr_t
101 uart_fdt_find_device(device_t dev)
102 {
103 	struct ofw_compat_data **cd;
104 	const struct ofw_compat_data *ocd;
105 
106 	SET_FOREACH(cd, uart_fdt_class_and_device_set) {
107 		ocd = ofw_bus_search_compatible(dev, *cd);
108 		if (ocd->ocd_data != 0)
109 			return (ocd->ocd_data);
110 	}
111 	return (0);
112 }
113 
114 static int
115 uart_fdt_probe(device_t dev)
116 {
117 	struct uart_softc *sc;
118 	phandle_t node;
119 	pcell_t clock, shift;
120 	int err;
121 
122 	sc = device_get_softc(dev);
123 
124 	if (!ofw_bus_status_okay(dev))
125 		return (ENXIO);
126 
127 	sc->sc_class = (struct uart_class *)uart_fdt_find_device(dev);
128 	if (sc->sc_class == NULL)
129 		return (ENXIO);
130 
131 	node = ofw_bus_get_node(dev);
132 
133 	if ((err = uart_fdt_get_clock(node, &clock)) != 0)
134 		return (err);
135 	uart_fdt_get_shift(node, &shift);
136 
137 	return (uart_bus_probe(dev, (int)shift, (int)clock, 0, 0));
138 }
139 
140 DRIVER_MODULE(uart, simplebus, uart_fdt_driver, uart_devclass, 0, 0);
141 DRIVER_MODULE(uart, ofwbus, uart_fdt_driver, uart_devclass, 0, 0);
142