versatile_scm.c revision 331402 
1/*
2 * Copyright (c) 2017 Oleksandr Tymoshenko <gonzo@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by Ben Gray.
16 * 4. The name of the company nor the name of the author may be used to
17 *    endorse or promote products derived from this software without specific
18 *    prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY BEN GRAY ``AS IS'' AND ANY EXPRESS OR
21 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23 * IN NO EVENT SHALL BEN GRAY BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * SCM - System Control Module
34 */
35#include <sys/cdefs.h>
36__FBSDID("$FreeBSD: stable/11/sys/arm/versatile/versatile_scm.c 331402 2018-03-23 01:37:31Z gonzo $");
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/kernel.h>
41#include <sys/module.h>
42#include <sys/bus.h>
43#include <sys/resource.h>
44#include <sys/rman.h>
45#include <sys/lock.h>
46#include <sys/mutex.h>
47
48#include <machine/bus.h>
49#include <machine/resource.h>
50
51#include <dev/ofw/openfirm.h>
52#include <dev/ofw/ofw_bus.h>
53#include <dev/ofw/ofw_bus_subr.h>
54
55#include "versatile_scm.h"
56
57struct versatile_scm_softc {
58	device_t		sc_dev;
59	struct resource *	sc_mem_res;
60};
61
62static struct versatile_scm_softc *versatile_scm_sc;
63
64#define	versatile_scm_read_4(sc, reg)		\
65    bus_read_4((sc)->sc_mem_res, (reg))
66#define	versatile_scm_write_4(sc, reg, val)		\
67    bus_write_4((sc)->sc_mem_res, (reg), (val))
68
69static int
70versatile_scm_probe(device_t dev)
71{
72	if (!ofw_bus_status_okay(dev))
73		return (ENXIO);
74
75	if (!ofw_bus_is_compatible(dev, "syscon"))
76		return (ENXIO);
77
78	if (versatile_scm_sc) {
79		return (EEXIST);
80	}
81
82	device_set_desc(dev, "Versatile Control Module");
83	return (BUS_PROBE_DEFAULT);
84}
85
86static int
87versatile_scm_attach(device_t dev)
88{
89	struct versatile_scm_softc *sc;
90	int rid;
91
92	sc = device_get_softc(dev);
93	sc->sc_dev = dev;
94
95	rid = 0;
96	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
97
98	if (sc->sc_mem_res == NULL) {
99		device_printf(dev, "could not allocate memory resources\n");
100		return (ENXIO);
101	}
102
103	versatile_scm_sc = sc;
104
105	return (0);
106}
107
108int
109versatile_scm_reg_read_4(uint32_t reg, uint32_t *val)
110{
111	if (!versatile_scm_sc)
112		return (ENXIO);
113
114	*val = versatile_scm_read_4(versatile_scm_sc, reg);
115	return (0);
116}
117
118int
119versatile_scm_reg_write_4(uint32_t reg, uint32_t val)
120{
121	if (!versatile_scm_sc)
122		return (ENXIO);
123
124	versatile_scm_write_4(versatile_scm_sc, reg, val);
125	return (0);
126}
127
128static device_method_t versatile_scm_methods[] = {
129	DEVMETHOD(device_probe,		versatile_scm_probe),
130	DEVMETHOD(device_attach,	versatile_scm_attach),
131
132	DEVMETHOD_END
133};
134
135static driver_t versatile_scm_driver = {
136	"scm",
137	versatile_scm_methods,
138	sizeof(struct versatile_scm_softc),
139};
140
141static devclass_t versatile_scm_devclass;
142
143EARLY_DRIVER_MODULE(versatile_scm, simplebus, versatile_scm_driver, versatile_scm_devclass, 0, 0,
144    BUS_PASS_BUS + BUS_PASS_ORDER_MIDDLE);
145