syscon.c revision 1.6 
1/*	$OpenBSD: syscon.c,v 1.6 2021/04/23 12:49:53 jsg Exp $	*/
2/*
3 * Copyright (c) 2017 Mark Kettenis
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/param.h>
19#include <sys/systm.h>
20#include <sys/device.h>
21
22#include <machine/bus.h>
23#include <machine/fdt.h>
24
25#include <dev/ofw/openfirm.h>
26#include <dev/ofw/ofw_misc.h>
27#include <dev/ofw/fdt.h>
28
29#ifdef __armv7__
30#include <arm/simplebus/simplebusvar.h>
31#elif defined(__riscv64__)
32#include <riscv64/dev/simplebusvar.h>
33#else
34#include <arm64/dev/simplebusvar.h>
35#endif
36
37extern void (*cpuresetfn)(void);
38extern void (*powerdownfn)(void);
39
40struct syscon_softc {
41	struct simplebus_softc	sc_sbus;
42	bus_space_tag_t		sc_iot;
43	bus_space_handle_t	sc_ioh;
44	uint32_t		sc_regmap;
45	bus_size_t		sc_offset;
46	uint32_t		sc_mask;
47	uint32_t		sc_value;
48};
49
50struct syscon_softc *syscon_reboot_sc;
51struct syscon_softc *syscon_poweroff_sc;
52
53int	syscon_match(struct device *, void *, void *);
54void	syscon_attach(struct device *, struct device *, void *);
55
56struct cfattach syscon_ca = {
57	sizeof(struct syscon_softc), syscon_match, syscon_attach
58};
59
60struct cfdriver syscon_cd = {
61	NULL, "syscon", DV_DULL
62};
63
64void	syscon_reset(void);
65void	syscon_powerdown(void);
66
67int
68syscon_match(struct device *parent, void *match, void *aux)
69{
70	struct fdt_attach_args *faa = aux;
71
72	return OF_is_compatible(faa->fa_node, "syscon") ||
73	    OF_is_compatible(faa->fa_node, "syscon-reboot") ||
74	    OF_is_compatible(faa->fa_node, "syscon-poweroff");
75}
76
77void
78syscon_attach(struct device *parent, struct device *self, void *aux)
79{
80	struct syscon_softc *sc = (struct syscon_softc *)self;
81	struct fdt_attach_args *faa = aux;
82	char name[32];
83
84	OF_getprop(faa->fa_node, "name", name, sizeof(name));
85	name[sizeof(name) - 1] = 0;
86
87	if (OF_is_compatible(faa->fa_node, "syscon")) {
88		if (faa->fa_nreg < 1) {
89			printf(": no registers\n");
90			return;
91		}
92
93		sc->sc_iot = faa->fa_iot;
94
95		if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
96		    faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
97			printf(": can't map registers\n");
98			return;
99		}
100
101		regmap_register(faa->fa_node, sc->sc_iot, sc->sc_ioh,
102		    faa->fa_reg[0].size);
103	}
104
105	if (OF_is_compatible(faa->fa_node, "simple-mfd"))
106		simplebus_attach(parent, &sc->sc_sbus.sc_dev, faa);
107	else
108		printf(": \"%s\"\n", name);
109
110	if (OF_is_compatible(faa->fa_node, "syscon-reboot") ||
111	    OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
112		sc->sc_regmap = OF_getpropint(faa->fa_node, "regmap", 0);
113		if (sc->sc_regmap == 0)
114			return;
115
116		if (OF_getproplen(faa->fa_node, "offset") != sizeof(uint32_t))
117			return;
118
119		/* At least one of "mask" and "value" should be provided. */
120		if (OF_getproplen(faa->fa_node, "mask") != sizeof(uint32_t) &&
121		    OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t))
122			return;
123
124		sc->sc_offset = OF_getpropint(faa->fa_node, "offset", 0);
125		sc->sc_mask = OF_getpropint(faa->fa_node, "mask", 0xffffffff);
126		sc->sc_value = OF_getpropint(faa->fa_node, "value", 0);
127
128		/*
129		 * Old binding used "mask" as the value to write with
130		 * an all-ones mask.  This is still supported.
131		 */
132		if (OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t)) {
133			sc->sc_value = sc->sc_mask;
134			sc->sc_mask = 0xffffffff;
135		}
136
137		if (OF_is_compatible(faa->fa_node, "syscon-reboot")) {
138			syscon_reboot_sc = sc;
139			cpuresetfn = syscon_reset;
140		} else if (OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
141			syscon_poweroff_sc = sc;
142			powerdownfn = syscon_powerdown;
143		}
144	}
145}
146
147void
148syscon_reset(void)
149{
150	struct syscon_softc *sc = syscon_reboot_sc;
151	struct regmap *rm;
152	uint32_t value;
153
154	rm = regmap_byphandle(sc->sc_regmap);
155	if (rm == NULL)
156		return;
157
158	value = regmap_read_4(rm, sc->sc_offset);
159	value &= ~sc->sc_mask;
160	value |= sc->sc_value;
161	regmap_write_4(rm, sc->sc_offset, value);
162	delay(1000000);
163}
164
165void
166syscon_powerdown(void)
167{
168	struct syscon_softc *sc = syscon_poweroff_sc;
169	struct regmap *rm;
170	uint32_t value;
171
172	rm = regmap_byphandle(sc->sc_regmap);
173	if (rm == NULL)
174		return;
175
176	value = regmap_read_4(rm, sc->sc_offset);
177	value &= ~sc->sc_mask;
178	value |= sc->sc_value;
179	regmap_write_4(rm, sc->sc_offset, value);
180	delay(1000000);
181}
182