syscon.c revision 1.5 
1/*	$OpenBSD: syscon.c,v 1.5 2021/04/23 12:38:00 kettenis 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#else
32#include <arm64/dev/simplebusvar.h>
33#endif
34
35extern void (*cpuresetfn)(void);
36extern void (*powerdownfn)(void);
37
38struct syscon_softc {
39	struct simplebus_softc	sc_sbus;
40	bus_space_tag_t		sc_iot;
41	bus_space_handle_t	sc_ioh;
42	uint32_t		sc_regmap;
43	bus_size_t		sc_offset;
44	uint32_t		sc_mask;
45	uint32_t		sc_value;
46};
47
48struct syscon_softc *syscon_reboot_sc;
49struct syscon_softc *syscon_poweroff_sc;
50
51int	syscon_match(struct device *, void *, void *);
52void	syscon_attach(struct device *, struct device *, void *);
53
54struct cfattach syscon_ca = {
55	sizeof(struct syscon_softc), syscon_match, syscon_attach
56};
57
58struct cfdriver syscon_cd = {
59	NULL, "syscon", DV_DULL
60};
61
62void	syscon_reset(void);
63void	syscon_powerdown(void);
64
65int
66syscon_match(struct device *parent, void *match, void *aux)
67{
68	struct fdt_attach_args *faa = aux;
69
70	return OF_is_compatible(faa->fa_node, "syscon") ||
71	    OF_is_compatible(faa->fa_node, "syscon-reboot") ||
72	    OF_is_compatible(faa->fa_node, "syscon-poweroff");
73}
74
75void
76syscon_attach(struct device *parent, struct device *self, void *aux)
77{
78	struct syscon_softc *sc = (struct syscon_softc *)self;
79	struct fdt_attach_args *faa = aux;
80	char name[32];
81
82	OF_getprop(faa->fa_node, "name", name, sizeof(name));
83	name[sizeof(name) - 1] = 0;
84
85	if (OF_is_compatible(faa->fa_node, "syscon")) {
86		if (faa->fa_nreg < 1) {
87			printf(": no registers\n");
88			return;
89		}
90
91		sc->sc_iot = faa->fa_iot;
92
93		if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
94		    faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
95			printf(": can't map registers\n");
96			return;
97		}
98
99		regmap_register(faa->fa_node, sc->sc_iot, sc->sc_ioh,
100		    faa->fa_reg[0].size);
101	}
102
103	if (OF_is_compatible(faa->fa_node, "simple-mfd"))
104		simplebus_attach(parent, &sc->sc_sbus.sc_dev, faa);
105	else
106		printf(": \"%s\"\n", name);
107
108	if (OF_is_compatible(faa->fa_node, "syscon-reboot") ||
109	    OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
110		sc->sc_regmap = OF_getpropint(faa->fa_node, "regmap", 0);
111		if (sc->sc_regmap == 0)
112			return;
113
114		if (OF_getproplen(faa->fa_node, "offset") != sizeof(uint32_t))
115			return;
116
117		/* At least one of "mask" and "value" should be provided. */
118		if (OF_getproplen(faa->fa_node, "mask") != sizeof(uint32_t) &&
119		    OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t))
120			return;
121
122		sc->sc_offset = OF_getpropint(faa->fa_node, "offset", 0);
123		sc->sc_mask = OF_getpropint(faa->fa_node, "mask", 0xffffffff);
124		sc->sc_value = OF_getpropint(faa->fa_node, "value", 0);
125
126		/*
127		 * Old binding used "mask" as the value to write with
128		 * an all-ones mask.  This is still supported.
129		 */
130		if (OF_getproplen(faa->fa_node, "value") != sizeof(uint32_t)) {
131			sc->sc_value = sc->sc_mask;
132			sc->sc_mask = 0xffffffff;
133		}
134
135		if (OF_is_compatible(faa->fa_node, "syscon-reboot")) {
136			syscon_reboot_sc = sc;
137			cpuresetfn = syscon_reset;
138		} else if (OF_is_compatible(faa->fa_node, "syscon-poweroff")) {
139			syscon_poweroff_sc = sc;
140			powerdownfn = syscon_powerdown;
141		}
142	}
143}
144
145void
146syscon_reset(void)
147{
148	struct syscon_softc *sc = syscon_reboot_sc;
149	struct regmap *rm;
150	uint32_t value;
151
152	rm = regmap_byphandle(sc->sc_regmap);
153	if (rm == NULL)
154		return;
155
156	value = regmap_read_4(rm, sc->sc_offset);
157	value &= ~sc->sc_mask;
158	value |= sc->sc_value;
159	regmap_write_4(rm, sc->sc_offset, value);
160	delay(1000000);
161}
162
163void
164syscon_powerdown(void)
165{
166	struct syscon_softc *sc = syscon_poweroff_sc;
167	struct regmap *rm;
168	uint32_t value;
169
170	rm = regmap_byphandle(sc->sc_regmap);
171	if (rm == NULL)
172		return;
173
174	value = regmap_read_4(rm, sc->sc_offset);
175	value &= ~sc->sc_mask;
176	value |= sc->sc_value;
177	regmap_write_4(rm, sc->sc_offset, value);
178	delay(1000000);
179}
180