1 /* $OpenBSD: apldog.c,v 1.4 2022/04/06 18:59:26 naddy Exp $ */
2 /*
3 * Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
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/fdt.h>
27
28 extern void (*cpuresetfn)(void);
29
30 /*
31 * This driver is based on preliminary device tree bindings and will
32 * almost certainly need changes once the official bindings land in
33 * mainline Linux. Support for these preliminary bindings will be
34 * dropped as soon as official bindings are available.
35 */
36
37 #define WDT_CHIP_CTL 0x000c
38 #define WDT_SYS_TMR 0x0010
39 #define WDT_SYS_RST 0x0014
40 #define WDT_SYS_RST_IMMEDIATE (1 << 0)
41 #define WDT_SYS_CTL 0x001c
42 #define WDT_SYS_CTL_ENABLE (1 << 2)
43
44 #define HREAD4(sc, reg) \
45 (bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg)))
46 #define HWRITE4(sc, reg, val) \
47 bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))
48
49 struct apldog_softc {
50 struct device sc_dev;
51 bus_space_tag_t sc_iot;
52 bus_space_handle_t sc_ioh;
53 };
54
55 struct apldog_softc *apldog_sc;
56
57 int apldog_match(struct device *, void *, void *);
58 void apldog_attach(struct device *, struct device *, void *);
59
60 const struct cfattach apldog_ca = {
61 sizeof (struct apldog_softc), apldog_match, apldog_attach
62 };
63
64 struct cfdriver apldog_cd = {
65 NULL, "apldog", DV_DULL
66 };
67
68 void apldog_reset(void);
69
70 int
apldog_match(struct device * parent,void * match,void * aux)71 apldog_match(struct device *parent, void *match, void *aux)
72 {
73 struct fdt_attach_args *faa = aux;
74
75 return OF_is_compatible(faa->fa_node, "apple,wdt");
76 }
77
78 void
apldog_attach(struct device * parent,struct device * self,void * aux)79 apldog_attach(struct device *parent, struct device *self, void *aux)
80 {
81 struct apldog_softc *sc = (struct apldog_softc *)self;
82 struct fdt_attach_args *faa = aux;
83
84 if (faa->fa_nreg < 1) {
85 printf(": no registers\n");
86 return;
87 }
88
89 sc->sc_iot = faa->fa_iot;
90 if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
91 faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
92 printf(": can't map registers\n");
93 return;
94 }
95
96 printf("\n");
97
98 /* Reset the watchdog timers. */
99 HWRITE4(sc, WDT_CHIP_CTL, 0);
100 HWRITE4(sc, WDT_SYS_CTL, 0);
101
102 apldog_sc = sc;
103 if (cpuresetfn == NULL)
104 cpuresetfn = apldog_reset;
105 }
106
107 void
apldog_reset(void)108 apldog_reset(void)
109 {
110 struct apldog_softc *sc = apldog_sc;
111
112 /* Trigger a system reset. */
113 HWRITE4(sc, WDT_SYS_RST, WDT_SYS_RST_IMMEDIATE);
114 HWRITE4(sc, WDT_SYS_CTL, WDT_SYS_CTL_ENABLE);
115 HWRITE4(sc, WDT_SYS_TMR, 0);
116
117 delay(1000000);
118 }
119