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      1 /* $NetBSD: apple_wdog.c,v 1.3 2022/04/05 05:04:04 skrll Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2021 Jared McNeill <jmcneill (at) invisible.ca>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: apple_wdog.c,v 1.3 2022/04/05 05:04:04 skrll Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/device.h>
     35 #include <sys/intr.h>
     36 #include <sys/kernel.h>
     37 #include <sys/lwp.h>
     38 #include <sys/systm.h>
     39 
     40 #include <dev/fdt/fdtvar.h>
     41 
     42 #define	WDOG_CHIP_CTL		0x000c
     43 #define	WDOG_SYS_TMR		0x0010
     44 #define	WDOG_SYS_RST		0x0014
     45 #define	WDOG_SYS_CTL		0x001c
     46 #define	 WDOG_SYS_CTL_ENABLE	__BIT(2)
     47 
     48 static const struct device_compatible_entry compat_data[] = {
     49 	{ .compat = "apple,wdt" },
     50 	{ .compat = "apple,reboot-v0" },
     51 	DEVICE_COMPAT_EOL
     52 };
     53 
     54 struct apple_wdog_softc {
     55 	device_t sc_dev;
     56 	bus_space_tag_t sc_bst;
     57 	bus_space_handle_t sc_bsh;
     58 };
     59 
     60 #define WDOG_READ(sc, reg) \
     61 	bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (reg))
     62 #define	WDOG_WRITE(sc, reg, val) \
     63 	bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (reg), (val))
     64 
     65 static void
     66 apple_wdog_reset(device_t dev)
     67 {
     68 	struct apple_wdog_softc * const sc = device_private(dev);
     69 
     70 	WDOG_WRITE(sc, WDOG_SYS_RST, 1);
     71 	WDOG_WRITE(sc, WDOG_SYS_CTL, WDOG_SYS_CTL_ENABLE);
     72 	WDOG_WRITE(sc, WDOG_SYS_TMR, 0);
     73 }
     74 
     75 static struct fdtbus_power_controller_func apple_wdog_power_funcs = {
     76 	.reset = apple_wdog_reset,
     77 };
     78 
     79 static int
     80 apple_wdog_match(device_t parent, cfdata_t cf, void *aux)
     81 {
     82 	struct fdt_attach_args * const faa = aux;
     83 
     84 	return of_compatible_match(faa->faa_phandle, compat_data);
     85 }
     86 
     87 static void
     88 apple_wdog_attach(device_t parent, device_t self, void *aux)
     89 {
     90 	struct apple_wdog_softc * const sc = device_private(self);
     91 	struct fdt_attach_args * const faa = aux;
     92 	const int phandle = faa->faa_phandle;
     93 	bus_addr_t addr;
     94 	bus_size_t size;
     95 
     96 	if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
     97 		aprint_error(": couldn't get registers\n");
     98 		return;
     99 	}
    100 
    101 	sc->sc_dev = self;
    102 	sc->sc_bst = faa->faa_bst;
    103 	if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
    104 		aprint_error(": couldn't map registers\n");
    105 		return;
    106 	}
    107 
    108 	aprint_naive("\n");
    109 	aprint_normal(": Apple Watchdog\n");
    110 
    111 	WDOG_WRITE(sc, WDOG_CHIP_CTL, 0);
    112 	WDOG_WRITE(sc, WDOG_SYS_CTL, 0);
    113 
    114 	fdtbus_register_power_controller(self, phandle,
    115 	    &apple_wdog_power_funcs);
    116 }
    117 
    118 CFATTACH_DECL_NEW(apple_wdog, sizeof(struct apple_wdog_softc),
    119 	apple_wdog_match, apple_wdog_attach, NULL, NULL);
    120