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      1 /* $NetBSD: wdog.c,v 1.12 2011/06/18 02:02:50 matt Exp $ */
      2 
      3 /*
      4  * Copyright (c) 2002 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Jason R. Thorpe and Simon Burge for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed for the NetBSD Project by
     20  *	Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 /*
     39  * Watchdog timer support for the IBM 405GP processor.
     40  */
     41 
     42 #include <sys/cdefs.h>
     43 __KERNEL_RCSID(0, "$NetBSD: wdog.c,v 1.12 2011/06/18 02:02:50 matt Exp $");
     44 
     45 #include <sys/param.h>
     46 #include <sys/systm.h>
     47 #include <sys/device.h>
     48 #include <sys/cpu.h>
     49 #include <sys/wdog.h>
     50 
     51 #include <prop/proplib.h>
     52 
     53 #include <powerpc/spr.h>
     54 #include <powerpc/ibm4xx/spr.h>
     55 #include <powerpc/ibm4xx/cpu.h>
     56 #include <powerpc/ibm4xx/dev/opbvar.h>
     57 
     58 #include <dev/sysmon/sysmonvar.h>
     59 
     60 static int wdog_match(device_t, cfdata_t, void *);
     61 static void wdog_attach(device_t, device_t, void *);
     62 static int wdog_tickle(struct sysmon_wdog *);
     63 static int wdog_setmode(struct sysmon_wdog *);
     64 
     65 struct wdog_softc {
     66 	device_t sc_dev;
     67 	struct sysmon_wdog sc_smw;
     68 	bool sc_wdog_armed;
     69 	int sc_wdog_period;
     70 };
     71 
     72 CFATTACH_DECL_NEW(wdog, sizeof(struct wdog_softc),
     73     wdog_match, wdog_attach, NULL, NULL);
     74 
     75 static int
     76 wdog_match(device_t parent, cfdata_t cf, void *aux)
     77 {
     78 	struct opb_attach_args * const oaa = aux;
     79 
     80 	/* match only watchdog devices */
     81 	if (strcmp(oaa->opb_name, cf->cf_name) != 0)
     82 		return (0);
     83 
     84 	return (1);
     85 }
     86 
     87 static void
     88 wdog_attach(device_t parent, device_t self, void *aux)
     89 {
     90 	struct wdog_softc * const sc = device_private(self);
     91 	unsigned int processor_freq;
     92 	prop_number_t freq;
     93 
     94 	freq = prop_dictionary_get(board_properties, "processor-frequency");
     95 	KASSERT(freq != NULL);
     96 	processor_freq = (unsigned int) prop_number_integer_value(freq);
     97 
     98 	sc->sc_wdog_period = (2LL << 29) / processor_freq;
     99 	aprint_normal(": %d second period\n", sc->sc_wdog_period);
    100 
    101 	sc->sc_dev = self;
    102 	sc->sc_smw.smw_name = device_xname(self);
    103 	sc->sc_smw.smw_cookie = sc;
    104 	sc->sc_smw.smw_setmode = wdog_setmode;
    105 	sc->sc_smw.smw_tickle = wdog_tickle;
    106 	sc->sc_smw.smw_period = sc->sc_wdog_period;
    107 
    108 	if (sysmon_wdog_register(&sc->sc_smw) != 0)
    109 		aprint_error_dev(self, "unable to register with sysmon\n");
    110 }
    111 
    112 static int
    113 wdog_tickle(struct sysmon_wdog *smw)
    114 {
    115 	uint32_t tsr;
    116 
    117 	tsr = mfspr(SPR_TSR);
    118 	tsr |= TSR_ENW | TSR_WIS;
    119 	mtspr(SPR_TSR, tsr);
    120 	return (0);
    121 }
    122 
    123 static int
    124 wdog_setmode(struct sysmon_wdog *smw)
    125 {
    126 	struct wdog_softc * const sc = smw->smw_cookie;
    127 
    128 	if ((smw->smw_mode & WDOG_MODE_MASK) == WDOG_MODE_DISARMED) {
    129 		if (sc->sc_wdog_armed) {
    130 			uint32_t tsr = mfspr(SPR_TSR);
    131 			tsr &= ~(TSR_ENW | TSR_WIS);
    132 			mtspr(SPR_TSR, tsr);
    133 			sc->sc_wdog_armed = false;
    134 		}
    135 	} else {
    136 		if (smw->smw_period == WDOG_PERIOD_DEFAULT)
    137 			smw->smw_period = sc->sc_wdog_period;
    138 		else if (smw->smw_period != sc->sc_wdog_period) {
    139 			/*
    140 			 * There's 4 set watchdog periods on the 405GP,
    141 			 * but we only support the longest one (2.684
    142 			 * seconds).
    143 			 */
    144 			return (EOPNOTSUPP);
    145 		}
    146 		sc->sc_wdog_armed = true;
    147 
    148 		uint32_t tcr = mfspr(SPR_TCR);
    149 		tcr |= TCR_WP_2_29 | TCR_WRC_SYSTEM;
    150 		mtspr(SPR_TCR, tcr);
    151 
    152 		/* Arm the watchdog. */
    153 		wdog_tickle(smw);
    154 	}
    155 	return (0);
    156 }
    157