00001 /* 00002 * Copyright (C) 2006 by egnite Software GmbH. All rights reserved. 00003 * 00004 * Redistribution and use in source and binary forms, with or without 00005 * modification, are permitted provided that the following conditions 00006 * are met: 00007 * 00008 * 1. Redistributions of source code must retain the above copyright 00009 * notice, this list of conditions and the following disclaimer. 00010 * 2. Redistributions in binary form must reproduce the above copyright 00011 * notice, this list of conditions and the following disclaimer in the 00012 * documentation and/or other materials provided with the distribution. 00013 * 3. Neither the name of the copyright holders nor the names of 00014 * contributors may be used to endorse or promote products derived 00015 * from this software without specific prior written permission. 00016 * 00017 * THIS SOFTWARE IS PROVIDED BY EGNITE SOFTWARE GMBH AND CONTRIBUTORS 00018 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 00019 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 00020 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL EGNITE 00021 * SOFTWARE GMBH OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 00022 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 00023 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 00024 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 00025 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 00026 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 00027 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 00028 * SUCH DAMAGE. 00029 * 00030 * For additional information see http://www.ethernut.de/ 00031 * 00032 */ 00033 00034 /* 00035 * $Log: wdt_at91.c,v $ 00036 * Revision 1.4 2009/01/17 11:26:37 haraldkipp 00037 * Getting rid of two remaining BSD types in favor of stdint. 00038 * Replaced 'u_int' by 'unsinged int' and 'uptr_t' by 'uintptr_t'. 00039 * 00040 * Revision 1.3 2008/08/11 06:59:13 haraldkipp 00041 * BSD types replaced by stdint types (feature request #1282721). 00042 * 00043 * Revision 1.2 2006/05/25 09:13:22 haraldkipp 00044 * Platform independent watchdog API added. 00045 * 00046 * Revision 1.1 2006/02/23 15:36:35 haraldkipp 00047 * Added support for AT91 watchdog timer. 00048 * 00049 */ 00050 00051 #include <sys/timer.h> 00052 #include <dev/watchdog.h> 00053 00058 00059 static ureg_t nested; 00060 00067 uint32_t At91WatchDogStart(uint32_t ms, uint32_t xmode) 00068 { 00069 unsigned int cmval; 00070 00071 At91WatchDogDisable(); 00072 00073 /* 00074 * The watchdog counts down a 16 bit value, of which the upper 00075 * 4 bits are configurable and the lower 12 bits are set to 1. 00076 * Calculate the number of cycles required to count down the 00077 * upper 4 bits. 00078 */ 00079 cmval = ((NutGetCpuClock() / 1000) * ms) >> 13; 00080 00081 /* Check if MCK/8 is slow enough. */ 00082 if (cmval < WD_HPCV) { 00083 cmval = (cmval & WD_HPCV) | WD_WDCLKS_MCK8; 00084 } 00085 /* Check if MCK/32 is slow enough. */ 00086 else if ((cmval >>= 2) < WD_HPCV) { 00087 cmval = (cmval & WD_HPCV) | WD_WDCLKS_MCK32; 00088 } 00089 /* Check if MCK/128 is slow enough. */ 00090 else if ((cmval >>= 2) < WD_HPCV) { 00091 cmval = (cmval & WD_HPCV) | WD_WDCLKS_MCK128; 00092 } 00093 /* Check if MCK/1024 is slow enough. */ 00094 else if ((cmval >>= 3) < WD_HPCV) { 00095 cmval = (cmval & WD_HPCV) | WD_WDCLKS_MCK1024; 00096 } 00097 /* Use maximum. */ 00098 else { 00099 cmval = WD_HPCV | WD_WDCLKS_MCK1024; 00100 } 00101 outr(WD_CMR, WD_CKEY | cmval); 00102 if (xmode == 0) { 00103 xmode |= WD_RSTEN; 00104 } 00105 At91WatchDogRestart(); 00106 outr(WD_OMR, WD_OKEY | WD_WDEN | xmode); 00107 nested = 1; 00108 00109 return ms; 00110 } 00111 00118 void At91WatchDogRestart(void) 00119 { 00120 outr(WD_CR, WD_RSTKEY); 00121 } 00122 00129 void At91WatchDogDisable(void) 00130 { 00131 if (nested) { 00132 nested++; 00133 } 00134 outr(WD_OMR, WD_OKEY | (inr(WD_OMR) & ~WD_WDEN)); 00135 } 00136 00143 void At91WatchDogEnable(void) 00144 { 00145 if (nested > 1 && --nested == 1) { 00146 At91WatchDogRestart(); 00147 outr(WD_OMR, WD_OKEY | inr(WD_OMR) | WD_WDEN); 00148 } 00149 } 00150