1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2013 Ian Lepore <ian@freebsd.org> 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 AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, 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 "opt_platform.h" 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/reboot.h> 37 #include <sys/devmap.h> 38 39 #include <vm/vm.h> 40 #include <vm/pmap.h> 41 42 #include <machine/armreg.h> 43 #include <machine/bus.h> 44 #include <machine/cpu.h> 45 #include <machine/machdep.h> 46 47 #include <arm/freescale/imx/imx_machdep.h> 48 #include <arm/freescale/imx/imx_wdogreg.h> 49 50 SYSCTL_NODE(_hw, OID_AUTO, imx, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 51 "i.MX container"); 52 53 static int last_reset_status; 54 SYSCTL_UINT(_hw_imx, OID_AUTO, last_reset_status, CTLFLAG_RD, 55 &last_reset_status, 0, "Last reset status register"); 56 57 SYSCTL_STRING(_hw_imx, OID_AUTO, last_reset_reason, CTLFLAG_RD, 58 "unknown", 0, "Last reset reason"); 59 60 /* 61 * This code which manipulates the watchdog hardware is here to implement 62 * cpu_reset() because the watchdog is the only way for software to reset the 63 * chip. Why here and not in imx_wdog.c? Because there's no requirement that 64 * the watchdog driver be compiled in, but it's nice to be able to reboot even 65 * if it's not. 66 */ 67 void 68 imx_wdog_cpu_reset(vm_offset_t wdcr_physaddr) 69 { 70 volatile uint16_t cr, *pcr; 71 72 if ((pcr = devmap_ptov(wdcr_physaddr, sizeof(*pcr))) == NULL) { 73 printf("imx_wdog_cpu_reset(): " 74 "cannot find control register... locking up now."); 75 for (;;) 76 cpu_spinwait(); 77 } 78 cr = *pcr; 79 80 /* 81 * If the watchdog hardware has been set up to trigger an external reset 82 * signal on watchdog timeout, then we do software-requested rebooting 83 * the same way, by asserting the external reset signal. 84 * 85 * Asserting external reset is supposed to result in some external 86 * component asserting the POR pin on the SoC, possibly after adjusting 87 * and stabilizing system voltages, or taking other system-wide reset 88 * actions. Just in case there is some kind of misconfiguration, we 89 * hang out and do nothing for a full second, then continue on into 90 * the code to assert a software reset as well. 91 */ 92 if (cr & WDOG_CR_WDT) { 93 cr &= ~WDOG_CR_WDA; /* Assert active-low ext reset bit. */ 94 *pcr = cr; 95 DELAY(1000000); 96 printf("imx_wdog_cpu_reset(): " 97 "External reset failed, trying internal cpu-reset\n"); 98 DELAY(10000); /* Time for printf to appear */ 99 } 100 101 /* 102 * Imx6 erratum ERR004346 says the SRS bit has to be cleared twice 103 * within the same cycle of the 32khz clock to reliably trigger the 104 * reset. Writing it 3 times in a row ensures at least 2 of the writes 105 * happen in the same 32k clock cycle. 106 */ 107 cr &= ~WDOG_CR_SRS; /* Assert active-low software reset bit. */ 108 *pcr = cr; 109 *pcr = cr; 110 *pcr = cr; 111 112 /* Reset happens on the next tick of the 32khz clock, wait for it. */ 113 for (;;) 114 cpu_spinwait(); 115 } 116 117 void 118 imx_wdog_init_last_reset(vm_offset_t wdsr_phys) 119 { 120 volatile uint16_t * psr; 121 122 if ((psr = devmap_ptov(wdsr_phys, sizeof(*psr))) == NULL) 123 return; 124 last_reset_status = *psr; 125 if (last_reset_status & WDOG_RSR_SFTW) { 126 sysctl___hw_imx_last_reset_reason.oid_arg1 = "SoftwareReset"; 127 } else if (last_reset_status & WDOG_RSR_TOUT) { 128 sysctl___hw_imx_last_reset_reason.oid_arg1 = "WatchdogTimeout"; 129 } else if (last_reset_status & WDOG_RSR_POR) { 130 sysctl___hw_imx_last_reset_reason.oid_arg1 = "PowerOnReset"; 131 } 132 } 133