1/* 2 * Watchdog driver for the SA11x0/PXA2xx 3 * 4 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> 5 * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide 13 * warranty for any of this software. This material is provided 14 * "AS-IS" and at no charge. 15 * 16 * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> 17 * 18 * 27/11/2000 Initial release 19 */ 20#include <linux/module.h> 21#include <linux/moduleparam.h> 22#include <linux/types.h> 23#include <linux/kernel.h> 24#include <linux/fs.h> 25#include <linux/miscdevice.h> 26#include <linux/watchdog.h> 27#include <linux/init.h> 28#include <linux/bitops.h> 29#include <linux/uaccess.h> 30#include <linux/timex.h> 31 32#ifdef CONFIG_ARCH_PXA 33#include <mach/regs-ost.h> 34#endif 35 36#include <mach/reset.h> 37#include <mach/hardware.h> 38 39static unsigned long oscr_freq; 40static unsigned long sa1100wdt_users; 41static unsigned int pre_margin; 42static int boot_status; 43 44/* 45 * Allow only one person to hold it open 46 */ 47static int sa1100dog_open(struct inode *inode, struct file *file) 48{ 49 if (test_and_set_bit(1, &sa1100wdt_users)) 50 return -EBUSY; 51 52 /* Activate SA1100 Watchdog timer */ 53 OSMR3 = OSCR + pre_margin; 54 OSSR = OSSR_M3; 55 OWER = OWER_WME; 56 OIER |= OIER_E3; 57 return nonseekable_open(inode, file); 58} 59 60/* 61 * The watchdog cannot be disabled. 62 * 63 * Previous comments suggested that turning off the interrupt by 64 * clearing OIER[E3] would prevent the watchdog timing out but this 65 * does not appear to be true (at least on the PXA255). 66 */ 67static int sa1100dog_release(struct inode *inode, struct file *file) 68{ 69 printk(KERN_CRIT "WATCHDOG: Device closed - timer will not stop\n"); 70 clear_bit(1, &sa1100wdt_users); 71 return 0; 72} 73 74static ssize_t sa1100dog_write(struct file *file, const char __user *data, 75 size_t len, loff_t *ppos) 76{ 77 if (len) 78 /* Refresh OSMR3 timer. */ 79 OSMR3 = OSCR + pre_margin; 80 return len; 81} 82 83static const struct watchdog_info ident = { 84 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT 85 | WDIOF_KEEPALIVEPING, 86 .identity = "SA1100/PXA255 Watchdog", 87 .firmware_version = 1, 88}; 89 90static long sa1100dog_ioctl(struct file *file, unsigned int cmd, 91 unsigned long arg) 92{ 93 int ret = -ENOTTY; 94 int time; 95 void __user *argp = (void __user *)arg; 96 int __user *p = argp; 97 98 switch (cmd) { 99 case WDIOC_GETSUPPORT: 100 ret = copy_to_user(argp, &ident, 101 sizeof(ident)) ? -EFAULT : 0; 102 break; 103 104 case WDIOC_GETSTATUS: 105 ret = put_user(0, p); 106 break; 107 108 case WDIOC_GETBOOTSTATUS: 109 ret = put_user(boot_status, p); 110 break; 111 112 case WDIOC_KEEPALIVE: 113 OSMR3 = OSCR + pre_margin; 114 ret = 0; 115 break; 116 117 case WDIOC_SETTIMEOUT: 118 ret = get_user(time, p); 119 if (ret) 120 break; 121 122 if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) { 123 ret = -EINVAL; 124 break; 125 } 126 127 pre_margin = oscr_freq * time; 128 OSMR3 = OSCR + pre_margin; 129 /*fall through*/ 130 131 case WDIOC_GETTIMEOUT: 132 ret = put_user(pre_margin / oscr_freq, p); 133 break; 134 } 135 return ret; 136} 137 138static const struct file_operations sa1100dog_fops = { 139 .owner = THIS_MODULE, 140 .llseek = no_llseek, 141 .write = sa1100dog_write, 142 .unlocked_ioctl = sa1100dog_ioctl, 143 .open = sa1100dog_open, 144 .release = sa1100dog_release, 145}; 146 147static struct miscdevice sa1100dog_miscdev = { 148 .minor = WATCHDOG_MINOR, 149 .name = "watchdog", 150 .fops = &sa1100dog_fops, 151}; 152 153static int margin __initdata = 60; /* (secs) Default is 1 minute */ 154 155static int __init sa1100dog_init(void) 156{ 157 int ret; 158 159 oscr_freq = get_clock_tick_rate(); 160 161 /* 162 * Read the reset status, and save it for later. If 163 * we suspend, RCSR will be cleared, and the watchdog 164 * reset reason will be lost. 165 */ 166 boot_status = (reset_status & RESET_STATUS_WATCHDOG) ? 167 WDIOF_CARDRESET : 0; 168 pre_margin = oscr_freq * margin; 169 170 ret = misc_register(&sa1100dog_miscdev); 171 if (ret == 0) 172 printk(KERN_INFO 173 "SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", 174 margin); 175 return ret; 176} 177 178static void __exit sa1100dog_exit(void) 179{ 180 misc_deregister(&sa1100dog_miscdev); 181} 182 183module_init(sa1100dog_init); 184module_exit(sa1100dog_exit); 185 186MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); 187MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); 188 189module_param(margin, int, 0); 190MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); 191 192MODULE_LICENSE("GPL"); 193MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 194