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 39 static unsigned long oscr_freq; 40 static unsigned long sa1100wdt_users; 41 static int pre_margin; 42 static int boot_status; 43 44 /* 45 * Allow only one person to hold it open 46 */ 47 static 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 */ 67 static 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 74 static 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 83 static const struct watchdog_info ident = { 84 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT 85 | WDIOF_KEEPALIVEPING, 86 .identity = "SA1100/PXA255 Watchdog", 87 }; 88 89 static long sa1100dog_ioctl(struct file *file, unsigned int cmd, 90 unsigned long arg) 91 { 92 int ret = -ENOTTY; 93 int time; 94 void __user *argp = (void __user *)arg; 95 int __user *p = argp; 96 97 switch (cmd) { 98 case WDIOC_GETSUPPORT: 99 ret = copy_to_user(argp, &ident, 100 sizeof(ident)) ? -EFAULT : 0; 101 break; 102 103 case WDIOC_GETSTATUS: 104 ret = put_user(0, p); 105 break; 106 107 case WDIOC_GETBOOTSTATUS: 108 ret = put_user(boot_status, p); 109 break; 110 111 case WDIOC_KEEPALIVE: 112 OSMR3 = OSCR + pre_margin; 113 ret = 0; 114 break; 115 116 case WDIOC_SETTIMEOUT: 117 ret = get_user(time, p); 118 if (ret) 119 break; 120 121 if (time <= 0 || time > 255) { 122 ret = -EINVAL; 123 break; 124 } 125 126 pre_margin = oscr_freq * time; 127 OSMR3 = OSCR + pre_margin; 128 /*fall through*/ 129 130 case WDIOC_GETTIMEOUT: 131 ret = put_user(pre_margin / oscr_freq, p); 132 break; 133 } 134 return ret; 135 } 136 137 static const struct file_operations sa1100dog_fops = { 138 .owner = THIS_MODULE, 139 .llseek = no_llseek, 140 .write = sa1100dog_write, 141 .unlocked_ioctl = sa1100dog_ioctl, 142 .open = sa1100dog_open, 143 .release = sa1100dog_release, 144 }; 145 146 static struct miscdevice sa1100dog_miscdev = { 147 .minor = WATCHDOG_MINOR, 148 .name = "watchdog", 149 .fops = &sa1100dog_fops, 150 }; 151 152 static int margin __initdata = 60; /* (secs) Default is 1 minute */ 153 154 static int __init sa1100dog_init(void) 155 { 156 int ret; 157 158 oscr_freq = get_clock_tick_rate(); 159 160 /* 161 * Read the reset status, and save it for later. If 162 * we suspend, RCSR will be cleared, and the watchdog 163 * reset reason will be lost. 164 */ 165 boot_status = (reset_status & RESET_STATUS_WATCHDOG) ? 166 WDIOF_CARDRESET : 0; 167 pre_margin = oscr_freq * margin; 168 169 ret = misc_register(&sa1100dog_miscdev); 170 if (ret == 0) 171 printk(KERN_INFO 172 "SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", 173 margin); 174 return ret; 175 } 176 177 static void __exit sa1100dog_exit(void) 178 { 179 misc_deregister(&sa1100dog_miscdev); 180 } 181 182 module_init(sa1100dog_init); 183 module_exit(sa1100dog_exit); 184 185 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); 186 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); 187 188 module_param(margin, int, 0); 189 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); 190 191 MODULE_LICENSE("GPL"); 192 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 193