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@redhat.com> 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 30 #ifdef CONFIG_ARCH_PXA 31 #include <asm/arch/pxa-regs.h> 32 #endif 33 34 #include <asm/hardware.h> 35 #include <asm/uaccess.h> 36 37 #define OSCR_FREQ CLOCK_TICK_RATE 38 39 static unsigned long sa1100wdt_users; 40 static int pre_margin; 41 static int boot_status; 42 43 /* 44 * Allow only one person to hold it open 45 */ 46 static int sa1100dog_open(struct inode *inode, struct file *file) 47 { 48 if (test_and_set_bit(1,&sa1100wdt_users)) 49 return -EBUSY; 50 51 /* Activate SA1100 Watchdog timer */ 52 OSMR3 = OSCR + pre_margin; 53 OSSR = OSSR_M3; 54 OWER = OWER_WME; 55 OIER |= OIER_E3; 56 return nonseekable_open(inode, file); 57 } 58 59 /* 60 * The watchdog cannot be disabled. 61 * 62 * Previous comments suggested that turning off the interrupt by 63 * clearing OIER[E3] would prevent the watchdog timing out but this 64 * does not appear to be true (at least on the PXA255). 65 */ 66 static int sa1100dog_release(struct inode *inode, struct file *file) 67 { 68 printk(KERN_CRIT "WATCHDOG: Device closed - timer will not stop\n"); 69 70 clear_bit(1, &sa1100wdt_users); 71 72 return 0; 73 } 74 75 static ssize_t sa1100dog_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) 76 { 77 if (len) 78 /* Refresh OSMR3 timer. */ 79 OSMR3 = OSCR + pre_margin; 80 81 return len; 82 } 83 84 static struct watchdog_info ident = { 85 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 86 .identity = "SA1100/PXA255 Watchdog", 87 }; 88 89 static int sa1100dog_ioctl(struct inode *inode, struct file *file, 90 unsigned int cmd, 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_SETTIMEOUT: 112 ret = get_user(time, p); 113 if (ret) 114 break; 115 116 if (time <= 0 || time > 255) { 117 ret = -EINVAL; 118 break; 119 } 120 121 pre_margin = OSCR_FREQ * time; 122 OSMR3 = OSCR + pre_margin; 123 /*fall through*/ 124 125 case WDIOC_GETTIMEOUT: 126 ret = put_user(pre_margin / OSCR_FREQ, p); 127 break; 128 129 case WDIOC_KEEPALIVE: 130 OSMR3 = OSCR + pre_margin; 131 ret = 0; 132 break; 133 } 134 return ret; 135 } 136 137 static const struct file_operations sa1100dog_fops = 138 { 139 .owner = THIS_MODULE, 140 .llseek = no_llseek, 141 .write = sa1100dog_write, 142 .ioctl = sa1100dog_ioctl, 143 .open = sa1100dog_open, 144 .release = sa1100dog_release, 145 }; 146 147 static struct miscdevice sa1100dog_miscdev = 148 { 149 .minor = WATCHDOG_MINOR, 150 .name = "watchdog", 151 .fops = &sa1100dog_fops, 152 }; 153 154 static int margin __initdata = 60; /* (secs) Default is 1 minute */ 155 156 static int __init sa1100dog_init(void) 157 { 158 int ret; 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 = (RCSR & RCSR_WDR) ? WDIOF_CARDRESET : 0; 166 pre_margin = OSCR_FREQ * margin; 167 168 ret = misc_register(&sa1100dog_miscdev); 169 if (ret == 0) 170 printk("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", 171 margin); 172 return ret; 173 } 174 175 static void __exit sa1100dog_exit(void) 176 { 177 misc_deregister(&sa1100dog_miscdev); 178 } 179 180 module_init(sa1100dog_init); 181 module_exit(sa1100dog_exit); 182 183 MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); 184 MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); 185 186 module_param(margin, int, 0); 187 MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); 188 189 MODULE_LICENSE("GPL"); 190 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 191