1/* 2 * PNX833x Hardware Watchdog Driver 3 * Copyright 2008 NXP Semiconductors 4 * Daniel Laird <daniel.j.laird@nxp.com> 5 * Andre McCurdy <andre.mccurdy@nxp.com> 6 * 7 * Heavily based upon - IndyDog 0.3 8 * A Hardware Watchdog Device for SGI IP22 9 * 10 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved. 11 * 12 * This program is free software; you can redistribute it and/or 13 * modify it under the terms of the GNU General Public License 14 * as published by the Free Software Foundation; either version 15 * 2 of the License, or (at your option) any later version. 16 * 17 * based on softdog.c by Alan Cox <alan@redhat.com> 18 */ 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/mm.h> 26#include <linux/miscdevice.h> 27#include <linux/watchdog.h> 28#include <linux/notifier.h> 29#include <linux/reboot.h> 30#include <linux/init.h> 31#include <asm/mach-pnx833x/pnx833x.h> 32 33#define PFX "pnx833x: " 34#define WATCHDOG_TIMEOUT 30 /* 30 sec Maximum timeout */ 35#define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */ 36#define PNX_WATCHDOG_TIMEOUT (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY) 37#define PNX_TIMEOUT_VALUE 2040000000U 38 39/** CONFIG block */ 40#define PNX833X_CONFIG (0x07000U) 41#define PNX833X_CONFIG_CPU_WATCHDOG (0x54) 42#define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58) 43#define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c) 44 45/** RESET block */ 46#define PNX833X_RESET (0x08000U) 47#define PNX833X_RESET_CONFIG (0x08) 48 49static int pnx833x_wdt_alive; 50 51/* Set default timeout in MHZ.*/ 52static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT; 53module_param(pnx833x_wdt_timeout, int, 0); 54MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default=" 55 __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds)."); 56 57static int nowayout = WATCHDOG_NOWAYOUT; 58module_param(nowayout, int, 0); 59MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 60 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 61 62#define START_DEFAULT 1 63static int start_enabled = START_DEFAULT; 64module_param(start_enabled, int, 0); 65MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion " 66 "(default=" __MODULE_STRING(START_DEFAULT) ")"); 67 68static void pnx833x_wdt_start(void) 69{ 70 /* Enable watchdog causing reset. */ 71 PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1; 72 /* Set timeout.*/ 73 PNX833X_REG(PNX833X_CONFIG + 74 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout; 75 /* Enable watchdog. */ 76 PNX833X_REG(PNX833X_CONFIG + 77 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1; 78 79 printk(KERN_INFO PFX "Started watchdog timer.\n"); 80} 81 82static void pnx833x_wdt_stop(void) 83{ 84 /* Disable watchdog causing reset. */ 85 PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE; 86 /* Disable watchdog.*/ 87 PNX833X_REG(PNX833X_CONFIG + 88 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE; 89 90 printk(KERN_INFO PFX "Stopped watchdog timer.\n"); 91} 92 93static void pnx833x_wdt_ping(void) 94{ 95 PNX833X_REG(PNX833X_CONFIG + 96 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout; 97} 98 99/* 100 * Allow only one person to hold it open 101 */ 102static int pnx833x_wdt_open(struct inode *inode, struct file *file) 103{ 104 if (test_and_set_bit(0, &pnx833x_wdt_alive)) 105 return -EBUSY; 106 107 if (nowayout) 108 __module_get(THIS_MODULE); 109 110 /* Activate timer */ 111 if (!start_enabled) 112 pnx833x_wdt_start(); 113 114 pnx833x_wdt_ping(); 115 116 printk(KERN_INFO "Started watchdog timer.\n"); 117 118 return nonseekable_open(inode, file); 119} 120 121static int pnx833x_wdt_release(struct inode *inode, struct file *file) 122{ 123 /* Shut off the timer. 124 * Lock it in if it's a module and we defined ...NOWAYOUT */ 125 if (!nowayout) 126 pnx833x_wdt_stop(); /* Turn the WDT off */ 127 128 clear_bit(0, &pnx833x_wdt_alive); 129 return 0; 130} 131 132static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) 133{ 134 /* Refresh the timer. */ 135 if (len) 136 pnx833x_wdt_ping(); 137 138 return len; 139} 140 141static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd, 142 unsigned long arg) 143{ 144 int options, new_timeout = 0; 145 uint32_t timeout, timeout_left = 0; 146 147 static const struct watchdog_info ident = { 148 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, 149 .firmware_version = 0, 150 .identity = "Hardware Watchdog for PNX833x", 151 }; 152 153 switch (cmd) { 154 default: 155 return -ENOTTY; 156 157 case WDIOC_GETSUPPORT: 158 if (copy_to_user((struct watchdog_info *)arg, 159 &ident, sizeof(ident))) 160 return -EFAULT; 161 return 0; 162 163 case WDIOC_GETSTATUS: 164 case WDIOC_GETBOOTSTATUS: 165 return put_user(0, (int *)arg); 166 167 case WDIOC_SETOPTIONS: 168 if (get_user(options, (int *)arg)) 169 return -EFAULT; 170 171 if (options & WDIOS_DISABLECARD) 172 pnx833x_wdt_stop(); 173 174 if (options & WDIOS_ENABLECARD) 175 pnx833x_wdt_start(); 176 177 return 0; 178 179 case WDIOC_KEEPALIVE: 180 pnx833x_wdt_ping(); 181 return 0; 182 183 case WDIOC_SETTIMEOUT: 184 { 185 if (get_user(new_timeout, (int *)arg)) 186 return -EFAULT; 187 188 pnx833x_wdt_timeout = new_timeout; 189 PNX833X_REG(PNX833X_CONFIG + 190 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout; 191 return put_user(new_timeout, (int *)arg); 192 } 193 194 case WDIOC_GETTIMEOUT: 195 timeout = PNX833X_REG(PNX833X_CONFIG + 196 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE); 197 return put_user(timeout, (int *)arg); 198 199 case WDIOC_GETTIMELEFT: 200 timeout_left = PNX833X_REG(PNX833X_CONFIG + 201 PNX833X_CONFIG_CPU_WATCHDOG); 202 return put_user(timeout_left, (int *)arg); 203 204 } 205} 206 207static int pnx833x_wdt_notify_sys(struct notifier_block *this, 208 unsigned long code, void *unused) 209{ 210 if (code == SYS_DOWN || code == SYS_HALT) 211 pnx833x_wdt_stop(); /* Turn the WDT off */ 212 213 return NOTIFY_DONE; 214} 215 216static const struct file_operations pnx833x_wdt_fops = { 217 .owner = THIS_MODULE, 218 .llseek = no_llseek, 219 .write = pnx833x_wdt_write, 220 .unlocked_ioctl = pnx833x_wdt_ioctl, 221 .open = pnx833x_wdt_open, 222 .release = pnx833x_wdt_release, 223}; 224 225static struct miscdevice pnx833x_wdt_miscdev = { 226 .minor = WATCHDOG_MINOR, 227 .name = "watchdog", 228 .fops = &pnx833x_wdt_fops, 229}; 230 231static struct notifier_block pnx833x_wdt_notifier = { 232 .notifier_call = pnx833x_wdt_notify_sys, 233}; 234 235static char banner[] __initdata = 236 KERN_INFO PFX "Hardware Watchdog Timer for PNX833x: Version 0.1\n"; 237 238static int __init watchdog_init(void) 239{ 240 int ret, cause; 241 242 /* Lets check the reason for the reset.*/ 243 cause = PNX833X_REG(PNX833X_RESET); 244 /*If bit 31 is set then watchdog was cause of reset.*/ 245 if (cause & 0x80000000) { 246 printk(KERN_INFO PFX "The system was previously reset due to " 247 "the watchdog firing - please investigate...\n"); 248 } 249 250 ret = register_reboot_notifier(&pnx833x_wdt_notifier); 251 if (ret) { 252 printk(KERN_ERR PFX 253 "cannot register reboot notifier (err=%d)\n", ret); 254 return ret; 255 } 256 257 ret = misc_register(&pnx833x_wdt_miscdev); 258 if (ret) { 259 printk(KERN_ERR PFX 260 "cannot register miscdev on minor=%d (err=%d)\n", 261 WATCHDOG_MINOR, ret); 262 unregister_reboot_notifier(&pnx833x_wdt_notifier); 263 return ret; 264 } 265 266 printk(banner); 267 if (start_enabled) 268 pnx833x_wdt_start(); 269 270 return 0; 271} 272 273static void __exit watchdog_exit(void) 274{ 275 misc_deregister(&pnx833x_wdt_miscdev); 276 unregister_reboot_notifier(&pnx833x_wdt_notifier); 277} 278 279module_init(watchdog_init); 280module_exit(watchdog_exit); 281 282MODULE_AUTHOR("Daniel Laird/Andre McCurdy"); 283MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x"); 284MODULE_LICENSE("GPL"); 285MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 286