1 /* riowd.c - driver for hw watchdog inside Super I/O of RIO 2 * 3 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net) 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/module.h> 8 #include <linux/types.h> 9 #include <linux/fs.h> 10 #include <linux/errno.h> 11 #include <linux/init.h> 12 #include <linux/miscdevice.h> 13 #include <linux/watchdog.h> 14 #include <linux/of.h> 15 #include <linux/of_device.h> 16 #include <linux/io.h> 17 #include <linux/uaccess.h> 18 19 20 /* RIO uses the NatSemi Super I/O power management logical device 21 * as its' watchdog. 22 * 23 * When the watchdog triggers, it asserts a line to the BBC (Boot Bus 24 * Controller) of the machine. The BBC can only be configured to 25 * trigger a power-on reset when the signal is asserted. The BBC 26 * can be configured to ignore the signal entirely as well. 27 * 28 * The only Super I/O device register we care about is at index 29 * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255). 30 * If set to zero, this disables the watchdog. When set, the system 31 * must periodically (before watchdog expires) clear (set to zero) and 32 * re-set the watchdog else it will trigger. 33 * 34 * There are two other indexed watchdog registers inside this Super I/O 35 * logical device, but they are unused. The first, at index 0x06 is 36 * the watchdog control and can be used to make the watchdog timer re-set 37 * when the PS/2 mouse or serial lines show activity. The second, at 38 * index 0x07 is merely a sampling of the line from the watchdog to the 39 * BBC. 40 * 41 * The watchdog device generates no interrupts. 42 */ 43 44 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); 45 MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO"); 46 MODULE_SUPPORTED_DEVICE("watchdog"); 47 MODULE_LICENSE("GPL"); 48 49 #define DRIVER_NAME "riowd" 50 #define PFX DRIVER_NAME ": " 51 52 struct riowd { 53 void __iomem *regs; 54 spinlock_t lock; 55 }; 56 57 static struct riowd *riowd_device; 58 59 #define WDTO_INDEX 0x05 60 61 static int riowd_timeout = 1; /* in minutes */ 62 module_param(riowd_timeout, int, 0); 63 MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes"); 64 65 static void riowd_writereg(struct riowd *p, u8 val, int index) 66 { 67 unsigned long flags; 68 69 spin_lock_irqsave(&p->lock, flags); 70 writeb(index, p->regs + 0); 71 writeb(val, p->regs + 1); 72 spin_unlock_irqrestore(&p->lock, flags); 73 } 74 75 static int riowd_open(struct inode *inode, struct file *filp) 76 { 77 nonseekable_open(inode, filp); 78 return 0; 79 } 80 81 static int riowd_release(struct inode *inode, struct file *filp) 82 { 83 return 0; 84 } 85 86 static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 87 { 88 static struct watchdog_info info = { 89 .options = WDIOF_SETTIMEOUT, 90 .firmware_version = 1, 91 .identity = DRIVER_NAME, 92 }; 93 void __user *argp = (void __user *)arg; 94 struct riowd *p = riowd_device; 95 unsigned int options; 96 int new_margin; 97 98 switch (cmd) { 99 case WDIOC_GETSUPPORT: 100 if (copy_to_user(argp, &info, sizeof(info))) 101 return -EFAULT; 102 break; 103 104 case WDIOC_GETSTATUS: 105 case WDIOC_GETBOOTSTATUS: 106 if (put_user(0, (int __user *)argp)) 107 return -EFAULT; 108 break; 109 110 case WDIOC_KEEPALIVE: 111 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 112 break; 113 114 case WDIOC_SETOPTIONS: 115 if (copy_from_user(&options, argp, sizeof(options))) 116 return -EFAULT; 117 118 if (options & WDIOS_DISABLECARD) 119 riowd_writereg(p, 0, WDTO_INDEX); 120 else if (options & WDIOS_ENABLECARD) 121 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 122 else 123 return -EINVAL; 124 125 break; 126 127 case WDIOC_SETTIMEOUT: 128 if (get_user(new_margin, (int __user *)argp)) 129 return -EFAULT; 130 if ((new_margin < 60) || (new_margin > (255 * 60))) 131 return -EINVAL; 132 riowd_timeout = (new_margin + 59) / 60; 133 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 134 /* Fall */ 135 136 case WDIOC_GETTIMEOUT: 137 return put_user(riowd_timeout * 60, (int __user *)argp); 138 139 default: 140 return -EINVAL; 141 }; 142 143 return 0; 144 } 145 146 static ssize_t riowd_write(struct file *file, const char __user *buf, 147 size_t count, loff_t *ppos) 148 { 149 struct riowd *p = riowd_device; 150 151 if (count) { 152 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 153 return 1; 154 } 155 156 return 0; 157 } 158 159 static const struct file_operations riowd_fops = { 160 .owner = THIS_MODULE, 161 .llseek = no_llseek, 162 .unlocked_ioctl = riowd_ioctl, 163 .open = riowd_open, 164 .write = riowd_write, 165 .release = riowd_release, 166 }; 167 168 static struct miscdevice riowd_miscdev = { 169 .minor = WATCHDOG_MINOR, 170 .name = "watchdog", 171 .fops = &riowd_fops 172 }; 173 174 static int __devinit riowd_probe(struct of_device *op, 175 const struct of_device_id *match) 176 { 177 struct riowd *p; 178 int err = -EINVAL; 179 180 if (riowd_device) 181 goto out; 182 183 err = -ENOMEM; 184 p = kzalloc(sizeof(*p), GFP_KERNEL); 185 if (!p) 186 goto out; 187 188 spin_lock_init(&p->lock); 189 190 p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME); 191 if (!p->regs) { 192 printk(KERN_ERR PFX "Cannot map registers.\n"); 193 goto out_free; 194 } 195 /* Make miscdev useable right away */ 196 riowd_device = p; 197 198 err = misc_register(&riowd_miscdev); 199 if (err) { 200 printk(KERN_ERR PFX "Cannot register watchdog misc device.\n"); 201 goto out_iounmap; 202 } 203 204 printk(KERN_INFO PFX "Hardware watchdog [%i minutes], " 205 "regs at %p\n", riowd_timeout, p->regs); 206 207 dev_set_drvdata(&op->dev, p); 208 return 0; 209 210 out_iounmap: 211 riowd_device = NULL; 212 of_iounmap(&op->resource[0], p->regs, 2); 213 214 out_free: 215 kfree(p); 216 217 out: 218 return err; 219 } 220 221 static int __devexit riowd_remove(struct of_device *op) 222 { 223 struct riowd *p = dev_get_drvdata(&op->dev); 224 225 misc_deregister(&riowd_miscdev); 226 of_iounmap(&op->resource[0], p->regs, 2); 227 kfree(p); 228 229 return 0; 230 } 231 232 static const struct of_device_id riowd_match[] = { 233 { 234 .name = "pmc", 235 }, 236 {}, 237 }; 238 MODULE_DEVICE_TABLE(of, riowd_match); 239 240 static struct of_platform_driver riowd_driver = { 241 .name = DRIVER_NAME, 242 .match_table = riowd_match, 243 .probe = riowd_probe, 244 .remove = __devexit_p(riowd_remove), 245 }; 246 247 static int __init riowd_init(void) 248 { 249 return of_register_driver(&riowd_driver, &of_bus_type); 250 } 251 252 static void __exit riowd_exit(void) 253 { 254 of_unregister_driver(&riowd_driver); 255 } 256 257 module_init(riowd_init); 258 module_exit(riowd_exit); 259