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/smp_lock.h> 14 #include <linux/watchdog.h> 15 #include <linux/of.h> 16 #include <linux/of_device.h> 17 #include <linux/io.h> 18 #include <linux/uaccess.h> 19 20 21 /* RIO uses the NatSemi Super I/O power management logical device 22 * as its' watchdog. 23 * 24 * When the watchdog triggers, it asserts a line to the BBC (Boot Bus 25 * Controller) of the machine. The BBC can only be configured to 26 * trigger a power-on reset when the signal is asserted. The BBC 27 * can be configured to ignore the signal entirely as well. 28 * 29 * The only Super I/O device register we care about is at index 30 * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255). 31 * If set to zero, this disables the watchdog. When set, the system 32 * must periodically (before watchdog expires) clear (set to zero) and 33 * re-set the watchdog else it will trigger. 34 * 35 * There are two other indexed watchdog registers inside this Super I/O 36 * logical device, but they are unused. The first, at index 0x06 is 37 * the watchdog control and can be used to make the watchdog timer re-set 38 * when the PS/2 mouse or serial lines show activity. The second, at 39 * index 0x07 is merely a sampling of the line from the watchdog to the 40 * BBC. 41 * 42 * The watchdog device generates no interrupts. 43 */ 44 45 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); 46 MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO"); 47 MODULE_SUPPORTED_DEVICE("watchdog"); 48 MODULE_LICENSE("GPL"); 49 50 #define DRIVER_NAME "riowd" 51 #define PFX DRIVER_NAME ": " 52 53 struct riowd { 54 void __iomem *regs; 55 spinlock_t lock; 56 }; 57 58 static struct riowd *riowd_device; 59 60 #define WDTO_INDEX 0x05 61 62 static int riowd_timeout = 1; /* in minutes */ 63 module_param(riowd_timeout, int, 0); 64 MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes"); 65 66 static void riowd_writereg(struct riowd *p, u8 val, int index) 67 { 68 unsigned long flags; 69 70 spin_lock_irqsave(&p->lock, flags); 71 writeb(index, p->regs + 0); 72 writeb(val, p->regs + 1); 73 spin_unlock_irqrestore(&p->lock, flags); 74 } 75 76 static int riowd_open(struct inode *inode, struct file *filp) 77 { 78 cycle_kernel_lock(); 79 nonseekable_open(inode, filp); 80 return 0; 81 } 82 83 static int riowd_release(struct inode *inode, struct file *filp) 84 { 85 return 0; 86 } 87 88 static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 89 { 90 static struct watchdog_info info = { 91 .options = WDIOF_SETTIMEOUT, 92 .firmware_version = 1, 93 .identity = DRIVER_NAME, 94 }; 95 void __user *argp = (void __user *)arg; 96 struct riowd *p = riowd_device; 97 unsigned int options; 98 int new_margin; 99 100 switch (cmd) { 101 case WDIOC_GETSUPPORT: 102 if (copy_to_user(argp, &info, sizeof(info))) 103 return -EFAULT; 104 break; 105 106 case WDIOC_GETSTATUS: 107 case WDIOC_GETBOOTSTATUS: 108 if (put_user(0, (int __user *)argp)) 109 return -EFAULT; 110 break; 111 112 case WDIOC_KEEPALIVE: 113 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 114 break; 115 116 case WDIOC_SETOPTIONS: 117 if (copy_from_user(&options, argp, sizeof(options))) 118 return -EFAULT; 119 120 if (options & WDIOS_DISABLECARD) 121 riowd_writereg(p, 0, WDTO_INDEX); 122 else if (options & WDIOS_ENABLECARD) 123 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 124 else 125 return -EINVAL; 126 127 break; 128 129 case WDIOC_SETTIMEOUT: 130 if (get_user(new_margin, (int __user *)argp)) 131 return -EFAULT; 132 if ((new_margin < 60) || (new_margin > (255 * 60))) 133 return -EINVAL; 134 riowd_timeout = (new_margin + 59) / 60; 135 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 136 /* Fall */ 137 138 case WDIOC_GETTIMEOUT: 139 return put_user(riowd_timeout * 60, (int __user *)argp); 140 141 default: 142 return -EINVAL; 143 }; 144 145 return 0; 146 } 147 148 static ssize_t riowd_write(struct file *file, const char __user *buf, 149 size_t count, loff_t *ppos) 150 { 151 struct riowd *p = riowd_device; 152 153 if (count) { 154 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 155 return 1; 156 } 157 158 return 0; 159 } 160 161 static const struct file_operations riowd_fops = { 162 .owner = THIS_MODULE, 163 .llseek = no_llseek, 164 .unlocked_ioctl = riowd_ioctl, 165 .open = riowd_open, 166 .write = riowd_write, 167 .release = riowd_release, 168 }; 169 170 static struct miscdevice riowd_miscdev = { 171 .minor = WATCHDOG_MINOR, 172 .name = "watchdog", 173 .fops = &riowd_fops 174 }; 175 176 static int __devinit riowd_probe(struct of_device *op, 177 const struct of_device_id *match) 178 { 179 struct riowd *p; 180 int err = -EINVAL; 181 182 if (riowd_device) 183 goto out; 184 185 err = -ENOMEM; 186 p = kzalloc(sizeof(*p), GFP_KERNEL); 187 if (!p) 188 goto out; 189 190 spin_lock_init(&p->lock); 191 192 p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME); 193 if (!p->regs) { 194 printk(KERN_ERR PFX "Cannot map registers.\n"); 195 goto out_free; 196 } 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 riowd_device = p; 209 err = 0; 210 211 out_iounmap: 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