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 #include <linux/slab.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 nonseekable_open(inode, filp); 79 return 0; 80 } 81 82 static int riowd_release(struct inode *inode, struct file *filp) 83 { 84 return 0; 85 } 86 87 static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 88 { 89 static const struct watchdog_info info = { 90 .options = WDIOF_SETTIMEOUT, 91 .firmware_version = 1, 92 .identity = DRIVER_NAME, 93 }; 94 void __user *argp = (void __user *)arg; 95 struct riowd *p = riowd_device; 96 unsigned int options; 97 int new_margin; 98 99 switch (cmd) { 100 case WDIOC_GETSUPPORT: 101 if (copy_to_user(argp, &info, sizeof(info))) 102 return -EFAULT; 103 break; 104 105 case WDIOC_GETSTATUS: 106 case WDIOC_GETBOOTSTATUS: 107 if (put_user(0, (int __user *)argp)) 108 return -EFAULT; 109 break; 110 111 case WDIOC_KEEPALIVE: 112 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 113 break; 114 115 case WDIOC_SETOPTIONS: 116 if (copy_from_user(&options, argp, sizeof(options))) 117 return -EFAULT; 118 119 if (options & WDIOS_DISABLECARD) 120 riowd_writereg(p, 0, WDTO_INDEX); 121 else if (options & WDIOS_ENABLECARD) 122 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 123 else 124 return -EINVAL; 125 126 break; 127 128 case WDIOC_SETTIMEOUT: 129 if (get_user(new_margin, (int __user *)argp)) 130 return -EFAULT; 131 if ((new_margin < 60) || (new_margin > (255 * 60))) 132 return -EINVAL; 133 riowd_timeout = (new_margin + 59) / 60; 134 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 135 /* Fall */ 136 137 case WDIOC_GETTIMEOUT: 138 return put_user(riowd_timeout * 60, (int __user *)argp); 139 140 default: 141 return -EINVAL; 142 }; 143 144 return 0; 145 } 146 147 static ssize_t riowd_write(struct file *file, const char __user *buf, 148 size_t count, loff_t *ppos) 149 { 150 struct riowd *p = riowd_device; 151 152 if (count) { 153 riowd_writereg(p, riowd_timeout, WDTO_INDEX); 154 return 1; 155 } 156 157 return 0; 158 } 159 160 static const struct file_operations riowd_fops = { 161 .owner = THIS_MODULE, 162 .llseek = no_llseek, 163 .unlocked_ioctl = riowd_ioctl, 164 .open = riowd_open, 165 .write = riowd_write, 166 .release = riowd_release, 167 }; 168 169 static struct miscdevice riowd_miscdev = { 170 .minor = WATCHDOG_MINOR, 171 .name = "watchdog", 172 .fops = &riowd_fops 173 }; 174 175 static int __devinit riowd_probe(struct platform_device *op) 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 platform_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 platform_driver riowd_driver = { 241 .driver = { 242 .name = DRIVER_NAME, 243 .owner = THIS_MODULE, 244 .of_match_table = riowd_match, 245 }, 246 .probe = riowd_probe, 247 .remove = __devexit_p(riowd_remove), 248 }; 249 250 module_platform_driver(riowd_driver); 251