| 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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 7 | |
| 8 | #include <linux/kernel.h> |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/types.h> |
| 11 | #include <linux/fs.h> |
| 12 | #include <linux/errno.h> |
| 13 | #include <linux/miscdevice.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 | #include <linux/slab.h> |
| 20 | |
| 21 | |
| 22 | /* RIO uses the NatSemi Super I/O power management logical device |
| 23 | * as its' watchdog. |
| 24 | * |
| 25 | * When the watchdog triggers, it asserts a line to the BBC (Boot Bus |
| 26 | * Controller) of the machine. The BBC can only be configured to |
| 27 | * trigger a power-on reset when the signal is asserted. The BBC |
| 28 | * can be configured to ignore the signal entirely as well. |
| 29 | * |
| 30 | * The only Super I/O device register we care about is at index |
| 31 | * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255). |
| 32 | * If set to zero, this disables the watchdog. When set, the system |
| 33 | * must periodically (before watchdog expires) clear (set to zero) and |
| 34 | * re-set the watchdog else it will trigger. |
| 35 | * |
| 36 | * There are two other indexed watchdog registers inside this Super I/O |
| 37 | * logical device, but they are unused. The first, at index 0x06 is |
| 38 | * the watchdog control and can be used to make the watchdog timer re-set |
| 39 | * when the PS/2 mouse or serial lines show activity. The second, at |
| 40 | * index 0x07 is merely a sampling of the line from the watchdog to the |
| 41 | * BBC. |
| 42 | * |
| 43 | * The watchdog device generates no interrupts. |
| 44 | */ |
| 45 | |
| 46 | MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); |
| 47 | MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO"); |
| 48 | MODULE_SUPPORTED_DEVICE("watchdog"); |
| 49 | MODULE_LICENSE("GPL"); |
| 50 | |
| 51 | #define DRIVER_NAME "riowd" |
| 52 | #define PFX DRIVER_NAME ": " |
| 53 | |
| 54 | struct riowd { |
| 55 | void __iomem *regs; |
| 56 | spinlock_t lock; |
| 57 | }; |
| 58 | |
| 59 | static struct riowd *riowd_device; |
| 60 | |
| 61 | #define WDTO_INDEX 0x05 |
| 62 | |
| 63 | static int riowd_timeout = 1; /* in minutes */ |
| 64 | module_param(riowd_timeout, int, 0); |
| 65 | MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes"); |
| 66 | |
| 67 | static void riowd_writereg(struct riowd *p, u8 val, int index) |
| 68 | { |
| 69 | unsigned long flags; |
| 70 | |
| 71 | spin_lock_irqsave(&p->lock, flags); |
| 72 | writeb(index, p->regs + 0); |
| 73 | writeb(val, p->regs + 1); |
| 74 | spin_unlock_irqrestore(&p->lock, flags); |
| 75 | } |
| 76 | |
| 77 | static int riowd_open(struct inode *inode, struct file *filp) |
| 78 | { |
| 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 const 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 riowd_probe(struct platform_device *op) |
| 177 | { |
| 178 | struct riowd *p; |
| 179 | int err = -EINVAL; |
| 180 | |
| 181 | if (riowd_device) |
| 182 | goto out; |
| 183 | |
| 184 | err = -ENOMEM; |
| 185 | p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL); |
| 186 | if (!p) |
| 187 | goto out; |
| 188 | |
| 189 | spin_lock_init(&p->lock); |
| 190 | |
| 191 | p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME); |
| 192 | if (!p->regs) { |
| 193 | pr_err("Cannot map registers\n"); |
| 194 | goto out; |
| 195 | } |
| 196 | /* Make miscdev useable right away */ |
| 197 | riowd_device = p; |
| 198 | |
| 199 | err = misc_register(&riowd_miscdev); |
| 200 | if (err) { |
| 201 | pr_err("Cannot register watchdog misc device\n"); |
| 202 | goto out_iounmap; |
| 203 | } |
| 204 | |
| 205 | pr_info("Hardware watchdog [%i minutes], regs at %p\n", |
| 206 | riowd_timeout, p->regs); |
| 207 | |
| 208 | platform_set_drvdata(op, p); |
| 209 | return 0; |
| 210 | |
| 211 | out_iounmap: |
| 212 | riowd_device = NULL; |
| 213 | of_iounmap(&op->resource[0], p->regs, 2); |
| 214 | |
| 215 | out: |
| 216 | return err; |
| 217 | } |
| 218 | |
| 219 | static int riowd_remove(struct platform_device *op) |
| 220 | { |
| 221 | struct riowd *p = platform_get_drvdata(op); |
| 222 | |
| 223 | misc_deregister(&riowd_miscdev); |
| 224 | of_iounmap(&op->resource[0], p->regs, 2); |
| 225 | |
| 226 | return 0; |
| 227 | } |
| 228 | |
| 229 | static const struct of_device_id riowd_match[] = { |
| 230 | { |
| 231 | .name = "pmc", |
| 232 | }, |
| 233 | {}, |
| 234 | }; |
| 235 | MODULE_DEVICE_TABLE(of, riowd_match); |
| 236 | |
| 237 | static struct platform_driver riowd_driver = { |
| 238 | .driver = { |
| 239 | .name = DRIVER_NAME, |
| 240 | .of_match_table = riowd_match, |
| 241 | }, |
| 242 | .probe = riowd_probe, |
| 243 | .remove = riowd_remove, |
| 244 | }; |
| 245 | |
| 246 | module_platform_driver(riowd_driver); |