| /* riowd.c - driver for hw watchdog inside Super I/O of RIO |
| * |
| * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net) |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/fs.h> |
| #include <linux/errno.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/of.h> |
| #include <linux/of_device.h> |
| #include <linux/io.h> |
| #include <linux/uaccess.h> |
| #include <linux/slab.h> |
| |
| |
| /* RIO uses the NatSemi Super I/O power management logical device |
| * as its' watchdog. |
| * |
| * When the watchdog triggers, it asserts a line to the BBC (Boot Bus |
| * Controller) of the machine. The BBC can only be configured to |
| * trigger a power-on reset when the signal is asserted. The BBC |
| * can be configured to ignore the signal entirely as well. |
| * |
| * The only Super I/O device register we care about is at index |
| * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255). |
| * If set to zero, this disables the watchdog. When set, the system |
| * must periodically (before watchdog expires) clear (set to zero) and |
| * re-set the watchdog else it will trigger. |
| * |
| * There are two other indexed watchdog registers inside this Super I/O |
| * logical device, but they are unused. The first, at index 0x06 is |
| * the watchdog control and can be used to make the watchdog timer re-set |
| * when the PS/2 mouse or serial lines show activity. The second, at |
| * index 0x07 is merely a sampling of the line from the watchdog to the |
| * BBC. |
| * |
| * The watchdog device generates no interrupts. |
| */ |
| |
| MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); |
| MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO"); |
| MODULE_SUPPORTED_DEVICE("watchdog"); |
| MODULE_LICENSE("GPL"); |
| |
| #define DRIVER_NAME "riowd" |
| #define PFX DRIVER_NAME ": " |
| |
| struct riowd { |
| void __iomem *regs; |
| spinlock_t lock; |
| }; |
| |
| static struct riowd *riowd_device; |
| |
| #define WDTO_INDEX 0x05 |
| |
| static int riowd_timeout = 1; /* in minutes */ |
| module_param(riowd_timeout, int, 0); |
| MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes"); |
| |
| static void riowd_writereg(struct riowd *p, u8 val, int index) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&p->lock, flags); |
| writeb(index, p->regs + 0); |
| writeb(val, p->regs + 1); |
| spin_unlock_irqrestore(&p->lock, flags); |
| } |
| |
| static int riowd_open(struct inode *inode, struct file *filp) |
| { |
| stream_open(inode, filp); |
| return 0; |
| } |
| |
| static int riowd_release(struct inode *inode, struct file *filp) |
| { |
| return 0; |
| } |
| |
| static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
| { |
| static const struct watchdog_info info = { |
| .options = WDIOF_SETTIMEOUT, |
| .firmware_version = 1, |
| .identity = DRIVER_NAME, |
| }; |
| void __user *argp = (void __user *)arg; |
| struct riowd *p = riowd_device; |
| unsigned int options; |
| int new_margin; |
| |
| switch (cmd) { |
| case WDIOC_GETSUPPORT: |
| if (copy_to_user(argp, &info, sizeof(info))) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| if (put_user(0, (int __user *)argp)) |
| return -EFAULT; |
| break; |
| |
| case WDIOC_KEEPALIVE: |
| riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
| break; |
| |
| case WDIOC_SETOPTIONS: |
| if (copy_from_user(&options, argp, sizeof(options))) |
| return -EFAULT; |
| |
| if (options & WDIOS_DISABLECARD) |
| riowd_writereg(p, 0, WDTO_INDEX); |
| else if (options & WDIOS_ENABLECARD) |
| riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
| else |
| return -EINVAL; |
| |
| break; |
| |
| case WDIOC_SETTIMEOUT: |
| if (get_user(new_margin, (int __user *)argp)) |
| return -EFAULT; |
| if ((new_margin < 60) || (new_margin > (255 * 60))) |
| return -EINVAL; |
| riowd_timeout = (new_margin + 59) / 60; |
| riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
| /* Fall */ |
| |
| case WDIOC_GETTIMEOUT: |
| return put_user(riowd_timeout * 60, (int __user *)argp); |
| |
| default: |
| return -EINVAL; |
| }; |
| |
| return 0; |
| } |
| |
| static ssize_t riowd_write(struct file *file, const char __user *buf, |
| size_t count, loff_t *ppos) |
| { |
| struct riowd *p = riowd_device; |
| |
| if (count) { |
| riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| static const struct file_operations riowd_fops = { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .unlocked_ioctl = riowd_ioctl, |
| .open = riowd_open, |
| .write = riowd_write, |
| .release = riowd_release, |
| }; |
| |
| static struct miscdevice riowd_miscdev = { |
| .minor = WATCHDOG_MINOR, |
| .name = "watchdog", |
| .fops = &riowd_fops |
| }; |
| |
| static int riowd_probe(struct platform_device *op) |
| { |
| struct riowd *p; |
| int err = -EINVAL; |
| |
| if (riowd_device) |
| goto out; |
| |
| err = -ENOMEM; |
| p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL); |
| if (!p) |
| goto out; |
| |
| spin_lock_init(&p->lock); |
| |
| p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME); |
| if (!p->regs) { |
| pr_err("Cannot map registers\n"); |
| goto out; |
| } |
| /* Make miscdev useable right away */ |
| riowd_device = p; |
| |
| err = misc_register(&riowd_miscdev); |
| if (err) { |
| pr_err("Cannot register watchdog misc device\n"); |
| goto out_iounmap; |
| } |
| |
| pr_info("Hardware watchdog [%i minutes], regs at %p\n", |
| riowd_timeout, p->regs); |
| |
| platform_set_drvdata(op, p); |
| return 0; |
| |
| out_iounmap: |
| riowd_device = NULL; |
| of_iounmap(&op->resource[0], p->regs, 2); |
| |
| out: |
| return err; |
| } |
| |
| static int riowd_remove(struct platform_device *op) |
| { |
| struct riowd *p = platform_get_drvdata(op); |
| |
| misc_deregister(&riowd_miscdev); |
| of_iounmap(&op->resource[0], p->regs, 2); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id riowd_match[] = { |
| { |
| .name = "pmc", |
| }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, riowd_match); |
| |
| static struct platform_driver riowd_driver = { |
| .driver = { |
| .name = DRIVER_NAME, |
| .of_match_table = riowd_match, |
| }, |
| .probe = riowd_probe, |
| .remove = riowd_remove, |
| }; |
| |
| module_platform_driver(riowd_driver); |