/* 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) { nonseekable_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);