diff options
Diffstat (limited to 'drivers/watchdog/riowd.c')
| -rw-r--r-- | drivers/watchdog/riowd.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/watchdog/riowd.c b/drivers/watchdog/riowd.c new file mode 100644 index 000000000..7008596a5 --- /dev/null +++ b/drivers/watchdog/riowd.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* 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); + fallthrough; + + 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, + .compat_ioctl = compat_ptr_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); |