--- /dev/null
+/* 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);
Code Review / kvmfornfv.git / blobdiff