--- /dev/null
+/*
+ * drivers/watchdog/orion5x_wdt.c
+ *
+ * Watchdog driver for Orion5x processors
+ *
+ * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+/*
+ * Watchdog timer block registers.
+ */
+#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
+#define WDT_EN 0x0010
+#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
+
+#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK)
+#define WDT_IN_USE 0
+#define WDT_OK_TO_CLOSE 1
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+static int heartbeat = WDT_MAX_DURATION; /* (seconds) */
+static unsigned long wdt_status;
+
+static void wdt_enable(void)
+{
+ u32 reg;
+
+ /* Set watchdog duration */
+ writel(ORION5X_TCLK * heartbeat, WDT_VAL);
+
+ /* Clear watchdog timer interrupt */
+ reg = readl(BRIDGE_CAUSE);
+ reg &= ~WDT_INT_REQ;
+ writel(reg, BRIDGE_CAUSE);
+
+ /* Enable watchdog timer */
+ reg = readl(TIMER_CTRL);
+ reg |= WDT_EN;
+ writel(reg, TIMER_CTRL);
+
+ /* Enable reset on watchdog */
+ reg = readl(CPU_RESET_MASK);
+ reg |= WDT_RESET;
+ writel(reg, CPU_RESET_MASK);
+}
+
+static void wdt_disable(void)
+{
+ u32 reg;
+
+ /* Disable reset on watchdog */
+ reg = readl(CPU_RESET_MASK);
+ reg &= ~WDT_RESET;
+ writel(reg, CPU_RESET_MASK);
+
+ /* Disable watchdog timer */
+ reg = readl(TIMER_CTRL);
+ reg &= ~WDT_EN;
+ writel(reg, TIMER_CTRL);
+}
+
+static int orion5x_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(WDT_IN_USE, &wdt_status))
+ return -EBUSY;
+ clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+ wdt_enable();
+ return nonseekable_open(inode, file);
+}
+
+static int orion5x_wdt_get_timeleft(int *time_left)
+{
+ *time_left = readl(WDT_VAL) / ORION5X_TCLK;
+ return 0;
+}
+
+static ssize_t orion5x_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ set_bit(WDT_OK_TO_CLOSE, &wdt_status);
+ }
+ }
+ wdt_enable();
+ }
+ return len;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
+ WDIOF_KEEPALIVEPING,
+ .identity = "Orion5x Watchdog",
+};
+
+
+static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ int ret = -ENOTTY;
+ int time;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ ret = copy_to_user((struct watchdog_info *)arg, &ident,
+ sizeof(ident)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ ret = put_user(0, (int *)arg);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ wdt_enable();
+ ret = 0;
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ ret = get_user(time, (int *)arg);
+ if (ret)
+ break;
+
+ if (time <= 0 || time > WDT_MAX_DURATION) {
+ ret = -EINVAL;
+ break;
+ }
+ heartbeat = time;
+ wdt_enable();
+ /* Fall through */
+
+ case WDIOC_GETTIMEOUT:
+ ret = put_user(heartbeat, (int *)arg);
+ break;
+
+ case WDIOC_GETTIMELEFT:
+ if (orion5x_wdt_get_timeleft(&time)) {
+ ret = -EINVAL;
+ break;
+ }
+ ret = put_user(time, (int *)arg);
+ break;
+ }
+ return ret;
+}
+
+static int orion5x_wdt_release(struct inode *inode, struct file *file)
+{
+ if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
+ wdt_disable();
+ else
+ printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
+ "timer will not stop\n");
+ clear_bit(WDT_IN_USE, &wdt_status);
+ clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
+
+ return 0;
+}
+
+
+static const struct file_operations orion5x_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = orion5x_wdt_write,
+ .unlocked_ioctl = orion5x_wdt_ioctl,
+ .open = orion5x_wdt_open,
+ .release = orion5x_wdt_release,
+};
+
+static struct miscdevice orion5x_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &orion5x_wdt_fops,
+};
+
+static int __init orion5x_wdt_init(void)
+{
+ int ret;
+
+ ret = misc_register(&orion5x_wdt_miscdev);
+ if (ret == 0)
+ printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
+ heartbeat);
+
+ return ret;
+}
+
+static void __exit orion5x_wdt_exit(void)
+{
+ misc_deregister(&orion5x_wdt_miscdev);
+}
+
+module_init(orion5x_wdt_init);
+module_exit(orion5x_wdt_exit);
+
+MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
+MODULE_DESCRIPTION("Orion5x Processor Watchdog");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
+ __MODULE_STRING(WDT_MAX_DURATION) ")");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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