--- /dev/null
+/*
+ * Watchdog driver for Kendin/Micrel KS8695.
+ *
+ * (C) 2007 Andrew Victor
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <mach/hardware.h>
+
+#define KS8695_TMR_OFFSET (0xF0000 + 0xE400)
+#define KS8695_TMR_VA (KS8695_IO_VA + KS8695_TMR_OFFSET)
+
+/*
+ * Timer registers
+ */
+#define KS8695_TMCON (0x00) /* Timer Control Register */
+#define KS8695_T0TC (0x08) /* Timer 0 Timeout Count Register */
+#define TMCON_T0EN (1 << 0) /* Timer 0 Enable */
+
+/* Timer0 Timeout Counter Register */
+#define T0TC_WATCHDOG (0xff) /* Enable watchdog mode */
+
+#define WDT_DEFAULT_TIME 5 /* seconds */
+#define WDT_MAX_TIME 171 /* seconds */
+
+static int wdt_time = WDT_DEFAULT_TIME;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(wdt_time, int, 0);
+MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="
+ __MODULE_STRING(WDT_DEFAULT_TIME) ")");
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+#endif
+
+
+static unsigned long ks8695wdt_busy;
+static DEFINE_SPINLOCK(ks8695_lock);
+
+/* ......................................................................... */
+
+/*
+ * Disable the watchdog.
+ */
+static inline void ks8695_wdt_stop(void)
+{
+ unsigned long tmcon;
+
+ spin_lock(&ks8695_lock);
+ /* disable timer0 */
+ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+ __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+ spin_unlock(&ks8695_lock);
+}
+
+/*
+ * Enable and reset the watchdog.
+ */
+static inline void ks8695_wdt_start(void)
+{
+ unsigned long tmcon;
+ unsigned long tval = wdt_time * KS8695_CLOCK_RATE;
+
+ spin_lock(&ks8695_lock);
+ /* disable timer0 */
+ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+ __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+
+ /* program timer0 */
+ __raw_writel(tval | T0TC_WATCHDOG, KS8695_TMR_VA + KS8695_T0TC);
+
+ /* re-enable timer0 */
+ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+ __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+ spin_unlock(&ks8695_lock);
+}
+
+/*
+ * Reload the watchdog timer. (ie, pat the watchdog)
+ */
+static inline void ks8695_wdt_reload(void)
+{
+ unsigned long tmcon;
+
+ spin_lock(&ks8695_lock);
+ /* disable, then re-enable timer0 */
+ tmcon = __raw_readl(KS8695_TMR_VA + KS8695_TMCON);
+ __raw_writel(tmcon & ~TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+ __raw_writel(tmcon | TMCON_T0EN, KS8695_TMR_VA + KS8695_TMCON);
+ spin_unlock(&ks8695_lock);
+}
+
+/*
+ * Change the watchdog time interval.
+ */
+static int ks8695_wdt_settimeout(int new_time)
+{
+ /*
+ * All counting occurs at KS8695_CLOCK_RATE / 128 = 0.256 Hz
+ *
+ * Since WDV is a 16-bit counter, the maximum period is
+ * 65536 / 0.256 = 256 seconds.
+ */
+ if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+ return -EINVAL;
+
+ /* Set new watchdog time. It will be used when
+ ks8695_wdt_start() is called. */
+ wdt_time = new_time;
+ return 0;
+}
+
+/* ......................................................................... */
+
+/*
+ * Watchdog device is opened, and watchdog starts running.
+ */
+static int ks8695_wdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &ks8695wdt_busy))
+ return -EBUSY;
+
+ ks8695_wdt_start();
+ return nonseekable_open(inode, file);
+}
+
+/*
+ * Close the watchdog device.
+ * If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
+ * disabled.
+ */
+static int ks8695_wdt_close(struct inode *inode, struct file *file)
+{
+ /* Disable the watchdog when file is closed */
+ if (!nowayout)
+ ks8695_wdt_stop();
+ clear_bit(0, &ks8695wdt_busy);
+ return 0;
+}
+
+static const struct watchdog_info ks8695_wdt_info = {
+ .identity = "ks8695 watchdog",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+};
+
+/*
+ * Handle commands from user-space.
+ */
+static long ks8695_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_value;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ks8695_wdt_info,
+ sizeof(ks8695_wdt_info)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_SETOPTIONS:
+ if (get_user(new_value, p))
+ return -EFAULT;
+ if (new_value & WDIOS_DISABLECARD)
+ ks8695_wdt_stop();
+ if (new_value & WDIOS_ENABLECARD)
+ ks8695_wdt_start();
+ return 0;
+ case WDIOC_KEEPALIVE:
+ ks8695_wdt_reload(); /* pat the watchdog */
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_value, p))
+ return -EFAULT;
+ if (ks8695_wdt_settimeout(new_value))
+ return -EINVAL;
+ /* Enable new time value */
+ ks8695_wdt_start();
+ /* Return current value */
+ return put_user(wdt_time, p);
+ case WDIOC_GETTIMEOUT:
+ return put_user(wdt_time, p);
+ default:
+ return -ENOTTY;
+ }
+}
+
+/*
+ * Pat the watchdog whenever device is written to.
+ */
+static ssize_t ks8695_wdt_write(struct file *file, const char *data,
+ size_t len, loff_t *ppos)
+{
+ ks8695_wdt_reload(); /* pat the watchdog */
+ return len;
+}
+
+/* ......................................................................... */
+
+static const struct file_operations ks8695wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .unlocked_ioctl = ks8695_wdt_ioctl,
+ .open = ks8695_wdt_open,
+ .release = ks8695_wdt_close,
+ .write = ks8695_wdt_write,
+};
+
+static struct miscdevice ks8695wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &ks8695wdt_fops,
+};
+
+static int ks8695wdt_probe(struct platform_device *pdev)
+{
+ int res;
+
+ if (ks8695wdt_miscdev.parent)
+ return -EBUSY;
+ ks8695wdt_miscdev.parent = &pdev->dev;
+
+ res = misc_register(&ks8695wdt_miscdev);
+ if (res)
+ return res;
+
+ pr_info("KS8695 Watchdog Timer enabled (%d seconds%s)\n",
+ wdt_time, nowayout ? ", nowayout" : "");
+ return 0;
+}
+
+static int ks8695wdt_remove(struct platform_device *pdev)
+{
+ int res;
+
+ res = misc_deregister(&ks8695wdt_miscdev);
+ if (!res)
+ ks8695wdt_miscdev.parent = NULL;
+
+ return res;
+}
+
+static void ks8695wdt_shutdown(struct platform_device *pdev)
+{
+ ks8695_wdt_stop();
+}
+
+#ifdef CONFIG_PM
+
+static int ks8695wdt_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ ks8695_wdt_stop();
+ return 0;
+}
+
+static int ks8695wdt_resume(struct platform_device *pdev)
+{
+ if (ks8695wdt_busy)
+ ks8695_wdt_start();
+ return 0;
+}
+
+#else
+#define ks8695wdt_suspend NULL
+#define ks8695wdt_resume NULL
+#endif
+
+static struct platform_driver ks8695wdt_driver = {
+ .probe = ks8695wdt_probe,
+ .remove = ks8695wdt_remove,
+ .shutdown = ks8695wdt_shutdown,
+ .suspend = ks8695wdt_suspend,
+ .resume = ks8695wdt_resume,
+ .driver = {
+ .name = "ks8695_wdt",
+ },
+};
+
+static int __init ks8695_wdt_init(void)
+{
+ /* Check that the heartbeat value is within range;
+ if not reset to the default */
+ if (ks8695_wdt_settimeout(wdt_time)) {
+ ks8695_wdt_settimeout(WDT_DEFAULT_TIME);
+ pr_info("ks8695_wdt: wdt_time value must be 1 <= wdt_time <= %i"
+ ", using %d\n", wdt_time, WDT_MAX_TIME);
+ }
+ return platform_driver_register(&ks8695wdt_driver);
+}
+
+static void __exit ks8695_wdt_exit(void)
+{
+ platform_driver_unregister(&ks8695wdt_driver);
+}
+
+module_init(ks8695_wdt_init);
+module_exit(ks8695_wdt_exit);
+
+MODULE_AUTHOR("Andrew Victor");
+MODULE_DESCRIPTION("Watchdog driver for KS8695");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ks8695_wdt");
Code Review / kvmfornfv.git / blobdiff