--- /dev/null
+/*
+ * NANO7240 SBC Watchdog device driver
+ *
+ * Based on w83877f.c by Scott Jennings,
+ *
+ * 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;
+ *
+ * Software distributed under the License is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or
+ * implied. See the License for the specific language governing
+ * rights and limitations under the License.
+ *
+ * (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/miscdevice.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+#include <asm/atomic.h>
+#include <asm/io.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#define SBC7240_PREFIX "sbc7240_wdt: "
+
+#define SBC7240_ENABLE_PORT 0x443
+#define SBC7240_DISABLE_PORT 0x043
+#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
+#define SBC7240_MAGIC_CHAR 'V'
+
+#define SBC7240_TIMEOUT 30
+#define SBC7240_MAX_TIMEOUT 255
+static int timeout = SBC7240_TIMEOUT; /* in seconds */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
+ __MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
+ __MODULE_STRING(SBC7240_TIMEOUT) ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
+
+#define SBC7240_OPEN_STATUS_BIT 0
+#define SBC7240_ENABLED_STATUS_BIT 1
+#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
+static unsigned long wdt_status;
+
+/*
+ * Utility routines
+ */
+
+static void wdt_disable(void)
+{
+ /* disable the watchdog */
+ if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
+ inb_p(SBC7240_DISABLE_PORT);
+ printk(KERN_INFO SBC7240_PREFIX
+ "Watchdog timer is now disabled.\n");
+ }
+}
+
+static void wdt_enable(void)
+{
+ /* enable the watchdog */
+ if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
+ inb_p(SBC7240_ENABLE_PORT);
+ printk(KERN_INFO SBC7240_PREFIX
+ "Watchdog timer is now enabled.\n");
+ }
+}
+
+static int wdt_set_timeout(int t)
+{
+ if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
+ printk(KERN_ERR SBC7240_PREFIX
+ "timeout value must be 1<=x<=%d\n",
+ SBC7240_MAX_TIMEOUT);
+ return -1;
+ }
+ /* set the timeout */
+ outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
+ timeout = t;
+ printk(KERN_INFO SBC7240_PREFIX "timeout set to %d seconds\n", t);
+ return 0;
+}
+
+/* Whack the dog */
+static inline void wdt_keepalive(void)
+{
+ if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
+ inb_p(SBC7240_ENABLE_PORT);
+}
+
+/*
+ * /dev/watchdog handling
+ */
+static ssize_t fop_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ size_t i;
+ char c;
+
+ if (count) {
+ if (!nowayout) {
+ clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
+ &wdt_status);
+
+ /* is there a magic char ? */
+ for (i = 0; i != count; i++) {
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == SBC7240_MAGIC_CHAR) {
+ set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
+ &wdt_status);
+ break;
+ }
+ }
+ }
+
+ wdt_keepalive();
+ }
+
+ return count;
+}
+
+static int fop_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
+ return -EBUSY;
+
+ wdt_enable();
+
+ return nonseekable_open(inode, file);
+}
+
+static int fop_close(struct inode *inode, struct file *file)
+{
+ if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
+ || !nowayout) {
+ wdt_disable();
+ } else {
+ printk(KERN_CRIT SBC7240_PREFIX
+ "Unexpected close, not stopping watchdog!\n");
+ wdt_keepalive();
+ }
+
+ clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
+ return 0;
+}
+
+static struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING|
+ WDIOF_SETTIMEOUT|
+ WDIOF_MAGICCLOSE,
+ .firmware_version = 1,
+ .identity = "SBC7240",
+};
+
+
+static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user
+ ((void __user *)arg, &ident, sizeof(ident))
+ ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, (int __user *)arg);
+ case WDIOC_KEEPALIVE:
+ wdt_keepalive();
+ return 0;
+ case WDIOC_SETOPTIONS:{
+ int options;
+ int retval = -EINVAL;
+
+ if (get_user(options, (int __user *)arg))
+ return -EFAULT;
+
+ if (options & WDIOS_DISABLECARD) {
+ wdt_disable();
+ retval = 0;
+ }
+
+ if (options & WDIOS_ENABLECARD) {
+ wdt_enable();
+ retval = 0;
+ }
+
+ return retval;
+ }
+ case WDIOC_SETTIMEOUT:{
+ int new_timeout;
+
+ if (get_user(new_timeout, (int __user *)arg))
+ return -EFAULT;
+
+ if (wdt_set_timeout(new_timeout))
+ return -EINVAL;
+
+ /* Fall through */
+ }
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, (int __user *)arg);
+ default:
+ return -ENOTTY;
+ }
+}
+
+static const struct file_operations wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = fop_write,
+ .open = fop_open,
+ .release = fop_close,
+ .ioctl = fop_ioctl,
+};
+
+static struct miscdevice wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &wdt_fops,
+};
+
+/*
+ * Notifier for system down
+ */
+
+static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ wdt_disable();
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block wdt_notifier = {
+ .notifier_call = wdt_notify_sys,
+};
+
+static void __exit sbc7240_wdt_unload(void)
+{
+ printk(KERN_INFO SBC7240_PREFIX "Removing watchdog\n");
+ misc_deregister(&wdt_miscdev);
+
+ unregister_reboot_notifier(&wdt_notifier);
+ release_region(SBC7240_ENABLE_PORT, 1);
+}
+
+static int __init sbc7240_wdt_init(void)
+{
+ int rc = -EBUSY;
+
+ if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
+ printk(KERN_ERR SBC7240_PREFIX
+ "I/O address 0x%04x already in use\n",
+ SBC7240_ENABLE_PORT);
+ rc = -EIO;
+ goto err_out;
+ }
+
+ /* The IO port 0x043 used to disable the watchdog
+ * is already claimed by the system timer, so we
+ * cant request_region() it ...*/
+
+ if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
+ timeout = SBC7240_TIMEOUT;
+ printk(KERN_INFO SBC7240_PREFIX
+ "timeout value must be 1<=x<=%d, using %d\n",
+ SBC7240_MAX_TIMEOUT, timeout);
+ }
+ wdt_set_timeout(timeout);
+ wdt_disable();
+
+ rc = register_reboot_notifier(&wdt_notifier);
+ if (rc) {
+ printk(KERN_ERR SBC7240_PREFIX
+ "cannot register reboot notifier (err=%d)\n", rc);
+ goto err_out_region;
+ }
+
+ rc = misc_register(&wdt_miscdev);
+ if (rc) {
+ printk(KERN_ERR SBC7240_PREFIX
+ "cannot register miscdev on minor=%d (err=%d)\n",
+ wdt_miscdev.minor, rc);
+ goto err_out_reboot_notifier;
+ }
+
+ printk(KERN_INFO SBC7240_PREFIX
+ "Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
+ nowayout);
+
+ return 0;
+
+err_out_reboot_notifier:
+ unregister_reboot_notifier(&wdt_notifier);
+err_out_region:
+ release_region(SBC7240_ENABLE_PORT, 1);
+err_out:
+ return rc;
+}
+
+module_init(sbc7240_wdt_init);
+module_exit(sbc7240_wdt_unload);
+
+MODULE_AUTHOR("Gilles Gigan");
+MODULE_DESCRIPTION("Watchdog device driver for single board"
+ " computers EPIC Nano 7240 from iEi");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+
projects / GitHub / exynos8895 / android_kernel_samsung_universal8895.git / commitdiff