SBC-FITPC2 watchdog support

[Denis Turischev <denis@compulab.co.il>]

Adds support to watchdog timer on SBC-FITPC2 board by Compulab.

Signed-off-by: Denis Turischev <denis@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>

diff -Nru linux-2.6.31-rc3.orig/drivers/watchdog/Kconfig
linux-2.6.31-rc3/drivers/watchdog/Kconfig
--- linux-2.6.31-rc3.orig/drivers/watchdog/Kconfig      2009-07-14
04:18:52.000000000 +0300
+++ linux-2.6.31-rc3/drivers/watchdog/Kconfig   2009-07-16
13:52:08.000000000 +0300
@@ -721,6 +721,28 @@
          To compile this driver as a module, choose M here: the
          module will be called sbc_epx_c3.

+config SBC_FITPC2_WATCHDOG
+       tristate "Compulab SBC-FITPC2 watchdog"
+       depends on X86
+       ---help---
+         This is the driver for the built-in watchdog timer on the fit-PC2
+         Single-board computer made by Compulab.
+
+         It`s possible to enable watchdog timer either from BIOS (F2)
or from booted Linux.
+         When "Watchdog Timer Value" enabled one can set 31-255 s
operational range.
+
+         Entering BIOS setup temporary disables watchdog operation
regardless to current state,
+         so system will not be restarted while user in BIOS setup.
+
+         Once watchdog was enabled the system will be restarted every
+         "Watchdog Timer Value" period, so to prevent it user can
restart or
+         disable the watchdog.
+
+         To compile this driver as a module, choose M here: the
+         module will be called sbc_fitpc2_wdt.
+
+         Most people will say N.
+
 # M32R Architecture

 # M68K Architecture
diff -Nru linux-2.6.31-rc3.orig/drivers/watchdog/Makefile
linux-2.6.31-rc3/drivers/watchdog/Makefile
--- linux-2.6.31-rc3.orig/drivers/watchdog/Makefile     2009-07-14
04:18:52.000000000 +0300
+++ linux-2.6.31-rc3/drivers/watchdog/Makefile  2009-07-16
13:47:44.000000000 +0300
@@ -93,6 +93,7 @@
 obj-$(CONFIG_W83977F_WDT) += w83977f_wdt.o
 obj-$(CONFIG_MACHZ_WDT) += machzwd.o
 obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
+obj-$(CONFIG_SBC_FITPC2_WATCHDOG) += sbc_fitpc2_wdt.o

 # M32R Architecture

diff -Nru linux-2.6.31-rc3.orig/drivers/watchdog/sbc_fitpc2_wdt.c
linux-2.6.31-rc3/drivers/watchdog/sbc_fitpc2_wdt.c
--- linux-2.6.31-rc3.orig/drivers/watchdog/sbc_fitpc2_wdt.c    
1970-01-01 02:00:00.000000000 +0200
+++ linux-2.6.31-rc3/drivers/watchdog/sbc_fitpc2_wdt.c  2009-07-16
14:03:35.000000000 +0300
@@ -0,0 +1,219 @@
+/*
+ * Watchdog driver for SBC-FITPC2 board
+ *
+ * Author: Denis Turischev <denis@compulab.co.il>
+ *
+ * Adapted from the IXP2000 watchdog driver by Deepak Saxena.
+ *
+ * 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/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/notifier.h>
+#include <linux/fs.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <asm/system.h>
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int margin = 60;       /* (secs) Default is 1 minute */
+static unsigned long wdt_status;
+static spinlock_t wdt_lock;
+
+#define        WDT_IN_USE              0
+#define        WDT_OK_TO_CLOSE         1
+
+#define COMMAND_PORT           0x4c
+#define DATA_PORT              0x48
+
+#define IFACE_ON_COMMAND       1
+#define REBOOT_COMMAND         2
+
+static void wdt_send_data(unsigned char command, unsigned char data)
+{
+       outb(command, COMMAND_PORT);
+       mdelay(100);
+       outb(data, DATA_PORT);
+       mdelay(200);
+}
+
+static void wdt_enable(void)
+{
+       spin_lock(&wdt_lock);
+       wdt_send_data(IFACE_ON_COMMAND, 1);
+       wdt_send_data(REBOOT_COMMAND, margin);
+       spin_unlock(&wdt_lock);
+}
+
+static void wdt_disable(void)
+{
+       spin_lock(&wdt_lock);
+       wdt_send_data(IFACE_ON_COMMAND, 0);
+       wdt_send_data(REBOOT_COMMAND, 0);
+       spin_unlock(&wdt_lock);
+}
+
+static int fitpc2_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 ssize_t
+fitpc2_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       = "SBC-FITPC2 Watchdog",
+};
+
+
+static long
+fitpc2_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:
+               ret = put_user(0, (int *)arg);
+               break;
+
+       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 < 31 || time > 255) {
+                       ret = -EINVAL;
+                       break;
+               }
+
+               margin = time;
+               wdt_enable();
+               /* Fall through */
+
+       case WDIOC_GETTIMEOUT:
+               ret = put_user(margin, (int *)arg);
+               break;
+       }
+
+       return ret;
+}
+
+static int fitpc2_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 fitpc2_wdt_fops = {
+       .owner          = THIS_MODULE,
+       .llseek         = no_llseek,
+       .write          = fitpc2_wdt_write,
+       .unlocked_ioctl = fitpc2_wdt_ioctl,
+       .open           = fitpc2_wdt_open,
+       .release        = fitpc2_wdt_release,
+};
+
+static struct miscdevice fitpc2_wdt_miscdev = {
+       .minor          = WATCHDOG_MINOR,
+       .name           = "watchdog",
+       .fops           = &fitpc2_wdt_fops,
+};
+
+static int __init fitpc2_wdt_init(void)
+{
+       if (margin < 31 || margin > 255) {
+               printk(KERN_CRIT "WATCHDOG: margin must be in range 31 -
255"
+               " seconds, you tried to set %d\n", margin);
+               return -EINVAL;
+       }
+       return misc_register(&fitpc2_wdt_miscdev);
+}
+
+static void __exit fitpc2_wdt_exit(void)
+{
+       misc_deregister(&fitpc2_wdt_miscdev);
+}
+
+module_init(fitpc2_wdt_init);
+module_exit(fitpc2_wdt_exit);
+
+MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
+MODULE_DESCRIPTION("SBC-FITPC2 Watchdog");
+
+module_param(margin, int, 0);
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)");
+
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+