[WATCHDOG] add Nano 7240 driver

Adds support for the built-in watchdog on EPIC Nano 7240 boards from IEI.

Tested on Nano-7240RS.

Hardware documentation of the platform (including watchdog) can be found
on the IEI website: http://www.ieiworld.com

Signed-off-by: Gilles Gigan <gilles.gigan@gmail.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

3 files changed, 338 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 126b554810c8..52dff40ec192 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -466,6 +466,19 @@ config SBC8360_WDT
 
           Most people will say N.
 
+config SBC7240_WDT
+        tristate "SBC Nano 7240 Watchdog Timer"
+        depends on X86_32
+        ---help---
+          This is the driver for the hardware watchdog found on the IEI
+          single board computers EPIC Nano 7240 (and likely others). This
+          watchdog simply watches your kernel to make sure it doesn't freeze,
+          and if it does, it reboots your computer after a certain amount of
+          time.
+
+          To compile this driver as a module, choose M here: the
+          module will be called sbc7240_wdt.
+
 config CPU5_WDT
         tristate "SMA CPU5 Watchdog"
         depends on X86
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e4779f76b1ed..87483cc63252 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -72,6 +72,7 @@ obj-$(CONFIG_SCx200_WDT) += scx200_wdt.o
 obj-$(CONFIG_PC87413_WDT) += pc87413_wdt.o
 obj-$(CONFIG_60XX_WDT) += sbc60xxwdt.o
 obj-$(CONFIG_SBC8360_WDT) += sbc8360.o
+obj-$(CONFIG_SBC7240_WDT) += sbc7240_wdt.o
 obj-$(CONFIG_CPU5_WDT) += cpu5wdt.o
 obj-$(CONFIG_SMSC37B787_WDT) += smsc37b787_wdt.o
 obj-$(CONFIG_W83627HF_WDT) += w83627hf_wdt.o
diff --git a/drivers/watchdog/sbc7240_wdt.c b/drivers/watchdog/sbc7240_wdt.c
new file mode 100644
index 000000000000..4c8cefbd8627
--- /dev/null
+++ b/drivers/watchdog/sbc7240_wdt.c
@@ -0,0 +1,324 @@
+/*
+ *      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);
+