[WATCHDOG] add SBC-FITPC2 watchdog driver

Add support for watchdog found on SBC-FITPC2 board.

Signed-off-by: Denis Turischev <denis@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

3 files changed, 290 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index b1ccc04f3c9a..1940a08d18de 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -369,6 +369,28 @@ config SC520_WDT
           You can compile this driver directly into the kernel, or use
           it as a module.  The module will be called sc520_wdt.
 
+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.
+
 config EUROTECH_WDT
         tristate "Eurotech CPU-1220/1410 Watchdog Timer"
         depends on X86
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 3d774294a2b7..6c58e7ccee2c 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o
 obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o
 obj-$(CONFIG_GEODE_WDT) += geodewdt.o
 obj-$(CONFIG_SC520_WDT) += sc520_wdt.o
+obj-$(CONFIG_SBC_FITPC2_WATCHDOG) += sbc_fitpc2_wdt.o
 obj-$(CONFIG_EUROTECH_WDT) += eurotechwdt.o
 obj-$(CONFIG_IB700_WDT) += ib700wdt.o
 obj-$(CONFIG_IBMASR) += ibmasr.o
diff --git a/drivers/watchdog/sbc_fitpc2_wdt.c b/drivers/watchdog/sbc_fitpc2_wdt.c
new file mode 100644
index 000000000000..852ca1977917
--- /dev/null
+++ b/drivers/watchdog/sbc_fitpc2_wdt.c
@@ -0,0 +1,267 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME " WATCHDOG: " fmt
+
+#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/fs.h>
+#include <linux/init.h>
+#include <linux/moduleparam.h>
+#include <linux/dmi.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 DEFINE_SPINLOCK(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
+
+#define WATCHDOG_NAME           "SBC-FITPC2 Watchdog"
+
+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)
+{
+        size_t i;
+
+        if (!len)
+                return 0;
+
+        if (nowayout) {
+                len = 0;
+                goto out;
+        }
+
+        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);
+        }
+
+out:
+        wdt_enable();
+
+        return len;
+}
+
+
+static struct watchdog_info ident = {
+        .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
+                                WDIOF_KEEPALIVEPING,
+        .identity       = WATCHDOG_NAME,
+};
+
+
+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();
+                pr_info("Device disabled\n");
+        } else {
+                pr_warning("Device closed unexpectedly -"
+                        " timer will not stop\n");
+                wdt_enable();
+        }
+
+        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)
+{
+        int err;
+
+        if (strcmp("SBC-FITPC2", dmi_get_system_info(DMI_BOARD_NAME))) {
+                pr_info("board name is: %s. Should be SBC-FITPC2\n",
+                        dmi_get_system_info(DMI_BOARD_NAME));
+                return -ENODEV;
+        }
+
+        if (!request_region(COMMAND_PORT, 1, WATCHDOG_NAME)) {
+                pr_err("I/O address 0x%04x already in use\n", COMMAND_PORT);
+                return -EIO;
+        }
+
+        if (!request_region(DATA_PORT, 1, WATCHDOG_NAME)) {
+                pr_err("I/O address 0x%04x already in use\n", DATA_PORT);
+                err = -EIO;
+                goto err_data_port;
+        }
+
+        if (margin < 31 || margin > 255) {
+                pr_err("margin must be in range 31 - 255"
+                       " seconds, you tried to set %d\n", margin);
+                err = -EINVAL;
+                goto err_margin;
+        }
+
+        err = misc_register(&fitpc2_wdt_miscdev);
+        if (!err) {
+                pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+                                                        WATCHDOG_MINOR, err);
+                goto err_margin;
+        }
+
+        return 0;
+
+err_margin:
+        release_region(DATA_PORT, 1);
+err_data_port:
+        release_region(COMMAND_PORT, 1);
+
+        return err;
+}
+
+static void __exit fitpc2_wdt_exit(void)
+{
+        misc_deregister(&fitpc2_wdt_miscdev);
+        release_region(DATA_PORT, 1);
+        release_region(COMMAND_PORT, 1);
+}
+
+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);
+