--- /dev/null
+/*
+ * 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);
+
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff