--- /dev/null
+/* Watchdog timer for machines with the CS5535/CS5536 companion chip
+ *
+ * Copyright (C) 2006-2007, Advanced Micro Devices, Inc.
+ * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/uaccess.h>
+
+#include <linux/cs5535.h>
+
+#define GEODEWDT_HZ 500
+#define GEODEWDT_SCALE 6
+#define GEODEWDT_MAX_SECONDS 131
+
+#define WDT_FLAGS_OPEN 1
+#define WDT_FLAGS_ORPHAN 2
+
+#define DRV_NAME "geodewdt"
+#define WATCHDOG_NAME "Geode GX/LX WDT"
+#define WATCHDOG_TIMEOUT 60
+
+static int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+ "Watchdog timeout in seconds. 1<= timeout <=131, default="
+ __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static struct platform_device *geodewdt_platform_device;
+static unsigned long wdt_flags;
+static struct cs5535_mfgpt_timer *wdt_timer;
+static int safe_close;
+
+static void geodewdt_ping(void)
+{
+ /* Stop the counter */
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
+
+ /* Reset the counter */
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
+
+ /* Enable the counter */
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
+}
+
+static void geodewdt_disable(void)
+{
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
+}
+
+static int geodewdt_set_heartbeat(int val)
+{
+ if (val < 1 || val > GEODEWDT_MAX_SECONDS)
+ return -EINVAL;
+
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0);
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ);
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0);
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN);
+
+ timeout = val;
+ return 0;
+}
+
+static int geodewdt_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
+ return -EBUSY;
+
+ if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
+ __module_get(THIS_MODULE);
+
+ geodewdt_ping();
+ return nonseekable_open(inode, file);
+}
+
+static int geodewdt_release(struct inode *inode, struct file *file)
+{
+ if (safe_close) {
+ geodewdt_disable();
+ module_put(THIS_MODULE);
+ } else {
+ pr_crit("Unexpected close - watchdog is not stopping\n");
+ geodewdt_ping();
+
+ set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
+ }
+
+ clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
+ safe_close = 0;
+ return 0;
+}
+
+static ssize_t geodewdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+ safe_close = 0;
+
+ for (i = 0; i != len; i++) {
+ char c;
+
+ if (get_user(c, data + i))
+ return -EFAULT;
+
+ if (c == 'V')
+ safe_close = 1;
+ }
+ }
+
+ geodewdt_ping();
+ }
+ return len;
+}
+
+static long geodewdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int interval;
+
+ static const struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING
+ | WDIOF_MAGICCLOSE,
+ .firmware_version = 1,
+ .identity = WATCHDOG_NAME,
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident,
+ sizeof(ident)) ? -EFAULT : 0;
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+
+ case WDIOC_SETOPTIONS:
+ {
+ int options, ret = -EINVAL;
+
+ if (get_user(options, p))
+ return -EFAULT;
+
+ if (options & WDIOS_DISABLECARD) {
+ geodewdt_disable();
+ ret = 0;
+ }
+
+ if (options & WDIOS_ENABLECARD) {
+ geodewdt_ping();
+ ret = 0;
+ }
+
+ return ret;
+ }
+ case WDIOC_KEEPALIVE:
+ geodewdt_ping();
+ return 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(interval, p))
+ return -EFAULT;
+
+ if (geodewdt_set_heartbeat(interval))
+ return -EINVAL;
+ /* Fall through */
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, p);
+
+ default:
+ return -ENOTTY;
+ }
+
+ return 0;
+}
+
+static const struct file_operations geodewdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = geodewdt_write,
+ .unlocked_ioctl = geodewdt_ioctl,
+ .open = geodewdt_open,
+ .release = geodewdt_release,
+};
+
+static struct miscdevice geodewdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &geodewdt_fops,
+};
+
+static int __init geodewdt_probe(struct platform_device *dev)
+{
+ int ret;
+
+ wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING);
+ if (!wdt_timer) {
+ pr_err("No timers were available\n");
+ return -ENODEV;
+ }
+
+ /* Set up the timer */
+
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP,
+ GEODEWDT_SCALE | (3 << 8));
+
+ /* Set up comparator 2 to reset when the event fires */
+ cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1);
+
+ /* Set up the initial timeout */
+
+ cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2,
+ timeout * GEODEWDT_HZ);
+
+ ret = misc_register(&geodewdt_miscdev);
+
+ return ret;
+}
+
+static int geodewdt_remove(struct platform_device *dev)
+{
+ misc_deregister(&geodewdt_miscdev);
+ return 0;
+}
+
+static void geodewdt_shutdown(struct platform_device *dev)
+{
+ geodewdt_disable();
+}
+
+static struct platform_driver geodewdt_driver = {
+ .remove = geodewdt_remove,
+ .shutdown = geodewdt_shutdown,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+
+static int __init geodewdt_init(void)
+{
+ int ret;
+
+ geodewdt_platform_device = platform_device_register_simple(DRV_NAME,
+ -1, NULL, 0);
+ if (IS_ERR(geodewdt_platform_device))
+ return PTR_ERR(geodewdt_platform_device);
+
+ ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe);
+ if (ret)
+ goto err;
+
+ return 0;
+err:
+ platform_device_unregister(geodewdt_platform_device);
+ return ret;
+}
+
+static void __exit geodewdt_exit(void)
+{
+ platform_device_unregister(geodewdt_platform_device);
+ platform_driver_unregister(&geodewdt_driver);
+}
+
+module_init(geodewdt_init);
+module_exit(geodewdt_exit);
+
+MODULE_AUTHOR("Advanced Micro Devices, Inc");
+MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff