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-rw-r--r--drivers/watchdog/xen_wdt.c208
1 files changed, 208 insertions, 0 deletions
diff --git a/drivers/watchdog/xen_wdt.c b/drivers/watchdog/xen_wdt.c
new file mode 100644
index 000000000..b343f421d
--- /dev/null
+++ b/drivers/watchdog/xen_wdt.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Xen Watchdog Driver
+ *
+ * (c) Copyright 2010 Novell, Inc.
+ */
+
+#define DRV_NAME "xen_wdt"
+
+#include <linux/bug.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/hrtimer.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <xen/xen.h>
+#include <asm/xen/hypercall.h>
+#include <xen/interface/sched.h>
+
+static struct platform_device *platform_device;
+static struct sched_watchdog wdt;
+static time64_t wdt_expires;
+
+#define WATCHDOG_TIMEOUT 60 /* in seconds */
+static unsigned int timeout;
+module_param(timeout, uint, S_IRUGO);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
+ "(default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, S_IRUGO);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static inline time64_t set_timeout(struct watchdog_device *wdd)
+{
+ wdt.timeout = wdd->timeout;
+ return ktime_get_seconds() + wdd->timeout;
+}
+
+static int xen_wdt_start(struct watchdog_device *wdd)
+{
+ time64_t expires;
+ int err;
+
+ expires = set_timeout(wdd);
+ if (!wdt.id)
+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+ else
+ err = -EBUSY;
+ if (err > 0) {
+ wdt.id = err;
+ wdt_expires = expires;
+ err = 0;
+ } else
+ BUG_ON(!err);
+
+ return err;
+}
+
+static int xen_wdt_stop(struct watchdog_device *wdd)
+{
+ int err = 0;
+
+ wdt.timeout = 0;
+ if (wdt.id)
+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+ if (!err)
+ wdt.id = 0;
+
+ return err;
+}
+
+static int xen_wdt_kick(struct watchdog_device *wdd)
+{
+ time64_t expires;
+ int err;
+
+ expires = set_timeout(wdd);
+ if (wdt.id)
+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+ else
+ err = -ENXIO;
+ if (!err)
+ wdt_expires = expires;
+
+ return err;
+}
+
+static unsigned int xen_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ return wdt_expires - ktime_get_seconds();
+}
+
+static struct watchdog_info xen_wdt_info = {
+ .identity = DRV_NAME,
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops xen_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = xen_wdt_start,
+ .stop = xen_wdt_stop,
+ .ping = xen_wdt_kick,
+ .get_timeleft = xen_wdt_get_timeleft,
+};
+
+static struct watchdog_device xen_wdt_dev = {
+ .info = &xen_wdt_info,
+ .ops = &xen_wdt_ops,
+ .timeout = WATCHDOG_TIMEOUT,
+};
+
+static int xen_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct sched_watchdog wd = { .id = ~0 };
+ int ret = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wd);
+
+ if (ret == -ENOSYS) {
+ dev_err(dev, "watchdog not supported by hypervisor\n");
+ return -ENODEV;
+ }
+
+ if (ret != -EINVAL) {
+ dev_err(dev, "unexpected hypervisor error (%d)\n", ret);
+ return -ENODEV;
+ }
+
+ watchdog_init_timeout(&xen_wdt_dev, timeout, NULL);
+ watchdog_set_nowayout(&xen_wdt_dev, nowayout);
+ watchdog_stop_on_reboot(&xen_wdt_dev);
+ watchdog_stop_on_unregister(&xen_wdt_dev);
+
+ ret = devm_watchdog_register_device(dev, &xen_wdt_dev);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "initialized (timeout=%ds, nowayout=%d)\n",
+ xen_wdt_dev.timeout, nowayout);
+
+ return 0;
+}
+
+static int xen_wdt_suspend(struct platform_device *dev, pm_message_t state)
+{
+ typeof(wdt.id) id = wdt.id;
+ int rc = xen_wdt_stop(&xen_wdt_dev);
+
+ wdt.id = id;
+ return rc;
+}
+
+static int xen_wdt_resume(struct platform_device *dev)
+{
+ if (!wdt.id)
+ return 0;
+ wdt.id = 0;
+ return xen_wdt_start(&xen_wdt_dev);
+}
+
+static struct platform_driver xen_wdt_driver = {
+ .probe = xen_wdt_probe,
+ .suspend = xen_wdt_suspend,
+ .resume = xen_wdt_resume,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+
+static int __init xen_wdt_init_module(void)
+{
+ int err;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ err = platform_driver_register(&xen_wdt_driver);
+ if (err)
+ return err;
+
+ platform_device = platform_device_register_simple(DRV_NAME,
+ -1, NULL, 0);
+ if (IS_ERR(platform_device)) {
+ err = PTR_ERR(platform_device);
+ platform_driver_unregister(&xen_wdt_driver);
+ }
+
+ return err;
+}
+
+static void __exit xen_wdt_cleanup_module(void)
+{
+ platform_device_unregister(platform_device);
+ platform_driver_unregister(&xen_wdt_driver);
+}
+
+module_init(xen_wdt_init_module);
+module_exit(xen_wdt_cleanup_module);
+
+MODULE_AUTHOR("Jan Beulich <jbeulich@novell.com>");
+MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
+MODULE_LICENSE("GPL");