diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/xen_wdt.c | 208 |
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"); |