--- /dev/null
+/*
+ * sun4v watchdog timer
+ * (c) Copyright 2016 Oracle Corporation
+ *
+ * Implement a simple watchdog driver using the built-in sun4v hypervisor
+ * watchdog support. If time expires, the hypervisor stops or bounces
+ * the guest domain.
+ *
+ * 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/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/watchdog.h>
+#include <asm/hypervisor.h>
+#include <asm/mdesc.h>
+
+#define WDT_TIMEOUT_MS 60000 /* 60 seconds */
+#define WDT_MAX_TIMEOUT_MS 180000 /* 180 seconds */
+#define WDT_MIN_TIMEOUT_MS 1000 /* 1 second */
+#define WDT_DEFAULT_RESOLUTION_MS 1000 /* 1 second */
+
+static unsigned int wdt_max_timeout_ms = WDT_MAX_TIMEOUT_MS;
+static unsigned int wdt_resolution_ms = WDT_DEFAULT_RESOLUTION_MS;
+
+static unsigned int timeout_ms = WDT_TIMEOUT_MS;
+module_param(timeout_ms, uint, S_IRUGO);
+MODULE_PARM_DESC(timeout_ms, "Watchdog timeout in ms (default="
+ __MODULE_STRING(WDT_TIMEOUT_MS) ")");
+
+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 int sun4v_wdt_stop(struct watchdog_device *wdd)
+{
+ sun4v_mach_set_watchdog(0, NULL);
+
+ return 0;
+}
+
+static int sun4v_wdt_ping(struct watchdog_device *wdd)
+{
+ int hverr;
+
+ hverr = sun4v_mach_set_watchdog(wdd->timeout, NULL);
+ if (hverr == HV_EINVAL)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int sun4v_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ wdd->timeout = timeout - (timeout % wdt_resolution_ms);
+
+ return 0;
+}
+
+static const struct watchdog_info sun4v_wdt_ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+ .identity = "sun4v hypervisor watchdog",
+ .firmware_version = 0,
+};
+
+static struct watchdog_ops sun4v_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = sun4v_wdt_ping,
+ .stop = sun4v_wdt_stop,
+ .ping = sun4v_wdt_ping,
+ .set_timeout = sun4v_wdt_set_timeout,
+};
+
+static struct watchdog_device wdd = {
+ .info = &sun4v_wdt_ident,
+ .ops = &sun4v_wdt_ops,
+ .min_timeout = WDT_MIN_TIMEOUT_MS,
+};
+
+static int hvapi_registered;
+
+static int __init sun4v_wdt_init(void)
+{
+ struct mdesc_handle *handle;
+ u64 node;
+ const u64 *value;
+ int ret = 0;
+ unsigned long major = 1, minor = 1;
+
+ if (sun4v_hvapi_register(HV_GRP_CORE, major, &minor) != 0)
+ return -ENODEV;
+ if (minor < 1) {
+ sun4v_hvapi_unregister(HV_GRP_CORE);
+ return -ENODEV;
+ }
+ hvapi_registered = 1;
+
+ /*
+ * There are 2 properties that can be set from the control
+ * domain for the watchdog.
+ * watchdog-resolution
+ * watchdog-max-timeout
+ *
+ * If there is no handle returned, this is no sun4v system
+ * so it's correct to return -ENODEV. Same for missing of the
+ * platform node.
+ */
+
+ handle = mdesc_grab();
+ if (!handle)
+ return -ENODEV;
+
+ node = mdesc_node_by_name(handle, MDESC_NODE_NULL, "platform");
+ if (node == MDESC_NODE_NULL) {
+ mdesc_release(handle);
+ return -ENODEV;
+ }
+
+ value = mdesc_get_property(handle, node, "watchdog-resolution", NULL);
+ if (value) {
+ wdt_resolution_ms = *value;
+ if (wdt_resolution_ms == 0 ||
+ wdt_resolution_ms > WDT_DEFAULT_RESOLUTION_MS)
+ wdt_resolution_ms = WDT_DEFAULT_RESOLUTION_MS;
+ }
+
+ value = mdesc_get_property(handle, node, "watchdog-max-timeout", NULL);
+ if (value) {
+ wdt_max_timeout_ms = *value;
+ /*
+ * If the property is defined to be smaller than default
+ * then set it to default.
+ */
+ if (wdt_max_timeout_ms < WDT_MIN_TIMEOUT_MS) {
+ mdesc_release(handle);
+ return -EINVAL;
+ }
+ }
+
+ mdesc_release(handle);
+
+ if (timeout_ms < WDT_MIN_TIMEOUT_MS)
+ timeout_ms = WDT_MIN_TIMEOUT_MS;
+ if (timeout_ms > WDT_MAX_TIMEOUT_MS)
+ timeout_ms = WDT_MAX_TIMEOUT_MS;
+ if (timeout_ms > wdt_max_timeout_ms)
+ timeout_ms = wdt_max_timeout_ms;
+
+ /*
+ * round to nearest smaller value
+ */
+ wdt_max_timeout_ms -= wdt_max_timeout_ms % wdt_resolution_ms;
+ timeout_ms -= timeout_ms % wdt_resolution_ms;
+
+ wdd.max_timeout = wdt_max_timeout_ms;
+ wdd.timeout = timeout_ms;
+
+ watchdog_set_nowayout(&wdd, nowayout);
+
+ ret = watchdog_register_device(&wdd);
+ if (ret) {
+ pr_err("Failed to register watchdog device\n");
+ return ret;
+ }
+
+ pr_info("initialized (timeout_ms=%dms, nowayout=%d)\n",
+ wdd.timeout, nowayout);
+
+ return 0;
+}
+
+
+static void __exit sun4v_wdt_exit(void)
+{
+ if (hvapi_registered)
+ sun4v_hvapi_unregister(HV_GRP_CORE);
+ sun4v_wdt_stop(&wdd);
+ watchdog_unregister_device(&wdd);
+}
+
+module_init(sun4v_wdt_init);
+module_exit(sun4v_wdt_exit);
+
+MODULE_AUTHOR("Wim Coekaerts <wim.coekaerts@oracle.com>");
+MODULE_DESCRIPTION("sun4v watchdog driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("sun4v_wdt");
projects / users / jedix / linux-maple.git / commitdiff