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ca0bb07980
This driver adds sparc hypervisor watchdog support. The default timeout is 60 seconds and the range is between 1 and 31536000 seconds. Both watchdog-resolution and watchdog-max-timeout MD properties settings are supported. Signed-off-by: Wim Coekaerts <wim.coekaerts@oracle.com> Reviewed-by: Julian Calaby <julian.calaby@gmail.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: David S. Miller <davem@davemloft.net>
192 lines
4.5 KiB
C
192 lines
4.5 KiB
C
/*
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* sun4v watchdog timer
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* (c) Copyright 2016 Oracle Corporation
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*
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* Implement a simple watchdog driver using the built-in sun4v hypervisor
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* watchdog support. If time expires, the hypervisor stops or bounces
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* the guest domain.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/watchdog.h>
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#include <asm/hypervisor.h>
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#include <asm/mdesc.h>
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#define WDT_TIMEOUT 60
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#define WDT_MAX_TIMEOUT 31536000
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#define WDT_MIN_TIMEOUT 1
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#define WDT_DEFAULT_RESOLUTION_MS 1000 /* 1 second */
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static unsigned int timeout;
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
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__MODULE_STRING(WDT_TIMEOUT) ")");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, S_IRUGO);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int sun4v_wdt_stop(struct watchdog_device *wdd)
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{
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sun4v_mach_set_watchdog(0, NULL);
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return 0;
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}
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static int sun4v_wdt_ping(struct watchdog_device *wdd)
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{
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int hverr;
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/*
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* HV watchdog timer will round up the timeout
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* passed in to the nearest multiple of the
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* watchdog resolution in milliseconds.
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*/
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hverr = sun4v_mach_set_watchdog(wdd->timeout * 1000, NULL);
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if (hverr == HV_EINVAL)
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return -EINVAL;
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return 0;
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}
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static int sun4v_wdt_set_timeout(struct watchdog_device *wdd,
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unsigned int timeout)
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{
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wdd->timeout = timeout;
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return 0;
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}
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static const struct watchdog_info sun4v_wdt_ident = {
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.options = WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE |
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WDIOF_KEEPALIVEPING,
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.identity = "sun4v hypervisor watchdog",
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.firmware_version = 0,
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};
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static struct watchdog_ops sun4v_wdt_ops = {
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.owner = THIS_MODULE,
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.start = sun4v_wdt_ping,
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.stop = sun4v_wdt_stop,
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.ping = sun4v_wdt_ping,
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.set_timeout = sun4v_wdt_set_timeout,
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};
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static struct watchdog_device wdd = {
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.info = &sun4v_wdt_ident,
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.ops = &sun4v_wdt_ops,
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.min_timeout = WDT_MIN_TIMEOUT,
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.max_timeout = WDT_MAX_TIMEOUT,
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.timeout = WDT_TIMEOUT,
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};
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static int __init sun4v_wdt_init(void)
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{
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struct mdesc_handle *handle;
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u64 node;
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const u64 *value;
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int err = 0;
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unsigned long major = 1, minor = 1;
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/*
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* There are 2 properties that can be set from the control
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* domain for the watchdog.
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* watchdog-resolution
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* watchdog-max-timeout
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*
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* We can expect a handle to be returned otherwise something
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* serious is wrong. Correct to return -ENODEV here.
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*/
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handle = mdesc_grab();
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if (!handle)
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return -ENODEV;
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node = mdesc_node_by_name(handle, MDESC_NODE_NULL, "platform");
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err = -ENODEV;
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if (node == MDESC_NODE_NULL)
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goto out_release;
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/*
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* This is a safe way to validate if we are on the right
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* platform.
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*/
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if (sun4v_hvapi_register(HV_GRP_CORE, major, &minor))
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goto out_hv_unreg;
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/* Allow value of watchdog-resolution up to 1s (default) */
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value = mdesc_get_property(handle, node, "watchdog-resolution", NULL);
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err = -EINVAL;
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if (value) {
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if (*value == 0 ||
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*value > WDT_DEFAULT_RESOLUTION_MS)
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goto out_hv_unreg;
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}
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value = mdesc_get_property(handle, node, "watchdog-max-timeout", NULL);
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if (value) {
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/*
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* If the property value (in ms) is smaller than
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* min_timeout, return -EINVAL.
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*/
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if (*value < wdd.min_timeout * 1000)
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goto out_hv_unreg;
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/*
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* If the property value is smaller than
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* default max_timeout then set watchdog max_timeout to
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* the value of the property in seconds.
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*/
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if (*value < wdd.max_timeout * 1000)
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wdd.max_timeout = *value / 1000;
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}
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watchdog_init_timeout(&wdd, timeout, NULL);
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watchdog_set_nowayout(&wdd, nowayout);
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err = watchdog_register_device(&wdd);
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if (err)
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goto out_hv_unreg;
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pr_info("initialized (timeout=%ds, nowayout=%d)\n",
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wdd.timeout, nowayout);
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mdesc_release(handle);
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return 0;
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out_hv_unreg:
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sun4v_hvapi_unregister(HV_GRP_CORE);
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out_release:
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mdesc_release(handle);
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return err;
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}
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static void __exit sun4v_wdt_exit(void)
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{
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sun4v_hvapi_unregister(HV_GRP_CORE);
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watchdog_unregister_device(&wdd);
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}
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module_init(sun4v_wdt_init);
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module_exit(sun4v_wdt_exit);
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MODULE_AUTHOR("Wim Coekaerts <wim.coekaerts@oracle.com>");
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MODULE_DESCRIPTION("sun4v watchdog driver");
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MODULE_LICENSE("GPL");
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