From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Subject: Re: [PATCH v6] Add sun4v_wdt watchdog driver To: Wim Coekaerts , wim@iguana.be, linux@roeck-us.net References: <1454017572-5235-1-git-send-email-wim.coekaerts@oracle.com> Cc: linux-watchdog@vger.kernel.org, sparclinux@vger.kernel.org From: Stanislav Kholmanskikh Message-ID: <56AB5358.9090405@oracle.com> Date: Fri, 29 Jan 2016 14:56:08 +0300 MIME-Version: 1.0 In-Reply-To: <1454017572-5235-1-git-send-email-wim.coekaerts@oracle.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit List-ID: Hi, Wim. One typo below. On 01/29/2016 12:46 AM, Wim Coekaerts wrote: > 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 > --- > Change in v6: > - Cleanup goto > - remove timeout checks and rely on watchdog_init_timout() > - move sun4v_hv_api_register under mdesc similar to ldc.c > > Change in v5: > - After proper review of the hv watchdog api, the hv takes care of > rounding to multiple of resolution internally so just check > if it's <= 1 second. > - Clean up _ping() and simplify _probe() value checking > > Change in v4: > - timeout in seconds > - call the hv with support for microsecond resolution > > Changes in v3: > - Modify sun4v_mach_set_watchdog to allow for NULL and remove > time_remaining > - Cleanup includes > - Consolidate _start and _ping into _ping since they were the same > - Fix checkpatch warnings > - Remove pr_info()s > - Clean up return codes to be standard kernel return values > - Consolidate _init and _probe into _init > Don't use platform_device anymore because this is really > just a driver that depends on a hv call. This now looks more > like softdog. > - Cleanly check for sun4v architecture and remove extra tests > - Convert to ms timer support and honor resolution > since most drivers use seconds I added _ms to make it clear > - Clean up validation against the properties > - Use sane values for MIN/MAX > --- > Documentation/watchdog/watchdog-parameters.txt | 4 + > arch/sparc/kernel/hvcalls.S | 3 +- > arch/sparc/kernel/sparc_ksyms_64.c | 1 + > drivers/watchdog/Kconfig | 11 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/sun4v_wdt.c | 196 ++++++++++++++++++++++++ > 6 files changed, 215 insertions(+), 1 deletions(-) > create mode 100644 drivers/watchdog/sun4v_wdt.c > > diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt > index 9f9ec9f..4e4b6f1 100644 > --- a/Documentation/watchdog/watchdog-parameters.txt > +++ b/Documentation/watchdog/watchdog-parameters.txt > @@ -400,3 +400,7 @@ wm8350_wdt: > nowayout: Watchdog cannot be stopped once started > (default=kernel config parameter) > ------------------------------------------------- > +sun4v_wdt: > +timeout_ms: Watchdog timeout in milliseconds 1..180000, default=60000) > +nowayout: Watchdog cannot be stopped once started > +------------------------------------------------- > diff --git a/arch/sparc/kernel/hvcalls.S b/arch/sparc/kernel/hvcalls.S > index afbaba5..d127130 100644 > --- a/arch/sparc/kernel/hvcalls.S > +++ b/arch/sparc/kernel/hvcalls.S > @@ -338,8 +338,9 @@ ENTRY(sun4v_mach_set_watchdog) > mov %o1, %o4 > mov HV_FAST_MACH_SET_WATCHDOG, %o5 > ta HV_FAST_TRAP > + brnz,a,pn %o4, 0f > stx %o1, [%o4] > - retl > +0: retl > nop > ENDPROC(sun4v_mach_set_watchdog) > > diff --git a/arch/sparc/kernel/sparc_ksyms_64.c b/arch/sparc/kernel/sparc_ksyms_64.c > index a92d5d2..9e034f2 100644 > --- a/arch/sparc/kernel/sparc_ksyms_64.c > +++ b/arch/sparc/kernel/sparc_ksyms_64.c > @@ -37,6 +37,7 @@ EXPORT_SYMBOL(sun4v_niagara_getperf); > EXPORT_SYMBOL(sun4v_niagara_setperf); > EXPORT_SYMBOL(sun4v_niagara2_getperf); > EXPORT_SYMBOL(sun4v_niagara2_setperf); > +EXPORT_SYMBOL(sun4v_mach_set_watchdog); > > /* from hweight.S */ > EXPORT_SYMBOL(__arch_hweight8); > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 4f0e7be..30d38ae 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -1565,6 +1565,17 @@ config WATCHDOG_RIO > machines. The watchdog timeout period is normally one minute but > can be changed with a boot-time parameter. > > +config WATCHDOG_SUN4V > + tristate "Sun4v Watchdog support" > + select WATCHDOG_CORE > + depends on SPARC64 > + help > + Say Y here to support the hypervisor watchdog capability embedded > + in the SPARC sun4v architecture. > + > + To compile this driver as a module, choose M here. The module will > + be called sun4v_wdt. > + > # XTENSA Architecture > > # Xen Architecture > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index f566753..f6a6a38 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -179,6 +179,7 @@ obj-$(CONFIG_SH_WDT) += shwdt.o > > obj-$(CONFIG_WATCHDOG_RIO) += riowd.o > obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o > +obj-$(CONFIG_WATCHDOG_SUN4V) += sun4v_wdt.o > > # XTENSA Architecture > > diff --git a/drivers/watchdog/sun4v_wdt.c b/drivers/watchdog/sun4v_wdt.c > new file mode 100644 > index 0000000..a01aec1 > --- /dev/null > +++ b/drivers/watchdog/sun4v_wdt.c > @@ -0,0 +1,196 @@ > +/* > + * 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define WDT_TIMEOUT 60 > +#define WDT_MAX_TIMEOUT 31536000 > +#define WDT_MIN_TIMEOUT 1 > +#define WDT_DEFAULT_RESOLUTION_MS 1000 /* 1 second */ > + > +static unsigned int wdt_max_timeout = WDT_MAX_TIMEOUT; > + > +static unsigned int timeout; > +module_param(timeout, uint, 0); > +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" > + __MODULE_STRING(WDT_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 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; > + > + /* > + * HV watchdog timer will round up the timeout > + * passed in to the nearest multiple of the > + * watchdog resolution in milliseconds. > + */ > + hverr = sun4v_mach_set_watchdog(wdd->timeout * 1000, 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; > + > + 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, > + .timeout = WDT_TIMEOUT, > +}; > + > +static int __init sun4v_wdt_init(void) > +{ > + struct mdesc_handle *handle; > + u64 node; > + const u64 *value; > + u64 wdt_max_property; > + u64 wdt_resolution_property; > + int err = 0; > + unsigned long major = 1, minor = 1; > + > + /* > + * There are 2 properties that can be set from the control > + * domain for the watchdog. > + * watchdog-resolution > + * watchdog-max-timeout > + * > + * We can expect a handle to be returned otherwise something > + * serious is wrong. Correct to return -ENODEV here. > + */ > + > + handle = mdesc_grab(); > + if (!handle) > + return -ENODEV; > + > + node = mdesc_node_by_name(handle, MDESC_NODE_NULL, "platform"); > + err = -ENODEV; > + if (node == MDESC_NODE_NULL) > + goto out_release; > + > + /* > + * This is a safe way to validate if we are on the right > + * platform. > + */ > + if (sun4v_hvapi_register(HV_GRP_CORE, major, &minor)) > + goto out_hv_unreg; > + > + /* Allow for resolution up to 1s (default) */ > + value = mdesc_get_property(handle, node, "watchdog-resolution", NULL); > + err = -EINVAL; > + if (value) { > + wdt_resolution_property = *value; > + if (wdt_resolution_property == 0 || > + wdt_resolution_property > WDT_DEFAULT_RESOLUTION_MS) > + goto out_hv_unreg; > + } > + > + value = mdesc_get_property(handle, node, "watchdog-max-timeout", NULL); > + if (value) { > + wdt_max_property = *value; > + /* > + * If the property (in ms) is set to a value smaller than > + * WDT_MIN_TIMEOUT, return -EINVAL. > + */ > + if (wdt_max_property < WDT_MIN_TIMEOUT * 1000) > + goto out_hv_unreg; > + > + /* > + * If the property is set to a value smaller than > + * WDT_MAX_TIMEOUT then set wdt_max_timeout to > + * the value of the property in seconds. > + */ > + if (wdt_max_property < wdt_max_timeout * 1000) > + wdt_max_timeout = wdt_max_property / 1000; > + } > + > + wdd.max_timeout = wdt_max_timeout; > + > + watchdog_init_timeout(&wdd, timeout, NULL); > + > + watchdog_set_nowayout(&wdd, nowayout); > + > + err = watchdog_register_device(&wdd); > + if (err) > + goto out_hv_unreg; > + > + pr_info("initialized (timeout=%dms, nowayout=%d)\n", > + wdd.timeout, nowayout); It looks like it should be "s" here instead of "ms". Thanks.