On 01/25/2016 12:38 PM, Wim Coekaerts wrote:
This driver adds sparc hypervisor watchdog support. Timeout is set in
milliseconds since that is the granularity supported and it honors
the settings of both the watchdog-resolution and watchdog-max-timeout
MD properties.
Default timeout is set at 60 seconds or 60000ms. The range is between
1 second and 180 seconds. The default resolution is 1000ms.
Signed-off-by: Wim Coekaerts <wim.coekaerts@xxxxxxxxxx>
---
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
You can not redefine the watchdog ABI to mean milli-seconds instead of seconds.
Guenter
- 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 | 203 ++++++++++++++++++++++++
6 files changed, 222 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..4da7726
--- /dev/null
+++ b/drivers/watchdog/sun4v_wdt.c
@@ -0,0 +1,203 @@
+/*
+ * 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;
+ u64 wdt_max_property;
+ int ret = 0;
+ unsigned long major = 1, minor = 1;
+
+ /*
+ * This is a safe way to validate if we are on the right
+ * platform.
+ */
+ 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
+ *
+ * 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");
+ 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_property = *value;
+ /*
+ * If the property is set to a value smaller than
+ * WDT_MIN_TIMEOUT_MS, return -EINVAL. If someone went
+ * through the trouble of setting the property then we should
+ * not silently ignore it and change it to something else.
+ */
+ if (wdt_max_property < WDT_MIN_TIMEOUT_MS) {
+ mdesc_release(handle);
+ return -EINVAL;
+ }
+ /* If the property is set to a value smaller than
+ * WDT_MAX_TIMEOUT_MS then set wdt_max_timeout_ms to
+ * the value of the property.
+ */
+ if (wdt_max_property < wdt_max_timeout_ms)
+ wdt_max_timeout_ms = wdt_max_property;
+ }
+
+ 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;
+
+ /*
+ * round to nearest smaller value to honor resolution
+ */
+ 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)
+ 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@xxxxxxxxxx>");
+MODULE_DESCRIPTION("sun4v watchdog driver");
+MODULE_LICENSE("GPL");
--
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