From: Wim Coekaerts <wim.coekaerts@xxxxxxxxxx>
This adds a simple watchdog timer for the SPARC sunv4 architecture.
Export the sun4v_mach_set_watchdog() hv call, and add the target.
The driver was based on the same model used by the Xen watchdog driver.
This was tested on T2, T4, T5 and T7.
Signed-off-by: Wim Coekaerts <wim.coekaerts@xxxxxxxxxx>
---
arch/sparc/kernel/sparc_ksyms_64.c | 1 +
drivers/watchdog/Kconfig | 10 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/sun4v_wdt.c | 421 ++++++++++++++++++++++++++++++++++++
4 files changed, 433 insertions(+), 0 deletions(-)
create mode 100644 drivers/watchdog/sun4v_wdt.c
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 1c427be..08834e4 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1516,6 +1516,16 @@ config UML_WATCHDOG
tristate "UML watchdog"
depends on UML
+# SPARC sun4v
+
+config WATCHDOG_SUN4V
+ tristate "Sun4v Watchdog support"
+ depends on SPARC64
+ help
+ Say Y here to support the hypervisor watchdog capability provided
+ by the sun4v architecture. The watchdog timeout period is normally one
+ minute but can be changed with a boot-time parameter.
+
#
# ISA-based Watchdog Cards
#
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 53d4827..9b8acb8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -175,6 +175,7 @@ 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..1213a1f
--- /dev/null
+++ b/drivers/watchdog/sun4v_wdt.c
@@ -0,0 +1,421 @@
+/*
+ * Sun4v Watchdog Driver
+ * (c) Copyright 2015 Oracle Corporation
+ *
+ * Heavily modified version of xen_wdt.c
+ * (c) Copyright 2010 Novell, Inc.
+ *
+ *
+ * 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
+
+#define DRV_NAME "sun4v_wdt"
+#define DRV_VERSION "0.01"
+
+#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/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+#include <asm/hypervisor.h>
+#include <asm/mdesc.h>
+
+
+static struct platform_device *platform_device;
+static DEFINE_SPINLOCK(wdt_lock);
+static __kernel_time_t wdt_expires;
+static unsigned long is_active;
+static bool expect_release;
+
+unsigned long wdt_timeout = 0;
+
+#define WATCHDOG_TIMEOUT 60 /* in seconds */
+static unsigned long timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, ulong, 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 __kernel_time_t set_timeout(void)
+{
+ /*
+ * The hypervisor specifies WD timeout in milliseconds
+ * Change it to seconds here and
+ * to do it in one place rather than every call to
+ * sun4v_mach_set_watchdog()
+ * The hvcall expects milliseconds while the parameters
+ * and the rest of the code expects seconds. wdt_timeout
+ * is the variable that we pass to the hvcall.
+ */
+ wdt_timeout = timeout * 1000;
+ return ktime_to_timespec(ktime_get()).tv_sec + timeout;
+}
+
+static int sun4v_wdt_start(void)
+{
+ __kernel_time_t expires;
+ unsigned long time_remaining;
+ int err;
+
+ spin_lock(&wdt_lock);
+
+ expires = set_timeout();
+ err = sun4v_mach_set_watchdog(wdt_timeout, &time_remaining);
+
+ spin_unlock(&wdt_lock);
+
+ pr_info("Watchdog timer enabled\n");
+ return err;
+}
+
+static int sun4v_wdt_stop(void)
+{
+ int err;
+ unsigned long time_remaining;
+
+ spin_lock(&wdt_lock);
+
+ err = sun4v_mach_set_watchdog(0, &time_remaining);
+
+ spin_unlock(&wdt_lock);
+
+ pr_info("Watchdog timer disabled\n");
+ return err;
+}
+
+static int sun4v_wdt_kick(void)
+{
+ __kernel_time_t expires;
+ int err;
+ unsigned long time_remaining;
+
+ spin_lock(&wdt_lock);
+
+ expires = set_timeout();
+ err = sun4v_mach_set_watchdog(wdt_timeout, &time_remaining);
+ if (!err)
+ wdt_expires = expires;
+
+ spin_unlock(&wdt_lock);
+
+ return err;
+}
+
+static int sun4v_wdt_open(struct inode *inode, struct file *file)
+{
+ int err;
+
+ /* /dev/watchdog can only be opened once */
+ if (test_and_set_bit(0, &is_active))
+ return -EBUSY;
+
+ /* prevent someone from rmmod'ing the module */
+ if (nowayout)
+ __module_get(THIS_MODULE);
+
+ err = sun4v_wdt_start();
+ if (err == -EBUSY) {
+ err = sun4v_wdt_kick();
+ }
+
+ return err ?: nonseekable_open(inode, file);
+}
+
+static int sun4v_wdt_release(struct inode *inode, struct file *file)
+{
+ int err;
+
+ if (expect_release)
+ err = sun4v_wdt_stop();
+ else {
+ pr_crit("Unexpected close, not stopping watchdog!\n");
+ sun4v_wdt_kick();
+ }
+
+ clear_bit(0, &is_active);
+ expect_release = false;
+
+ return 0;
+}
+
+static ssize_t sun4v_wdt_write(struct file *file, const char __user *data,
+ size_t len, loff_t *ppos)
+{
+ /* See if we got the magic character 'V' and reload the timer */
+ if (len) {
+ if (!nowayout) {
+ size_t i;
+
+ /* in case it was set long ago */
+ expect_release = false;
+
+ /* scan to see whether or not we got the magic
+ character */
+ for (i = 0; i != len; i++) {
+ char c;
+ if (get_user(c, data + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_release = true;
+ }
+ }
+
+ /* someone wrote to us, we should reload the timer */
+ sun4v_wdt_kick();
+ }
+ return len;
+}
+
+static long sun4v_wdt_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ int new_options, retval = -EINVAL;
+ int new_timeout;
+ int __user *argp = (void __user *)arg;
+ static const struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+ .firmware_version = 0,
+ .identity = "SUN4V Watchdog",
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, argp);
+
+ case WDIOC_SETOPTIONS:
+ if (get_user(new_options, argp))
+ return -EFAULT;
+
+ if (new_options & WDIOS_DISABLECARD)
+ retval = sun4v_wdt_stop();
+ if (new_options & WDIOS_ENABLECARD) {
+ retval = sun4v_wdt_start();
+ if (retval == -EBUSY)
+ retval = sun4v_wdt_kick();
+ }
+ return retval;
+
+ case WDIOC_KEEPALIVE:
+ sun4v_wdt_kick();
+ return 0;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_timeout, argp))
+ return -EFAULT;
+ if (!new_timeout)
+ return -EINVAL;
+ timeout = new_timeout;
+ sun4v_wdt_kick();
+ /* fall through */
+ case WDIOC_GETTIMEOUT:
+ return put_user(timeout, argp);
+
+ case WDIOC_GETTIMELEFT:
+ retval = wdt_expires - ktime_to_timespec(ktime_get()).tv_sec;
+ return put_user(retval, argp);
+ }
+
+ return -ENOTTY;
+}
+
+static const struct file_operations sun4v_wdt_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = sun4v_wdt_write,
+ .unlocked_ioctl = sun4v_wdt_ioctl,
+ .open = sun4v_wdt_open,
+ .release = sun4v_wdt_release,
+};
+
+static struct miscdevice sun4v_wdt_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &sun4v_wdt_fops,
+};
+
+static int sun4v_wdt_probe(struct platform_device *dev)
+{
+ unsigned long wd_timeout = 0;
+ unsigned long time_remaining;
+ int ret;
+
+ ret = sun4v_mach_set_watchdog(wd_timeout, &time_remaining);
+
+ switch (ret) {
+ case HV_EOK:
+ if (!timeout) {
+ timeout = WATCHDOG_TIMEOUT;
+ pr_info("timeout value invalid, using %lu\n", timeout);
+ }
+
+ ret = misc_register(&sun4v_wdt_miscdev);
+ if (ret) {
+ pr_err("cannot register miscdev on minor=%d (%d)\n",
+ WATCHDOG_MINOR, ret);
+ break;
+ }
+
+ pr_info("initialized (timeout=%lus, nowayout=%d)\n",
+ timeout, nowayout);
+ break;
+
+ case -ENOSYS:
+ pr_info("not supported\n");
+ ret = -ENODEV;
+ break;
+
+ default:
+ pr_info("bogus return value %d\n", ret);
+ break;
+ }
+
+ return ret;
+}
+
+static int sun4v_wdt_remove(struct platform_device *dev)
+{
+ /* Stop the timer before we leave */
+
+ if (!nowayout)
+ sun4v_wdt_stop();
+
+ misc_deregister(&sun4v_wdt_miscdev);
+
+ return 0;
+}
+
+static void sun4v_wdt_shutdown(struct platform_device *dev)
+{
+ sun4v_wdt_stop();
+}
+
+static int sun4v_wdt_suspend(struct platform_device *dev, pm_message_t state)
+{
+ int ret = sun4v_wdt_stop();
+ return ret;
+}
+
+static int sun4v_wdt_resume(struct platform_device *dev)
+{
+ return sun4v_wdt_start();
+}
+
+static struct platform_driver sun4v_wdt_driver = {
+ .probe = sun4v_wdt_probe,
+ .remove = sun4v_wdt_remove,
+ .shutdown = sun4v_wdt_shutdown,
+ .suspend = sun4v_wdt_suspend,
+ .resume = sun4v_wdt_resume,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+
+static int __init sun4v_wdt_init_module(void)
+{
+ int err;
+ struct mdesc_handle *hp;
+ u64 pn;
+ const u64 *v;
+ u64 max_timeout = 0;
+ u64 resolution;
+
+ /*
+ * There are 2 properties that can be set from the control
+ * domain for the watchdog.
+ * watchdog-resolution (in ms defaulting to 1000)
+ * watchdog-max-timeout (in ms)
+ * Right now, only support the default 1s (1000ms) resolution
+ * so just verify against the property, and make sure
+ * max timeout is taken into account, if set.
+ */
+ hp = mdesc_grab();
+ pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
+
+ if (pn == MDESC_NODE_NULL) {
+ pr_info("No platform node \n");
+ return -ENODEV;
+ }
+
+ v = mdesc_get_property(hp, pn, "watchdog-resolution", NULL);
+ if (v) {
+ resolution = *v;
+ pr_info("Platform watchdog-resolution [%llux]\n", *v);
+ /* default resolution is 1000ms, should be fine */
+ /* not supporting anything else right now */
+ if (resolution != 1000) {
+ pr_crit("Only 1000ms is supported.\n");
+ return -EINVAL;
+ }
+ }
+
+ v = mdesc_get_property(hp, pn, "watchdog-max-timeout", NULL);
+ if (v) {
+ max_timeout = *v;
+ pr_info("Platform watchdog-max-timeout [%llu ms]\n", *v);
+ if (max_timeout < 1000) {
+ pr_crit("Timeout should be at least 1s(1000ms)\n");
+ return -EINVAL;
+ }
+ }
+
+ /* have to convert timeout in seconds to timeout in milliseconds */
+ if (timeout * 1000 > max_timeout) {
+ /* and convert down to seconds again */
+ timeout = max_timeout / 1000;
+ pr_info("Timeout larger than watchdog-max-timeout\n");
+ pr_info("Setting timeout to watchdog-max-timeout [%llu ms]\n", max_timeout);
+ }
+
+ pr_info("Sun4v WatchDog Timer Driver v%s\n", DRV_VERSION);
+
+ err = platform_driver_register(&sun4v_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(&sun4v_wdt_driver);
+ }
+
+ return err;
+}
+
+static void __exit sun4v_wdt_cleanup_module(void)
+{
+ platform_device_unregister(platform_device);
+ platform_driver_unregister(&sun4v_wdt_driver);
+ pr_info("module unloaded\n");
+}
+
+module_init(sun4v_wdt_init_module);
+module_exit(sun4v_wdt_cleanup_module);
+
+MODULE_AUTHOR("Wim Coekaerts <wim.coekaerts@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Sun4v WatchDog Timer Driver");
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE("GPL");
--
1.7.1
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