From: Corey Minyard <cminyard@xxxxxxxxxx>
When a pretimeout occurs, provide a byte of data on the watchdog
device.
Signed-off-by: Corey Minyard <cminyard@xxxxxxxxxx>
---
drivers/watchdog/Kconfig | 16 +++++++++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/pretimeout_read_data.c | 47 +++++++++++++++++++++++++
drivers/watchdog/watchdog_pretimeout.h | 2 ++
4 files changed, 66 insertions(+)
create mode 100644 drivers/watchdog/pretimeout_read_data.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 8188963a405b..3578b7bc863c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -105,6 +105,14 @@ config WATCHDOG_PRETIMEOUT_GOV_PANIC
Panic watchdog pretimeout governor, on watchdog pretimeout
event put the kernel into panic.
+config WATCHDOG_PRETIMEOUT_GOV_READ_DATA
+ tristate "Read data watchdog pretimeout governor"
+ depends on WATCHDOG_CORE
+ default WATCHDOG_CORE
+ help
+ Read data watchdog pretimeout governor, on watchdog pretimeout
+ event provide a byte of data on the watchdog device.
+
choice
prompt "Default Watchdog Pretimeout Governor"
default WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC
@@ -129,6 +137,14 @@ config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC
a watchdog pretimeout event happens, consider that
a watchdog feeder is dead and reboot is unavoidable.
+config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_READ_DATA
+ bool "read_data"
+ depends on WATCHDOG_PRETIMEOUT_GOV_READ_DATA
+ help
+ Use read data watchdog pretimeout governor by default, if
+ a watchdog pretimeout event happens, provide a byte of read
+ data on the watchdog device.
+
endchoice
endif # WATCHDOG_PRETIMEOUT_GOV
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 7caa920e7e60..9cfe4ad32dc4 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -12,6 +12,7 @@ watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o
obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP) += pretimeout_noop.o
obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_PANIC) += pretimeout_panic.o
+obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_READ_DATA) += pretimeout_read_data.o
# Only one watchdog can succeed. We probe the ISA/PCI/USB based
# watchdog-cards first, then the architecture specific watchdog
diff --git a/drivers/watchdog/pretimeout_read_data.c b/drivers/watchdog/pretimeout_read_data.c
new file mode 100644
index 000000000000..197e9d692044
--- /dev/null
+++ b/drivers/watchdog/pretimeout_read_data.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019 MontaVista Software, LLC
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/watchdog.h>
+
+#include "watchdog_pretimeout.h"
+
+/**
+ * pretimeout_read_data - Cause a read to return on the watchdog device.
+ * @wdd - watchdog_device
+ */
+static void pretimeout_read_data(struct watchdog_device *wdd)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&wdd->readlock, flags);
+ wdd->data_to_read = 1;
+ wake_up_interruptible(&wdd->read_q);
+ kill_fasync(&wdd->fasync_q, SIGIO, POLL_IN);
+ spin_unlock_irqrestore(&wdd->readlock, flags);
+}
+
+static struct watchdog_governor watchdog_gov_read_data = {
+ .name = "read_data",
+ .pretimeout = pretimeout_read_data,
+};
+
+static int __init watchdog_gov_read_data_register(void)
+{
+ return watchdog_register_governor(&watchdog_gov_read_data);
+}
+
+static void __exit watchdog_gov_read_data_unregister(void)
+{
+ watchdog_unregister_governor(&watchdog_gov_read_data);
+}
+module_init(watchdog_gov_read_data_register);
+module_exit(watchdog_gov_read_data_unregister);
+
+MODULE_AUTHOR("Corey Minyard <cminyard@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Read data watchdog pretimeout governor");
+MODULE_LICENSE("GPL");
diff --git a/drivers/watchdog/watchdog_pretimeout.h b/drivers/watchdog/watchdog_pretimeout.h
index a3f1abc68839..819517ed0138 100644
--- a/drivers/watchdog/watchdog_pretimeout.h
+++ b/drivers/watchdog/watchdog_pretimeout.h
@@ -28,6 +28,8 @@ int watchdog_pretimeout_governor_set(struct watchdog_device *wdd,
#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "noop"
#elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_PANIC)
#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "panic"
+#elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_READ_DATA)
+#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "read_data"
#endif
#else
--
2.17.1
