[PATCH 02/11] watchdog: WatchDog Timer Driver Core - Add basicioctl functionality

From: Wim Van Sebroeck
Date: Mon Jul 11 2011 - 10:21:41 EST


This part add's the basic ioctl functionality to the
WatchDog Timer Driver Core framework. The supported
ioctl call's are:
WDIOC_GETSUPPORT
WDIOC_GETSTATUS
WDIOC_GETBOOTSTATUS

Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxx>
---
Documentation/watchdog/watchdog-kernel-api.txt | 6 ++++
drivers/watchdog/watchdog_dev.c | 33 ++++++++++++++++++++++++
include/linux/watchdog.h | 2 +
3 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/Documentation/watchdog/watchdog-kernel-api.txt b/Documentation/watchdog/watchdog-kernel-api.txt
index 03c1066..544eb19 100644
--- a/Documentation/watchdog/watchdog-kernel-api.txt
+++ b/Documentation/watchdog/watchdog-kernel-api.txt
@@ -41,6 +41,7 @@ The watchdog device structure looks like this:
struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
+ unsigned int bootstatus;
void *priv;
unsigned long status;
};
@@ -49,6 +50,8 @@ It contains following fields:
* info: a pointer to a watchdog_info structure. This structure gives some
additional information about the watchdog timer itself. (Like it's unique name)
* ops: a pointer to the list of watchdog operations that the watchdog supports.
+* bootstatus: status of the device after booting (reported with watchdog
+ WDIOF_* status bits).
* priv: a pointer to the private data of a watchdog device
* status: this field contains a number of status bits that give extra
information about the status of the device (Like: is the device opened via
@@ -63,6 +66,7 @@ struct watchdog_ops {
int (*stop)(struct watchdog_device *);
/* optional operations */
int (*ping)(struct watchdog_device *);
+ unsigned int (*status)(struct watchdog_device *);
};

It is important that you first define the module owner of the watchdog timer
@@ -95,6 +99,8 @@ they are supported. These optional routines/operations are:
the watchdog timer driver core does: to send a keepalive ping to the watchdog
timer hardware it will either use the ping operation (when available) or the
start operation (when the ping operation is not available).
+* status: this routine checks the status of the watchdog timer device. The
+ status of the device is reported with watchdog WDIOF_* status flags/bits.

The status bits should (preferably) be set with the set_bit and clear_bit alike
bit-operations. The status bits that are defined are:
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index c47154c..bebea38 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -106,6 +106,38 @@ static ssize_t watchdog_write(struct file *file, const char __user *data,
}

/*
+ * watchdog_ioctl: handle the different ioctl's for the watchdog device.
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all watchdogs
+ * according to their available features.
+ */
+
+static long watchdog_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ unsigned int val;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, wdd->info,
+ sizeof(struct watchdog_info)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ val = wdd->ops->status ? wdd->ops->status(wdd) : 0;
+ return put_user(val, p);
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(wdd->bootstatus, p);
+ default:
+ return -ENOTTY;
+ }
+ return -ENOTTY;
+}
+
+/*
* watchdog_open: open the /dev/watchdog device.
* @inode: inode of device
* @file: file handle to device
@@ -181,6 +213,7 @@ static const struct file_operations watchdog_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = watchdog_write,
+ .unlocked_ioctl = watchdog_ioctl,
.open = watchdog_open,
.release = watchdog_release,
};
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 40333ff..a2b639b 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -70,12 +70,14 @@ struct watchdog_ops {
int (*stop)(struct watchdog_device *);
/* optional operations */
int (*ping)(struct watchdog_device *);
+ unsigned int (*status)(struct watchdog_device *);
};

/* The structure that defines a watchdog device */
struct watchdog_device {
const struct watchdog_info *info;
const struct watchdog_ops *ops;
+ unsigned int bootstatus;
void *priv;
unsigned long status;
/* Bit numbers for status flags */
--
1.7.6

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