powerpc/watchdog: Allow the Book-E driver to be compiled as a module

Register the __init and __exit functions in the PowerPC Book-E Watchdog
driver as module entry/exit functions, and modify the Kconfig entry.

Add a .release method for the PowerPC Book-E Watchdog driver, so that the
watchdog is disabled when the driver is closed.

Loosely based on original code from Jiang Yutang <b14898@freescale.com>.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 24efd8ea41bb04bab6830cfddfd2281881ec9ae7..a6812eb31fa1e91c7d0ad08ad4b0951c20715807 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -957,9 +957,12 @@ config PIKA_WDT
          the Warp platform.
 
 config BOOKE_WDT
-       bool "PowerPC Book-E Watchdog Timer"
+       tristate "PowerPC Book-E Watchdog Timer"
        depends on BOOKE || 4xx
        ---help---
+         Watchdog driver for PowerPC Book-E chips, such as the Freescale
+         MPC85xx SOCs and the IBM PowerPC 440.
+
          Please see Documentation/watchdog/watchdog-api.txt for
          more information.
 

diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
index 3d49671cdf5aebf1f78e52d0a92a185dd9026a31..a9899981fd97774a87f0b666af9dd3e9ad28b110 100644 (file)
--- a/drivers/watchdog/booke_wdt.c
+++ b/drivers/watchdog/booke_wdt.c
@@ -4,7 +4,7 @@
  * Author: Matthew McClintock
  * Maintainer: Kumar Gala <galak@kernel.crashing.org>
  *
- * Copyright 2005, 2008 Freescale Semiconductor Inc.
+ * Copyright 2005, 2008, 2010 Freescale Semiconductor 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
@@ -114,6 +114,27 @@ static void __booke_wdt_enable(void *data)
        mtspr(SPRN_TCR, val);
 }
 
+/**
+ * booke_wdt_disable - disable the watchdog on the given CPU
+ *
+ * This function is called on each CPU.  It disables the watchdog on that CPU.
+ *
+ * TCR[WRC] cannot be changed once it has been set to non-zero, but we can
+ * effectively disable the watchdog by setting its period to the maximum value.
+ */
+static void __booke_wdt_disable(void *data)
+{
+       u32 val;
+
+       val = mfspr(SPRN_TCR);
+       val &= ~(TCR_WIE | WDTP_MASK);
+       mtspr(SPRN_TCR, val);
+
+       /* clear status to make sure nothing is pending */
+       __booke_wdt_ping(NULL);
+
+}
+
 static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
                                size_t count, loff_t *ppos)
 {
@@ -193,12 +214,21 @@ static int booke_wdt_open(struct inode *inode, struct file *file)
        return nonseekable_open(inode, file);
 }
 
+static int booke_wdt_release(struct inode *inode, struct file *file)
+{
+       on_each_cpu(__booke_wdt_disable, NULL, 0);
+       booke_wdt_enabled = 0;
+
+       return 0;
+}
+
 static const struct file_operations booke_wdt_fops = {
        .owner = THIS_MODULE,
        .llseek = no_llseek,
        .write = booke_wdt_write,
        .unlocked_ioctl = booke_wdt_ioctl,
        .open = booke_wdt_open,
+       .release = booke_wdt_release,
 };
 
 static struct miscdevice booke_wdt_miscdev = {
@@ -237,4 +267,9 @@ static int __init booke_wdt_init(void)
 
        return ret;
 }
-device_initcall(booke_wdt_init);
+
+module_init(booke_wdt_init);
+module_exit(booke_wdt_exit);
+
+MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
+MODULE_LICENSE("GPL");