watchdog: Propagate Book E WDT period changes to all cores

[mv-sheeva.git] / drivers / watchdog / booke_wdt.c

diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
index 3d49671cdf5aebf1f78e52d0a92a185dd9026a31..7e7ec9c35b6a442e1569f4c25d5711ea6668e586 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
@@ -33,14 +33,8 @@
  * occur, and the final time the board will reset.
  */
 
-#ifdef CONFIG_FSL_BOOKE
-#define WDT_PERIOD_DEFAULT 38  /* Ex. wdt_period=28 bus=333Mhz,reset=~40sec */
-#else
-#define WDT_PERIOD_DEFAULT 3   /* Refer to the PPC40x and PPC4xx manuals */
-#endif                         /* for timing information */
-
 u32 booke_wdt_enabled;
-u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
+u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
 
 #ifdef CONFIG_FSL_BOOKE
 #define WDTP(x)                ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
@@ -91,6 +85,22 @@ static unsigned int sec_to_period(unsigned int secs)
        return 0;
 }
 
+static void __booke_wdt_set(void *data)
+{
+       u32 val;
+
+       val = mfspr(SPRN_TCR);
+       val &= ~WDTP_MASK;
+       val |= WDTP(booke_wdt_period);
+
+       mtspr(SPRN_TCR, val);
+}
+
+static void booke_wdt_set(void)
+{
+       on_each_cpu(__booke_wdt_set, NULL, 0);
+}
+
 static void __booke_wdt_ping(void *data)
 {
        mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
@@ -114,6 +124,27 @@ 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)
 {
@@ -166,8 +197,7 @@ static long booke_wdt_ioctl(struct file *file,
 #else
                booke_wdt_period = tmp;
 #endif
-               mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP_MASK) |
-                                               WDTP(booke_wdt_period));
+               booke_wdt_set();
                return 0;
        case WDIOC_GETTIMEOUT:
                return put_user(booke_wdt_period, p);
@@ -178,8 +208,15 @@ static long booke_wdt_ioctl(struct file *file,
        return 0;
 }
 
+/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
+static unsigned long wdt_is_active;
+
 static int booke_wdt_open(struct inode *inode, struct file *file)
 {
+       /* /dev/watchdog can only be opened once */
+       if (test_and_set_bit(0, &wdt_is_active))
+               return -EBUSY;
+
        spin_lock(&booke_wdt_lock);
        if (booke_wdt_enabled == 0) {
                booke_wdt_enabled = 1;
@@ -193,12 +230,30 @@ 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)
+{
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+       /* Normally, the watchdog is disabled when /dev/watchdog is closed, but
+        * if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
+        * watchdog should remain enabled.  So we disable it only if
+        * CONFIG_WATCHDOG_NOWAYOUT is not defined.
+        */
+       on_each_cpu(__booke_wdt_disable, NULL, 0);
+       booke_wdt_enabled = 0;
+#endif
+
+       clear_bit(0, &wdt_is_active);
+
+       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 +292,9 @@ 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");