[PATCH] i8xx_tco.c: arm watchdog only when started

i8xx_tco.c v0.08: only "arm" the watchdog when the watchdog has been
started.  (Kernel Bug 4251: system reset when battery is read and i8xx_tco
driver loaded)

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/watchdog/i8xx_tco.c b/drivers/char/watchdog/i8xx_tco.c
index f975dab1ddf95417f4c6214a0057661a0cf71c7c..a13395e2c372a9b27355040c9c94eae21040992b 100644 (file)
--- a/drivers/char/watchdog/i8xx_tco.c
+++ b/drivers/char/watchdog/i8xx_tco.c
@@ -1,5 +1,5 @@
 /*
- *     i8xx_tco 0.07:  TCO timer driver for i8xx chipsets
+ *     i8xx_tco:       TCO timer driver for i8xx chipsets
  *
  *     (c) Copyright 2000 kernel concepts <nils@kernelconcepts.de>, All Rights Reserved.
  *                             http://www.kernelconcepts.de
@@ -63,6 +63,9 @@
  *  20050128 Wim Van Sebroeck <wim@iguana.be>
  *     0.07 Added support for the ICH4-M, ICH6, ICH6R, ICH6-M, ICH6W and ICH6RW
  *          chipsets. Also added support for the "undocumented" ICH7 chipset.
+ *  20050807 Wim Van Sebroeck <wim@iguana.be>
+ *     0.08 Make sure that the watchdog is only "armed" when started.
+ *          (Kernel Bug 4251)
  */
 
 /*
@@ -87,7 +90,7 @@
 #include "i8xx_tco.h"
 
 /* Module and version information */
-#define TCO_VERSION "0.07"
+#define TCO_VERSION "0.08"
 #define TCO_MODULE_NAME "i8xx TCO timer"
 #define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
 #define PFX TCO_MODULE_NAME ": "
@@ -125,10 +128,18 @@ static int tco_timer_start (void)
        unsigned char val;
 
        spin_lock(&tco_lock);
+
+       /* disable chipset's NO_REBOOT bit */
+       pci_read_config_byte (i8xx_tco_pci, 0xd4, &val);
+       val &= 0xfd;
+       pci_write_config_byte (i8xx_tco_pci, 0xd4, val);
+
+       /* Bit 11: TCO Timer Halt -> 0 = The TCO timer is enabled to count */
        val = inb (TCO1_CNT + 1);
        val &= 0xf7;
        outb (val, TCO1_CNT + 1);
        val = inb (TCO1_CNT + 1);
+
        spin_unlock(&tco_lock);
 
        if (val & 0x08)
@@ -138,13 +149,20 @@ static int tco_timer_start (void)
 
 static int tco_timer_stop (void)
 {
-       unsigned char val;
+       unsigned char val, val1;
 
        spin_lock(&tco_lock);
+       /* Bit 11: TCO Timer Halt -> 1 = The TCO timer is disabled */
        val = inb (TCO1_CNT + 1);
        val |= 0x08;
        outb (val, TCO1_CNT + 1);
        val = inb (TCO1_CNT + 1);
+
+       /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
+       pci_read_config_byte (i8xx_tco_pci, 0xd4, &val1);
+       val1 |= 0x02;
+       pci_write_config_byte (i8xx_tco_pci, 0xd4, val1);
+
        spin_unlock(&tco_lock);
 
        if ((val & 0x08) == 0)
@@ -155,6 +173,7 @@ static int tco_timer_stop (void)
 static int tco_timer_keepalive (void)
 {
        spin_lock(&tco_lock);
+       /* Reload the timer by writing to the TCO Timer Reload register */
        outb (0x01, TCO1_RLD);
        spin_unlock(&tco_lock);
        return 0;
@@ -417,9 +436,8 @@ static unsigned char __init i8xx_tco_getdevice (void)
                        printk (KERN_ERR PFX "failed to get TCOBASE address\n");
                        return 0;
                }
-               /*
-                * Check chipset's NO_REBOOT bit
-                */
+
+               /* Check chipset's NO_REBOOT bit */
                pci_read_config_byte (i8xx_tco_pci, 0xd4, &val1);
                if (val1 & 0x02) {
                        val1 &= 0xfd;
@@ -430,6 +448,10 @@ static unsigned char __init i8xx_tco_getdevice (void)
                                return 0;       /* Cannot reset NO_REBOOT bit */
                        }
                }
+               /* Disable reboots untill the watchdog starts */
+               val1 |= 0x02;
+               pci_write_config_byte (i8xx_tco_pci, 0xd4, val1);
+
                /* Set the TCO_EN bit in SMI_EN register */
                if (!request_region (SMI_EN + 1, 1, "i8xx TCO")) {
                        printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
@@ -505,17 +527,10 @@ out:
 
 static void __exit watchdog_cleanup (void)
 {
-       u8 val;
-
        /* Stop the timer before we leave */
        if (!nowayout)
                tco_timer_stop ();
 
-       /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
-       pci_read_config_byte (i8xx_tco_pci, 0xd4, &val);
-       val |= 0x02;
-       pci_write_config_byte (i8xx_tco_pci, 0xd4, val);
-
        /* Deregister */
        misc_deregister (&i8xx_tco_miscdev);
        unregister_reboot_notifier(&i8xx_tco_notifier);