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[WATCHDOG] Winbond SMsC37B787 watchdog fixes
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* Added io spinlocking
* Deleted WATCHDOG_MINOR (it's in the miscdevice include
* Changed timer_enabled to use set_bit functions
* WDIOC_GETSUPPORT should return -EFAULT or 0
* timeout should be correct before we initialize the watchdog
* we should initialize the watchdog before we give access
  to userspace
* Third parameter of module_param is not the default or
  initial value

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
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Wim Van Sebroeck committed Oct 4, 2006
1 parent 8386c8c commit aa1fd4d
Showing 1 changed file with 30 additions and 17 deletions.
47 changes: 30 additions & 17 deletions drivers/char/watchdog/smsc37b787_wdt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,7 @@
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/spinlock.h>

#include <asm/io.h>
#include <asm/uaccess.h>
Expand All @@ -72,18 +73,18 @@
#define MODNAME "smsc37b787_wdt: "
#define VERSION "1.1"

#define WATCHDOG_MINOR 130

#define IOPORT 0x3F0
#define IOPORT_SIZE 2
#define IODEV_NO 8

static int unit = UNIT_SECOND; /* timer's unit */
static int timeout = 60; /* timeout value: default is 60 "units" */
static int timer_enabled = 0; /* is the timer enabled? */
static unsigned long timer_enabled = 0; /* is the timer enabled? */

static char expect_close; /* is the close expected? */

static spinlock_t io_lock; /* to guard the watchdog from io races */

static int nowayout = WATCHDOG_NOWAYOUT;

/* -- Low level function ----------------------------------------*/
Expand Down Expand Up @@ -210,6 +211,7 @@ static void wb_smsc_wdt_initialize(void)
{
unsigned char old;

spin_lock(&io_lock);
open_io_config();
select_io_device(IODEV_NO);

Expand All @@ -234,12 +236,14 @@ static void wb_smsc_wdt_initialize(void)
wdt_timer_units(old);

close_io_config();
spin_unlock(&io_lock);
}

/* shutdown the watchdog */

static void wb_smsc_wdt_shutdown(void)
{
spin_lock(&io_lock);
open_io_config();
select_io_device(IODEV_NO);

Expand All @@ -257,12 +261,14 @@ static void wb_smsc_wdt_shutdown(void)
wdt_timeout_value(0x00);

close_io_config();
spin_unlock(&io_lock);
}

/* set timeout => enable watchdog */

static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
{
spin_lock(&io_lock);
open_io_config();
select_io_device(IODEV_NO);

Expand All @@ -273,6 +279,7 @@ static void wb_smsc_wdt_set_timeout(unsigned char new_timeout)
wdt_timeout_value(new_timeout);

close_io_config();
spin_unlock(&io_lock);
}

/* get timeout */
Expand All @@ -281,10 +288,12 @@ static unsigned char wb_smsc_wdt_get_timeout(void)
{
unsigned char set_timeout;

spin_lock(&io_lock);
open_io_config();
select_io_device(IODEV_NO);
set_timeout = read_io_cr(0xF2);
close_io_config();
spin_unlock(&io_lock);

return set_timeout;
}
Expand All @@ -309,6 +318,7 @@ static void wb_smsc_wdt_enable(void)

static void wb_smsc_wdt_reset_timer(void)
{
spin_lock(&io_lock);
open_io_config();
select_io_device(IODEV_NO);

Expand All @@ -317,6 +327,7 @@ static void wb_smsc_wdt_reset_timer(void)
wdt_timer_conf(0x08);

close_io_config();
spin_unlock(&io_lock);
}

/* return, if the watchdog is enabled (timeout is set...) */
Expand All @@ -335,14 +346,13 @@ static int wb_smsc_wdt_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */

if (timer_enabled)
if (test_and_set_bit(0, &timer_enabled))
return -EBUSY;

if (nowayout)
__module_get(THIS_MODULE);

/* Reload and activate timer */
timer_enabled = 1;
wb_smsc_wdt_enable();

printk(KERN_INFO MODNAME "Watchdog enabled. Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
Expand All @@ -364,7 +374,7 @@ static int wb_smsc_wdt_release(struct inode *inode, struct file *file)
wb_smsc_wdt_reset_timer();
}

timer_enabled = 0;
clear_bit(0, &timer_enabled);
expect_close = 0;
return 0;
}
Expand Down Expand Up @@ -425,7 +435,8 @@ static int wb_smsc_wdt_ioctl(struct inode *inode, struct file *file,
return -ENOTTY;

case WDIOC_GETSUPPORT:
return copy_to_user(uarg.ident, &ident, sizeof(ident));
return copy_to_user(uarg.ident, &ident,
sizeof(ident)) ? -EFAULT : 0;

case WDIOC_GETSTATUS:
return put_user(wb_smsc_wdt_status(), uarg.i);
Expand Down Expand Up @@ -506,12 +517,12 @@ static struct file_operations wb_smsc_wdt_fops =
.write = wb_smsc_wdt_write,
.ioctl = wb_smsc_wdt_ioctl,
.open = wb_smsc_wdt_open,
.release = wb_smsc_wdt_release
.release = wb_smsc_wdt_release,
};

static struct notifier_block wb_smsc_wdt_notifier =
{
.notifier_call = wb_smsc_wdt_notify_sys
.notifier_call = wb_smsc_wdt_notify_sys,
};

static struct miscdevice wb_smsc_wdt_miscdev =
Expand All @@ -529,6 +540,8 @@ static int __init wb_smsc_wdt_init(void)
{
int ret;

spin_lock_init(&io_lock);

printk("SMsC 37B787 watchdog component driver " VERSION " initialising...\n");

if (!request_region(IOPORT, IOPORT_SIZE, "SMsC 37B787 watchdog")) {
Expand All @@ -537,6 +550,13 @@ static int __init wb_smsc_wdt_init(void)
goto out_pnp;
}

// set new maximum, if it's too big
if (timeout > MAX_TIMEOUT)
timeout = MAX_TIMEOUT;

// init the watchdog timer
wb_smsc_wdt_initialize();

ret = register_reboot_notifier(&wb_smsc_wdt_notifier);
if (ret) {
printk(KERN_ERR MODNAME "Unable to register reboot notifier err = %d\n", ret);
Expand All @@ -549,13 +569,6 @@ static int __init wb_smsc_wdt_init(void)
goto out_rbt;
}

// init the watchdog timer
wb_smsc_wdt_initialize();

// set new maximum, if it's too big
if (timeout > MAX_TIMEOUT)
timeout = MAX_TIMEOUT;

// output info
printk(KERN_INFO MODNAME "Timeout set to %d %s.\n", timeout, (unit == UNIT_SECOND) ? "second(s)" : "minute(s)");
printk(KERN_INFO MODNAME "Watchdog initialized and sleeping (nowayout=%d)...\n", nowayout);
Expand Down Expand Up @@ -607,7 +620,7 @@ module_param(unit, int, 0);
MODULE_PARM_DESC(unit, "set unit to use, 0=seconds or 1=minutes, default is 0");
#endif

module_param(timeout, int, 60);
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "range is 1-255 units, default is 60");

module_param(nowayout, int, 0);
Expand Down

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