[PATCH v10 0/2] Make all it87 drivers SMP safe

[PATCH v10 0/2] Make all it87 drivers SMP safe

[Nat Gurumoorthy]

There are 3 different drivers that touch the it87 hardware registers.
The 3 drivers have been written independently and access the it87 hardware
registers assuming they are the only driver accessing it. This change
attempts to serialize access to the hardware by using
"request_muxed_region" macro defined by Alan Cox. Call to this macro
will hold off the requestor if the resource is currently busy.
The use of the above macro makes it possible to get rid of
spinlocks in it8712f_wdt.c and it87_wdt.c watchdog drivers.
This also greatly simplifies the implementation of it87_wdt.c driver.

01 - Changes to it87 watchdog driver to use "request_muxed_region"
 drivers/watchdog/it8712f_wdt.c
 drivers/watchdog/it87_wdt.c

02 - Chages to hwmon it87 driver to use "request_muxed_region"
 drivers/hwmon/it87.c

 drivers/hwmon/it87.c           |   31 +++++---
 drivers/watchdog/it8712f_wdt.c |   62 +++++++++++----
 drivers/watchdog/it87_wdt.c    |  169 +++++++++++++++++++++------------------
 3 files changed, 155 insertions(+), 107 deletions(-)

Signed-off-by: Nat Gurumoorthy <natg@google.com>

Patch History:
v10:
- More clean up in drivers/watchdog/it87_wdt.c in it87_wdt_init
  and it87_wdt_ioctl routines.

v9:
- More clean up in drivers/hwmon/it87.c. More fixes that of
  the type in V8 that got missed in drivers/watchdog/it8712f_wdt.c.

v8:
- Return the error actually returned by superio_enter and not -EBUSY.
  Notifier routines return NOTIFY_DONE even if underlying calls from
  notifier to routines that invoke superio_enter return with error.
  Make sure release routines returns do proper clean up even if calls to
  superio_enter fail.

v7:
- superio_enter return error if call to "request_muxed_region" fails. Rest
  of the changes deal with error returns from superio_enter. Changes to
  it87_wdt.c are untested.

v6:
- Pay attention to value returned by request_muxed_region. The first call to
  request_muxed_region will attempt 10 times to reserve the region before it
  gives up. This will typically get called from the driver init routines. If this
  succeeds then subsequent calls wait forever for the resource to be available.

v5:
- Remove unnecessary while from superio_enter.

v4:
- Remove extra braces in superio_enter routines.

v3:
- Totally abandon the spinlock based approach and use "request_muxed_region" to
  hold off requestors if the resource is busy.

v2:
- More verbose patch headers. Add In-Reply-To: field.

[PATCH v10 1/2] Use "request_muxed_region" in it87 watchdog drivers

[Nat Gurumoorthy]

01 - Changes to it87 watchdog driver to use "request_muxed_region"
Serialize access to the hardware by using "request_muxed_region" macro defined
by Alan Cox. Call to this macro will hold off the requestor if the resource is
currently busy. 

The use of the above macro makes it possible to get rid of
spinlocks in it8712f_wdt.c and it87_wdt.c watchdog drivers.
This also greatly simplifies the implementation of it87_wdt.c driver.

 "superio_enter" will return an error if call to "request_muxed_region" fails. 
Rest of the code change is to ripple an error return from superio_enter to
the top level.

Signed-off-by: Nat Gurumoorthy <natg@google.com>
---

diff --git a/drivers/watchdog/it8712f_wdt.c b/drivers/watchdog/it8712f_wdt.c
index 6143f52..c8677ac 100644
--- a/drivers/watchdog/it8712f_wdt.c
+++ b/drivers/watchdog/it8712f_wdt.c
@@ -51,7 +51,6 @@ MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
 
 static unsigned long wdt_open;
 static unsigned expect_close;
-static spinlock_t io_lock;
 static unsigned char revision;
 
 /* Dog Food address - We use the game port address */
@@ -121,20 +120,27 @@ static inline void superio_select(int ldn)
 	outb(ldn, VAL);
 }
 
-static inline void superio_enter(void)
+static inline int
+superio_enter(void)
 {
-	spin_lock(&io_lock);
+	/*
+	 * Try to reserve REG and REG + 1 for exclusive access.
+	 */
+	if (!request_muxed_region(REG, 2, NAME))
+		return -EBUSY;
+
 	outb(0x87, REG);
 	outb(0x01, REG);
 	outb(0x55, REG);
 	outb(0x55, REG);
+	return 0;
 }
 
 static inline void superio_exit(void)
 {
 	outb(0x02, REG);
 	outb(0x02, VAL);
-	spin_unlock(&io_lock);
+	release_region(REG, 2);
 }
 
 static inline void it8712f_wdt_ping(void)
@@ -173,10 +179,13 @@ static int it8712f_wdt_get_status(void)
 		return 0;
 }
 
-static void it8712f_wdt_enable(void)
+static int it8712f_wdt_enable(void)
 {
+	int ret = superio_enter();
+	if (ret)
+		return ret;
+
 	printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
-	superio_enter();
 	superio_select(LDN_GPIO);
 
 	superio_outb(wdt_control_reg, WDT_CONTROL);
@@ -186,13 +195,17 @@ static void it8712f_wdt_enable(void)
 	superio_exit();
 
 	it8712f_wdt_ping();
+
+	return 0;
 }
 
-static void it8712f_wdt_disable(void)
+static int it8712f_wdt_disable(void)
 {
-	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
+	int ret = superio_enter();
+	if (ret)
+		return ret;
 
-	superio_enter();
+	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
 	superio_select(LDN_GPIO);
 
 	superio_outb(0, WDT_CONFIG);
@@ -202,6 +215,7 @@ static void it8712f_wdt_disable(void)
 	superio_outb(0, WDT_TIMEOUT);
 
 	superio_exit();
+	return 0;
 }
 
 static int it8712f_wdt_notify(struct notifier_block *this,
@@ -252,6 +266,7 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 						WDIOF_MAGICCLOSE,
 	};
 	int value;
+	int ret;
 
 	switch (cmd) {
 	case WDIOC_GETSUPPORT:
@@ -259,7 +274,9 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 			return -EFAULT;
 		return 0;
 	case WDIOC_GETSTATUS:
-		superio_enter();
+		ret = superio_enter();
+		if (ret)
+			return ret;
 		superio_select(LDN_GPIO);
 
 		value = it8712f_wdt_get_status();
@@ -280,7 +297,9 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 		if (value > (max_units * 60))
 			return -EINVAL;
 		margin = value;
-		superio_enter();
+		ret = superio_enter();
+		if (ret)
+			return ret;
 		superio_select(LDN_GPIO);
 
 		it8712f_wdt_update_margin();
@@ -299,10 +318,14 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
 
 static int it8712f_wdt_open(struct inode *inode, struct file *file)
 {
+	int ret;
 	/* only allow one at a time */
 	if (test_and_set_bit(0, &wdt_open))
 		return -EBUSY;
-	it8712f_wdt_enable();
+
+	ret = it8712f_wdt_enable();
+	if (ret)
+		return ret;
 	return nonseekable_open(inode, file);
 }
 
@@ -313,7 +336,8 @@ static int it8712f_wdt_release(struct inode *inode, struct file *file)
 			": watchdog device closed unexpectedly, will not"
 			" disable the watchdog timer\n");
 	} else if (!nowayout) {
-		it8712f_wdt_disable();
+		if (it8712f_wdt_disable())
+			printk(KERN_WARNING NAME "Watchdog disable failed\n");
 	}
 	expect_close = 0;
 	clear_bit(0, &wdt_open);
@@ -340,8 +364,10 @@ static int __init it8712f_wdt_find(unsigned short *address)
 {
 	int err = -ENODEV;
 	int chip_type;
+	int ret = superio_enter();
+	if (ret)
+		return ret;
 
-	superio_enter();
 	chip_type = superio_inw(DEVID);
 	if (chip_type != IT8712F_DEVID)
 		goto exit;
@@ -382,8 +408,6 @@ static int __init it8712f_wdt_init(void)
 {
 	int err = 0;
 
-	spin_lock_init(&io_lock);
-
 	if (it8712f_wdt_find(&address))
 		return -ENODEV;
 
@@ -392,7 +416,11 @@ static int __init it8712f_wdt_init(void)
 		return -EBUSY;
 	}
 
-	it8712f_wdt_disable();
+	err = it8712f_wdt_disable();
+	if (err) {
+		printk(KERN_ERR NAME ": unable to disable watchdog timer.\n");
+		goto out;
+	}
 
 	err = register_reboot_notifier(&it8712f_wdt_notifier);
 	if (err) {
diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
index b1bc72f..e3c03a9 100644
--- a/drivers/watchdog/it87_wdt.c
+++ b/drivers/watchdog/it87_wdt.c
@@ -137,7 +137,6 @@
 
 static	unsigned int base, gpact, ciract, max_units, chip_type;
 static	unsigned long wdt_status;
-static	DEFINE_SPINLOCK(spinlock);
 
 static	int nogameport = DEFAULT_NOGAMEPORT;
 static	int exclusive  = DEFAULT_EXCLUSIVE;
@@ -163,18 +162,27 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
 
 /* Superio Chip */
 
-static inline void superio_enter(void)
+static inline int
+superio_enter(void)
 {
+	/*
+	 * Try to reserve REG and REG + 1 for exclusive access.
+	 */
+	if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
+		return -EBUSY;
+
 	outb(0x87, REG);
 	outb(0x01, REG);
 	outb(0x55, REG);
 	outb(0x55, REG);
+	return 0;
 }
 
 static inline void superio_exit(void)
 {
 	outb(0x02, REG);
 	outb(0x02, VAL);
+	release_region(REG, 2);
 }
 
 static inline void superio_select(int ldn)
@@ -255,12 +263,11 @@ static void wdt_keepalive(void)
 	set_bit(WDTS_KEEPALIVE, &wdt_status);
 }
 
-static void wdt_start(void)
+static int wdt_start(void)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&spinlock, flags);
-	superio_enter();
+	int ret = superio_enter();
+	if (ret)
+		return ret;
 
 	superio_select(GPIO);
 	if (test_bit(WDTS_USE_GP, &wdt_status))
@@ -270,15 +277,15 @@ static void wdt_start(void)
 	wdt_update_timeout();
 
 	superio_exit();
-	spin_unlock_irqrestore(&spinlock, flags);
+
+	return 0;
 }
 
-static void wdt_stop(void)
+static int wdt_stop(void)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&spinlock, flags);
-	superio_enter();
+	int ret = superio_enter();
+	if (ret)
+		return ret;
 
 	superio_select(GPIO);
 	superio_outb(0x00, WDTCTRL);
@@ -288,7 +295,7 @@ static void wdt_stop(void)
 		superio_outb(0x00, WDTVALMSB);
 
 	superio_exit();
-	spin_unlock_irqrestore(&spinlock, flags);
+	return 0;
 }
 
 /**
@@ -303,8 +310,6 @@ static void wdt_stop(void)
 
 static int wdt_set_timeout(int t)
 {
-	unsigned long flags;
-
 	if (t < 1 || t > max_units * 60)
 		return -EINVAL;
 
@@ -313,14 +318,15 @@ static int wdt_set_timeout(int t)
 	else
 		timeout = t;
 
-	spin_lock_irqsave(&spinlock, flags);
 	if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
-		superio_enter();
+		int ret = superio_enter();
+		if (ret)
+			return ret;
+
 		superio_select(GPIO);
 		wdt_update_timeout();
 		superio_exit();
 	}
-	spin_unlock_irqrestore(&spinlock, flags);
 	return 0;
 }
 
@@ -339,12 +345,12 @@ static int wdt_set_timeout(int t)
 
 static int wdt_get_status(int *status)
 {
-	unsigned long flags;
-
 	*status = 0;
 	if (testmode) {
-		spin_lock_irqsave(&spinlock, flags);
-		superio_enter();
+		int ret = superio_enter();
+		if (ret)
+			return ret;
+
 		superio_select(GPIO);
 		if (superio_inb(WDTCTRL) & WDT_ZERO) {
 			superio_outb(0x00, WDTCTRL);
@@ -353,7 +359,6 @@ static int wdt_get_status(int *status)
 		}
 
 		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
 	}
 	if (test_and_clear_bit(WDTS_KEEPALIVE, &wdt_status))
 		*status |= WDIOF_KEEPALIVEPING;
@@ -379,9 +384,17 @@ static int wdt_open(struct inode *inode, struct file *file)
 	if (exclusive && test_and_set_bit(WDTS_DEV_OPEN, &wdt_status))
 		return -EBUSY;
 	if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
+		int ret;
 		if (nowayout && !test_and_set_bit(WDTS_LOCKED, &wdt_status))
 			__module_get(THIS_MODULE);
-		wdt_start();
+
+		ret = wdt_start();
+		if (ret) {
+			clear_bit(WDTS_LOCKED, &wdt_status);
+			clear_bit(WDTS_TIMER_RUN, &wdt_status);
+			clear_bit(WDTS_DEV_OPEN, &wdt_status);
+			return ret;
+		}
 	}
 	return nonseekable_open(inode, file);
 }
@@ -403,7 +416,16 @@ static int wdt_release(struct inode *inode, struct file *file)
 {
 	if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
 		if (test_and_clear_bit(WDTS_EXPECTED, &wdt_status)) {
-			wdt_stop();
+			int ret = wdt_stop();
+			if (ret) {
+				/*
+				 * Stop failed. Just keep the watchdog alive
+				 * and hope nothing bad happens.
+				 */
+				set_bit(WDTS_EXPECTED, &wdt_status);
+				wdt_keepalive();
+				return ret;
+			}
 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
 		} else {
 			wdt_keepalive();
@@ -484,7 +506,9 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 				    &ident, sizeof(ident)) ? -EFAULT : 0;
 
 	case WDIOC_GETSTATUS:
-		wdt_get_status(&status);
+		rc = wdt_get_status(&status);
+		if (rc)
+			return rc;
 		return put_user(status, uarg.i);
 
 	case WDIOC_GETBOOTSTATUS:
@@ -500,14 +524,22 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 
 		switch (new_options) {
 		case WDIOS_DISABLECARD:
-			if (test_bit(WDTS_TIMER_RUN, &wdt_status))
-				wdt_stop();
+			if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
+				rc = wdt_stop();
+				if (rc)
+					return rc;
+			}
 			clear_bit(WDTS_TIMER_RUN, &wdt_status);
 			return 0;
 
 		case WDIOS_ENABLECARD:
-			if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status))
-				wdt_start();
+			if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
+				rc = wdt_start();
+				if (rc) {
+					clear_bit(WDTS_TIMER_RUN, &wdt_status);
+					return rc;
+				}
+			}
 			return 0;
 
 		default:
@@ -560,16 +592,17 @@ static int __init it87_wdt_init(void)
 	int rc = 0;
 	int try_gameport = !nogameport;
 	u8  chip_rev;
-	unsigned long flags;
+	int gp_rreq_fail = 0;
 
 	wdt_status = 0;
 
-	spin_lock_irqsave(&spinlock, flags);
-	superio_enter();
+	rc = superio_enter();
+	if (rc)
+		return rc;
+
 	chip_type = superio_inw(CHIPID);
 	chip_rev  = superio_inb(CHIPREV) & 0x0f;
 	superio_exit();
-	spin_unlock_irqrestore(&spinlock, flags);
 
 	switch (chip_type) {
 	case IT8702_ID:
@@ -603,8 +636,9 @@ static int __init it87_wdt_init(void)
 		return -ENODEV;
 	}
 
-	spin_lock_irqsave(&spinlock, flags);
-	superio_enter();
+	rc = superio_enter();
+	if (rc)
+		return rc;
 
 	superio_select(GPIO);
 	superio_outb(WDT_TOV1, WDTCFG);
@@ -620,21 +654,16 @@ static int __init it87_wdt_init(void)
 		}
 		gpact = superio_inb(ACTREG);
 		superio_outb(0x01, ACTREG);
-		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
 		if (request_region(base, 1, WATCHDOG_NAME))
 			set_bit(WDTS_USE_GP, &wdt_status);
 		else
-			rc = -EIO;
-	} else {
-		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
+			gp_rreq_fail = 1;
 	}
 
 	/* If we haven't Gameport support, try to get CIR support */
 	if (!test_bit(WDTS_USE_GP, &wdt_status)) {
 		if (!request_region(CIR_BASE, 8, WATCHDOG_NAME)) {
-			if (rc == -EIO)
+			if (gp_rreq_fail)
 				printk(KERN_ERR PFX
 					"I/O Address 0x%04x and 0x%04x"
 					" already in use\n", base, CIR_BASE);
@@ -646,21 +675,16 @@ static int __init it87_wdt_init(void)
 			goto err_out;
 		}
 		base = CIR_BASE;
-		spin_lock_irqsave(&spinlock, flags);
-		superio_enter();
 
 		superio_select(CIR);
 		superio_outw(base, BASEREG);
 		superio_outb(0x00, CIR_ILS);
 		ciract = superio_inb(ACTREG);
 		superio_outb(0x01, ACTREG);
-		if (rc == -EIO) {
+		if (gp_rreq_fail) {
 			superio_select(GAMEPORT);
 			superio_outb(gpact, ACTREG);
 		}
-
-		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
 	}
 
 	if (timeout < 1 || timeout > max_units * 60) {
@@ -704,6 +728,7 @@ static int __init it87_wdt_init(void)
 		"nogameport=%d)\n", chip_type, chip_rev, timeout,
 		nowayout, testmode, exclusive, nogameport);
 
+	superio_exit();
 	return 0;
 
 err_out_reboot:
@@ -711,49 +736,37 @@ err_out_reboot:
 err_out_region:
 	release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);
 	if (!test_bit(WDTS_USE_GP, &wdt_status)) {
-		spin_lock_irqsave(&spinlock, flags);
-		superio_enter();
 		superio_select(CIR);
 		superio_outb(ciract, ACTREG);
-		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
 	}
 err_out:
 	if (try_gameport) {
-		spin_lock_irqsave(&spinlock, flags);
-		superio_enter();
 		superio_select(GAMEPORT);
 		superio_outb(gpact, ACTREG);
-		superio_exit();
-		spin_unlock_irqrestore(&spinlock, flags);
 	}
 
+	superio_exit();
 	return rc;
 }
 
 static void __exit it87_wdt_exit(void)
 {
-	unsigned long flags;
-	int nolock;
-
-	nolock = !spin_trylock_irqsave(&spinlock, flags);
-	superio_enter();
-	superio_select(GPIO);
-	superio_outb(0x00, WDTCTRL);
-	superio_outb(0x00, WDTCFG);
-	superio_outb(0x00, WDTVALLSB);
-	if (max_units > 255)
-		superio_outb(0x00, WDTVALMSB);
-	if (test_bit(WDTS_USE_GP, &wdt_status)) {
-		superio_select(GAMEPORT);
-		superio_outb(gpact, ACTREG);
-	} else {
-		superio_select(CIR);
-		superio_outb(ciract, ACTREG);
+	if (superio_enter() == 0) {
+		superio_select(GPIO);
+		superio_outb(0x00, WDTCTRL);
+		superio_outb(0x00, WDTCFG);
+		superio_outb(0x00, WDTVALLSB);
+		if (max_units > 255)
+			superio_outb(0x00, WDTVALMSB);
+		if (test_bit(WDTS_USE_GP, &wdt_status)) {
+			superio_select(GAMEPORT);
+			superio_outb(gpact, ACTREG);
+		} else {
+			superio_select(CIR);
+			superio_outb(ciract, ACTREG);
+		}
+		superio_exit();
 	}
-	superio_exit();
-	if (!nolock)
-		spin_unlock_irqrestore(&spinlock, flags);
 
 	misc_deregister(&wdt_miscdev);
 	unregister_reboot_notifier(&wdt_notifier);

Re: [PATCH v10 1/2] Use "request_muxed_region" in it87 watchdog drivers

[Guenter Roeck]

On Mon, May 09, 2011 at 02:45:07PM -0400, Nat Gurumoorthy wrote:
> 01 - Changes to it87 watchdog driver to use "request_muxed_region"
> Serialize access to the hardware by using "request_muxed_region" macro defined
> by Alan Cox. Call to this macro will hold off the requestor if the resource is
> currently busy.
> 
> The use of the above macro makes it possible to get rid of
> spinlocks in it8712f_wdt.c and it87_wdt.c watchdog drivers.
> This also greatly simplifies the implementation of it87_wdt.c driver.
> 
>  "superio_enter" will return an error if call to "request_muxed_region" fails.
> Rest of the code change is to ripple an error return from superio_enter to
> the top level.
> 
> Signed-off-by: Nat Gurumoorthy <natg@google.com>

One comment inline below; ok with me but others may have concerns.

Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

> ---
> 
> diff --git a/drivers/watchdog/it8712f_wdt.c b/drivers/watchdog/it8712f_wdt.c
> index 6143f52..c8677ac 100644
> --- a/drivers/watchdog/it8712f_wdt.c
> +++ b/drivers/watchdog/it8712f_wdt.c
> @@ -51,7 +51,6 @@ MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
> 
>  static unsigned long wdt_open;
>  static unsigned expect_close;
> -static spinlock_t io_lock;
>  static unsigned char revision;
> 
>  /* Dog Food address - We use the game port address */
> @@ -121,20 +120,27 @@ static inline void superio_select(int ldn)
>         outb(ldn, VAL);
>  }
> 
> -static inline void superio_enter(void)
> +static inline int
> +superio_enter(void)
>  {
> -       spin_lock(&io_lock);
> +       /*
> +        * Try to reserve REG and REG + 1 for exclusive access.
> +        */
> +       if (!request_muxed_region(REG, 2, NAME))
> +               return -EBUSY;
> +
>         outb(0x87, REG);
>         outb(0x01, REG);
>         outb(0x55, REG);
>         outb(0x55, REG);
> +       return 0;
>  }
> 
>  static inline void superio_exit(void)
>  {
>         outb(0x02, REG);
>         outb(0x02, VAL);
> -       spin_unlock(&io_lock);
> +       release_region(REG, 2);
>  }
> 
>  static inline void it8712f_wdt_ping(void)
> @@ -173,10 +179,13 @@ static int it8712f_wdt_get_status(void)
>                 return 0;
>  }
> 
> -static void it8712f_wdt_enable(void)
> +static int it8712f_wdt_enable(void)
>  {
> +       int ret = superio_enter();
> +       if (ret)
> +               return ret;
> +
>         printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
> -       superio_enter();
>         superio_select(LDN_GPIO);
> 
>         superio_outb(wdt_control_reg, WDT_CONTROL);
> @@ -186,13 +195,17 @@ static void it8712f_wdt_enable(void)
>         superio_exit();
> 
>         it8712f_wdt_ping();
> +
> +       return 0;
>  }
> 
> -static void it8712f_wdt_disable(void)
> +static int it8712f_wdt_disable(void)
>  {
> -       printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
> +       int ret = superio_enter();
> +       if (ret)
> +               return ret;
> 
> -       superio_enter();
> +       printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
>         superio_select(LDN_GPIO);
> 
>         superio_outb(0, WDT_CONFIG);
> @@ -202,6 +215,7 @@ static void it8712f_wdt_disable(void)
>         superio_outb(0, WDT_TIMEOUT);
> 
>         superio_exit();
> +       return 0;
>  }
> 
>  static int it8712f_wdt_notify(struct notifier_block *this,
> @@ -252,6 +266,7 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
>                                                 WDIOF_MAGICCLOSE,
>         };
>         int value;
> +       int ret;
> 
>         switch (cmd) {
>         case WDIOC_GETSUPPORT:
> @@ -259,7 +274,9 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
>                         return -EFAULT;
>                 return 0;
>         case WDIOC_GETSTATUS:
> -               superio_enter();
> +               ret = superio_enter();
> +               if (ret)
> +                       return ret;
>                 superio_select(LDN_GPIO);
> 
>                 value = it8712f_wdt_get_status();
> @@ -280,7 +297,9 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
>                 if (value > (max_units * 60))
>                         return -EINVAL;
>                 margin = value;
> -               superio_enter();
> +               ret = superio_enter();
> +               if (ret)
> +                       return ret;
>                 superio_select(LDN_GPIO);
> 
>                 it8712f_wdt_update_margin();
> @@ -299,10 +318,14 @@ static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
> 
>  static int it8712f_wdt_open(struct inode *inode, struct file *file)
>  {
> +       int ret;
>         /* only allow one at a time */
>         if (test_and_set_bit(0, &wdt_open))
>                 return -EBUSY;
> -       it8712f_wdt_enable();
> +
> +       ret = it8712f_wdt_enable();
> +       if (ret)
> +               return ret;
>         return nonseekable_open(inode, file);
>  }
> 
> @@ -313,7 +336,8 @@ static int it8712f_wdt_release(struct inode *inode, struct file *file)
>                         ": watchdog device closed unexpectedly, will not"
>                         " disable the watchdog timer\n");
>         } else if (!nowayout) {
> -               it8712f_wdt_disable();
> +               if (it8712f_wdt_disable())
> +                       printk(KERN_WARNING NAME "Watchdog disable failed\n");
>         }
>         expect_close = 0;
>         clear_bit(0, &wdt_open);
> @@ -340,8 +364,10 @@ static int __init it8712f_wdt_find(unsigned short *address)
>  {
>         int err = -ENODEV;
>         int chip_type;
> +       int ret = superio_enter();
> +       if (ret)
> +               return ret;
> 
> -       superio_enter();
>         chip_type = superio_inw(DEVID);
>         if (chip_type != IT8712F_DEVID)
>                 goto exit;
> @@ -382,8 +408,6 @@ static int __init it8712f_wdt_init(void)
>  {
>         int err = 0;
> 
> -       spin_lock_init(&io_lock);
> -
>         if (it8712f_wdt_find(&address))
>                 return -ENODEV;
> 
> @@ -392,7 +416,11 @@ static int __init it8712f_wdt_init(void)
>                 return -EBUSY;
>         }
> 
> -       it8712f_wdt_disable();
> +       err = it8712f_wdt_disable();
> +       if (err) {
> +               printk(KERN_ERR NAME ": unable to disable watchdog timer.\n");
> +               goto out;
> +       }
> 
>         err = register_reboot_notifier(&it8712f_wdt_notifier);
>         if (err) {
> diff --git a/drivers/watchdog/it87_wdt.c b/drivers/watchdog/it87_wdt.c
> index b1bc72f..e3c03a9 100644
> --- a/drivers/watchdog/it87_wdt.c
> +++ b/drivers/watchdog/it87_wdt.c
> @@ -137,7 +137,6 @@
> 
>  static unsigned int base, gpact, ciract, max_units, chip_type;
>  static unsigned long wdt_status;
> -static DEFINE_SPINLOCK(spinlock);
> 
>  static int nogameport = DEFAULT_NOGAMEPORT;
>  static int exclusive  = DEFAULT_EXCLUSIVE;
> @@ -163,18 +162,27 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
> 
>  /* Superio Chip */
> 
> -static inline void superio_enter(void)
> +static inline int
> +superio_enter(void)
>  {
> +       /*
> +        * Try to reserve REG and REG + 1 for exclusive access.
> +        */
> +       if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
> +               return -EBUSY;
> +
>         outb(0x87, REG);
>         outb(0x01, REG);
>         outb(0x55, REG);
>         outb(0x55, REG);
> +       return 0;
>  }
> 
>  static inline void superio_exit(void)
>  {
>         outb(0x02, REG);
>         outb(0x02, VAL);
> +       release_region(REG, 2);
>  }
> 
>  static inline void superio_select(int ldn)
> @@ -255,12 +263,11 @@ static void wdt_keepalive(void)
>         set_bit(WDTS_KEEPALIVE, &wdt_status);
>  }
> 
> -static void wdt_start(void)
> +static int wdt_start(void)
>  {
> -       unsigned long flags;
> -
> -       spin_lock_irqsave(&spinlock, flags);
> -       superio_enter();
> +       int ret = superio_enter();
> +       if (ret)
> +               return ret;
> 
>         superio_select(GPIO);
>         if (test_bit(WDTS_USE_GP, &wdt_status))
> @@ -270,15 +277,15 @@ static void wdt_start(void)
>         wdt_update_timeout();
> 
>         superio_exit();
> -       spin_unlock_irqrestore(&spinlock, flags);
> +
> +       return 0;
>  }
> 
> -static void wdt_stop(void)
> +static int wdt_stop(void)
>  {
> -       unsigned long flags;
> -
> -       spin_lock_irqsave(&spinlock, flags);
> -       superio_enter();
> +       int ret = superio_enter();
> +       if (ret)
> +               return ret;
> 
>         superio_select(GPIO);
>         superio_outb(0x00, WDTCTRL);
> @@ -288,7 +295,7 @@ static void wdt_stop(void)
>                 superio_outb(0x00, WDTVALMSB);
> 
>         superio_exit();
> -       spin_unlock_irqrestore(&spinlock, flags);
> +       return 0;
>  }
> 
>  /**
> @@ -303,8 +310,6 @@ static void wdt_stop(void)
> 
>  static int wdt_set_timeout(int t)
>  {
> -       unsigned long flags;
> -
>         if (t < 1 || t > max_units * 60)
>                 return -EINVAL;
> 
> @@ -313,14 +318,15 @@ static int wdt_set_timeout(int t)
>         else
>                 timeout = t;
> 
> -       spin_lock_irqsave(&spinlock, flags);
>         if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
> -               superio_enter();
> +               int ret = superio_enter();
> +               if (ret)
> +                       return ret;
> +
>                 superio_select(GPIO);
>                 wdt_update_timeout();
>                 superio_exit();
>         }
> -       spin_unlock_irqrestore(&spinlock, flags);
>         return 0;
>  }
> 
> @@ -339,12 +345,12 @@ static int wdt_set_timeout(int t)
> 
>  static int wdt_get_status(int *status)
>  {
> -       unsigned long flags;
> -
>         *status = 0;
>         if (testmode) {
> -               spin_lock_irqsave(&spinlock, flags);
> -               superio_enter();
> +               int ret = superio_enter();
> +               if (ret)
> +                       return ret;
> +
>                 superio_select(GPIO);
>                 if (superio_inb(WDTCTRL) & WDT_ZERO) {
>                         superio_outb(0x00, WDTCTRL);
> @@ -353,7 +359,6 @@ static int wdt_get_status(int *status)
>                 }
> 
>                 superio_exit();
> -               spin_unlock_irqrestore(&spinlock, flags);
>         }
>         if (test_and_clear_bit(WDTS_KEEPALIVE, &wdt_status))
>                 *status |= WDIOF_KEEPALIVEPING;
> @@ -379,9 +384,17 @@ static int wdt_open(struct inode *inode, struct file *file)
>         if (exclusive && test_and_set_bit(WDTS_DEV_OPEN, &wdt_status))
>                 return -EBUSY;
>         if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
> +               int ret;
>                 if (nowayout && !test_and_set_bit(WDTS_LOCKED, &wdt_status))
>                         __module_get(THIS_MODULE);
> -               wdt_start();
> +
> +               ret = wdt_start();
> +               if (ret) {
> +                       clear_bit(WDTS_LOCKED, &wdt_status);
> +                       clear_bit(WDTS_TIMER_RUN, &wdt_status);
> +                       clear_bit(WDTS_DEV_OPEN, &wdt_status);
> +                       return ret;
> +               }
>         }
>         return nonseekable_open(inode, file);
>  }
> @@ -403,7 +416,16 @@ static int wdt_release(struct inode *inode, struct file *file)
>  {
>         if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
>                 if (test_and_clear_bit(WDTS_EXPECTED, &wdt_status)) {
> -                       wdt_stop();
> +                       int ret = wdt_stop();
> +                       if (ret) {
> +                               /*
> +                                * Stop failed. Just keep the watchdog alive
> +                                * and hope nothing bad happens.
> +                                */
> +                               set_bit(WDTS_EXPECTED, &wdt_status);
> +                               wdt_keepalive();
> +                               return ret;
> +                       }
>                         clear_bit(WDTS_TIMER_RUN, &wdt_status);
>                 } else {
>                         wdt_keepalive();
> @@ -484,7 +506,9 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
>                                     &ident, sizeof(ident)) ? -EFAULT : 0;
> 
>         case WDIOC_GETSTATUS:
> -               wdt_get_status(&status);
> +               rc = wdt_get_status(&status);
> +               if (rc)
> +                       return rc;
>                 return put_user(status, uarg.i);
> 
>         case WDIOC_GETBOOTSTATUS:
> @@ -500,14 +524,22 @@ static long wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> 
>                 switch (new_options) {
>                 case WDIOS_DISABLECARD:
> -                       if (test_bit(WDTS_TIMER_RUN, &wdt_status))
> -                               wdt_stop();
> +                       if (test_bit(WDTS_TIMER_RUN, &wdt_status)) {
> +                               rc = wdt_stop();
> +                               if (rc)
> +                                       return rc;
> +                       }
>                         clear_bit(WDTS_TIMER_RUN, &wdt_status);
>                         return 0;
> 
>                 case WDIOS_ENABLECARD:
> -                       if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status))
> -                               wdt_start();
> +                       if (!test_and_set_bit(WDTS_TIMER_RUN, &wdt_status)) {
> +                               rc = wdt_start();
> +                               if (rc) {
> +                                       clear_bit(WDTS_TIMER_RUN, &wdt_status);
> +                                       return rc;
> +                               }
> +                       }
>                         return 0;
> 
>                 default:
> @@ -560,16 +592,17 @@ static int __init it87_wdt_init(void)
>         int rc = 0;
>         int try_gameport = !nogameport;
>         u8  chip_rev;
> -       unsigned long flags;
> +       int gp_rreq_fail = 0;
> 
>         wdt_status = 0;
> 
> -       spin_lock_irqsave(&spinlock, flags);
> -       superio_enter();
> +       rc = superio_enter();
> +       if (rc)
> +               return rc;
> +
>         chip_type = superio_inw(CHIPID);
>         chip_rev  = superio_inb(CHIPREV) & 0x0f;
>         superio_exit();
> -       spin_unlock_irqrestore(&spinlock, flags);
> 
>         switch (chip_type) {
>         case IT8702_ID:
> @@ -603,8 +636,9 @@ static int __init it87_wdt_init(void)
>                 return -ENODEV;
>         }
> 
> -       spin_lock_irqsave(&spinlock, flags);
> -       superio_enter();
> +       rc = superio_enter();
> +       if (rc)
> +               return rc;
> 
>         superio_select(GPIO);
>         superio_outb(WDT_TOV1, WDTCFG);
> @@ -620,21 +654,16 @@ static int __init it87_wdt_init(void)
>                 }
>                 gpact = superio_inb(ACTREG);
>                 superio_outb(0x01, ACTREG);
> -               superio_exit();
> -               spin_unlock_irqrestore(&spinlock, flags);
>                 if (request_region(base, 1, WATCHDOG_NAME))
>                         set_bit(WDTS_USE_GP, &wdt_status);
>                 else
> -                       rc = -EIO;
> -       } else {
> -               superio_exit();
> -               spin_unlock_irqrestore(&spinlock, flags);
> +                       gp_rreq_fail = 1;
>         }
> 
>         /* If we haven't Gameport support, try to get CIR support */
>         if (!test_bit(WDTS_USE_GP, &wdt_status)) {
>                 if (!request_region(CIR_BASE, 8, WATCHDOG_NAME)) {
> -                       if (rc == -EIO)
> +                       if (gp_rreq_fail)
>                                 printk(KERN_ERR PFX
>                                         "I/O Address 0x%04x and 0x%04x"
>                                         " already in use\n", base, CIR_BASE);
> @@ -646,21 +675,16 @@ static int __init it87_wdt_init(void)
>                         goto err_out;
>                 }
>                 base = CIR_BASE;
> -               spin_lock_irqsave(&spinlock, flags);
> -               superio_enter();
> 
>                 superio_select(CIR);
>                 superio_outw(base, BASEREG);
>                 superio_outb(0x00, CIR_ILS);
>                 ciract = superio_inb(ACTREG);
>                 superio_outb(0x01, ACTREG);
> -               if (rc == -EIO) {
> +               if (gp_rreq_fail) {
>                         superio_select(GAMEPORT);
>                         superio_outb(gpact, ACTREG);
>                 }
> -
> -               superio_exit();

This is one possible solution; we'll have to see if the maintainer 
accepts it. There may be some concerns about blocking superio 
access during the calls to register_reboot_notifier() and misc_register().

> -               spin_unlock_irqrestore(&spinlock, flags);
>         }
> 
>         if (timeout < 1 || timeout > max_units * 60) {
> @@ -704,6 +728,7 @@ static int __init it87_wdt_init(void)
>                 "nogameport=%d)\n", chip_type, chip_rev, timeout,
>                 nowayout, testmode, exclusive, nogameport);
> 
> +       superio_exit();
>         return 0;
> 
>  err_out_reboot:
> @@ -711,49 +736,37 @@ err_out_reboot:
>  err_out_region:
>         release_region(base, test_bit(WDTS_USE_GP, &wdt_status) ? 1 : 8);
>         if (!test_bit(WDTS_USE_GP, &wdt_status)) {
> -               spin_lock_irqsave(&spinlock, flags);
> -               superio_enter();
>                 superio_select(CIR);
>                 superio_outb(ciract, ACTREG);
> -               superio_exit();
> -               spin_unlock_irqrestore(&spinlock, flags);
>         }
>  err_out:
>         if (try_gameport) {
> -               spin_lock_irqsave(&spinlock, flags);
> -               superio_enter();
>                 superio_select(GAMEPORT);
>                 superio_outb(gpact, ACTREG);
> -               superio_exit();
> -               spin_unlock_irqrestore(&spinlock, flags);
>         }
> 
> +       superio_exit();
>         return rc;
>  }
> 
>  static void __exit it87_wdt_exit(void)
>  {
> -       unsigned long flags;
> -       int nolock;
> -
> -       nolock = !spin_trylock_irqsave(&spinlock, flags);
> -       superio_enter();
> -       superio_select(GPIO);
> -       superio_outb(0x00, WDTCTRL);
> -       superio_outb(0x00, WDTCFG);
> -       superio_outb(0x00, WDTVALLSB);
> -       if (max_units > 255)
> -               superio_outb(0x00, WDTVALMSB);
> -       if (test_bit(WDTS_USE_GP, &wdt_status)) {
> -               superio_select(GAMEPORT);
> -               superio_outb(gpact, ACTREG);
> -       } else {
> -               superio_select(CIR);
> -               superio_outb(ciract, ACTREG);
> +       if (superio_enter() == 0) {
> +               superio_select(GPIO);
> +               superio_outb(0x00, WDTCTRL);
> +               superio_outb(0x00, WDTCFG);
> +               superio_outb(0x00, WDTVALLSB);
> +               if (max_units > 255)
> +                       superio_outb(0x00, WDTVALMSB);
> +               if (test_bit(WDTS_USE_GP, &wdt_status)) {
> +                       superio_select(GAMEPORT);
> +                       superio_outb(gpact, ACTREG);
> +               } else {
> +                       superio_select(CIR);
> +                       superio_outb(ciract, ACTREG);
> +               }
> +               superio_exit();
>         }
> -       superio_exit();
> -       if (!nolock)
> -               spin_unlock_irqrestore(&spinlock, flags);
> 
>         misc_deregister(&wdt_miscdev);
>         unregister_reboot_notifier(&wdt_notifier);

[PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Nat Gurumoorthy]

02 - Chages to hwmon it87 driver to use "request_muxed_region"
Serialize access to the hardware by using "request_muxed_region" macro defined
by Alan Cox. Call to this macro will hold off the requestor if the resource is
currently busy. "superio_enter" will return an error if call to 
"request_muxed_region" fails. Rest of the code change is to ripple an error
return from superio_enter to the top level.

Signed-off-by: Nat Gurumoorthy <natg@google.com>
---

diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 316b648..bb6405b 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -77,15 +77,13 @@ static struct platform_device *pdev;
 #define	DEVID	0x20	/* Register: Device ID */
 #define	DEVREV	0x22	/* Register: Device Revision */
 
-static inline int
-superio_inb(int reg)
+static inline int superio_inb(int reg)
 {
 	outb(reg, REG);
 	return inb(VAL);
 }
 
-static inline void
-superio_outb(int reg, int val)
+static inline void superio_outb(int reg, int val)
 {
 	outb(reg, REG);
 	outb(val, VAL);
@@ -101,27 +99,32 @@ static int superio_inw(int reg)
 	return val;
 }
 
-static inline void
-superio_select(int ldn)
+static inline void superio_select(int ldn)
 {
 	outb(DEV, REG);
 	outb(ldn, VAL);
 }
 
-static inline void
-superio_enter(void)
+static inline int superio_enter(void)
 {
+	/*
+	 * Try to reserve REG and REG + 1 for exclusive access.
+	 */
+	if (!request_muxed_region(REG, 2, DRVNAME))
+		return -EBUSY;
+
 	outb(0x87, REG);
 	outb(0x01, REG);
 	outb(0x55, REG);
 	outb(0x55, REG);
+	return 0;
 }
 
-static inline void
-superio_exit(void)
+static inline void superio_exit(void)
 {
 	outb(0x02, REG);
 	outb(0x02, VAL);
+	release_region(REG, 2);
 }
 
 /* Logical device 4 registers */
@@ -1542,11 +1545,15 @@ static const struct attribute_group it87_group_label = {
 static int __init it87_find(unsigned short *address,
 	struct it87_sio_data *sio_data)
 {
-	int err = -ENODEV;
+	int err;
 	u16 chip_type;
 	const char *board_vendor, *board_name;
 
-	superio_enter();
+	err = superio_enter();
+	if (err)
+		return err;
+
+	err = -ENODEV;
 	chip_type = force_id ? force_id : superio_inw(DEVID);
 
 	switch (chip_type) {
-- 
1.7.3.1

Re: [PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Guenter Roeck]

On Mon, May 09, 2011 at 02:45:31PM -0400, Nat Gurumoorthy wrote:
> 02 - Chages to hwmon it87 driver to use "request_muxed_region"
> Serialize access to the hardware by using "request_muxed_region" macro defined
> by Alan Cox. Call to this macro will hold off the requestor if the resource is
> currently busy. "superio_enter" will return an error if call to 
> "request_muxed_region" fails. Rest of the code change is to ripple an error
> return from superio_enter to the top level.
> 
> Signed-off-by: Nat Gurumoorthy <natg@google.com>

Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

Re: [PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Jean Delvare]

On Tue, 10 May 2011 19:53:38 -0700, Guenter Roeck wrote:
> On Mon, May 09, 2011 at 02:45:31PM -0400, Nat Gurumoorthy wrote:
> > 02 - Chages to hwmon it87 driver to use "request_muxed_region"
> > Serialize access to the hardware by using "request_muxed_region" macro defined
> > by Alan Cox. Call to this macro will hold off the requestor if the resource is
> > currently busy. "superio_enter" will return an error if call to 
> > "request_muxed_region" fails. Rest of the code change is to ripple an error
> > return from superio_enter to the top level.
> > 
> > Signed-off-by: Nat Gurumoorthy <natg@google.com>
> 
> Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

What's the merge plan for this patch set? I am under the impression
that, given the current implementation, both patches can be committed
separately, so each would go upstream through its own tree?

If this is the case, then I guess Guenter expects me to pick the it87
part in my hwmon tree? If you prefer to take it in yours, I don't mind,
I don't have any pending change to the it87 driver.

-- 
Jean Delvare

Re: [PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Guenter Roeck]

On Wed, May 11, 2011 at 03:00:44AM -0400, Jean Delvare wrote:
> On Tue, 10 May 2011 19:53:38 -0700, Guenter Roeck wrote:
> > On Mon, May 09, 2011 at 02:45:31PM -0400, Nat Gurumoorthy wrote:
> > > 02 - Chages to hwmon it87 driver to use "request_muxed_region"
> > > Serialize access to the hardware by using "request_muxed_region" macro defined
> > > by Alan Cox. Call to this macro will hold off the requestor if the resource is
> > > currently busy. "superio_enter" will return an error if call to 
> > > "request_muxed_region" fails. Rest of the code change is to ripple an error
> > > return from superio_enter to the top level.
> > > 
> > > Signed-off-by: Nat Gurumoorthy <natg@google.com>
> > 
> > Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
> 
> What's the merge plan for this patch set? I am under the impression
> that, given the current implementation, both patches can be committed
> separately, so each would go upstream through its own tree?
> 
> If this is the case, then I guess Guenter expects me to pick the it87
> part in my hwmon tree? If you prefer to take it in yours, I don't mind,
> I don't have any pending change to the it87 driver.
> 
Frankly, I have not thought about it. But you are right, we can pick it up
separately from the other patch. No preference either way, so please go ahead
and pick it up.

Thanks,
Guenter

Re: [PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Alan Cox]

> What's the merge plan for this patch set? I am under the impression
> that, given the current implementation, both patches can be committed
> separately, so each would go upstream through its own tree?

Yes - and the parallel port one I've already submitted via GregKH

Re: [PATCH v10 2/2] Use "request_muxed_region" in it87 hwmon drivers

[Jean Delvare]

On Mon,  9 May 2011 11:45:31 -0700, Nat Gurumoorthy wrote:
> 02 - Chages to hwmon it87 driver to use "request_muxed_region"
> Serialize access to the hardware by using "request_muxed_region" macro defined
> by Alan Cox. Call to this macro will hold off the requestor if the resource is
> currently busy. "superio_enter" will return an error if call to 
> "request_muxed_region" fails. Rest of the code change is to ripple an error
> return from superio_enter to the top level.
> 
> Signed-off-by: Nat Gurumoorthy <natg@google.com>
> ---
> (...)

Patch applied, thanks.

-- 
Jean Delvare