linux-kernel - Re: [PATCH 1/2] hwmon: f71882fg: use a muxed resource lock for the Super I/O port

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Message-ID: <4C59514A.7090401@redhat.com>
Date:	Wed, 04 Aug 2010 13:38:50 +0200
From:	Hans de Goede <hdegoede@...hat.com>
To:	Giel van Schijndel <me@...tis.eu>
CC:	Laurens Leemans <laurens@...nips.com>,
	Jonathan Cameron <jic23@....ac.uk>,
	Jean Delvare <khali@...ux-fr.org>, lm-sensors@...sensors.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] hwmon: f71882fg: use a muxed resource lock for the
 Super I/O port

Ack!

Acked-by: Hans de Goede <hdegoede@...hat.com>

On 08/01/2010 03:30 PM, Giel van Schijndel wrote:
> Sleep while acquiring a resource lock on the Super I/O port. This should
> prevent collisions from causing the hardware probe to fail with -EBUSY.
>
> Signed-off-by: Giel van Schijndel<me@...tis.eu>
> ---
>   drivers/hwmon/f71882fg.c |   32 +++++++++++++++++++-------------
>   1 files changed, 19 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c
> index 7857ed3..267cb92 100644
> --- a/drivers/hwmon/f71882fg.c
> +++ b/drivers/hwmon/f71882fg.c
> @@ -113,7 +113,7 @@ static struct platform_device *f71882fg_pdev;
>   /* Super-I/O Function prototypes */
>   static inline int superio_inb(int base, int reg);
>   static inline int superio_inw(int base, int reg);
> -static inline void superio_enter(int base);
> +static inline int superio_enter(int base);
>   static inline void superio_select(int base, int ld);
>   static inline void superio_exit(int base);
>
> @@ -883,11 +883,20 @@ static int superio_inw(int base, int reg)
>   	return val;
>   }
>
> -static inline void superio_enter(int base)
> +static inline int superio_enter(int base)
>   {
> +	/* Don't step on other drivers' I/O space by accident */
> +	if (!request_muxed_region(base, 2, DRVNAME)) {
> +		printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
> +				base);
> +		return -EBUSY;
> +	}
> +
>   	/* according to the datasheet the key must be send twice! */
>   	outb(SIO_UNLOCK_KEY, base);
>   	outb(SIO_UNLOCK_KEY, base);
> +
> +	return 0;
>   }
>
>   static inline void superio_select(int base, int ld)
> @@ -899,6 +908,7 @@ static inline void superio_select(int base, int ld)
>   static inline void superio_exit(int base)
>   {
>   	outb(SIO_LOCK_KEY, base);
> +	release_region(base, 2);
>   }
>
>   static inline int fan_from_reg(u16 reg)
> @@ -2239,21 +2249,15 @@ static int f71882fg_remove(struct platform_device *pdev)
>   static int __init f71882fg_find(int sioaddr, unsigned short *address,
>   	struct f71882fg_sio_data *sio_data)
>   {
> -	int err = -ENODEV;
>   	u16 devid;
> -
> -	/* Don't step on other drivers' I/O space by accident */
> -	if (!request_region(sioaddr, 2, DRVNAME)) {
> -		printk(KERN_ERR DRVNAME ": I/O address 0x%04x already in use\n",
> -				(int)sioaddr);
> -		return -EBUSY;
> -	}
> -
> -	superio_enter(sioaddr);
> +	int err = superio_enter(sioaddr);
> +	if (err)
> +		return err;
>
>   	devid = superio_inw(sioaddr, SIO_REG_MANID);
>   	if (devid != SIO_FINTEK_ID) {
>   		pr_debug(DRVNAME ": Not a Fintek device\n");
> +		err = -ENODEV;
>   		goto exit;
>   	}
>
> @@ -2280,6 +2284,7 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
>   	default:
>   		printk(KERN_INFO DRVNAME ": Unsupported Fintek device: %04x\n",
>   		       (unsigned int)devid);
> +		err = -ENODEV;
>   		goto exit;
>   	}
>
> @@ -2290,12 +2295,14 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
>
>   	if (!(superio_inb(sioaddr, SIO_REG_ENABLE)&  0x01)) {
>   		printk(KERN_WARNING DRVNAME ": Device not activated\n");
> +		err = -ENODEV;
>   		goto exit;
>   	}
>
>   	*address = superio_inw(sioaddr, SIO_REG_ADDR);
>   	if (*address == 0) {
>   		printk(KERN_WARNING DRVNAME ": Base address not set\n");
> +		err = -ENODEV;
>   		goto exit;
>   	}
>   	*address&= ~(REGION_LENGTH - 1);	/* Ignore 3 LSB */
> @@ -2306,7 +2313,6 @@ static int __init f71882fg_find(int sioaddr, unsigned short *address,
>   		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
>   exit:
>   	superio_exit(sioaddr);
> -	release_region(sioaddr, 2);
>   	return err;
>   }
>
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