Re: [PATCH 2/2] rt2x00: Fix BUG on rt2800usb when trying to read eFuse EEPROM.

[Ivo van Doorn <ivdoorn@xxxxxxxxx>]

On Saturday 14 November 2009, Gertjan van Wingerde wrote:
> Current tree hits a BUG_ON in rt2x00_regbusy_read, because the eFuse EEPROM
> reading code of rt2800lib uses the function without the csr_mutex locked.
> 
> Fix this by locking the csr_mutex for the of the EEPROM reading cycly and
> using the _lock variants of the register reading and writing functions.
> 
> This also introcudes the register_read_lock function pointer in the
> rt2800_ops structure.
> 
> Signed-off-by: Gertjan van Wingerde <gwingerde@xxxxxxxxx>

Acked-by: Ivo van Doorn <IvDoorn@xxxxxxxxx>

> ---
>  drivers/net/wireless/rt2x00/rt2800lib.c |   24 ++++++++++++++----------
>  drivers/net/wireless/rt2x00/rt2800lib.h |   11 +++++++++++
>  drivers/net/wireless/rt2x00/rt2800pci.c |    1 +
>  drivers/net/wireless/rt2x00/rt2800usb.c |    1 +
>  4 files changed, 27 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
> index c710805..621dac1 100644
> --- a/drivers/net/wireless/rt2x00/rt2800lib.c
> +++ b/drivers/net/wireless/rt2x00/rt2800lib.c
> @@ -1684,24 +1684,28 @@ static void rt2800_efuse_read(struct rt2x00_dev *rt2x00dev, unsigned int i)
>  {
>  	u32 reg;
>  
> -	rt2800_register_read(rt2x00dev, EFUSE_CTRL, &reg);
> +	mutex_lock(&rt2x00dev->csr_mutex);
> +
> +	rt2800_register_read_lock(rt2x00dev, EFUSE_CTRL, &reg);
>  	rt2x00_set_field32(&reg, EFUSE_CTRL_ADDRESS_IN, i);
>  	rt2x00_set_field32(&reg, EFUSE_CTRL_MODE, 0);
>  	rt2x00_set_field32(&reg, EFUSE_CTRL_KICK, 1);
> -	rt2800_register_write(rt2x00dev, EFUSE_CTRL, reg);
> +	rt2800_register_write_lock(rt2x00dev, EFUSE_CTRL, reg);
>  
>  	/* Wait until the EEPROM has been loaded */
>  	rt2800_regbusy_read(rt2x00dev, EFUSE_CTRL, EFUSE_CTRL_KICK, &reg);
>  
>  	/* Apparently the data is read from end to start */
> -	rt2800_register_read(rt2x00dev, EFUSE_DATA3,
> -				(u32 *)&rt2x00dev->eeprom[i]);
> -	rt2800_register_read(rt2x00dev, EFUSE_DATA2,
> -				(u32 *)&rt2x00dev->eeprom[i + 2]);
> -	rt2800_register_read(rt2x00dev, EFUSE_DATA1,
> -				(u32 *)&rt2x00dev->eeprom[i + 4]);
> -	rt2800_register_read(rt2x00dev, EFUSE_DATA0,
> -				(u32 *)&rt2x00dev->eeprom[i + 6]);
> +	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA3,
> +					(u32 *)&rt2x00dev->eeprom[i]);
> +	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA2,
> +					(u32 *)&rt2x00dev->eeprom[i + 2]);
> +	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA1,
> +					(u32 *)&rt2x00dev->eeprom[i + 4]);
> +	rt2800_register_read_lock(rt2x00dev, EFUSE_DATA0,
> +					(u32 *)&rt2x00dev->eeprom[i + 6]);
> +
> +	mutex_unlock(&rt2x00dev->csr_mutex);
>  }
>  
>  void rt2800_read_eeprom_efuse(struct rt2x00_dev *rt2x00dev)
> diff --git a/drivers/net/wireless/rt2x00/rt2800lib.h b/drivers/net/wireless/rt2x00/rt2800lib.h
> index 7c79011..535ce22 100644
> --- a/drivers/net/wireless/rt2x00/rt2800lib.h
> +++ b/drivers/net/wireless/rt2x00/rt2800lib.h
> @@ -23,6 +23,8 @@
>  struct rt2800_ops {
>  	void (*register_read)(struct rt2x00_dev *rt2x00dev,
>  			      const unsigned int offset, u32 *value);
> +	void (*register_read_lock)(struct rt2x00_dev *rt2x00dev,
> +				   const unsigned int offset, u32 *value);
>  	void (*register_write)(struct rt2x00_dev *rt2x00dev,
>  			       const unsigned int offset, u32 value);
>  	void (*register_write_lock)(struct rt2x00_dev *rt2x00dev,
> @@ -49,6 +51,15 @@ static inline void rt2800_register_read(struct rt2x00_dev *rt2x00dev,
>  	rt2800ops->register_read(rt2x00dev, offset, value);
>  }
>  
> +static inline void rt2800_register_read_lock(struct rt2x00_dev *rt2x00dev,
> +					     const unsigned int offset,
> +					     u32 *value)
> +{
> +	const struct rt2800_ops *rt2800ops = rt2x00dev->priv;
> +
> +	rt2800ops->register_read_lock(rt2x00dev, offset, value);
> +}
> +
>  static inline void rt2800_register_write(struct rt2x00_dev *rt2x00dev,
>  					 const unsigned int offset,
>  					 u32 value)
> diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
> index 46750f6..bb65ffa 100644
> --- a/drivers/net/wireless/rt2x00/rt2800pci.c
> +++ b/drivers/net/wireless/rt2x00/rt2800pci.c
> @@ -1058,6 +1058,7 @@ static int rt2800pci_validate_eeprom(struct rt2x00_dev *rt2x00dev)
>  
>  static const struct rt2800_ops rt2800pci_rt2800_ops = {
>  	.register_read		= rt2x00pci_register_read,
> +	.register_read_lock	= rt2x00pci_register_read, /* same for PCI */
>  	.register_write		= rt2x00pci_register_write,
>  	.register_write_lock	= rt2x00pci_register_write, /* same for PCI */
>  
> diff --git a/drivers/net/wireless/rt2x00/rt2800usb.c b/drivers/net/wireless/rt2x00/rt2800usb.c
> index b57999b..b1d6393 100644
> --- a/drivers/net/wireless/rt2x00/rt2800usb.c
> +++ b/drivers/net/wireless/rt2x00/rt2800usb.c
> @@ -682,6 +682,7 @@ static int rt2800usb_validate_eeprom(struct rt2x00_dev *rt2x00dev)
>  
>  static const struct rt2800_ops rt2800usb_rt2800_ops = {
>  	.register_read		= rt2x00usb_register_read,
> +	.register_read_lock	= rt2x00usb_register_read_lock,
>  	.register_write		= rt2x00usb_register_write,
>  	.register_write_lock	= rt2x00usb_register_write_lock,
>  


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