Re: [PATCH v3 3/5] i2c-piix4: Request base address index region once for SB800

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Sat, 2015-11-07 at 12:35 +0100, Christian Fetzer wrote:
> Request the SMBus base address index region once in piix4_probe. This
> is particularly useful when using the multiplexed adapter in SB800 as
> it avoids requesting and releasing the region on every transfer.
> 
> Signed-off-by: Christian Fetzer <fetzer.ch@gmail.com>
> ---
>  drivers/i2c/busses/i2c-piix4.c | 37 ++++++++++++++++++++++++------
> -------
>  1 file changed, 24 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-
> piix4.c
> index 0e4ae60..67ada1e 100644
> --- a/drivers/i2c/busses/i2c-piix4.c
> +++ b/drivers/i2c/busses/i2c-piix4.c
> @@ -78,6 +78,9 @@
>  /* Multi-port constants */
>  #define PIIX4_MAX_ADAPTERS 4
>  
> +/* SB800 constants */
> +#define SB800_PIIX4_SMB_IDX 0xCD6

Small letters for value?

> +
>  /* insmod parameters */
>  
>  /* If force is set to anything different from 0, we forcibly enable
> the
> @@ -125,6 +128,9 @@ static const struct dmi_system_id piix4_dmi_ibm[]
> = {
>  	{ },
>  };
>  
> +/* SB800 globals */
> +static bool piix4_smb_idx_sb800;
> +

By the way, could it be part of driver data, i.e. member of struct
i2c_piix4_adapdata?

> 
>  struct i2c_piix4_adapdata {
>  	unsigned short smba;
>  };
> @@ -232,7 +238,6 @@ static int piix4_setup_sb800(struct pci_dev
> *PIIX4_dev,
>  			     const struct pci_device_id *id, u8 aux)
>  {
>  	unsigned short piix4_smba;
> -	unsigned short smba_idx = 0xcd6;
>  	u8 smba_en_lo, smba_en_hi, smb_en, smb_en_status;
>  	u8 i2ccfg, i2ccfg_offset = 0x10;
>  
> @@ -254,16 +259,10 @@ static int piix4_setup_sb800(struct pci_dev
> *PIIX4_dev,
>  	else
>  		smb_en = (aux) ? 0x28 : 0x2c;
>  
> -	if (!request_region(smba_idx, 2, "smba_idx")) {
> -		dev_err(&PIIX4_dev->dev, "SMBus base address index
> region "
> -			"0x%x already in use!\n", smba_idx);
> -		return -EBUSY;
> -	}
> -	outb_p(smb_en, smba_idx);
> -	smba_en_lo = inb_p(smba_idx + 1);
> -	outb_p(smb_en + 1, smba_idx);
> -	smba_en_hi = inb_p(smba_idx + 1);
> -	release_region(smba_idx, 2);
> +	outb_p(smb_en, SB800_PIIX4_SMB_IDX);
> +	smba_en_lo = inb_p(SB800_PIIX4_SMB_IDX + 1);
> +	outb_p(smb_en + 1, SB800_PIIX4_SMB_IDX);
> +	smba_en_hi = inb_p(SB800_PIIX4_SMB_IDX + 1);
>  
>  	if (!smb_en) {
>  		smb_en_status = smba_en_lo & 0x10;
> @@ -621,11 +620,20 @@ static int piix4_probe(struct pci_dev *dev,
> const struct pci_device_id *id)
>  	if ((dev->vendor == PCI_VENDOR_ID_ATI &&
>  	     dev->device == PCI_DEVICE_ID_ATI_SBX00_SMBUS &&
>  	     dev->revision >= 0x40) ||
> -	    dev->vendor == PCI_VENDOR_ID_AMD)
> +	    dev->vendor == PCI_VENDOR_ID_AMD) {
> +		if (!request_region(SB800_PIIX4_SMB_IDX, 2,
> "smba_idx")) {
> +			dev_err(&dev->dev,
> +			"SMBus base address index region 0x%x
> already in use!\n",
> +			SB800_PIIX4_SMB_IDX);
> +			return -EBUSY;
> +		}
> +		piix4_smb_idx_sb800 = true;
> +
>  		/* base address location etc changed in SB800 */
>  		retval = piix4_setup_sb800(dev, id, 0);
> -	else
> +	} else {
>  		retval = piix4_setup(dev, id);
> +	}
>  
>  	/* If no main SMBus found, give up */
>  	if (retval < 0)
> @@ -692,6 +700,9 @@ static void piix4_remove(struct pci_dev *dev)
>  		piix4_adap_remove(piix4_aux_adapter, true);
>  		piix4_aux_adapter = NULL;
>  	}
> +
> +	if (piix4_smb_idx_sb800)
> +		release_region(SB800_PIIX4_SMB_IDX, 2);
>  }
>  
>  static struct pci_driver piix4_driver = {

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy