Re: [PATCH v2 1/2] PCI: vmd: Add bus 224-255 restriction decode

[Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>]

On Tue, Nov 12, 2019 at 05:47:52AM -0700, Jon Derrick wrote:
> VMD bus restrictions are required when IO fabric is multiplexed such
> that VMD cannot use the entire bus range. This patch adds another bus
> restriction decode bit that can be set by firmware to restrict the VMD
> bus range to between 224-255.
> 
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> ---
>  drivers/pci/controller/vmd.c | 30 ++++++++++++++++++++++--------
>  1 file changed, 22 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index a35d3f3..15302a1 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -602,16 +602,30 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
>  
>  	/*
>  	 * Certain VMD devices may have a root port configuration option which
> -	 * limits the bus range to between 0-127 or 128-255
> +	 * limits the bus range to between 0-127, 128-255, or 224-255
>  	 */
>  	if (features & VMD_FEAT_HAS_BUS_RESTRICTIONS) {
> -		u32 vmcap, vmconfig;
> -
> -		pci_read_config_dword(vmd->dev, PCI_REG_VMCAP, &vmcap);
> -		pci_read_config_dword(vmd->dev, PCI_REG_VMCONFIG, &vmconfig);
> -		if (BUS_RESTRICT_CAP(vmcap) &&
> -		    (BUS_RESTRICT_CFG(vmconfig) == 0x1))
> -			vmd->busn_start = 128;
> +		u16 reg16;
> +
> +		pci_read_config_word(vmd->dev, PCI_REG_VMCAP, &reg16);
> +		if (BUS_RESTRICT_CAP(reg16)) {
> +			pci_read_config_word(vmd->dev, PCI_REG_VMCONFIG,
> +					     &reg16);
> +
> +			switch (BUS_RESTRICT_CFG(reg16)) {
> +			case 1:
> +				vmd->busn_start = 128;
> +				break;
> +			case 2:
> +				vmd->busn_start = 224;
> +				break;
> +			case 3:
> +				pci_err(vmd->dev, "Unknown Bus Offset Setting\n");

Technically this error+message should be present in the current kernel
as well but anyway, I have applied the series to pci/vmd.

Thanks,
Lorenzo

> +				return -ENODEV;
> +			default:
> +				break;
> +			}
> +		}
>  	}
>  
>  	res = &vmd->dev->resource[VMD_CFGBAR];
> -- 
> 1.8.3.1
>