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

["Derrick, Jonathan" <jonathan.derrick@intel.com>]

On Wed, 2019-11-20 at 16:47 +0000, Lorenzo Pieralisi wrote:
> 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@intel.com>
> > ---
> >  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.
Agreed. It was an ambiguous definition in a previous spec.


> 
> Thanks,
> Lorenzo
Thank you


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