Re: [Qemu-devel] [PATCH v3 3/6] spapr_pci: encode class code including Prog IF register

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, May 05, 2015 at 02:23:53PM +0530, Nikunj A Dadhania wrote:
> Current code missed the Prog IF register. All Class Code, Subclass,
> and Prog IF registers are needed to identify the accurate device type.
> 
> For example: USB controllers use the PROG IF for denoting: USB
> FullSpeed, HighSpeed or SuperSpeed.
> 
> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>

Um.. I'm guessing the CLASS_PROG register essentially includes the
CLASS_DEVICE value?  Otherwise it looks like you're losing the
CLASS_DEVICE value.

For the benefit of those who don't remember the PCI spec from memory,
can you explain in more detail what the situation is with the several
class registers and how they overlap / interact.

> ---
>  hw/ppc/spapr_pci.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index ea1a092..8b02a3e 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -899,8 +899,7 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
>      _FDT(fdt_setprop_cell(fdt, offset, "revision-id",
>                            pci_default_read_config(dev, PCI_REVISION_ID, 1)));
>      _FDT(fdt_setprop_cell(fdt, offset, "class-code",
> -                          pci_default_read_config(dev, PCI_CLASS_DEVICE, 2)
> -                            << 8));
> +                          pci_default_read_config(dev, PCI_CLASS_PROG, 3)));
>      if (pci_default_read_config(dev, PCI_INTERRUPT_PIN, 1)) {
>          _FDT(fdt_setprop_cell(fdt, offset, "interrupts",
>                   pci_default_read_config(dev, PCI_INTERRUPT_PIN, 1)));

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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