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Subject: Re: Neophyte questions about PCIe
From: Mason <slash.tmp@free.fr>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci <linux-pci@vger.kernel.org>, Rob Herring <robh@kernel.org>,
 Ard Biesheuvel <ard.biesheuvel@linaro.org>,
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 Phuong Nguyen <phuong_nguyen@sigmadesigns.com>,
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Date: Tue, 14 Mar 2017 15:00:11 +0100
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On 10/03/2017 18:49, Mason wrote:

> /* Root complex reports incorrect device class */
> static void tango_pcie_fixup_class(struct pci_dev *dev)
> {
> 	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
> }

Gen1 controller reports class/rev = 0x04800001
Gen2 controller reports class/rev = 0x06000001

#define PCI_CLASS_BRIDGE_HOST		0x0600
#define PCI_CLASS_BRIDGE_ISA		0x0601
#define PCI_CLASS_BRIDGE_EISA		0x0602
#define PCI_CLASS_BRIDGE_MC		0x0603
#define PCI_CLASS_BRIDGE_PCI		0x0604
#define PCI_CLASS_BRIDGE_PCMCIA		0x0605
#define PCI_CLASS_BRIDGE_NUBUS		0x0606
#define PCI_CLASS_BRIDGE_CARDBUS	0x0607
#define PCI_CLASS_BRIDGE_RACEWAY	0x0608
#define PCI_CLASS_BRIDGE_OTHER		0x0680

My fixup replaces 0x048000 with 0x060400.

	0x060400 != 0x060000

Which is correct:
PCI_CLASS_BRIDGE_HOST or PCI_CLASS_BRIDGE_PCI?

Naively, I would expect Host/PCI bridge to be more correct
for a root complex.

Regards.