Linux and multy domain PCIe.

DISCUSSION fpaolo63 2 participants 4 messages Oct 31, 2012 1 message not in the archive PCI

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fpaolo63

author

2012-10-31 10:12 UTC #0 lore raw

Hi guru,

I'm working on a multi socket intel xeon platform.

We have 2 sockets and each socket has a PCIe RootComplex, and we'd to implement hw with 2 separated PCIe tree.

Can Linux kernel handle the 2 RC assigning a PCIe domain each one?

Do we need special BIOS in order to configure correctly the 2 sockets, QDPI channel, MMIO and MMU?

Can some one point me to one example or documents?

thanks in advanced

Paolo

Bjorn Helgaas

maintainer

2012-10-31 12:23 UTC #1 lore raw

Quoted 7 lines · On Wed, Oct 31, 2012 at 4:02 AM, fpaolo63 <[email protected]> wrote:

Hi guru,
I'm working on a multi socket intel xeon platform.
We have 2 sockets and each socket has a PCIe RootComplex, and we'd to implement hw with 2 separated PCIe tree.

Quoted 6 lines

Can Linux kernel handle the 2 RC assigning a PCIe domain each one?
Do we need special BIOS in order to configure correctly the 2 sockets, QDPI channel, MMIO and MMU?
Can some one point me to one example or documents?

Yes, Linux supports multiple PCI domains (also known as PCI segment groups).

On x86, the BIOS should provide a ACPI PNP0A08/PNP0A03 device for each root complex. See drivers/acpi/pci_root.c for details.

A message that is not in the archive (sent off-list or not yet received): CABZ6j6qH5q=txhAv4CntXpT3d4mzTapSdavz-8vsLw4Kism0QQ@mail.gmail.com

paolo faverio

author

2012-10-31 14:28 UTC #3 lore raw

resend to list

---------- Forwarded message ----------
From: paolo faverio <[email protected]>
Date: Wed, Oct 31, 2012 at 3:21 PM
Subject: Re: Linux and multy domain PCIe.
To: Bjorn Helgaas <[email protected]>
Cc: [email protected]

Thanks Bjorn,
I'm going to dig on it.

one silly question
Enabling both the RC, do l have 255 pci bus ids for each PCI segment group?

thanks
paolo

Quoted 22 lines · Bjorn Helgaas

Quoted 7 lines · On Wed, Oct 31, 2012 at 4:02 AM, fpaolo63 <[email protected]> wrote:
Hi guru,
I'm working on a multi socket intel xeon platform.
We have 2 sockets and each socket has a PCIe RootComplex, and we'd to implement hw with 2 separated PCIe tree.
Quoted 7 lines
Can Linux kernel handle the 2 RC assigning a PCIe domain each one?
Do we need special BIOS in order to configure correctly the 2 sockets, QDPI
channel, MMIO and MMU?
Can some one point me to one example or documents?
Yes, Linux supports multiple PCI domains (also known as PCI segment groups).
On x86, the BIOS should provide a ACPI PNP0A08/PNP0A03 device for each root complex. See drivers/acpi/pci_root.c for details.

Bjorn Helgaas

maintainer

2012-10-31 15:33 UTC #4 lore raw

In reply to a message not in the archive

Quoted 6 lines · paolo faverio

Thanks Bjorn,
I'm going to dig on it.
one silly question
Enabling both the RC, do l have 255 pci bus ids for each PCI segment group?

Yes. 256, actually (0x00-0xff).

Quoted 25 lines · Bjorn Helgaas

Quoted 22 lines · On Wed, Oct 31, 2012 at 4:02 AM, fpaolo63 <[email protected]> wrote:
Quoted 7 lines
Hi guru,
I'm working on a multi socket intel xeon platform.
We have 2 sockets and each socket has a PCIe RootComplex, and we'd to implement hw with 2 separated PCIe tree.
Quoted 7 lines
Can Linux kernel handle the 2 RC assigning a PCIe domain each one?
Do we need special BIOS in order to configure correctly the 2 sockets, QDPI
channel, MMIO and MMU?
Can some one point me to one example or documents?
Yes, Linux supports multiple PCI domains (also known as PCI segment groups).
On x86, the BIOS should provide a ACPI PNP0A08/PNP0A03 device for each root complex. See drivers/acpi/pci_root.c for details.