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List:       dpdk-dev
Subject:    [dpdk-dev] Access to the PCI config space
From:       stephen () networkplumber ! org (Stephen Hemminger)
Date:       2013-08-22 1:55:07
Message-ID: 20130821185507.5d6a8539 () nehalam ! linuxnetplumber ! net
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On Wed, 21 Aug 2013 18:13:21 -0700
Patrick Mahan <mahan at mahan.org> wrote:

> Has anyone contemplated providing access to the PCI config space
> (pci_read_config_[byte|word|dword]) for DPDK?  It seems simple to
> perform, some preliminary testing by me seems to indicate opening
> the /sys/bus/pci/devices/<domain:bus:loc.func>/config file, seeking
> to the correct offset and reading off the value.
> 
> It seems to be correctly returning expected values and sysfs-pci.txt
> seems to indicate that this is RW so you can set values as well.
> It would seem a natural to make the PCI support code in DPDK more
> fully capable of porting PCI drivers.
> 
> I realize that somethings should be avoid (ie. causing interrupts),
> but I know that my device needs to modify bits in both the DEVCTL
> field of the PCI config and a BAR0 register to ensure they have
> the same value.
> 
> Thoughts?
> 
> Thanks,
> 
> Patrick

I played with that and it worked, but proved be unnecessary for the
hardware we support. If your device needs it, then sure it makes sense
to be supported genericly.

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