From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: Access to the PCI config space Date: Wed, 21 Aug 2013 18:55:07 -0700 Message-ID: <20130821185507.5d6a8539@nehalam.linuxnetplumber.net> References: <521565B1.9020506@mahan.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "dev-VfR2kkLFssw@public.gmane.org" To: Patrick Mahan Return-path: In-Reply-To: <521565B1.9020506-5dHXHCkEAVbYtjvyW6yDsg@public.gmane.org> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On Wed, 21 Aug 2013 18:13:21 -0700 Patrick Mahan 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//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.