From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Sean O. Stalley" Subject: Re: [PATCH v4 0/5] PCI: Add support for PCI Enhanced Allocation "BARs" Date: Mon, 5 Oct 2015 16:05:05 -0700 Message-ID: <20151005230505.GD4821@sean.stalley.intel.com> References: <1443825476-26880-1-git-send-email-ddaney.cavm@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Yinghai Lu Cc: David Daney , Bjorn Helgaas , Linux Kernel Mailing List , "linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "Michael S. Tsirkin" , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rajat Jain , "gong.chen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org" , David Daney List-Id: linux-api@vger.kernel.org On Fri, Oct 02, 2015 at 08:16:48PM -0700, Yinghai Lu wrote: > On Fri, Oct 2, 2015 at 3:37 PM, David Daney w= rote: > > From: David Daney > > > > PCI Enhanced Allocation is a new method of allocating MMIO & IO > > resources for PCI devices & bridges. It can be used instead > > of the traditional PCI method of using BARs. > > > > EA entries are hardware-initialized to a fixed address. > > Unlike BARs, regions described by EA are cannot be moved. > > Because of this, only devices which are permanently connected to > > the PCI bus can use EA. A removable PCI card must not use EA. > > > > The Enhanced Allocation ECN is publicly available here: > > https://www.pcisig.com/specifications/conventional/ECN_Enhanced_All= ocation_23_Oct_2014_Final.pdf >=20 > Looks like the EA will support more than just fixed address later. >=20 > "Enhanced Allocation is an optional Conventional PCI Capability that > may be implemented by > Functions to indicate fixed (non reprogrammable) I/O and memory range= s > assigned to the > Function, as well as supporting new resource =E2=80=9Ctype=E2=80=9D d= efinitions and > future extensibility to also > support reprogrammable allocations." >=20 > so I would prefer to think more to make frame configurable to leave > space for that. >=20 > Bjorn, >=20 > I wonder if we need to revive the add-on resource support patchset > that i suggested couple years ago, > so we can extend it to support EA features. >=20 > URL: https://lkml.org/lkml/2012/3/19/86 >=20 > Thanks >=20 > Yinghai This might be useful for fixed resources as well. =46or some BEI values, EA allows for an arbitrary number of EA entries. =46or PF & VF resource ranges, it allows 2 ranges. (one below the 4GB boundry, and one above). I don't think the current pci_dev struct can handle that many resources= =2E -Sean