From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751893AbbJEXHo (ORCPT ); Mon, 5 Oct 2015 19:07:44 -0400 Received: from mga03.intel.com ([134.134.136.65]:2039 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751369AbbJEXHm (ORCPT ); Mon, 5 Oct 2015 19:07:42 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,641,1437462000"; d="scan'208";a="785222554" Date: Mon, 5 Oct 2015 16:05:05 -0700 From: "Sean O. Stalley" To: Yinghai Lu Cc: David Daney , Bjorn Helgaas , Linux Kernel Mailing List , "linux-pci@vger.kernel.org" , "Michael S. Tsirkin" , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , linux-api@vger.kernel.org, Rajat Jain , "gong.chen@linux.intel.com" , David Daney Subject: Re: [PATCH v4 0/5] PCI: Add support for PCI Enhanced Allocation "BARs" 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-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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 wrote: > > 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_Allocation_23_Oct_2014_Final.pdf > > Looks like the EA will support more than just fixed address later. > > "Enhanced Allocation is an optional Conventional PCI Capability that > may be implemented by > Functions to indicate fixed (non reprogrammable) I/O and memory ranges > assigned to the > Function, as well as supporting new resource “type” definitions and > future extensibility to also > support reprogrammable allocations." > > so I would prefer to think more to make frame configurable to leave > space for that. > > Bjorn, > > 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. > > URL: https://lkml.org/lkml/2012/3/19/86 > > Thanks > > Yinghai This might be useful for fixed resources as well. For some BEI values, EA allows for an arbitrary number of EA entries. For 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. -Sean