From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH V5 2/3] ARM64 LPC: Add missing range exception for special ISA Date: Fri, 18 Nov 2016 10:22:46 +0100 Message-ID: <11716372.n451O5j8Vs@wuerfel> References: <1478576829-112707-1-git-send-email-yuanzhichang@hisilicon.com> <5900275.i4NZvtxTcC@wuerfel> <20161114111111.1b753dc3@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161114111111.1b753dc3@lxorguk.ukuu.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: linux-arm-kernel@lists.infradead.org Cc: Mark Rutland , One Thousand Gnomes , catalin.marinas@arm.com, gabriele.paoloni@huawei.com, benh@kernel.crashing.org, will.deacon@arm.com, linuxarm@huawei.com, lorenzo.pieralisi@arm.com, xuwei5@hisilicon.com, linux-serial@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, minyard@acm.org, marc.zyngier@arm.com, liviu.dudau@arm.com, john.garry@huawei.com, olof@lixom.net, robh+dt@kernel.org, bhelgaas@google.com, kantyzc@163.com, zhichang.yuan02@gmail.com, linux-kernel@vger.kernel.org, "zhichang.yuan" , zourongrong@gmail.com List-Id: devicetree@vger.kernel.org On Monday, November 14, 2016 11:11:11 AM CET One Thousand Gnomes wrote: > > > It's not a safe assumption for x86 at least. There are a few systems with > > > multiple ISA busses particularly older laptops with a docking station. > > > > But do they have multiple ISA domains? There is no real harm in supporting > > it, the (small) downsides I can think of are: > > I don't believe they x86 class ones have multiple ISA domains. But as > I've said I don't know how the electronics in the older ThinkPad worked > when it used two PIIX4s with some LPC or ISA stuff on each. > > It works in DOS and unmodified Linux so I'm pretty sure there are no > additional domains. Likewise the various x86 schemes that route some bits > of ISA bus off into strange places work in DOS and don't have any > overlaps. > > yenta_socket handles PCI/PCMCIA bridging and routes a range of that flat > ISA space appropriately to the card. Right, that's what I had expected, so we still don't even need to handle multiple ISA I/O address spaces for the only known case of multiple ISA buses, though we may decide to generalize the code like that anyway. Arnd