From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from IE1EHSOBE006.bigfish.com (outbound-dub.frontbridge.com [213.199.154.16]) by ozlabs.org (Postfix) with ESMTP id B2484DE0F3 for ; Wed, 20 May 2009 02:25:18 +1000 (EST) MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Subject: RE: Musings on PCI busses Date: Tue, 19 May 2009 09:25:09 -0700 In-Reply-To: References: From: Stephen Neuendorffer To: "Grant Likely" , "Benjamin Herrenschmidt" , "Kumar Gala" , "Josh Boyer" , "Roderick Colenbrander" , "John Linn" , "linuxppc-dev" Message-ID: <20090519162511.7454D17E8058@mail19-dub.bigfish.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > 1) Probe the host controller in an of_platform driver. This has the > advantage of simplicity. The probe routine will get automatically > called when the PCI host controller device tree node is registered > with the of_platform bus. The bus parenthood also gets reflected in > the device model and sysfs. The disadvantage is that it defers PCI > bus probing until after the of_platform bus is probed (maybe this is > okay; maybe this already happens anyway). > = > 2) Probe the host controller in an subsys_initcall(). Advantage is > PCI can be probed earlier in the init path. Disadvantages (minor) are > that it will always get called if the driver is enabled, and it needs > to manually search the device tree for PCI nodes. > = > I'm leaning towards making it an of_platform driver. Doing so also > makes it available to other powerpc processors (not just virtex) in > the case where a Xilinx FPGA is welded up to a discrete SoC and a host > controller instance is put into the FPGA. (one of those weird things > people do when they have an FPGA in their system). I agree that something is called for... The first might be slightly simpler, since it would probably transparently deal with the presence of more than one PLB->PCI bridge? Steve This email and any attachments are intended for the sole use of the named r= ecipient(s) and contain(s) confidential information that may be proprietary= , privileged or copyrighted under applicable law. If you are not the intend= ed recipient, do not read, copy, or forward this email message or any attac= hments. Delete this email message and any attachments immediately.