From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from db8outboundpool.messaging.microsoft.com (mail-db8lp0189.outbound.messaging.microsoft.com [213.199.154.189]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "MSIT Machine Auth CA 2" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 4A73B2C009D for ; Fri, 31 May 2013 04:55:12 +1000 (EST) Date: Thu, 30 May 2013 13:54:59 -0500 From: Scott Wood Subject: Re: [PATCH 1/3] powerpc/mpc85xx: remove the unneeded pci init functions for corenet ds board To: Kevin Hao References: <1369137900-5748-1-git-send-email-haokexin@gmail.com> <1369137900-5748-2-git-send-email-haokexin@gmail.com> <1369781529.18630.25@snotra> <20130530102034.GB18702@pek-khao-d1.corp.ad.wrs.com> In-Reply-To: <20130530102034.GB18702@pek-khao-d1.corp.ad.wrs.com> (from haokexin@gmail.com on Thu May 30 05:20:34 2013) Message-ID: <1369940099.14679.14@snotra> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; delsp=Yes; format=Flowed Cc: linuxppc List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 05/30/2013 05:20:34 AM, Kevin Hao wrote: > On Tue, May 28, 2013 at 05:52:09PM -0500, Scott Wood wrote: > > On 05/21/2013 07:04:58 AM, Kevin Hao wrote: > > >It also seems that we don't support ISA on all the current corenet =20 > ds > > >boards. So picking a primary bus seems useless, remove that =20 > function > > >too. > > > > IIRC that was due to some bugs in the PPC PCI code in the absence of > > any primary bus. >=20 > Do you know more about these bugs? Not off the top of my head -- either search the archives or ask Ben. > > fsl_pci_assign_primary() will arbitrarily pick one > > to be primary if there's no ISA. Have the bugs been fixed? >=20 > I know there should be some reason that we put the =20 > fsl_pci_assign_primary() > here. But frankly I am not sure what bugs this workaround try to fix. =20 > For these > corenet boards picking one to be primary has no effect to the 64bit =20 > kernel. > And for 32bit kernel, the only effect of this is that isa_io_base is =20 > set to the > io virtual base of the primary bus. But the isa_io_base only make =20 > sense when > we do have a isa bus, so that we can access some well-known io ports =20 > directly > by using outx/inx. But if we don't have isa bus on the board, the =20 > value of > isa_io_base should make no sense at all. So we really don't need to =20 > pick a > fake primary bus. Of course I may miss something, correct me if I am =20 > wrong. :-) outx/inx can also be used for PCI I/O BARs. -Scott=