From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.182]) by ozlabs.org (Postfix) with ESMTP id 8912CDDE31 for ; Thu, 22 Jan 2009 05:01:00 +1100 (EST) Received: by wa-out-1112.google.com with SMTP id l24so1002779waf.9 for ; Wed, 21 Jan 2009 10:00:58 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <3725D962-7F25-4A77-8D87-9BBA0A78D406@kernel.crashing.org> References: <3725D962-7F25-4A77-8D87-9BBA0A78D406@kernel.crashing.org> Date: Wed, 21 Jan 2009 11:00:58 -0700 Message-ID: Subject: Re: Non-contiguous physical memory From: Aaron Pace To: Kumar Gala Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , > > Its possible in that Linux supports this. However the PPC32 code does not > exist and would need to be added to support non-contiguous memory ranges. > > What exact PCI-E needs do you have? Is PCI-E performance critical? Is > (are) your pci device(s) 64-bit address capable? > > I ask because depending on the answers doing straight 4G and PCI above that > range might be sufficient for your needs. > > - k > Hello, thanks for responding. The first take at this used your idea of mapping the PCI-E ranges above the 4G boundary. We have a localbus bridge device on the PCI-E bus that only supports 32-bit MMIO, but I believe we could satisfactorily work around that problem using the ATMU registers. However, one question that I had that I wasn't able to verify to my satisfaction was whether I could ioremap a 36-bit physical address when building for ppc32, as the PCI-E devices have memory ranges that need to be accessible from userspace. If that is possible, then this may be the way to go, although it would still be nice not to lose the 128 meg for the localbus & CCSR region. Thanks, -Aaron