From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Wed, 8 Jun 2016 16:27:50 +0200 From: Thomas Petazzoni To: Arnd Bergmann Subject: Re: [PATCH 1/3] dt-bindings: add DT binding for the Aardvark PCIe controller Message-ID: <20160608162750.712916ce@free-electrons.com> In-Reply-To: <33469694.MLbpCUJe2G@wuerfel> References: <1464858585-10963-1-git-send-email-thomas.petazzoni@free-electrons.com> <1464858585-10963-2-git-send-email-thomas.petazzoni@free-electrons.com> <33469694.MLbpCUJe2G@wuerfel> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lior Amsalem , Andrew Lunn , Yehuda Yitschak , Jason Cooper , linux-pci@vger.kernel.org, Hanna Hawa , Nadav Haklai , Gregory Clement , Bjorn Helgaas , Marcin Wojtas , linux-arm-kernel@lists.infradead.org, Sebastian Hesselbarth Content-Type: text/plain; charset="us-ascii" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+bjorn=helgaas.com@lists.infradead.org List-ID: Hello, Thanks for your review! On Thu, 02 Jun 2016 11:35:38 +0200, Arnd Bergmann wrote: > On Thursday, June 2, 2016 11:09:43 AM CEST Thomas Petazzoni wrote: > > + ranges = <0x82000000 0 0xe8000000 0 0xe8000000 0 0x1000000 /* Port 0 MEM */ > > + 0x81000000 0 0xe9000000 0 0xe9000000 0 0x10000>; /* Port 0 IO*/ > > > > Any reason for not having a 64-bit MEM prefetchable area in the example? > Does the host not support that? I'll have to admit I am not sure how to find this out from the datasheet. My datasheet says about the PCIe controller: """ 64-bit PCIe address and system address space for outbound transactions """ So I guess this would indicate that a 64-bit MEM area is possible. However, since anyway the area used above is at 0xe8000000 for a length of 0x1000000, what would be the benefit of declaring this range as a 64-bit one ? Regarding the prefetchable aspect, I couldn't find any reference in the datasheet. However, the original driver code explicitly errors out if there is no non-prefetchable memory area, so I guess prefetchable areas is not supported. In of_bus_pci_get_flags(), both the 32-bit and 64-bit cases are handled in the same way, so is this distinction actually being used by the kernel? Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel