From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v3 2/3] arm64: dts: Add APM X-Gene DMA device and DMA clock DTS nodes Date: Mon, 19 Jan 2015 14:40:36 +0100 Message-ID: <2407238.x2YxDm0cd4@wuerfel> References: <1421671269-19441-1-git-send-email-rsahu@apm.com> <1421671269-19441-3-git-send-email-rsahu@apm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1421671269-19441-3-git-send-email-rsahu@apm.com> Sender: linux-kernel-owner@vger.kernel.org To: Rameshwar Prasad Sahu Cc: vinod.koul@intel.com, dan.j.williams@intel.com, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ddutile@redhat.com, jcm@redhat.com, patches@apm.com, Loc Ho List-Id: devicetree@vger.kernel.org On Monday 19 January 2015 18:11:08 Rameshwar Prasad Sahu wrote: > diff --git a/arch/arm64/boot/dts/apm/apm-storm.dtsi b/arch/arm64/boot/dts/apm/apm-storm.dtsi > index f1ad9c2..e20da23 100644 > --- a/arch/arm64/boot/dts/apm/apm-storm.dtsi > +++ b/arch/arm64/boot/dts/apm/apm-storm.dtsi > @@ -103,6 +103,9 @@ > #size-cells = <2>; > ranges; > > + /* DDR range is 42-bit addressing */ > + dma-ranges = <0x40 0x0 0x40 0x0 0x1ff 0xffffffff>; > + > The comment above is misleading, and the value is wrong. I assume you copied these from the AMD patch that introduced the respective property. The value should be dma-ranges = <0x40 0x0 0x40 0x0 0x200 0>; to say that any DMA to physical addresses from 0 to 0x3f.ffffffff is disallowed and dma to physical addresses from 0x40.00000000 to 0x23f.ffffffff is allowed and gets translated using an identity mapping. I also see that on Mustang, all memory is outside of this range, which is a bit suspicious, while your PCI memory space is included. It would be best to match the numbers up with your data sheet. Arnd