From: Arnd Bergmann <arnd@arndb.de>
To: Rameshwar Prasad Sahu <rsahu@apm.com>
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 <lho@apm.com>
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 [thread overview]
Message-ID: <2407238.x2YxDm0cd4@wuerfel> (raw)
In-Reply-To: <1421671269-19441-3-git-send-email-rsahu@apm.com>
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
next prev parent reply other threads:[~2015-01-19 13:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-19 12:41 [PATCH v3 0/3] dmaengine: APM X-Gene SoC DMA engine driver support Rameshwar Prasad Sahu
2015-01-19 12:41 ` [PATCH v3 1/3] dmaengine: Add support for APM X-Gene SoC DMA engine driver Rameshwar Prasad Sahu
[not found] ` <1421671269-19441-2-git-send-email-rsahu-qTEPVZfXA3Y@public.gmane.org>
2015-01-19 13:41 ` Arnd Bergmann
2015-01-19 12:41 ` [PATCH v3 2/3] arm64: dts: Add APM X-Gene DMA device and DMA clock DTS nodes Rameshwar Prasad Sahu
2015-01-19 13:40 ` Arnd Bergmann [this message]
[not found] ` <CAFd313wyVqsqGNdxrAzmGCCYd-RAEcrX6f4y2Gngi44OOkbx-Q@mail.gmail.com>
2015-01-19 14:45 ` Rameshwar Sahu
2015-01-19 15:17 ` Arnd Bergmann
2015-01-19 12:41 ` [PATCH v3 3/3] Documentation: dma: Add APM X-Gene SoC DMA engine driver documentation Rameshwar Prasad Sahu
2015-01-19 13:41 ` Arnd Bergmann
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