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SubjectRe: [PATCH v2 1/9] arm: mvebu: Limit the DMA zone when LPAE is selected
On 04/05/2013 10:41 PM, Arnd Bergmann wrote:
> On Friday 05 April 2013, Gregory CLEMENT wrote:
>> When LPAE is activated on Armada XP, all registers and IOs are still
>> 32bit, the 40bit extension is on the CPU to DRAM path (windows) only.
>> That means that all the DMA transfer are restricted to the low 32 bits
>> address space. This is limitation is achieved by selecting ZONE_DMA.
>>
>> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
>
>
> Shouldn't that be ZONE_DMA32?
>

Well common code for ARM don't manage the ZONE_DMA32. Whereas with
ZONE_DMA, setup_dma_zone() in arch/arm/mm/init.c does exactly what
I want: setting arm_dma_limit to 0xffffffff.

ZONE_DMA32 is used on arm64 however.

> Arnd
>


--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com


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