lkml.org 
[lkml]   [2016]   [Sep]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 0/2] Add memcpy support for tegra210-adma
From
Date

On 06/09/16 14:04, Jon Hunter wrote:
>
> On 06/09/16 13:03, Dmitry Osipenko wrote:
>> On 06.09.2016 14:33, Jon Hunter wrote:
>>>
>>> On 03/09/16 01:32, Nicolin Chen wrote:
>>>> This series of patches add memcpy support for tegra210 ADMA engine.
>>>
>>> Thanks. Any reason you choose this DMA and not the APB DMA? The APB DMA
>>> is more of a generic DMA and so for memcpy it would seem to be a good
>>> choice and it is available on all Tegras not just Tegra210.
>>>
>>
>> Just a small clarification:
>>
>> If I'm not mistaken, APB DMA is mem-to-device, while AHB DMA is mem-to-mem. So,
>> you probably meant AHB and not the APB.
>
> Description from the Tegra TRM:
>
> "The APB DMA Controller is placed between the AHB Bus and the APB Bus
> and is a master on both buses.
>
> The APB DMA Controller is used for block data transfers from a source
> location to the destination location. The source may be
> DRAM or IRAM, and the destination location could be devices placed on
> APB Bus; or vice versa."

Sorry this appears to be a completely worthless response :-(

I had made the assumption that if the DMA can transfer from APB-to-AHB
and AHB-to-APB, it could also do AHB to AHB. However, now I look closely
at the registers I see that it cannot and therefore, cannot support
memcpy at all! Ok, so ignore my comment here, as it appears only the
ADMA can support memcpy. Weird.

Jon

--
nvpublic

\
 
 \ /
  Last update: 2016-09-17 09:58    [W:0.057 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site