# Re: \[PATCH 1/6\] rapidio: add common mapping APIs for RapidIO memory access

- From: Kumar Gala \<hidden\>
- Date: 2009-06-11 13:34:48 
- List: netdev
- Page: https://ratatoskr.run/netdev/2009/06/1262631
- Thread: https://ratatoskr.run/netdev/2009/05/1249321/t.md

```text

On Jun 11, 2009, at 4:47 AM, Li Yang-R58472 wrote:

>> On May 12, 2009, at 3:35 AM, Li Yang wrote:
>>
>>> Add the mapping functions used to support direct IO memory access of
>>> rapidIO.
>>>
>>> Signed-off-by: Zhang Wei <zw@zh-kernel.org>
>>> Signed-off-by: Li Yang <redacted>
>>
>> Use inbnd/outbnd instead of inb/outb which make one think of
>> byte level io accessors.
>>
>> As I look at this I don't think this is the correct API.  I
>> think we should be using the DMA mapping API to hide these
>> details.  The concept of mapping like this seems to be more a
>> function of FSL's Address translation/mapping unit (ATMU) than
>> anything specific to the RIO bus standard.
>
> This is a separate RIO block level ATMU.  Although it looks like the
> system level ATMU, system ATMU doesn't have the knowledge of rapidIO
> target device ID.  The mapping need to be dynamic, as it's easy to have
> more RIO devices than the outbound windows.

I understand that.  What I'm saying is the RIO block level ATMU is a Freescale specific detail and not part of any standard RIO bus programming model.  We have mapping APIs that we can connect to for this via the DMA API layer.

- k
```