Beginning work on BSP for i.MX RT 10xx (1052 specifically)

[Christian Mauderer]

On 09/02/2020 17:24, dufault at hda.com wrote:
> 
> 
>> On Feb 9, 2020, at 09:33 , Christian Mauderer <list at c-mauderer.de> wrote:
>>
>> Hello Peter,
>>
>> On 08/02/2020 21:16, Peter Dufault wrote:
>>> I will begin working on a BSP for the i.MX RT 10xx family.  I require support for a 1052 but will be developing on a 1064 so those two variants will have some test coverage.
>>>
>>> I plan to start my work by making this a variant of the "imx" BSP.  That currently supports the "i.MX7D Applications Processor".
>>>
>>> I think that the network support provided by the "libbsd" "if_ffec" driver will work with the ENET interface on the i.MX RT.
>>> I think that initial support will be a straight-forward collection of already working pieces.
>>>
>>> - If anyone has any warnings or "heads-up"s then let me know.
>>
>> Note that we (embedded brains) are currently working on the imx BSP too.
>> Our target is imx6ul/ull support (for some Phytec modules). I'll try to
>> clean up the patches that are already nearly ready and send them to the
>> list as soon as possible. For the ones that are not ready yet I'll try
>> to give early warnings. Would be good if you could do the same thing.
> 
> This sure is convenient.  Looking at the data sheet I see many of the same peripherals.
> - The same 10/100 ENET module;
> - The same ADC module, but apparently without the external trigger module on the imx6ul.
> etc.  It looks like the imx6  uses the same "smart DMA" as the imx7, while the imx-rt uses the "enhanced DMA" which I think is what was on the MPC5554.  Again, I'm just starting to review the manuals. 

Yes, the i.mx6ul and 7 are quite similar. I don't think that big
adaptions are necessary.

> 
>>
>>> - I haven't been working with "device trees".  These are required for the "imx" BSP.  Is this the preferred direction for a BSP?
>>
>> From my point of view it would be good to use the device tree for all
>> targets that use a device tree for Linux or FreeBSD too. Especially if
>> you want to use libbsd you can save a lot of necessary adaptions.
>>
>>> - If anyone has any suggestions for how to ultimately arrange things then let me know.  Right now, before I've gotten started, I plan to make this BSP a variant in the "imx" BSP and to try to either re-use existing "chip" library routines or add new ones.
>>
>> For the imx6 I still hope that no variant is necessary. But I planned to
>> discuss this with Sebastian.
> 
> I'm not sure if "variant" is the correct term.  I look forward to seeing what your approach is.

Yes sorry. I didn't look up the established term. From what I can tell
now, I don't think that there will be any conditional compiling
necessary. That would mean that imx6ul and imx7 can use the same BSP.
There are differences for the clocks but these are already covered by
configure variables.

> 
> Peter
> -----------------
> Peter Dufault
> HD Associates, Inc.      Software and System Engineering
> 
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