[U-Boot] [PATCH v7] socfpga: Adding Scan Manager driver

[Michal Simek <monstr@monstr.eu>]

On 04/03/2014 11:35 AM, Pavel Machek wrote:
> Hi!
> 
>>>>>> Actually socfpga board folder includes code to support both Cyclone V
>>>>>> and Arria V soc dev kit. 
>>>>>
>>>>> ok. I expect that you are talking about 2 completely different boards
>>>>> which are here
>>>>>
>>>>> http://www.altera.com/products/devkits/altera/kit-cyclone-v-soc.html
>>>>> http://www.altera.com/products/devkits/altera/kit-arria-v-soc.html
>>>>>
>>>>> Can you use the same configuration on both of them at the same time?
>>>>> I hardly believe that everything just match.
>>>>
>>>> Actually, there's third board, called SoCrates, and yes, exactly same
>>>> configuration works on it and cyclone-v.
>>>
>>> What about Arria-V?
>>>
>>>>
>>>> So you better start believing :-).
>>>
>>> Maybe I will start to believe that Altera design all board
>>> the same like position of pins for uarts, spi, ethernet, etc.
>>>
>>
>> At least Sockit and Socrates are pretty similar in that regard.
>> Apart from the things that are not ;-)
>>
>> Take for example the DDR3 pins on the FPGA side.
>> The Sockit has DDR3-RAM, the Socrates hasn't. So, the pinsetup is different
>> for both. And when you mess that up in the prebootloader, you can't AFAIK
>> change that later.
>> The boards will boot just fine with the same barebox image, but that doesn't
>> mean, that everything is setup correctly.
> 
> That is what I meant -- you still have useful box running
> Linux. Having something useful that boots out of the box is important.
> 
> And it seems to be same(-enough) between Socrates and Arria, too.

It is more about user expectation and explanation it was sent.

1. Here Chin was referring that it is one board
http://lists.denx.de/pipermail/u-boot/2014-March/174866.html

and here you are saying that it is for all Altera's development boards.
It means it is generic board support what I was telling from the start
and this configuration just luckily fits to more boards.

2. Altera is likely designing boards in very similar way that use the same console,
same DDRs(or working with the same timing), i2c pins, spi pins, whatever.
You are just lucky that one configuration
is working for more boards but they are not 100% fit.
I expect that they use the same oscillator and when someone change it
then this default configuration just stop to work.

That's why you should at least print any message that this is
"default" or "minimum" or "fail-safe" configuration and none should
use it in final product because simple it doesn't match what they have setup
in design tool.
Or just write that this configuration is for this development board
and it also working for these development boards.

From that WARNING, everybody should be aware that they have to replace that
generated files by their custom files which fit their design.
Then it is clear that they have something what it boots but they
have something what they shouldn't use in final product.

3. Have something useful that boots can be done with less lines
than it is done right now. From my experience with Zynq you don't need
600 lines of magic setting to have something useful which boots.

4. It is just question of time when Altera release the board where
different uart or oscillator is used and you won't have something
useful what boot.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform


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