[U-Boot] [PATCH] ns16550: allow UART address to be set dynamically

[Graeme Russ]

Hi Wolfgang,

On 15/12/12 09:26, Wolfgang Denk wrote:
> Dear Tom Rini,
> 
> In message <50CB8ED1.7020503 at ti.com> you wrote:
>>
>> The other part is, take a look at the Allwinner thread from a week or
>> so ago.  We really need to define how we want early board specific
>> data to come in because if we start saying we'll accept per-SoC
>> solutions we'll be drowning in them in short time.  We want to say
>> here's our preferred way to pass this information in.
> 
> ACK!
> 
> And we already have a well-defined way to do this, which is the device
> tree.  So any attempts to implement something different should be
> reviewed very carefully.

I'm not sure I 100% get this, but from what I understand, the SoC (or maybe
even some EEPROM on a particular board family) may contain device
enumeration data in some vendor specific format (i.e. not in a device tree
compatible format).

The way I see it, there is no way that U-Boot can dictate to SoC and board
vendors and say that data must be stored in DT format. So shouldn't U-Boot
instead implement a board/SoC specific translation layer which converts
this custom data into DT format (maybe in SPL if possible)?

But the other problem is if this data includes console specific information
(UART configuration). We are left blind until the DT functions become
available. So maybe we need some small standard interface to allow the
console to be configured early. But we need to prevent this from being
abused (i.e. being used to do all kinds of hardware setting from the raw
data and bypassing DT)

Am I understanding this right?

Regards,

Graeme