Re: [PATCH 2/3] [ARM] msm: make debugging UART (for DEBUG_LL) configurable

[Brian Swetland <swetland@google.com>]

On Mon, Jun 15, 2009 at 11:34 AM, Pavel Machek<pavel@ucw.cz> wrote:
>> > ...and those that do, have it at fixed uart, no?
>>
>> Well, I'd like to support the SoC generally, not just Dream -- it's
>> used in a bunch of different devices, and there's nothing that forces
>> you to use UART3 everywhere (I certainly have seen some 7k hardware
>> that uses UART1 as the debug serial port).
>
> Aha, ok, I guess that should go to the changelog. (Nice bonus would be
> if it was automatically/correctly set up when user selects machine
> type... Actually, how does that work if you support few boards with
> same kernel...?)

At this point a kernel for multiple boards with different DEBUG_LL
uarts doesn't work correctly -- I'm not sure this could be done
without making the debug macro code, etc, a lot messier (since it has
to write to the physical uart address in early boot and I believe that
happens before the machine type is determined, though maybe I'm
wrong).

For a shipping kernel that's just including the serial driver and not
the DEBUG_LL stuff, it doesn't have a problem (since the uart is
configured from the board file a bit later in boot).

Brian