[U-Boot] [PATCH v2 03/22] powerpc/mpc85xx: move debug tlb entry after TLB is in known state

[McClintock Matthew-B29882]

On Wed, Oct 31, 2012 at 5:43 PM, Matthew McClintock <msm at freescale.com> wrote:
> On Wed, Oct 31, 2012 at 5:08 PM, Scott Wood <scottwood at freescale.com> wrote:
>> On 10/31/2012 01:17:31 AM, Prabhakar Kushwaha wrote:
>>>
>>> On 10/31/2012 02:37 AM, Scott Wood wrote:
>>>>
>>>> On 10/30/2012 04:26:16 AM, Prabhakar Kushwaha wrote:
>>>> I'd rather not see this split this up.  This file is too much of a
>>>> complicated ifdef mess already.
>>>>
>>>> The window during which you won't be able to use breakpoints is not that
>>>> large.
>>>> There are other debugging techniques that can be used.
>>>
>>>
>>> Can you please share the other techniques. It will help us in future.
>>
>>
>> For debugging early boot hangs I usually put a branch-to-self somewhere in
>> the sequence, and use CCS to see if we're spinning there or if we went off
>> to some exception or other badness.  Then I do a binary search, moving the
>> branch to self around, to determine where things went wrong.
>
> LR can be handy to look at too to see what the calling function / branch was.

And to add more... It's even more helpful when you did not instrument
your code with a branch to self yet, since sometimes you can find out
a good starting point for placing the branch to self in the first
place.

-M