[U-Boot] Watchdog doesn't get triggered on U-Boot command line

[Wolfgang Denk]

Dear Jens,

In message <47F3F98010FF784EBEE6526EAAB078D103AC7230 at tq-mailsrv.tq-net.de> you wrote:
> 
> > Normally the console I/O routines will  trigger  the  watchdog  while
> > waiting  for characters to arrive or to be sent. Obviously you missed
> > to add such code.
> 
> On 2008-09-14 in "Re: [U-Boot] Watchdog support." you wrote to Luigi, that
> this souldn't be necessary.

I see. Indeed I wasn;t really clear about that, there. I was ignoring
the first part of the question and just replying the the second  half
("lot  of commands (copy in flash, tftp, ...)") - that's what I meant
when I wrote " the common infeastructure should work just fine."

> Why couldn't it be in the main loop of U-Boot?

Because it wouldn't work. When you are waiting  for  input,  you  are
usually  blocking  in  a getc() which waits for some status bit to be
set that will indicate that the next character was received. You will
have to trigger the watchdog in this polling loop.

> It seems, PPC uses real interrupts. Up to now I thought U-Boot doesn't
> handle interrupts at all.

U-Boot usually doesn't use them, but they are  avaiable  and  can  be
used  where  it  makes  sense. It's just that usually it doesn;t make
sense - it only adds complexity to the code without advantages, so we
tend to avoid it.

Best regards,

Wolfgang Denk

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