[coreboot] Boot flow flexibility changes

Aaron Durbin adurbin at chromium.org
Thu Apr 25 23:04:02 CEST 2013

On Thu, Apr 25, 2013 at 3:45 PM, Marc Jones <marcj303 at gmail.com> wrote:
> The timer scheduler for hardware init scares me a bit... but I'd like
> to see an implementation.

It's similar to the boot state callbacks. There is a free running
timer. One can say run this in 10milliseconds. In 10 milliseconds (or
after) the callback will be called. The timer callbacks would be
evaluated between boot state transitions. Stand by on the

Fwiw, the free running timer is the hard part because we aren't
talking about an interrupt but a polling method. Therefore we need to
somehow ensure the longest period between polls is not sufficiently
long (1/2 the global timer period) to not detect a roll over.

> On Thu, Apr 25, 2013 at 11:59 AM, Aaron Durbin <adurbin at chromium.org> wrote:
>> On Thu, Apr 25, 2013 at 12:52 PM, ron minnich <rminnich at gmail.com> wrote:
>>>  we really need the timer scheduler on newer platforms.
>>> Some of the platforms are so old they may not be testable.
>>> My plan is to provide timer_us for all platforms I can test, and then
>>> have only the new platforms use timer queue interface. I think we can
>>> manage this with proper configuration of makefiles.
>> OK. Let me look into it more then. I can probably have something next
>> week some time once I tease out the weird implementations of the
>> current udelay() functions. The only thing we'll have to get a handle
>> on is roll over in whatever hardware is providing a the free running
>> timer.
>> -Aaron
>> --
>> coreboot mailing list: coreboot at coreboot.org
>> http://www.coreboot.org/mailman/listinfo/coreboot
> --
> http://se-eng.com

More information about the coreboot mailing list