[U-Boot] [PATCH 14/28] drivers/fsl-mc: Changed MC firmware loading for new boot architecture

[Kim Phillips]

On Thu, 26 Mar 2015 18:57:02 -0500
Rivera Jose-B46482 <German.Rivera at freescale.com> wrote:

> > From: Kim Phillips [mailto:kim.phillips at freescale.com]
> > Sent: Wednesday, March 25, 2015 4:13 PM
> > 
> > On Tue, 24 Mar 2015 21:32:56 -0500
> > Stuart Yoder <b08248 at gmail.com> wrote:
> > 
> > > On a system with the MC running with caches on, u-boot took 20 seconds
> > > to boot.   The MC took about 5 seconds of that, most of that in DPL
> > > processing.
> > >
> > > We would welcome help analyzing u-boot boot time and where the time is
> > > going.   But, seriously,  saving 1 ms is not going to help at all.
> > 
> > I did a quick experiment and saved ~50ms when setting both udelays down
> > to 50, which, sure, isn't a big deal given it's out of the order of
> > 10sec, but it's something, and, like I said, development time for our
> > users can be seriously helped if MC initialization were omitted from the
> > main u-boot boot sequence, and occurred only when necessary, i.e., when
> > users want to use one of the DP net interfaces.  Most of the time when we
> > boot today, we don't use DP net interfaces, so MC init - with or without
> > DPL processing - is just a waste of our time!
> > 
> The 50ms improvement you claim will not make any difference to save time
> For development users, since 50ms is not something humans can perceive. 
> As Stuart said, we (the MC team) should first analyze where is the bulk of
> The DPL processing by the MC fw is being spent, to see how much we can
> reduce the 5 seconds spent there. That is, we should be concerned first
> about where we can save big bucks, before being concerned about where we
> can save one penny or two.

my point is that all 10 seconds of MC processing should be removed
from u-boot startup time, and moved to only when u-boot needs to use
MC-based ethernet, e.g., when a tftp command is invoked.

and, fwiw, the 50ms figure will improve as MC firmware performance
improves.

Kim