at91sam7s startup patch

["John Eigelaar" <john at kses dot net>]

Hi all,

Recently we had some problems during production with the startup of a batch
of at91sam7s512 and at91sam7x512 processors.

Some of these would not startup although they could be programmed through
USB and DBGU with SAM-BA. Whilst running the CPUs would
also fail to start after a soft reset. With some digging and scratching and
a bit of insight provided by a piece of Atmel sample code the problem was
traced
to the clock setup sequence in the startup code i.e. hal_platform_setup.h .

Firstly the second flash controller needed to be setup for parts that has
one.
Then it seems that the master oscillator takes far longer to settle for
these parts than any of the at91sam7 parts. 
therefore the MOSCCOUNT number, which is really only expected MOSC startup
time, had to be increased.
The final hurdle was the fact that a soft reset still caused the CPU to hang
as it seems that the internal reset line was
being released before the slow clock was stable.

This patch is my remedy for the situation.

I have added the initialization for the second EFC, I have added a wait loop
in the clock setup to check that we have a stable clock before we start
fiddling with it
and finally  I turned both the PLL_COUNT and MOSCCOUNT configurations into
CDL configurable values.

Regards
John Eigelaar

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