Flash programmer via ethernet

Great to hear everything is working now. So now you play with scripting. E.g. --

automatically attempt an NFS download and execute the download on success,

otherwise jump into flash ;-)

Some notes:

> I had originally set CFG_NIOS_TMRMS to 1 thinking I had to match the default hw.

The timer stuff can be confusing. The two most important macros are:

cfg_nios_tmrms -- number of milliseconds between each timer interrupt.

cfg_hz -- the frequency of the timer interrupt.

The two are of course redundant, but they're both defined to encourage using the

preprocessor for divide/multiply where possible.

Sine the Nios timer may be configured with/without the period registers, another

macro, cfg_nios_tmrcnt is used. If this macro is defined, the value is

written into the timer's period registers when u-boot starts, but is otherwise

never referenced. If the macro is not defined, the period registers are never

accessed, period. The intent of CFG_NIOS_TMRCNT is to allow users to slow down

the interrupt rate when the period is programmable. A 1 ms rate is (normally)

overkill in a boot monitor.

Since I have a tendency to misplace the decimal point, I use the sleep command

to do a sanity check. Try for example, "sleep 10" while looking at your watch ;-)

BTW: the timer macros are (indirectly) used by most of the network protocol

modules, and by the flash programming code.

>I guess it does not matter that I have no cache.

Correct, the cache instructions behave as NOP when no cache is configured -- so

the bogus instructions do little more than add an unnecessary delay loop when they're

left in the code.

After downloading, u-boot invalidates the region that was loaded (both data and

instruction caches) to ensure everything is coherent.