[ECOS] Update on Axiom CME555 Redboot FLASH Memory Problems

[Mike Pashea]

Hi All,

I have an update to report on the Axiom CME-555 Redboot crash that I posted 
about last week.

I am certain that this is the same crash that Miguel Vega reported in 
earlier posts. However, I havenÂ’t seen any follow-up postings where he 
described any permanent solution.

Newer Axiom CME-555 boards have twice as much FLASH as the older boards 
because 29LV400Â’s are used instead of the 29LV200Â’s that were used when eCOS 
was ported to the CME-555. Modifying am29xxxxx_parts.inl to add the LV400 is 
pretty straightforward, but Redboot will crash with a segmentation fault on 
startup when it tries to run load_flash_config()located in flash.c.

I found that in addition to adding the LV400 description, you also have to 
change the OR1 mask in line 89 of cme555.S:

lwi     r4, 0xfff80032

should be changed to:

lwi     r4, 0xfff00032

The new mask prevents the MPC555 memory unit from generating a fault when 
the upper half of the 29LV400 is accessed.

One stray bit can sure cause a lot of problemsÂ…

Mike Pashea

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