Re: Yay! for mvme5500

[Till Straumann <strauman at slac dot stanford dot edu>]

Peter Dufault wrote:

> I did "hello world", finally, on the MVME5500 on 4.7
>
> A few "heads up", though.  Take these with a grain of salt since I'm 
> just starting out, but I think they're real problems.
>
> 1. The linkcmds in the BSP in 4.7 (and supplied for 4.6) don't seem to 
> correspond to the linkcmds used to build the "mvme5500-cexp.bin" that 
> came with the MVME5500 patches for 4.6.  That binary obviously starts 
> at 4000000, but the linkcmds put the start at 4000100.  Maybe the 
> folks at Brookhaven only use incremental linking using cexp as a boot 
> loader and haven't noticed?  Don't get me started on "incremental 
> linking considered dangerous", you should see some of the vxWorks 
> startup scripts I've seen.
>
> 2. bspstart.c is calling "initialize_exceptions()" before setting up 
> Cpu_table.  For me (and I hope this is how it should be) this results 
> in a call to mpc6xx/exceptions/raw_exception.c, and that checks 
> Cpu_table.exceptions_in_RAM as a boolean to decide what to do.  Since 
> I kept carefully zeroing out memory for repeatability before starting 
> things up, that was testing false, and nothing was working. When I saw 
> what was going on I initialized Cpu_table.exceptions_in_RAM to 1 
> before calling initialize_exceptions(), and then things started 
> working. (I assume that test is done before BSS is defined to be 
> cleared out). 

Hmm - this seems to be broken by 4.7 ? The code flow in my 4.6 BSP is 
different:

libbsp/powerpc/shared/vectors/vectors_init.c:initialize_exceptions()  
(calls)->
libcpu/powerpc/mpc6xx/exceptions/raw_exception.c:mpc60x_init_exceptions()

neither of which is using the Cpu_table...

-- Till


> A quick check of other powerpc bspstart.c's shows that they also call 
> initialize_exceptions before setting up Cpu_table, they should maybe 
> be checked for similar problems.
>
> 3. I get all my "Hello World" output, but the Motorola "MOTBoot" 
> dramatically complains when it finishes up.  I assume this is just my 
> getting started.
>
> Peter
>
> Peter Dufault
> HD Associates, Inc.