RE: Successful master window access
From: Heater, Daniel (GE Infrastructure) <hidden>
Date: 2004-06-02 14:38:26
Sorry I didn't respond to your earlier post. This was a holiday weekend in the US, and I've been trying to catch up. To answer your earlier question:
Did VMIC run into similar problems when trying to run the driver module on the VMIVME7050 (750FX/GX IBM PowerPC board)? Because it is not yet in the list of supported boards?
We have not done that port yet, but I'm sure the same problem exists.
While vme_dma_read() and vme_dma_write() worked already, even on the PowerPC, vme_peek() and vme_poke() (both based on PCI master windows) did not work. Today I successfully made accesses using that functions with my modified module, giving me the desired results: 1st test: MVME2100 (PPC) master - MVME162 (68k) slave vme_dma_read -A <VME address @ slave board> -d VME_D32 vme_peek -A <VME address @ slave board> -d VME_D32 Produced the same result for both accesses. 2nd test: MVME2100 (PPC) master - MVME162 (68k) slave vme_dma_write -A <VME address @ slave board> -d VME_D32 0xDEADFACE vme_peek -A <VME address @ slave board> -d VME_D32 Produced the written value on reading. It seems, though I have to verify 1st, doing two things did the trick: 1.) Acquiring the PCI Window address range from the PCI bus address range of the bridge's PCI bus. 2.) Writing a help function that converts the physical address to a PCI bus address (doing nothing for x86, and on PPC doing a conversion). Only this address may be used when writing to the Universe window registers. It seems this may be a solution that should work for both platforms. Somehow I'm very excited and happy! :)
Very cool.
I will go clean up that code, test it more thoroughly (with tracers enabled), focus on slave windows afterwards, and maybe even get to test it on a VMIVME7698 - to verify it is still correct on Intel. When I got something more substantial than the current hack, I'll submit it to you, of course.
Fantastic, you're a good guy! ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/