[ECOS] 8260 driver cannot access DPRAM

[Todd Smith <todds at aztek-eng dot com>]

I am writing an HDLC driver using SCC3 on an 8250 (an 8260 variant). 
Using a build a coworker has done for the rattler card, I've started on 
a basic driver. My problem is that my code cannot access the DPRAM. 
Using the address 0x04700000 as the base of this RAM, I get a 
segmentation violation when I try to access anything there. In fact, gdb 
can't even access that memory (e.g. when I try to dump at that address). 
I know this is the same memory the serial and ethernet driver also 
access so it must be possible. Seems like some memory protection is 
going on. In an attempt to take some baby steps and get something basic 
running, I have not added my driver as a package (not sure if this makes 
a difference) but I have added an init function to the drivers table via 
the DEVTAB_ENTRY macro. The init function gets a segmentation violation 
as soon as it tries to access the cpcr register in the DPRAM.

Any help would be greatly appreciated.

--Todd




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