17 Mar
2009
17 Mar
'09
10:32 p.m.
On Tue, Mar 17, 2009 at 01:44:43PM -0700, SortaSBS Guy wrote:
- Does u-boot/linux make any assumptions about how particular BAT
registers are used? For example, we're not using PCI, and I was going to use those BAT registers to cover some memory-mapped peripheral I/O space (ex: icecube.c, DBAT3 and 4 are used for PCI, so I would use them instead for our I/O ranges.)
No, it's up to the individual board config.
- Do you need a separate BAT register for each memory mapped I/O
space? We have 4 chip selects, but could I arrange the chip selects to use a contiguous range and presumably cover that with a single BAT register?
Yes, if they all have the same mapping attributes. Make sure you set the guarded bit if there are any holes.
- Would I need separate BAT registers for 8-bit vs. 16-bit devices?
No.
-Scott