I'm working with a custom hardware based on Cirrus Logic EP9315 processor. As the on-chip SDRAM controller is unable to map the memory in contiguous regions, I have to use the MMU to do that.
... if you need it. Maybe one bank of memory is sufficient for the operation of U-Boot?
It is definitively sufficient for U-Boot/Linux but I think it is not for (please don't blame me) WindowsCE (brrrrr!).
- The second questions refers to memory tags. They should describe
_physical_
mapping, right? If this is correct, the bd->bi_dram fields should be
extended
Right.
in order to describe both physical and virtual regions. Does it make sense?
Why would you need virtual addresses? U-Boot does not need these for operation, and Linux will not use these anyway.
For example U-Boot should let the user to use one virtual and contiguous memory region (for this purpose I suggest to introduce something like bd->bi_dram_v). For "regular" operations, it could use the existing bd->bi_dram fields (for example to set up the memory tags for the kernel).
Regards,
llandre
DAVE Electronics System House - R&D Department web: http://www.dave-tech.it email: r&d2@dave-tech.it