I'm writing a kernel driver and am struggling to understand the virtual memory
mapping. Looking at Matthiew Crapet's drivers, I see in ts72xx.h that there are
two ways of specifying the same memory and io loations - virtual and physical.
It seems that all the inline functions that test for the presence of a device
use virtual memory, yet all driver resources are specified in physical memory.
Are they equivalent? Can I swap one definition for the other in a function
call? I see that all resources specify physical addresses (presumably because
they will be re-mapped with ioremap() in the driver later..)
How do I calculate the virtual address? How were the values arrived at in the
header file?
And the last question - for boards with 64m of ram, do I still need to specify
the 8M regions on the kernel boot line like this?
exec -c "mem= mem= mem= mem= ... <other options>"
will my boot fail silently if I don't?
thanks Dominic
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