30 Sep
2010
30 Sep
'10
10:34 p.m.
On Fri, 2010-10-01 at 00:29 +0200, Andreas Färber wrote:
So how does the firmware tell the OS that a device is on a 64 bit physical address if it only knows about 32 bit wide cells?
By concatenating two 32 bit wide cells in Big Endian order, it seems. :)
This is actually all well documented in 1275 :-)
#address-cells defines the number of cells for an address for children of the node containing that property. #size-cells does the same for region "sizes". Thus, "reg" properties size is a multiple of the parent's #address-cells + #size-cells.
Then ranges properties mix the parent and child sizes to defined translations accross domains, etc...
Cheers, Ben