Kumar Gala wrote:
On Jul 9, 2008, at 10:17 AM, Jerry Van Baren wrote:
Kumar Gala wrote:
If the path we are trying to print doesn't exist see if it matches an aliases. We don't do anything fancy at this point, but just strip the leading '/' if it exists and see if we have an exact match to an alias. In the future we could try and prefix matching so the alias could be used as a shorter path reference. Signed-off-by: Kumar Gala galak@kernel.crashing.org
Cool and useful too. Out of curiousity, does "real" Open Firmware do this sort of thing with aliases?
I'm pretty sure it the Apple OF implementation does. However I dont remember to what extent it does from my playing around with OF on Apple HW.
Sounds like I'm going to have to preempt my kids on the olpc and see what OF does on it. :-)
One reservation I have (which may disappear if the answer to the previous question is "yes"), it automatically and silently dereferences the /aliases/X node when asked to display /X or X (but only if /X doesn't exist in the dtb). This is not an obvious behavior since X isn't real.
we could print out something about using an alias so the user knows that its happening.
Should we have a different display syntax to force the dereference of an alias X? Assuming "*" is a good choice, this would change the behavior fdt print *ethernet0 to dereference /aliases/ethernet0 and print out /soc8360@e0000000/.../enet0 (or whatever).
Lets says I have an alias for 'soc' to 'soc8360@e000000'. I want to be able to in the future do print /soc/enet0 and have that work. Introducing some new syntax would make that difficult and more ugly.
- k
Thinking out loud... we could define the syntax that a leading "*" indicates the first part of the path is a dereference of /aliases.
Assuming /aliases/soc = /soc8360@e000000 /aliases/ethernet0 = /soc8360@e0000000/.../enet0 then print *soc/enet0 and print *ethernet0 would both work and print the right thing. You *would* have to know that the first element of the path is an /aliases dereference. Your original patch did not require that piece of knowledge (but silently and automagically, which makes me nervous).
gvb