AW: Re: __setup_cpu_be problem

[Geoff Levand]

Benjamin Herrenschmidt wrote:
>> [/me is sing webmail from some distant location in .nz, sorry if
>>  the mail gets messed up]
>> 
>> Doing it in the firmware sounds like the right solution to me.
>> I would however not want to do that if the current firmware
>> sets the wrong page sizes.


Then we should consider support to change page sizes a firmware
bug work-around.


>> I know that Hartmut wanted me to provide him with the right device
>> tree information that he needs to create to say that the page
>> size are 16M, 64k and 4k. Maybe we can find a combined solution
>> for these problems. Using __setup_cpu_power4 should be ok.
> 
> I don't completely understand your statement ... sorry
> 
>> We could probably do a fallback in the cell setup to see if
>> the properties are in the device tree and do our own HID6 
>> setup stuff if not, normally expecting that the firmware settings
>> match the device tree.
> 
> We should not touch HID6 at all ... we should assume the firmware set it
> appropriately and have setup matching page size entries in the
> device-tree. I don't think we need to support changing that value
> especially since the kernel doesn't quite support 1M large page sizes
> anyway.


This seems reasonable.  In the general case we shouldn't change the
sizes.


>> Ben, could you point Hartmut (and maybe Geoff) to the documentation
>> for how the device tree needs to look like?
> 
> I'm not sure we published that yet :) I would suggest looking at what
> the kernel does to parse these instead in hash_utils.c until I get a
> former IBM approval for the spec to be published


It seems we can work with the info in hash_utils_64.c, but it would be
good to get the documentation.


-Geoff