ath10k: calibration data through Device Tree?

[Andy Lutomirski]

On Fri, Oct 3, 2014 at 9:42 AM, Arnd Bergmann <arnd at arndb.de> wrote:
> On Friday 03 October 2014 17:25:13 Mark Rutland wrote:
>> > From a system design point, it's still horrible that you have to use
>> > DT for a device that is on a discoverable bus like PCI, but as you describe,
>> > the reality is that products are shipping that use ath10k PCI devices
>> > without this data in them.
>>
>> I'd see any DT property for this as a workaround, the use of which
>> should be discouraged.
>
> By extension though, any use of DT is really a workaround for the fact
> that embedded systems and SoCs don't use discoverable buses, and it should
> be discouraged. x86 SoCs actually get this right to a large degree by
> making on-chip devices appear as PCI devices that can be used standalone,
> although Intel's latest generation SoCs are regressing in this regard
> and you still need DT (or something like it) to describe off-chip devices
> there.
>
>> A fun question that springs to mind is can the ath10k chip be removed,
>> and if so am I able to place it into a non-DT system (whereupon I have
>> no calibration data, so it won't work)?
>
> Some can be removed, others cannot. If the chip is on a removable pcie
> mini card and doesn't have that data on the card itself, it's already
> impossible to put it into another system. I don't think we need to solve
> that case.

Do these minipcie devices have any sort of unique identifier?  If so,
one could shove the calibration data in
/lib/firmware/ath10k/caldata_[CARDID].dat and, as long as that file
followed the minipcie card around, it would work just fine.

--Andy