Re: [PATCHv2] of: Add generic handling for ePAPR 1.1 fail-sss states

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On 09/08/2016 08:38 AM, Rob Herring wrote:
On Wed, Aug 31, 2016 at 4:41 PM, Tony Lindgren <tony@xxxxxxxxxxx> wrote:
[...]
It is unfortunate that Linux has adopted the practice of overloading status
to determine whether a piece of hardware exists or does not exist.  This
is extremely useful for the way we structure the .dts and .dtsi files but
should have used a new property name.  We are stuck with that choice of
using the status property for two purposes, first the state of a device,
and secondly the hardware description of existing or not existing.

I don't agree. Generally, disabled means the h/w is there, but don't
use it. There may be some cases where the hardware doesn't exist for
the convenience of having a single dts, but that's the exception.


Minor point here: when SoCs are manufactured, even though the silicon die may have a hardware block, it is completely efused out based on paper spin. in effect such a hardware block "does not exist". The number of such paper spins are not exception cases, but rather standard for SoC vendors - maintaining dts per paper spin is just too impossible to maintain (DRA7 as an example maintains a single dra7.dtsi as the root for all paper spins.. the variations if maintained as seperate dts might infact end up being larger in number than all the dts we have in arch/arm/boot/dts) - typically as an soc vendor pushes a specific SoC to multiple markets, this tends to be a norm.

--
Regards,
Nishanth Menon
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