[RFC PATCH 2/2] ARM: DT: kernel: DT cpu node bindings update

[Nicolas Pitre]

On Wed, 17 Apr 2013, Stephen Warren wrote:

> On 04/17/2013 03:14 AM, Mark Rutland wrote:
> > Hi Stephen,
> > 
> >>> +	- enable-method
> >>> +		Usage: required on ARM 64-bit systems, optional on ARM 32-bit
> >>> +		       systems
> >>> +		Value type: <string>
> >>> +		Definition: On ARM 64-bit systems must be "spin-table" [1].
> >>
> >> Can that be an integer instead? with dtc+cpp support, that shouldn't
> >> hurt the eyes too much any more.
> > 
> > The "enable-method" property is described as a stringlist by ePAPR, and is
> > currently in use on arm64 as such. It *must* remain a string(list) for arm64.
> > 
> > Having it as an integer for arm is only going to cause us additional work,
> > makes it impossible to share a common dt between 64bit and 32bit, and goes
> > against the standard. I think it should be a stringlist for arm.
> 
> OK, that's a great reason for this case.
> 
> I hope we don't introduce any more standards that use strings, but that
> may just be my personal preference...

I think in any standard, strings are far easier to deal with.  
Especially with config stuff which is far from being performance 
critical. Strings are much less prone to conflicts.  It is too easy to 
"extend" a standard by assigning meanings to free numerical values just 
to discover that someone else did use the same numbers for other 
meanings.

In order to avoid this issue, a central authority has to be established 
to assign numbers out while strings are fine without that most of the 
time.

Not that I advocate for everyone to go wild and create their own 
strings, but if they do it anyway this won't be a catastrophy like 
conflicting numbers are.


Nicolas