How to handle parameter variation across different boards but same platform

Vaibhav Hiremath hvaibhav at ti.com
Thu Jul 5 01:42:32 EDT 2012



On 7/4/2012 7:57 PM, Mark Brown wrote:
> On Wed, Jul 04, 2012 at 02:17:48PM +0000, Hebbar, Gururaja wrote:
>> On Wed, Jul 04, 2012 at 19:31:18, Mark Brown wrote:
> 
>>> If these are totally different boards they should have different machine
>>> IDs set so machine_is_() should identify.  If that isn't there then you
>>> need to do something custom to your products to identify the boards
>>> further.
> 
>> They are different boards with same SoC (AM33xx). So they both are true for
>> machine_is_am33xx().
> 

What if the device only supports Linux boot from DT, where we set
machine_desc.nr = ~0 ??

Does machine ID still gets set? May be I am missing something...

As part of my debugging, on AM335xEVM platform machine_is_am33xx()
returns false, since the value of machine_desc.nr is set to ~0.

Thanks,
Vaibhav

> That's not how this stuff is supposed to work - machine is the board,
> you should have cpu_is_() for identifying the SoC.
> 
>> We have a means to detect the type of board but in arch/arm/mach-omap2/ 
>> board file. However, I believe it is not recommended to call boards api
>> inside drivers.
> 
> Only for generic drivers, board specific drivers are obviously board
> specific.  The point is that you shouldn't make something that could run
> on many boards depend on an API specific to a particular board.
> 
> 
> 
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