[PATCH 05/11] ARM: OMAP2+: hwmod code/data: fix 32K sync timer

Hiremath, Vaibhav hvaibhav at ti.com
Fri Jun 8 15:10:47 EDT 2012


On Fri, Jun 08, 2012 at 01:33:46, Paul Walmsley wrote:
> Hi
> 
> On Thu, 7 Jun 2012, Hiremath, Vaibhav wrote:
> 
> > I couldn't finish my testing today, got into continuous meetings.
> 
> No worries, I understand.
> 
> > Tomorrow, I will test it and update you on this.
> 
> That would be great.
> 
> I took a look at SPRUH73F and sure enough, at least one module (CONTROL) 
> doesn't support smart-idle -- per Table 14-217 "CONTROL Register Field 
> Descriptions".  I'd guess that the PRCM won't idle-req this IP block until 
> the kernel is not running, so we might be able to get away with the 
> existing approach; but the TRM also says:
> 
> "By definition, initiator may generate read/write transaction as long as
> it is out of IDLE state."
> 
> Which pretty much matches my understanding too of the implicit interface 
> contract here.
> 
> So I think we'd better go back to the flag approach as implemented in this 
> patch:
> 
> http://www.spinics.net/lists/arm-kernel/msg176836.html
> 
> The WBU 32k sync timer's behavior is what relies on quirks of the 
> integration that are hard to identify via other means, so it seems to be 
> safest to tag it explicitly.
> 

Paul,

I tested it on AM335x platform just now, it booted up to the Linux prompt, 
but I am sure it is going to impact low power state usecases on AM33xx.

So, I also feel that, flag based approach should be used here. 

Thanks,
Vaibhav




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