Re: [PATCH v4 1/2] ARM: socfpga: support suspend to ram

[Pavel Machek <pavel-ynQEQJNshbs@public.gmane.org>]

Hi!

> Thanks for the feedback.
> 
> Yes I agree.
> 
> One possibility is that I could add a suspend function to EDAC that
> always fails with a helpful message like "Suspend with EDAC not
> supported."  If someone wants to suspend, they'll have to take the
> EDAC out of the device tree so its probe will bomb out.  I'm not
> sure how normal it is to have suspend functions in the kernel
> that always fail, though.

"Interesting" solution, but better than config exclusion, I'd say.

> > > +	/*
> > > +	 * This code assumes that the bootloader has already
> > > +	 * properly configured the sdram controller:
> > 
> > Which bootloaders can do that? 
> 
> Whatever bootloader is configuring the sdram controller for the
> board.

Ok, so direct question: will mainline u-boot 2015.04 configure the
controller correctly?

> > > +	 * sdr.ctrlcfg.lowpwreq.selfrfshmask = 3
> > > +	 * sdr.ctrlcfg.lowpwrtiming.clkdisablecycles = 8
> > > +	 * sdr.ctrlcfg.dramtiming4.selfrfshexit = 512
> > 
> > Would it make sense to configure it in Linux?
> 
> The bootloader is responsible for configuring the sdram
> controller with parameters appropriate for whatever vendor's DDR
> is on the board, so that's where this must go.
> 
> Now I realize I should make this message more general, since it is
> true for the socfpga cyclone5 devkit, but may need to be adjusted
> for other boards.

Aha, ok, the comment really needs to be fixed.
								Pavel
-- 
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