[PATCH 08/10] ARM: OMAP5: hwmod data: Create initial OMAP5 SOC hwmod data

Tony Lindgren tony at atomide.com
Tue Jan 22 13:32:14 EST 2013

* Benoit Cousson <b-cousson at ti.com> [130122 04:59]:
> Hi Tony,
> On 01/21/2013 07:01 PM, Tony Lindgren wrote:
> > * Santosh Shilimkar <santosh.shilimkar at ti.com> [130121 07:09]:
> >>>
> >> So I looked at this one with help of Rajendra. We can get rid of the
> >> IRQ and DMA data(needs DMA biding updates) easily. The address
> >> space though is needed since hwmod code uses it to setup the
> >> sysconfig registers.
> > 
> > OK great. The address space tinkering in hwmod code should be
> > moved to be done in the drivers.
> > 
> > As discussed earlier, there should be a driver specific reset
> > function driver_xyz_reset() in the driver header file so the
> > hwmod code can call it too in a late_initcall if no driver is
> > loaded.
> > 
> >> Extracting that from DT code seems to be really expensive and
> >> ugly [1]. I am yet to try out DMA lines removal but that seems
> >> to be doable by pulling Vinod'd DMA engine branch and updating
> >> DT file.
> > 
> > The overhead here does not matter as it should only happen in a
> > late_initcall and only for some of the drivers. For that to
> > happen we just need to go through the list of modules not yet
> > probed. We also need to have some locking in the driver specific
> > reset function to avoid races with the loadable modules.
> Mmm, not really, that address is used by *every* hwmod for sysconfig
> access. So iterating over every DT nodes for every hwmods seems pretty
> ugly and un-optimized.

I think you missed one point. Iterating over all the modules should
only happen for the unused modules. With sysconfig access moved to the
drivers getting the ioaddress is done in the standard way in the driver
probe instead of iterating over all of them.
> That being said, it might worth checking the overhead. That will not
> make the fix nicer anyway, but at least it will allow a smooth
> transition toward a real clean solution. Assuming someone will work on
> that later, which might never happen.

Right, so who is going to do all the work needed?



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