[PATCH 1/1] ARM: OMAP2+: hwmod: Print an error message if no match exists for a hwmod class

Hi Paul,

On Thu, Aug 09, 2012 at 01:49:34, Paul Walmsley wrote:

Hi Vaibhav

On Wed, 8 Aug 2012, Bedia, Vaibhav wrote:

quoted

On Wed, Aug 08, 2012 at 19:35:50, Paul Walmsley wrote:

quoted

It doesn't seem to me that this would necessarily always be an error.  
Suppose some init code to create cpsw devices is running on an OMAP3430.  
Then a omap_hwmod_for_each_by_class() that doesn't locate anything 
wouldn't be an error, right?

Well, I think a failed lookup operation will be a bit expensive since it
iterates over the whole list of registered hwmods and hence put in the
pr_err().

If performance is a serious problem there, we can maintain a list of hwmod 
pointers inside each struct omap_hwmod_class, updated when the hwmods are 
registered.  But as far as I know, performance hasn't been an issue here 
yet.  If performance is the real motivation, I'd rather see an 
implementation of per-class lists as described above.

Ok. I'll try to do some profiling using a timer to see how much time we
spend over here. On AM335x there are 2 such lookups, one for the dma
and one for the mcbsp. I could get this done today but will get to it
tomorrow. Based on how this goes I'll try out the omap_hwmod_class list
like you suggested.

quoted

But I don't see how the SoC specific example that you pointed out
could be handled without putting in cpu_is_* checks in the registration
process itself :(

Hmm, why not?

To continue the earlier example, the init code in the platform code simply 
calls omap_hwmod_for_each_by_class(), and creates the appropriate device 
if anything was found.  If no cpsw IP blocks are present on a given SoC, 
nothing would happen.  No cpu_is_*() would be needed.

I was thinking of avoiding the lookup process itself and hence mentioned
the need for cpu checks surrounding the platform init code. The current
API does help avoid all this in an excellent manner.

Regards,
Vaibhav B.