Subject: [PATCH V2 05/19] irqchip: crossbar: Change allocation logic by reversing search for free irqs

From: [email-masked] (Sricharan R)
Date: Fri, 13 Jun 2014 11:39:39 +0530

Hi Jason,

On Thursday 12 June 2014 06:26 PM, Jason Cooper wrote:
> On Thu, Jun 12, 2014 at 05:23:13PM +0530, Sricharan R wrote:
>> From: Nishanth Menon <[email-masked]>
>>
>> Reverse the search algorithm to ensure that address mapping and IRQ
>> allocation logics are proper. This can open up new bugs which are
>> easily fixable rather than wait till allocation logic approaches
>> the limit to find new bugs.
> 
> Could you expand on this logic some more?  What class of bugs are you
> hoping to discover more easily?
> 

class 1. address space errors -> example:
reg = <a size_b>
ti,max-irqs =  is a wrong parameter

class 2: irq-reserved list - which decides which entries in the
address space is not actually wired in

class 3: wrong list of routable-irqs.

in general allocating from max to min tends to have benefits in
ensuring the different issues that may be present in dts is easily
caught at definition time, rather than at a later point in time.

Regards,
 Sricharan