David, On 12/14/2011 08:32 PM, David Daney wrote: > From: David Daney <david.daney@xxxxxxxxxx> > > Back in early Nov. I send the first version of this patch set. Now > things are heating up again in the world of irq_domain, so I wanted to > try to get some closure on the issues I had. The Octeon patch is > included here to show how I am using irq_domain, but is part of a much > larger effort to merge Octeon device tree support. > > The basic problem I am attempting to solve is using irq domains when > there is a 'non-linear' mapping of hwirq <--> irq within a domain. > Octeon has a single set of irq numbers that is used across two > different implementations of the interrupt controller as well as more > than 10 different SOCs all which use different subsets of the irq > number space. The result is that the hwirq to irq mapping function > contains many gaps and discontinuities, it is really quite random. > > The existing irq domain infrastructure assumes a continuous linear > mapping of hwirq to irq that can be encapsulated by the irq_base, > hwirq_base and nr_irq elements of struct irq_domain. This is not > suitable for the Octeon implementation. > > The gist of my change is to add an optional iterator function to > irq_domain_ops which knows how to iterate over the irq numbers in a > given domain. For simple linear domains (those currently supported), > we iterate using the current method based on irq_base, hwirq_base and > nr_irq. > > Summary of the patches: > > 1) Get rid of some unused code to make subsequent changes simpler. > > 2) Cleanup the data type used by various hwirq functions and users. > > 3) Add the irq iterator, and fix up the ARM GIC code to use it instead > of the current irq_domain_for_each_irq(). > > 4) Add the Octeon users of the interface. > > In an earlier exchange, Rob Herring had said: > > ... Handling sparse irqs is a potentially common problem, so we > should address that in the core irqdomain code. > > Which is what this patch set is doing. > > There was a suggestion that perhaps having .to_irq() return a magic > value if there was no mapping would also work. However I prefer this > approach as it separates the concepts of iteration and mapping of irq > numbers. > > Please comment. Can we first have a patch that just allows irq domains to be enabled on MIPS. It collides because of multiple versions of irq_create_of_mapping. Rob
