Messages in this thread | | | From | Grant Likely <> | Date | Sat, 16 Jun 2012 00:16:32 -0600 | Subject | Re: [PATCH 08/12] irqdomain: Replace LEGACY mapping with LINEAR |
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On Sat, Jun 16, 2012 at 12:01 AM, Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote: > On Fri, 2012-06-15 at 23:01 -0600, Grant Likely wrote: >> The LEGACY mapping unnecessarily complicates the irqdomain code and >> can easily be implemented with a linear mapping. By ripping it out >> and replacing it with the LINEAR mapping the object size of >> irqdomain.c shrinks by about 330 bytes (ARMv7) which offsets the >> additional allocation required by the linear map. It also makes it >> possible for current LEGACY map users to pre-allocate irq_descs for a >> subset of the hwirqs and dynamically allocate the rest as needed. > > The point of legacy was to reserve 0...15, they could only be handed out > to that controller, that guarantees that ancient crap x86 drivers with > hard coded irq numbers would fail ... unless you have an x86-style > chipset (PReP, some CHRP, ...). > > I'd like to keep that functionality a way or another.
The functionality is still entirely there; it's just implemented with a linear map that gets populated with mappings to reserved irqs. Everything *should* keep working correctly.
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