Re: [PATCH 02/14] irqchip: irq-pic32-evic: Add support for PIC32 interrupt controller

From: Marc Zyngier
Date: Sun Nov 22 2015 - 06:46:24 EST


On Fri, 20 Nov 2015 17:17:14 -0700
Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx> wrote:

Joshua, Cristian,

> From: Cristian Birsan <cristian.birsan@xxxxxxxxxxxxx>
>
> This adds support for the EVIC present on a PIC32MZDA.
>
> The following features are supported:
> - DT properties for EVIC and for devices that use interrupt lines
> - persistent and non-persistent interrupt handling
> - Priority, sub-priority and polariy settings for each interrupt line
> - irqdomain support
>

I haven't reviewed the code yet, but the fact that you allow (and
actually request) the interrupt priorities to be encoded in the DT
raises some concerns:

- Aren't priorities entirely under software control (and hence don't
belong in DT)?
- More crucially, how do you deal with nested interrupts when you have
interrupts running at different priorities? Most parts of Linux
cannot cope with that without additional support.

Thanks,

M.
--
Jazz is not dead. It just smells funny.
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