Date: Sat, 17 Jan 2015 15:07:57 +0100 From: Svatopluk Kraus <onwahe@gmail.com> To: Ian Lepore <ian@freebsd.org> Cc: freebsd-arm@freebsd.org Subject: Re: interrupt framework Message-ID: <CAFHCsPUP%2BPh9NPh=tcKEkeY1BQ78LxskMxYNpK5rNvecMt-ORA@mail.gmail.com> In-Reply-To: <1421425502.14601.294.camel@freebsd.org> References: <CAFHCsPX5kG_v-F-cjpyMQsT_b386eok=mqWW0%2BEUb_4-_1Otnw@mail.gmail.com> <20150115192624.122066dd@bender.lan> <CAFHCsPW5q=jMsehuYro7V5g56pMXK1tENP-_ibpg0q76LLWxJQ@mail.gmail.com> <20150116120315.7f343f66@bender.lan> <CAFHCsPVn=L=kk%2BKhkUAZY%2BbChhmDC2bHR-X0k7jnacJpABhetQ@mail.gmail.com> <1421425502.14601.294.camel@freebsd.org>
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On Fri, Jan 16, 2015 at 5:25 PM, Ian Lepore <ian@freebsd.org> wrote: > On Fri, 2015-01-16 at 17:08 +0100, Svatopluk Kraus wrote: >> On Fri, Jan 16, 2015 at 1:03 PM, Andrew Turner <andrew@fubar.geek.nz> wrote: >> > On Fri, 16 Jan 2015 12:44:22 +0100 >> > Svatopluk Kraus <onwahe@gmail.com> wrote: >> > ... >> >> It's just a few things from quick look now which are different in our >> >> design. However, my intention is not read our code on behalf of you. I >> >> still think that our design is more general mainly and can serve for >> >> interrupt controllers better. >> > >> > I was asking on the differences as I'm already in the process of >> > importing the arm_intrng project branch as I need something like it on >> > arm64. It is also based on the same code from Jakub and Ian, I haven't >> > looked at changing the design, just cleaning up the code to import into >> > head. >> > >> > I would be happy to merge your code instead, along with my existing >> > cleanups, however I would need to know why I should spend time on it as >> > opposed to the current development branch. If we do decide to with your >> > change I would like to import it into the arm_intrng project branch >> > first to assist the import into head. >> > >> > Andrew >> >> >> Well, this is the main difference in our design: >> >> (1) We use one global table for all interrupt sources for framework >> needs. Each interrupt source is allocated only once and has been >> assigned to unique interrupt number from the beginning. >> > > While we don't have any existing examples of it, interrupt controllers > can actually come and go at runtime; they can be associated with hotplug > hardware. An example would be something like an i2c-based gpio extender > that can generate interrupts on its gpio pins. > > Does the single global table allow for hotplug things to be added? Even > trickier, what about when those things disappear later? I don't think > we need to support this right away, I'm just asking if supporting it > some day will be impossible or not. > > -- Ian > > Yes, we keep it in our minds. Michal reminds me of that at least once a day. ;) However, you know, we are in kernel. Interrupt framework does not support a removing of an interrupt handler (mean disappearing of handler code) without disabling of its source. The same way an interrupt controller cannot be detached without some actions done before. Svata
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