Date: Mon, 5 Jan 2015 12:31:47 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Warner Losh <imp@bsdimp.com> Cc: Warner Losh <imp@freebsd.org>, Ian Lepore <ian@freebsd.org>, John Baldwin <jhb@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org> Subject: Re: interrupt muxes, bus memory space and other fun amusing things Message-ID: <CAJ-VmokGtqFZ=sDUgetwEdoGagR7hz1Rfys_ph%2BnbtdRuFsBNQ@mail.gmail.com> In-Reply-To: <5F7CBB50-6C91-49C9-BF69-301496DDE792@bsdimp.com> References: <CAJ-Vmo=LqZ6Z9oYU5Usv4rHY4AffZPy4QBqwN4onr2STq5OfMg@mail.gmail.com> <5F7CBB50-6C91-49C9-BF69-301496DDE792@bsdimp.com>
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On 5 January 2015 at 08:41, Warner Losh <imp@bsdimp.com> wrote: > >> So if I were Linux, I'd just implement a mux that pretends to trigger >> interrupts in a much bigger IRQ space. Ie, they map IP0..IP7 to >> irq0..7, then they pick another IRQ range for the AHB interrupts, and >> another IRQ range for the IP2/IP3 interrupt mux. They have a >> hard-coded mux that takes care of triggering the software IRQ based on >> the hardware interrupt and mux register contents. >> >> So, how should I approach this? > > Same way. You=E2=80=99d create an interrupt device that registers an inte= rrupt > for the mux, then farms it out based on the contents of the registers. > The MIPS interrupt handler might need some work (arm did) to > allow this to happen, but it isn=E2=80=99t super difficult (though IIRc i= t is tedious). Ok. So I can do that, but then devices hang off of which bus? nexus0? Or this mux? Can I create a mux bus to hang things off of that just pass all the memory region requests up to the parent bus (nexus in this case) ? -adrian
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