Date: Mon, 14 Jul 2003 20:34:31 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: nate@root.org Cc: current@freebsd.org Subject: Re: newbus questions Message-ID: <20030714.203431.85413817.imp@bsdimp.com> In-Reply-To: <20030714173017.F18544@root.org> References: <20030714173017.F18544@root.org>
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In message: <20030714173017.F18544@root.org>
Nate Lawson <nate@root.org> writes:
: I'm working on ECDT support for ACPI and ran into a couple newbus-related
: questions.
:
: 1. I'm using the identify entry as a way to get called early on in the
: boot process. However, this does not happen before $PIR evaluation. How
: should I hook in a routine for pre-$PIR execution?
You cannot with newbus. discovery of $PIR happens as part of the BIOS
scans, of which pci bios is one. why do you need to do this? It
seems like a very odd question.
: 2. I need to call bus_alloc_resource() to get access to some io ports.
: However, calling BUS_READ_IVAR in the identify routine gets a bad pointer
: deref. So how do I get a handle to use for allocating the IO ports
: (first arg of bus_alloc_resource)?
You need a device and a parent device. If you do not have one, then
you must get one.
: 3. It appears bus_alloc_resource() takes a range of values. If I know the
: exact value to use, I request it via "value, value" instead of "0, ~0".
: Is this correct?
Yes. However, typically the parent bus identifies these resources,
and the child device swallows it. The child device typically has no
say in the matter. However, the foo_identify routines can set what it
thinks are the right addresses.
: The framework for this code is in ec_identify() and ec_attach() in
: sys/dev/acpica/acpi_ec.c.
This really isn't a identify routine. You must hook into other things
if you want to get access early.
Let's take a step back. What are you trying to do?
Warner
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