Date: Fri, 16 Oct 2009 12:25:39 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: jkim@FreeBSD.org Cc: xcllnt@mac.com, freebsd-arch@FreeBSD.org Subject: Re: x86BIOS and the ISA bus and low memory in general... Message-ID: <20091016.122539.-1383511515.imp@bsdimp.com> In-Reply-To: <200910161400.00564.jkim@FreeBSD.org> References: <4890688A-D2DB-431C-ADB6-03A39A8FD10E@mac.com> <200910161346.03066.jkim@FreeBSD.org> <200910161400.00564.jkim@FreeBSD.org>
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In message: <200910161400.00564.jkim@FreeBSD.org>
Jung-uk Kim <jkim@FreeBSD.org> writes:
: On Friday 16 October 2009 01:46 pm, Jung-uk Kim wrote:
: > On Thursday 15 October 2009 04:37 pm, Marcel Moolenaar wrote:
: > > On Oct 15, 2009, at 12:45 PM, M. Warner Losh wrote:
: > > > [[ redirected to arch@ ]]
: > > >
: > > > In message: <200910151431.53236.jkim@FreeBSD.org>
: > > > Jung-uk Kim <jkim@FreeBSD.org> writes:
: > > > <snip>
: > > >
: > > > : This is actually very interesting discussion for me because
: > > > : one of
: > > >
: > > > my
: > > >
: > > > : pet projects is extending x86bios to support non-PC
: > > > : architectures. If anyone is interested, the current source
: > > > : tarball is here:
: > > > :
: > > > : http://people.freebsd.org/~jkim/x86bios-20091015.tar.bz2
: > > > :
: > > > : Especially, please see the code around #ifdef
: > > > : X86BIOS_COMPAT_ARCH. Basically, mapping I/O ports and orm(4)
: > > > : is missing. We don't have
: > > >
: > > > to
: > > >
: > > > : implement I/O ports but orm(4) vs. bus_space(9) is critical
: > > > : to make it a reality. Please consider it as a real practical
: > > > : example for orm, not just a blackhole driver. :-)
: > > >
: > > > I thought that most video cards had I/O ports as well as video
: > > > RAM that needed to be mapped... Am I crazy?
: > >
: > > It depends on the platform. On an Itanium machine I have the
: > > VGA frame buffer is at physical address 0xA0000-0xC0000.
: >
: > The address is the same, then. :-)
: >
: > > The only requirement is that you use non-cached I/O, otherwise
: > > you get a machine check. This can mean a non-identity mapping
: > > or not. It all depends...
: >
: > I couldn't find a way to manipulate memory attribute directly on
: > ia64, i.e., mem_range_attr_{get,set}() and pmap_mapdev_attr() only
: > exist on amd64 and i386. Does pmap_mapdev() set the attribute as
: > UC?
:
: It seems pmap_mapdev() on ia64 uses IA64_PHYS_TO_RR6() macro. If I
: read the source correctly, then it is gives UC mapped "view" of the
: physical address, right? If so, orm(4) can simply do
: pmap_mapdev()/pmap_unmapdev() around bus_space_read_region_1(). Am I
: right?
I don't think that's the right solution here. The pmap_mapdev stuff
should happen when the resource is activated...
Warner
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