Date: Mon, 09 Jun 2003 08:11:41 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: cd_freebsd <cd_freebsd@gatorzone.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Mapping Physical Memory without a Device? Message-ID: <XFMail.20030609081141.jhb@FreeBSD.org> In-Reply-To: <200306090752.AA157221012@gatorzone.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On 09-Jun-2003 cd_freebsd wrote: > jmallett@freebsd.org writes > >>> You may also want to consider pmap_map. It depends on what your >>requirements are? > > while Bruce M Simpson [bms@spc.org] writes > >>>It's quite evil and not machine independent..avoid. > > -Who is right? (I like Juli's answer and she has FreeBSD.org in her name :) ) > -Why is pmap_mapdev bad? > -What makes it machine dependent? > -What is the difference between pmap_devmap and pmap_map? > > My requirements would be to map some or all of the following memory areas that are not associated > with any device I own: > 1) BIOS & UMB ram (0xC0000-0xFFFFF) > 2) VGA Video buffer (0xA0000-0xBFFFF) The first 1 meg of memory is 1:1 mapped at KERNBASE. IOW, you can get to the BIOS at KERNBASE + 0xc0000. That should cover these first two items. > 3) Video Frame buffer (0x????0000-0x????0000) Since this is not real RAM but device memory, pmap_mapdev() is ok for this. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?XFMail.20030609081141.jhb>