Date: Tue, 31 Jul 2012 20:41:01 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Artem Belevich <artemb@gmail.com> Cc: freebsd-net@freebsd.org, Venkat Duvvuru <venkatduvvuru.ml@gmail.com> Subject: Re: PCI BAR mmap Message-ID: <20120731174101.GE2676@deviant.kiev.zoral.com.ua> In-Reply-To: <CAFqOu6g%2BTypQngY6tyeFigPZahixL1QGTiwaEwABqDyMWA-3uw@mail.gmail.com> References: <CAGdae7a0xuKnFaeOTUykLcUKuCf17TTuYD_MuG4t7FKbHNoqAg@mail.gmail.com> <CAFqOu6g%2BTypQngY6tyeFigPZahixL1QGTiwaEwABqDyMWA-3uw@mail.gmail.com>
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[-- Attachment #1 --] On Tue, Jul 31, 2012 at 10:15:22AM -0700, Artem Belevich wrote: > On Tue, Jul 31, 2012 at 5:48 AM, Venkat Duvvuru > <venkatduvvuru.ml@gmail.com> wrote: > > Hi, > > How to mmap PCI BARs from userland in freebsd? > > In Linux the PCI BAR appears as a file in the sysfs file system. How can I > > access PCI BAR as a file in freebsd to mmap it? > > It's a bit of a hack, but if you are root, you can access physical > memory via /dev/mem. > > memfd = open(/dev/mem) > ptr = mmap(NULL, bar_size, PROT_READ, 0, memfd, bar_address); > > You can even use dd: > > dd if=/dev/mem bs=4k skip=<BAR_ADDRESS/4k> count=<BAR_SIZE/4k> of=bar.dump This probably only works on x86, only for memory BARs, and only if BAR is already activated. But yes, I did grabbed scanouts (i.e. screen) on Intel GPUs this way. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlAYGK0ACgkQC3+MBN1Mb4iH9ACgoTJJhSV/GWg6sFqtIoSNlWU8 7MYAoJ0M0yK2K2how1jdmkO8O16lqfbH =LpXT -----END PGP SIGNATURE-----help
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