Date: Tue, 22 Mar 2011 20:58:01 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Matthew Fleming <mdf356@gmail.com> Cc: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Re: DMA controller on Northbridge? Message-ID: <20110322185801.GW78089@deviant.kiev.zoral.com.ua> In-Reply-To: <AANLkTikEg77e3t0K4K%2Bbs75O8N9jusPidRk=Erbcoxpu@mail.gmail.com> References: <AANLkTinjmMtF=qrNCXJ84Wir0AYErtCdZ5LeLFOPJeFg@mail.gmail.com> <20110322181219.GU78089@deviant.kiev.zoral.com.ua> <AANLkTikEg77e3t0K4K%2Bbs75O8N9jusPidRk=Erbcoxpu@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--eOOSeChkSGCyDSuc Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 22, 2011 at 11:55:59AM -0700, Matthew Fleming wrote: > On Tue, Mar 22, 2011 at 11:12 AM, Kostik Belousov <kostikbel@gmail.com> w= rote: > > On Tue, Mar 22, 2011 at 10:11:04AM -0700, Matthew Fleming wrote: > >> How can I tell if the Northbridge on a machine has a built-in DMA > >> controller? =9AAnd if it does, what device would I use to control it? > >> > >> I ask because I'm working with a PCI card that has a 36-bit physical > >> address limit, and that means bounce buffers when using more than 64GB > >> of memory. =9AI'd prefer not to use bounce buffers, and since the card= 's > >> memory that I'm using is mapped into the physical space of the FreeBSD > >> host, the entire address space of the card that I care about is > >> available to FreeBSD. =9ASo while pio to the card's memory is too slow > >> to be useful, if there was a way to use a DMA controller on the > >> motherboard to get data into and out of the card, that may be > >> preferable to using the card's DMAC with the limited address space. > >> > >> But all that's just theory -- I have no idea how to tell whether the > >> mobo has a DMAC, and if it does, how to control it. =9AHelp? :-) > >> > >> Attached is the boot dmesg; I can also run pciconf commands, etc., to > >> help out with figuring out what I have. > > > > I believe what are you looking for is > > ftp://download.intel.com/technology/.../Intel(r)_VT_for_Direct_IO.pdf Oops. ftp://download.intel.com/technology/computing/vptech/Intel(r)_VT_for_Direct= _IO.pdf >=20 > This link doesn't work for me. >=20 > > On my X58 machine it is shown like this: > > none6@pci0:0:22:2: =9A class=3D0x088000 card=3D0xf38015d9 chip=3D0x3432= 8086 rev=3D0x12 hdr=3D0x00 > > =9A =9Avendor =9A =9A =3D 'Intel Corporation' > > =9A =9Adevice =9A =9A =3D 'DMA Engine' > > =9A =9Aclass =9A =9A =9A=3D base peripheral > > =9A =9Acap 11[80] =3D MSI-X supports 1 message in map 0x10 > > =9A =9Acap 10[90] =3D PCI-Express 2 root endpoint max data 128(128) lin= k x0(x0) > > =9A =9Acap 01[e0] =3D powerspec 3 =9Asupports D0 D3 =9Acurrent D0 >=20 > I do seem to have several DMA Engine entries in pciconf on this > hardware. Hopefully the above doc will explain what to do. :-) >=20 > Thanks, > matthew --eOOSeChkSGCyDSuc Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEARECAAYFAk2I8TkACgkQC3+MBN1Mb4ihfACfQkWJTF9skHJ5Omk59moxN0j4 04cAn2bzAg33v3i8FbB/h+I9MJ2Z7BES =+cn0 -----END PGP SIGNATURE----- --eOOSeChkSGCyDSuc--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110322185801.GW78089>