Date: Mon, 14 Aug 2000 13:59:13 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Bill Clinton <biffey@hotmail.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: dma to userland address Message-ID: <Pine.BSF.4.10.10008141359020.13324-100000@beppo.feral.com> In-Reply-To: <F89TuHZncJfKHmj9n1x00001510@hotmail.com>
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Look at what physio does. On Mon, 14 Aug 2000, Bill Clinton wrote: > lets say, hypothetically, that i have an ioctl interface to my device > driver that takes a buffer that looks something like: > > struct { > int length; > char *buf; > } mystruct; > > and lets say, hypothetically, that i wanted to dma directly > to/from 'buf'. how would i do that? > > i've tried doing vtophys on buf, but that doesn't seem to work. > > i've tried doing vtophys on a kernel-allocated block and the mmapping it > through /dev/mem in userland, but that doesn't seem to work either (this > may have a bug, though - it worked under linux, but was about 10x slower > than just leaving the kernel/user copy in there). > > so what am i missing here? > > - j > ________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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