From: Ned Forrester <nforrester-/d+BM93fTQY@public.gmane.org>
To: David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
Cc: spi-devel
<spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Subject: Re: SPI TX andRX buffer overlap
Date: Fri, 14 Nov 2008 18:10:50 -0500 [thread overview]
Message-ID: <491E057A.9040507@whoi.edu> (raw)
In-Reply-To: <491E033E.9010008-/d+BM93fTQY@public.gmane.org>
Ned Forrester wrote:
> Is calling dma_map_single() twice on the same block of memory supposed
> to be OK? "Linux Device Drivers" does not discuss this, but it seems
> unlikely that it is acceptable. Maybe you have to unmap in the reverse
> order of mapping; I will test that.
Nope, it fails either way. It does not look like double mapping is a
good idea.
--
Ned Forrester nforrester-/d+BM93fTQY@public.gmane.org
Oceanographic Systems Lab 508-289-2226
Applied Ocean Physics and Engineering Dept.
Woods Hole Oceanographic Institution Woods Hole, MA 02543, USA
http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212
http://www.whoi.edu/hpb/Site.do?id=1532
http://www.whoi.edu/page.do?pid=10079
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next prev parent reply other threads:[~2008-11-14 23:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-13 20:02 SPI TX andRX buffer overlap Ned Forrester
[not found] ` <491C87BF.6030905-/d+BM93fTQY@public.gmane.org>
2008-11-14 22:30 ` David Brownell
[not found] ` <200811141430.53146.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-11-14 23:01 ` Ned Forrester
[not found] ` <491E033E.9010008-/d+BM93fTQY@public.gmane.org>
2008-11-14 23:10 ` Ned Forrester [this message]
2008-11-14 23:41 ` David Brownell
[not found] ` <200811141541.46799.david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>
2008-11-15 3:53 ` Ned Forrester
[not found] ` <491E47BD.5080005-/d+BM93fTQY@public.gmane.org>
2008-11-15 4:41 ` David Brownell
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