From: Dan Williams <dan.j.williams@intel.com>
Date: Fri, 28 Aug 2009 21:32:04 +0000 (-0700)
Subject: iop-adma: P+Q support for iop13xx adma engines
X-Git-Tag: v2.6.32-rc1~60^2^2~14^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7bf649aee8ac93ecc280f8745dcf8ec19d7b9fb1;p=pandora-kernel.git

iop-adma: P+Q support for iop13xx adma engines

iop33x support is not included because that engine is a bit more awkward
to handle in that it can either be in xor mode or pq mode.  The
dmaengine/async_tx layers currently only comprehend static capabilities.

Note iop13xx does not support hardware PQ continuation so the driver
must handle the DMA_PREP_CONTINUE flag for operations across > 16
sources. From the comment for dma_maxpq:

/* When an engine does not support native continuation we need 3 extra
 * source slots to reuse P and Q with the following coefficients:
 * 1/ {00} * P : remove P from Q', but use it as a source for P'
 * 2/ {01} * Q : use Q to continue Q' calculation
 * 3/ {00} * Q : subtract Q from P' to cancel (2)
 */

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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