From: Haavard Skinnemoen <hskinnemoen@atmel.com>
Date: Wed, 6 Feb 2008 09:38:11 +0000 (-0800)
Subject: atmel_spi throughput improvement
X-Git-Tag: v2.6.25-rc1~657
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1eed29df472a33bba013d5a2ea2f9e32f4414397;p=pandora-kernel.git

atmel_spi throughput improvement

Don't insert (undesirable) delays between consecutive words (DLYBCT) or when
activating chipselects (DLYBS).

Removing the between-word delays improves the performance of bulk transfers
(such as mtd_dataflash, m25p80, mmc_spi) significantly.  In one test, the
improvement was a factor of more than eight!

(The large DLYBCT value came from the legacy at91 SPI driver, and it's not
clear why it used such a huge value.)

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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