From: Ben Nizette <bn@niasdigital.com>
Date: Tue, 15 Dec 2009 06:20:20 +0000 (-0800)
Subject: atmel_spi: fix dma addr calculation for len > BUFFER_SIZE
X-Git-Tag: v2.6.33-rc1~9^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6aed4ee9b4610cd1e0315c90855b32e59ee81a15;p=pandora-kernel.git

atmel_spi: fix dma addr calculation for len > BUFFER_SIZE

If len > BUFFER_LEN and !xfer->rx_buf we end up calculating the tx buffer
address as

*tx_dma = xfer->tx_dma + xfer->len - BUFFER_SIZE;

which is constant; i.e.  we just send the last BUFFER_SIZE data over again
until we've reached the right number of bytes.

This patch gets around this by using the /requested/ length when
calculating addresses.

Note there's no way len != *plen when we calculate the rx buffer address
but conceptually we should be using *plen and I don't want someone to come
through later, see the calculations for rx and tx are different and "clean
up" back to what we had.

Signed-off-by: Ben Nizette <bn@niasdigital.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---

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