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authorBen Nizette <bn@niasdigital.com>2009-12-14 22:20:20 -0800
committerGrant Likely <grant.likely@secretlab.ca>2009-12-17 08:57:07 -0700
commit6aed4ee9b4610cd1e0315c90855b32e59ee81a15 (patch)
tree5866dec5080de784cb01ce3a6426a8d4d111636e /drivers/spi
parentbec0806cfec6ded1a7e097bb95279e521a796129 (diff)
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>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/atmel_spi.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index f5b3fdbb1e2..8ce70cbdbb9 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -189,14 +189,14 @@ static void atmel_spi_next_xfer_data(struct spi_master *master,
/* use scratch buffer only when rx or tx data is unspecified */
if (xfer->rx_buf)
- *rx_dma = xfer->rx_dma + xfer->len - len;
+ *rx_dma = xfer->rx_dma + xfer->len - *plen;
else {
*rx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
}
if (xfer->tx_buf)
- *tx_dma = xfer->tx_dma + xfer->len - len;
+ *tx_dma = xfer->tx_dma + xfer->len - *plen;
else {
*tx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)