The patch titled
atmel_spi dma address bugfix
has been added to the -mm tree. Its filename is
atmel_spi-dma-address-bugfix.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: atmel_spi dma address bugfix
From: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
When either rx_buf or tx_buf is not being used, i.e. for plain read- or
write operations, the atmel_spi uses a fixed-size DMA buffer instead. If
the transfer is longer than the size of this buffer, it is split into
multiple DMA transfers.
When the transfer is split like this, the atmel_spi driver ends up using
the same DMA address again and again even for the buffer that came from the
user, which is of course wrong. Fix this by adding the number of bytes
already transferred to the DMA address so that the data ends up in the
right place.
Thanks to Wu Xuan for discovering this bug.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/spi/atmel_spi.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff -puN drivers/spi/atmel_spi.c~atmel_spi-dma-address-bugfix drivers/spi/atmel_spi.c
--- a/drivers/spi/atmel_spi.c~atmel_spi-dma-address-bugfix
+++ a/drivers/spi/atmel_spi.c
@@ -113,16 +113,16 @@ static void atmel_spi_next_xfer(struct s
len = as->remaining_bytes;
- tx_dma = xfer->tx_dma;
- rx_dma = xfer->rx_dma;
+ tx_dma = xfer->tx_dma + xfer->len - len;
+ rx_dma = xfer->rx_dma + xfer->len - len;
/* use scratch buffer only when rx or tx data is unspecified */
- if (rx_dma == INVALID_DMA_ADDRESS) {
+ if (!xfer->rx_buf) {
rx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
}
- if (tx_dma == INVALID_DMA_ADDRESS) {
+ if (!xfer->tx_buf) {
tx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
_
Patches currently in -mm which might be from hskinnemoen@xxxxxxxxx are
lots-of-architectures-enable-arbitary-speed-tty-support.patch
avr32-ratelimit-segfault-reporting-rate.patch
atmel_spi-dma-address-bugfix.patch
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