From 5a9a62bb035b1f74e7d017e3bd48d1c687d7de3c Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Fri, 1 Jun 2007 00:47:00 -0700 Subject: [PATCH] atmel_spi dma address bugfix 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 Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/spi/atmel_spi.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index 1d8a2f6bb8e..8b2601de363 100644 --- a/drivers/spi/atmel_spi.c +++ b/drivers/spi/atmel_spi.c @@ -113,16 +113,16 @@ static void atmel_spi_next_xfer(struct spi_master *master, 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; -- 2.20.1