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authorRini van Zetten <rini@arvoo.nl>2007-12-10 15:49:34 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-12-10 19:43:55 -0800
commitd84248bf46582a406116c55b94405c05193773b1 (patch)
treeeb27fdfc1ea343f2af847e1c93cc39386d0b4f45
parent6650e0a517bbfa1c47aa3da6b3562fcb1a066c63 (diff)
downloadlinux-d84248bf46582a406116c55b94405c05193773b1.tar.bz2
atmel_spi: reload RCR before TCR
We have a wifi module connected to the spi bus and got sometimes FIFO overrun errors on the spi bus. After some investigation i found that the driver loads the TCR (transmit count) register before the RCR (receive count). When the transfer list is not empty the atmel_spi_next_message is called while tx and rx are enabled. As soon as the TCR is loaded, hardware starts transfer and causes a rx fifo overrun because the RCR is not loaded yet. Load the RCR before the TCR. After this patch the fifo overrun disapears at out setup. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Rini van Zetten <rini@arvoo.nl> 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>
-rw-r--r--drivers/spi/atmel_spi.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index ff6a14bf1280..ff10808183a3 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -195,8 +195,8 @@ static void atmel_spi_next_xfer(struct spi_master *master,
xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
xfer->rx_buf, xfer->rx_dma, spi_readl(as, IMR));
- spi_writel(as, TCR, len);
spi_writel(as, RCR, len);
+ spi_writel(as, TCR, len);
spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
}