Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=d84248bf46582a406116c55b94405c05193773b1
Commit: d84248bf46582a406116c55b94405c05193773b1
Parent: 6650e0a517bbfa1c47aa3da6b3562fcb1a066c63
Author: Rini van Zetten <[EMAIL PROTECTED]>
AuthorDate: Mon Dec 10 15:49:34 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon Dec 10 19:43:55 2007 -0800
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 <[EMAIL PROTECTED]>
Signed-off-by: Rini van Zetten <[EMAIL PROTECTED]>
Signed-off-by: David Brownell <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
drivers/spi/atmel_spi.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index ff6a14b..ff10808 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));
}
-
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