diff options
| author | Rini van Zetten <rini@arvoo.nl> | 2007-12-10 15:49:34 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-12-10 19:43:55 -0800 |
| commit | d84248bf46582a406116c55b94405c05193773b1 (patch) | |
| tree | eb27fdfc1ea343f2af847e1c93cc39386d0b4f45 | |
| parent | 6650e0a517bbfa1c47aa3da6b3562fcb1a066c63 (diff) | |
| download | op-kernel-dev-d84248bf46582a406116c55b94405c05193773b1.zip op-kernel-dev-d84248bf46582a406116c55b94405c05193773b1.tar.gz | |
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.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)); } |
