From: Rini van Zetten Date: Mon, 10 Dec 2007 23:49:34 +0000 (-0800) Subject: atmel_spi: reload RCR before TCR X-Git-Tag: v2.6.24-rc5~4 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=d84248bf46582a406116c55b94405c05193773b1;p=linux-2.6-omap-h63xx.git 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 Signed-off-by: Rini van Zetten Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index ff6a14bf128..ff10808183a 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)); }