From c6b4f031d96a4e1d59761b294829b058b098f3df Mon Sep 17 00:00:00 2001 From: Eugeniy Paltsev Date: Thu, 22 Mar 2018 13:50:43 +0300 Subject: [PATCH] DW SPI: fix tx data loss on FIFO flush In current implementation if some data still exists in Tx FIFO it can be silently flushed, i.e. dropped on disabling of the controller, which happens when writing 0 to DW_SPI_SSIENR (it happens in the beginning of new transfer) So add wait for current transmit operation to complete to be sure that current transmit operation is finished before new one. Signed-off-by: Eugeniy Paltsev Reviewed-by: Jagan Teki --- drivers/spi/designware_spi.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c index c501aee..5e196b2 100644 --- a/drivers/spi/designware_spi.c +++ b/drivers/spi/designware_spi.c @@ -18,6 +18,7 @@ #include #include #include +#include #include DECLARE_GLOBAL_DATA_PTR; @@ -342,6 +343,7 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen, u8 *rx = din; int ret = 0; u32 cr0 = 0; + u32 val; u32 cs; /* spi core configured to do 8 bit transfers */ @@ -394,6 +396,19 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen, /* Start transfer in a polling loop */ ret = poll_transfer(priv); + /* + * Wait for current transmit operation to complete. + * Otherwise if some data still exists in Tx FIFO it can be + * silently flushed, i.e. dropped on disabling of the controller, + * which happens when writing 0 to DW_SPI_SSIENR which happens + * in the beginning of new transfer. + */ + if (readl_poll_timeout(priv->regs + DW_SPI_SR, val, + !(val & SR_TF_EMPT) || (val & SR_BUSY), + RX_TIMEOUT * 1000)) { + ret = -ETIMEDOUT; + } + return ret; }