From be3034d9f9f3ea28588932d10bba6d06b71489a7 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Sun, 20 Sep 2020 14:23:15 +0300 Subject: [PATCH] spi: dw-dma: Check rx_buf availability in the xfer method Checking rx_buf for being NULL and returning NULL from the Rx-channel preparation method doesn't let us to distinguish that situation from errors happening during the Rx SG-list preparation. So it's better to make sure that the rx_buf not-NULL and full-duplex communication is requested prior calling the Rx preparation method. Signed-off-by: Serge Semin Link: https://lore.kernel.org/r/20200920112322.24585-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown --- drivers/spi/spi-dw-dma.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c index da17897..d2a67de 100644 --- a/drivers/spi/spi-dw-dma.c +++ b/drivers/spi/spi-dw-dma.c @@ -369,9 +369,6 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws, { struct dma_async_tx_descriptor *rxdesc; - if (!xfer->rx_buf) - return NULL; - rxdesc = dmaengine_prep_slave_sg(dws->rxchan, xfer->rx_sg.sgl, xfer->rx_sg.nents, @@ -435,10 +432,12 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) return -EINVAL; /* Prepare the RX dma transfer */ - rxdesc = dw_spi_dma_prepare_rx(dws, xfer); + if (xfer->rx_buf) { + rxdesc = dw_spi_dma_prepare_rx(dws, xfer); + if (!rxdesc) + return -EINVAL; - /* rx must be started before tx due to spi instinct */ - if (rxdesc) { + /* rx must be started before tx due to spi instinct */ set_bit(RX_BUSY, &dws->dma_chan_busy); dmaengine_submit(rxdesc); dma_async_issue_pending(dws->rxchan); @@ -458,7 +457,7 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer) return ret; } - if (rxdesc && dws->master->cur_msg->status == -EINPROGRESS) + if (xfer->rx_buf && dws->master->cur_msg->status == -EINPROGRESS) ret = dw_spi_dma_wait_rx_done(dws); return ret; -- 2.7.4