From 2cbee7f886b2ab6b723745b295379ec6475f2ee3 Mon Sep 17 00:00:00 2001 From: Cezary Gapinski Date: Mon, 24 Dec 2018 23:00:29 +0100 Subject: spi: stm32: fix DMA configuration with only one channel When SPI driver is configured to work only with TX or RX DMA channel then dmaengine functions can dereferene NULL pointer. Running full-duplex mode when when only RX or TX DMA channel is available can cause overrun condition or incorrect writing to transmit buffer so disable this types of DMA configuration and go back to interrupt mode. Signed-off-by: Cezary Gapinski Signed-off-by: Mark Brown --- drivers/spi/spi-stm32.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) (limited to 'drivers/spi/spi-stm32.c') diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 51d7f720127b..8310f14fe273 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -427,9 +427,9 @@ static void stm32_spi_disable(struct stm32_spi *spi) if (!spi->cur_usedma && spi->rx_buf && (spi->rx_len > 0)) stm32_spi_read_rxfifo(spi, true); - if (spi->cur_usedma && spi->tx_buf) + if (spi->cur_usedma && spi->dma_tx) dmaengine_terminate_all(spi->dma_tx); - if (spi->cur_usedma && spi->rx_buf) + if (spi->cur_usedma && spi->dma_rx) dmaengine_terminate_all(spi->dma_rx); stm32_spi_clr_bits(spi, STM32_SPI_CR1, SPI_CR1_SPE); @@ -750,7 +750,7 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi, spin_lock_irqsave(&spi->lock, flags); rx_dma_desc = NULL; - if (spi->rx_buf) { + if (spi->rx_buf && spi->dma_rx) { stm32_spi_dma_config(spi, &rx_dma_conf, DMA_DEV_TO_MEM); dmaengine_slave_config(spi->dma_rx, &rx_dma_conf); @@ -765,7 +765,7 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi, } tx_dma_desc = NULL; - if (spi->tx_buf) { + if (spi->tx_buf && spi->dma_tx) { stm32_spi_dma_config(spi, &tx_dma_conf, DMA_MEM_TO_DEV); dmaengine_slave_config(spi->dma_tx, &tx_dma_conf); @@ -776,8 +776,11 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi, DMA_PREP_INTERRUPT); } - if ((spi->tx_buf && !tx_dma_desc) || - (spi->rx_buf && !rx_dma_desc)) + if ((spi->tx_buf && spi->dma_tx && !tx_dma_desc) || + (spi->rx_buf && spi->dma_rx && !rx_dma_desc)) + goto dma_desc_error; + + if (spi->cur_comm == SPI_FULL_DUPLEX && (!tx_dma_desc || !rx_dma_desc)) goto dma_desc_error; if (rx_dma_desc) { @@ -822,7 +825,7 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi, return 1; dma_submit_error: - if (spi->rx_buf) + if (spi->dma_rx) dmaengine_terminate_all(spi->dma_rx); dma_desc_error: @@ -832,6 +835,7 @@ dma_desc_error: dev_info(spi->dev, "DMA issue: fall back to irq transfer\n"); + spi->cur_usedma = false; return stm32_spi_transfer_one_irq(spi); } @@ -984,7 +988,7 @@ static int stm32_spi_transfer_one(struct spi_master *master, spi->rx_len = spi->rx_buf ? transfer->len : 0; spi->cur_usedma = (master->can_dma && - stm32_spi_can_dma(master, spi_dev, transfer)); + master->can_dma(master, spi_dev, transfer)); ret = stm32_spi_transfer_one_setup(spi, spi_dev, transfer); if (ret) { -- cgit v1.2.3