From c67ad368cf75d4999d5ef86543d082b4b35dd2d7 Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Tue, 27 Jun 2017 17:45:19 +0200 Subject: spi: stm32: enhance DMA error management This patch reworks DMA error management. In case the DMA callback is called while EOT (End Of Transfer) flag is not set, that means that DMA encountered an error. This error will result in an auto-suspend of SPI flow, which could also result in an overrun. So, in DMA mode, SUSP and OVR flags are a condition to stop the current transfer. Moreover, stm32_spi_can_dma doesn't care about the state of dma channels. During driver probe, master->can_dma is initialised if dma channel request is successful. That's why we must use master->can_dma to know if dma use is possible (dma channel are successfully requested and the transfer size is greater than fifo size). Signed-off-by: Amelie Delaunay Signed-off-by: Mark Brown --- drivers/spi/spi-stm32.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) (limited to 'drivers/spi/spi-stm32.c') diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 392c9453c2e6..8a6bff379b21 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -514,6 +514,12 @@ static irqreturn_t stm32_spi_irq(int irq, void *dev_id) dev_warn(spi->dev, "Communication suspended\n"); if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, false); + /* + * If communication is suspended while using DMA, it means + * that something went wrong, so stop the current transfer + */ + if (spi->cur_usedma) + end = true; } if (sr & SPI_SR_MODF) { @@ -525,6 +531,12 @@ static irqreturn_t stm32_spi_irq(int irq, void *dev_id) dev_warn(spi->dev, "Overrun: received value discarded\n"); if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, false); + /* + * If overrun is detected while using DMA, it means that + * something went wrong, so stop the current transfer + */ + if (spi->cur_usedma) + end = true; } if (sr & SPI_SR_EOT) { @@ -645,12 +657,10 @@ static void stm32_spi_dma_cb(void *data) spin_unlock_irqrestore(&spi->lock, flags); - if (!(sr & SPI_SR_EOT)) { - dev_warn(spi->dev, "DMA callback (sr=0x%08x)\n", sr); + if (!(sr & SPI_SR_EOT)) + dev_warn(spi->dev, "DMA error (sr=0x%08x)\n", sr); - spi_finalize_current_transfer(spi->master); - stm32_spi_disable(spi); - } + /* Now wait for EOT, or SUSP or OVR in case of error */ } /** @@ -986,7 +996,8 @@ static int stm32_spi_transfer_one(struct spi_master *master, spi->tx_len = spi->tx_buf ? transfer->len : 0; spi->rx_len = spi->rx_buf ? transfer->len : 0; - spi->cur_usedma = stm32_spi_can_dma(master, spi_dev, transfer); + spi->cur_usedma = (master->can_dma && + stm32_spi_can_dma(master, spi_dev, transfer)); ret = stm32_spi_transfer_one_setup(spi, spi_dev, transfer); if (ret) { -- cgit v1.2.3