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[v2,5/9] spi: dw-mid: take care of FIFO overrun/underrun when do DMA

Message ID 1425320166-13788-6-git-send-email-andriy.shevchenko@linux.intel.com (mailing list archive)
State Accepted
Commit f051fc8f117d95baaa3654d40e779c56c2c6d180
Headers show

Commit Message

Andy Shevchenko March 2, 2015, 6:16 p.m. UTC 
In according to documentation SPI in DMA mode may encounter underrun/overrun
failures in rare cases. When such failure occurs, an error recovery protocol is
expected to be implemented in the device driver so that the failed transaction
can be restarted.

This patch enables FIFO overrun / underrun interrupts in DMA case and adds a
handler for that.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/spi/spi-dw-mid.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
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Patch

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index 4b4d266..3729cdd 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -100,6 +100,22 @@  static void mid_spi_dma_exit(struct dw_spi *dws)
 	dma_release_channel(dws->rxchan);
 }
 
+static irqreturn_t dma_transfer(struct dw_spi *dws)
+{
+	u16 irq_status = dw_readw(dws, DW_SPI_ISR);
+
+	if (!irq_status)
+		return IRQ_NONE;
+
+	dw_readw(dws, DW_SPI_ICR);
+	spi_reset_chip(dws);
+
+	dev_err(&dws->master->dev, "%s: FIFO overrun/underrun\n", __func__);
+	dws->master->cur_msg->status = -EIO;
+	spi_finalize_current_transfer(dws->master);
+	return IRQ_HANDLED;
+}
+
 static enum dma_slave_buswidth convert_dma_width(u32 dma_width) {
 	if (dma_width == 1)
 		return DMA_SLAVE_BUSWIDTH_1_BYTE;
@@ -220,6 +236,11 @@  static int mid_spi_dma_setup(struct dw_spi *dws)
 		dma_ctrl |= SPI_DMA_RDMAE;
 	dw_writew(dws, DW_SPI_DMACR, dma_ctrl);
 
+	/* Set the interrupt mask */
+	spi_umask_intr(dws, SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI);
+
+	dws->transfer_handler = dma_transfer;
+
 	return 0;
 }