spi: dw: Enable interrupts in accordance with DMA xfer mode

It's pointless to track the Tx overrun interrupts if Rx-only SPI
transfer is issued. Similarly there is no need in handling the Rx
overrun/underrun interrupts if Tx-only SPI transfer is executed.
So lets unmask the interrupts only if corresponding SPI
transactions are implied.

Co-developed-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Signed-off-by: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200522000806.7381-3-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index f9757a3..1578dfe 100644 (file)
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -243,19 +243,23 @@ static struct dma_async_tx_descriptor *dw_spi_dma_prepare_rx(struct dw_spi *dws,
 
 static int mid_spi_dma_setup(struct dw_spi *dws, struct spi_transfer *xfer)
 {
-       u16 dma_ctrl = 0;
+       u16 imr = 0, dma_ctrl = 0;
 
        dw_writel(dws, DW_SPI_DMARDLR, 0xf);
        dw_writel(dws, DW_SPI_DMATDLR, 0x10);
 
-       if (xfer->tx_buf)
+       if (xfer->tx_buf) {
                dma_ctrl |= SPI_DMA_TDMAE;
-       if (xfer->rx_buf)
+               imr |= SPI_INT_TXOI;
+       }
+       if (xfer->rx_buf) {
                dma_ctrl |= SPI_DMA_RDMAE;
+               imr |= SPI_INT_RXUI | SPI_INT_RXOI;
+       }
        dw_writel(dws, DW_SPI_DMACR, dma_ctrl);
 
        /* Set the interrupt mask */
-       spi_umask_intr(dws, SPI_INT_TXOI | SPI_INT_RXUI | SPI_INT_RXOI);
+       spi_umask_intr(dws, imr);
 
        dws->transfer_handler = dma_transfer;