[PATCH 4.4 049/101] spi: dw: Enable interrupts in accordance with DMA xfer mode

Greg Kroah-Hartman
2020-06-19T14:37:27Z

From: Serge Semin <Sergey.Semin@baikalelectronics.ru>

[ Upstream commit 43dba9f3f98c2b184a19f856f06fe22817bfd9e0 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/spi/spi-dw-mid.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index 4d6434b244e2..bd116f117b02 100644
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -228,19 +228,23 @@ 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;

--
2.25.1