Unverified Commit f0410bbf authored May 29, 2020 by Serge Semin Committed by Mark Brown May 29, 2020

spi: dw: Return any value retrieved from the dma_transfer callback



DW APB SSI DMA-part of the driver may need to perform the requested
SPI-transfer synchronously. In that case the dma_transfer() callback
will return 0 as a marker of the SPI transfer being finished so the
SPI core doesn't need to wait and may proceed with the SPI message
trasnfers pumping procedure. This will be needed to fix the problem
when DMA transactions are finished, but there is still data left in
the SPI Tx/Rx FIFOs being sent/received. But for now make dma_transfer
to return 1 as the normal dw_spi_transfer_one() method.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>
Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Feng Tang <feng.tang@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/20200529131205.31838-3-Sergey.Semin@baikalelectronics.ru


Signed-off-by: Mark Brown <broonie@kernel.org>

parent de4c2875

drivers/spi/spi-dw-mid.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -288,7 +288,7 @@ static int mid_spi_dma_transfer(struct dw_spi dws, struct spi_transfer xfer)
		dma_async_issue_pending(dws->txchan);
		}

		return 0;
		return 1;
		}

		static void mid_spi_dma_stop(struct dw_spi *dws)

drivers/spi/spi-dw.c

+2 −5

Original line number	Diff line number	Diff line
		@@ -389,11 +389,8 @@ static int dw_spi_transfer_one(struct spi_controller *master,

		spi_enable_chip(dws, 1);

		if (dws->dma_mapped) {
		ret = dws->dma_ops->dma_transfer(dws, transfer);
		if (ret < 0)
		return ret;
		}
		if (dws->dma_mapped)
		return dws->dma_ops->dma_transfer(dws, transfer);

		return 1;
		}

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