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

[ Upstream commit f0410bbf7d ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Serge Semin 2020-05-29 16:11:51 +03:00 committed by Greg Kroah-Hartman
parent 2c95fc879a
commit cf33598698
2 changed files with 3 additions and 6 deletions
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2
drivers/spi/spi-dw-mid.c
View File

@ -266,7 +266,7 @@ 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)

7
drivers/spi/spi-dw.c
View File

@ -381,11 +381,8 @@ 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);
if (chip->poll_mode)
return poll_transfer(dws);