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

[ Upstream commit f0410bbf7d0fb80149e3b17d11d31f5b5197873e ]

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>

diff --git a/drivers/spi/spi-dw-mid.c b/drivers/spi/spi-dw-mid.c
index bd116f117b022cb5566b51d63b48432005178c20..14902efae621b06975fe3ff0c29a9973c14fe131 100644 (file)
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -274,7 +274,7 @@ 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)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index 295249843e7c478dd3a1d94b20c55d1b15ef3948..8076fa708b24f994905e441c52e344a9cfd8ac61 100644 (file)
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -385,11 +385,8 @@ static int dw_spi_transfer_one(struct spi_master *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);