spi: s3c64xx: move dma_release_channel to unprepare

This fixes the sequence of dma_release_channel.
Since commit f52b03c70744 ("spi: s3c64xx: requests spi-dma channel only
during data transfer"),
dma_release_channel has been located in the s3c64xx_spi_transfer_one
but this makes invalid return of can_dma callback.
__spi_unmap_msg will check whether the request is requested by dma or
not via can_dma callback. When it is calling to check it, the channels
will be already released at the end of s3c64xx_spi_transfer_one so the
callback function will return always "false". So, they can't be unmapped
from __spi_unmap_msg call. To fix this, we need to add
unprepare_transfer_hardware callback and move the dma_release_channel
from s3c64xx_spi_transfer_one to there.

Fixes: f52b03c70744 ("spi: s3c64xx: requests spi-dma channel only during data transfer")
Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Link: https://lore.kernel.org/r/20220627013845.138350-1-chanho61.park@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 499c56dd875e43f2d4e24980f2bde348e483bdbb..302c1d4a28b1ecdc3f1ff8d01ad045deed6498a6 100644 (file)
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -373,6 +373,24 @@ static int s3c64xx_spi_prepare_transfer(struct spi_master *spi)
        return 0;
 }
 
+static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi)
+{
+       struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi);
+
+       if (is_polling(sdd))
+               return 0;
+
+       /* Releases DMA channels if they are allocated */
+       if (sdd->rx_dma.ch && sdd->tx_dma.ch) {
+               dma_release_channel(sdd->rx_dma.ch);
+               dma_release_channel(sdd->tx_dma.ch);
+               sdd->rx_dma.ch = 0;
+               sdd->tx_dma.ch = 0;
+       }
+
+       return 0;
+}
+
 static bool s3c64xx_spi_can_dma(struct spi_master *master,
                                struct spi_device *spi,
                                struct spi_transfer *xfer)
@@ -804,14 +822,6 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
                xfer->len = origin_len;
        }
 
-       /* Releases DMA channels after data transfer is completed */
-       if (sdd->rx_dma.ch && sdd->tx_dma.ch) {
-               dma_release_channel(sdd->rx_dma.ch);
-               dma_release_channel(sdd->tx_dma.ch);
-               sdd->rx_dma.ch = NULL;
-               sdd->tx_dma.ch = NULL;
-       }
-
        return status;
 }
 
@@ -1128,6 +1138,7 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
        master->setup = s3c64xx_spi_setup;
        master->cleanup = s3c64xx_spi_cleanup;
        master->prepare_transfer_hardware = s3c64xx_spi_prepare_transfer;
+       master->unprepare_transfer_hardware = s3c64xx_spi_unprepare_transfer;
        master->prepare_message = s3c64xx_spi_prepare_message;
        master->transfer_one = s3c64xx_spi_transfer_one;
        master->num_chipselect = sci->num_cs;