spi/s3c64xx: Prevent unnecessary map-unmap

Since we use DMA mode only for xfers bigger than FIFO size,
do not map/unmap buffers for polling mode transfers.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/spi/spi_s3c64xx.c b/drivers/spi/spi_s3c64xx.c
index c3038da2648a..e7b893f2a21b 100644
--- a/drivers/spi/spi_s3c64xx.c
+++ b/drivers/spi/spi_s3c64xx.c
@@ -499,6 +499,7 @@ static void s3c64xx_spi_dma_txcb(struct s3c2410_dma_chan *chan, void *buf_id,
 static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
                                                 struct spi_message *msg)
 {
+        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
         struct device *dev = &sdd->pdev->dev;
         struct spi_transfer *xfer;
 
@@ -514,6 +515,9 @@ static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
         /* Map until end or first fail */
         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 
+                if (xfer->len <= ((sci->fifo_lvl_mask >> 1) + 1))
+                        continue;
+
                 if (xfer->tx_buf != NULL) {
                         xfer->tx_dma = dma_map_single(dev,
                                         (void *)xfer->tx_buf, xfer->len,
@@ -545,6 +549,7 @@ static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
 static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
                                                 struct spi_message *msg)
 {
+        struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
         struct device *dev = &sdd->pdev->dev;
         struct spi_transfer *xfer;
 
@@ -553,6 +558,9 @@ static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
 
         list_for_each_entry(xfer, &msg->transfers, transfer_list) {
 
+                if (xfer->len <= ((sci->fifo_lvl_mask >> 1) + 1))
+                        continue;
+
                 if (xfer->rx_buf != NULL
                                 && xfer->rx_dma != XFER_DMAADDR_INVALID)
                         dma_unmap_single(dev, xfer->rx_dma,