From e02ddd442a532c73e547ae3735c8012e3bd719a5 Mon Sep 17 00:00:00 2001 From: Jassi Brar Date: Wed, 29 Sep 2010 17:31:31 +0900 Subject: [PATCH] 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 Signed-off-by: Grant Likely --- drivers/spi/spi_s3c64xx.c | 8 ++++++++ 1 file changed, 8 insertions(+) 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, -- 2.20.1