From 727c10e3e54c4404f6842d246b15fe3703d33556 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Tue, 4 Sep 2012 04:40:17 +0200 Subject: [PATCH] mxs/spi: Decrement the DMA/PIO border This driver checks the length of transfer to be made and based on this information, either chooses to transfer data via DMA or PIO. Decrement this border further to gain better performace eg. during SPI flash writes. Empiric measurement shows that this gives extra 3kB/s write speed with a M25P80 flash clocked at 40MHz. Signed-off-by: Marek Vasut Signed-off-by: Mark Brown --- drivers/spi/spi-mxs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-mxs.c b/drivers/spi/spi-mxs.c index 138c852..21e1dca 100644 --- a/drivers/spi/spi-mxs.c +++ b/drivers/spi/spi-mxs.c @@ -445,7 +445,7 @@ static int mxs_spi_transfer_one(struct spi_master *master, * DMA only: 2.164808 seconds, 473.0KB/s * Combined: 1.676276 seconds, 610.9KB/s */ - if (t->len <= 256) { + if (t->len < 32) { writel(BM_SSP_CTRL1_DMA_ENABLE, ssp->base + HW_SSP_CTRL1(ssp) + STMP_OFFSET_REG_CLR); -- 2.7.4