Commit 727c10e3 authored Sep 04, 2012 by Marek Vasut Committed by Mark Brown Sep 06, 2012

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 <marex@denx.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

parent 204e706f

drivers/spi/spi-mxs.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -445,7 +445,7 @@ static int mxs_spi_transfer_one(struct spi_master *master,
	* DMA only: 2.164808 seconds, 473.0KB/s		* DMA only: 2.164808 seconds, 473.0KB/s
	* Combined: 1.676276 seconds, 610.9KB/s		* Combined: 1.676276 seconds, 610.9KB/s
	*/		*/
	if (t->len <= 256) {		if (t->len < 32) {
	writel(BM_SSP_CTRL1_DMA_ENABLE,		writel(BM_SSP_CTRL1_DMA_ENABLE,
	ssp->base + HW_SSP_CTRL1(ssp) +		ssp->base + HW_SSP_CTRL1(ssp) +
	STMP_OFFSET_REG_CLR);		STMP_OFFSET_REG_CLR);