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mxs/spi: Decrement the DMA/PIO border

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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>
This commit is contained in:
Marek Vasut 2012-09-04 04:40:17 +02:00 committed by Mark Brown
parent 204e706fa2
commit 727c10e3e5
1 changed files with 1 additions and 1 deletions
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2
drivers/spi/spi-mxs.c
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@ -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);