From: batt <batt@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Fri, 9 Jul 2010 10:43:19 +0000 (+0000)
Subject: Flush the transfer before exiting from write function.
X-Git-Tag: 2.6.0~299
X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=b44c11e480505f754d0f7b4ac3067e4ebf5adcc2;p=bertos.git

Flush the transfer before exiting from write function.

Since the buffer is used by the DMA, if we return early we run the
risk of having the buffer overwritten before the transfer will be
completed.
Waiting for the flush could be theorically a pessimization, but from
tests, since the typical use involves mixed reads/writes, we already
wait for the transfers to be completed, and performance are
almost the same.


git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4017 38d2e660-2303-0410-9eaa-f027e97ec537
---

diff --git a/bertos/cpu/arm/drv/spi_dma_at91.c b/bertos/cpu/arm/drv/spi_dma_at91.c
index 03b98d85..25a10410 100644
--- a/bertos/cpu/arm/drv/spi_dma_at91.c
+++ b/bertos/cpu/arm/drv/spi_dma_at91.c
@@ -76,11 +76,11 @@ static int spi_dma_flush(UNUSED_ARG(struct KFile *, fd))
 
 static size_t spi_dma_write(struct KFile *fd, const void *_buf, size_t size)
 {
-	spi_dma_flush(fd);
 	SPI0_PTCR = BV(PDC_TXTDIS);
 	SPI0_TPR = (reg32_t)_buf;
 	SPI0_TCR = size;
 	SPI0_PTCR = BV(PDC_TXTEN);
+	spi_dma_flush(fd);
 	return size;
 }
 
@@ -97,8 +97,6 @@ static size_t spi_dma_read(struct KFile *fd, void *_buf, size_t size)
 	size_t count, total_rx = 0;
 	uint8_t *buf = (uint8_t *)_buf;
 
-	spi_dma_flush(fd);
-
 	while (size)
 	{
 		count = MIN(size, (size_t)CONFIG_SPI_DMA_MAX_RX);