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FromBryan Wu <>
Subject[PATCH 01/16] Blackfin SPI Driver: ensure cache coherency before doing DMA
DateTue, 18 Nov 2008 15:52:25 +0800
From: Vitja Makarov <vitja.makarov@gmail.com>

flush or invalidate caches before doing DMA transfer, if needed.

Signed-off-by: Vitja Makarov <vitja.makarov@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
---
 drivers/spi/spi_bfin5xx.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 7fea3cf..e9b7366 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -26,6 +26,10 @@
 #include <asm/portmux.h>
 #include <asm/bfin5xx_spi.h>
 
+/* reserved_mem_dcache_on and cache friends */
+#include <asm/cplbinit.h>
+#include <asm/cacheflush.h>
+
 #define DRV_NAME	"bfin-spi"
 #define DRV_AUTHOR	"Bryan Wu, Luke Yang"
 #define DRV_DESC	"Blackfin BF5xx on-chip SPI Controller Driver"
@@ -795,6 +799,12 @@ static void pump_transfers(unsigned long data)
 			/* set transfer mode, and enable SPI */
 			dev_dbg(&drv_data->pdev->dev, "doing DMA in.\n");
 
+			/* invalidate caches, if needed */
+			if (bfin_addr_dcachable((unsigned long) drv_data->rx))
+				invalidate_dcache_range((unsigned long) drv_data->rx,
+							(unsigned long) (drv_data->rx +
+							drv_data->len));
+
 			/* clear tx reg soformer data is not shifted out */
 			write_TDBR(drv_data, 0xFFFF);
 
@@ -815,6 +825,12 @@ static void pump_transfers(unsigned long data)
 		} else if (drv_data->tx != NULL) {
 			dev_dbg(&drv_data->pdev->dev, "doing DMA out.\n");
 
+			/* flush caches, if needed */
+			if (bfin_addr_dcachable((unsigned long) drv_data->tx))
+				flush_dcache_range((unsigned long) drv_data->tx,
+						(unsigned long) (drv_data->tx +
+						drv_data->len));
+
 			/* start dma */
 			dma_enable_irq(drv_data->dma_channel);
 			dma_config = (RESTART | dma_width | DI_EN);
-- 
1.5.6.3

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