[U-Boot] [PATCH 15/27] Blackfin: dma_memcpy(): fix random failures

[Mike Frysinger]

We have to make sure the DMA channel is actually disabled in hardware before
attempting to reprogram it.  Otherwise the new settings are ignored and we
end up with random hangs/failures.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
---
 lib_blackfin/string.c |   19 +++++++++++--------
 1 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/lib_blackfin/string.c b/lib_blackfin/string.c
index 36eecdf..e458718 100644
--- a/lib_blackfin/string.c
+++ b/lib_blackfin/string.c
@@ -136,6 +136,14 @@ int strncmp(const char *cs, const char *ct, size_t count)
  */
 void dma_memcpy_nocache(void *dst, const void *src, size_t count)
 {
+	/* Disable DMA in case it's still running (older u-boot's did not
+	 * always turn them off).  Do it before the if statement below so
+	 * we can be cheap and not do a SSYNC() due to the forced abort.
+	 */
+	bfin_write_MDMA_D0_CONFIG(0);
+	bfin_write_MDMA_S0_CONFIG(0);
+	bfin_write_MDMA_D0_IRQ_STATUS(DMA_RUN | DMA_DONE | DMA_ERR);
+
 	/* Scratchpad cannot be a DMA source or destination */
 	if (((unsigned long)src >= L1_SRAM_SCRATCH &&
 	     (unsigned long)src < L1_SRAM_SCRATCH_END) ||
@@ -143,10 +151,6 @@ void dma_memcpy_nocache(void *dst, const void *src, size_t count)
 	     (unsigned long)dst < L1_SRAM_SCRATCH_END))
 		hang();
 
-	bfin_write_MDMA_S0_CONFIG(0);
-	bfin_write_MDMA_D0_CONFIG(0);
-	bfin_write_MDMA_D0_IRQ_STATUS(DMA_RUN | DMA_DONE | DMA_ERR);
-
 	/* Copy sram functions from sdram to sram */
 	/* Setup destination start address */
 	bfin_write_MDMA_D0_START_ADDR(dst);
@@ -164,14 +168,13 @@ void dma_memcpy_nocache(void *dst, const void *src, size_t count)
 
 	/* Enable source DMA */
 	bfin_write_MDMA_S0_CONFIG(DMAEN);
-
-	bfin_write_MDMA_D0_CONFIG(WNR | DMAEN);
+	bfin_write_MDMA_D0_CONFIG(WNR | DMAEN | DI_EN);
 	SSYNC();
 
-	while (bfin_read_MDMA_D0_IRQ_STATUS() & DMA_RUN)
+	while (!(bfin_read_MDMA_D0_IRQ_STATUS() & DMA_DONE))
 		continue;
 
-	bfin_write_MDMA_D0_IRQ_STATUS(bfin_read_MDMA_D0_IRQ_STATUS() | DMA_RUN | DMA_DONE | DMA_ERR);
+	bfin_write_MDMA_D0_IRQ_STATUS(DMA_RUN | DMA_DONE | DMA_ERR);
 	bfin_write_MDMA_D0_CONFIG(0);
 	bfin_write_MDMA_S0_CONFIG(0);
 }
-- 
1.6.1.1