diff --git a/arch/blackfin/include/asm/dma.h b/arch/blackfin/include/asm/dma.h
index 264feb4eb175aec957cc106334a9ef1b3224725a..f58ca64d729c8a572abec435e008e51e41d5c34a 100644
--- a/arch/blackfin/include/asm/dma.h
+++ b/arch/blackfin/include/asm/dma.h
@@ -205,7 +205,9 @@ static inline unsigned long get_dma_curr_addr(unsigned int channel)
 
 static inline void set_dma_sg(unsigned int channel, struct dmasg *sg, int ndsize)
 {
-	dma_ch[channel].regs->cfg |= ((ndsize & 0x0F) << 8);
+	dma_ch[channel].regs->cfg =
+		(dma_ch[channel].regs->cfg & ~(0xf << 8)) |
+		((ndsize & 0xf) << 8);
 	dma_ch[channel].regs->next_desc_ptr = sg;
 }