[PATCH v2] MTD: OneNAND: Fix loop hang when DMA error at Samsung SoCs

[Kyungmin Park <kmpark@infradead.org>]

From: Kyungmin Park <kyungmin.park@samsung.com>

When DMA error occurs. it's loop hang since it can't exit the loop.
and it's the right DMA handling code as Spec.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
Changelog v1
	Add the timeout as Artem comment
	
 drivers/mtd/onenand/samsung.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/onenand/samsung.c b/drivers/mtd/onenand/samsung.c
index d604629..bdaa228 100644
--- a/drivers/mtd/onenand/samsung.c
+++ b/drivers/mtd/onenand/samsung.c
@@ -535,6 +535,7 @@ static int s5pc110_dma_ops(void *dst, void *src, size_t count, int direction)
 {
 	void __iomem *base = onenand->dma_addr;
 	int status;
+	unsigned long timeout;
 
 	writel(src, base + S5PC110_DMA_SRC_ADDR);
 	writel(dst, base + S5PC110_DMA_DST_ADDR);
@@ -552,15 +553,17 @@ static int s5pc110_dma_ops(void *dst, void *src, size_t count, int direction)
 
 	writel(S5PC110_DMA_TRANS_CMD_TR, base + S5PC110_DMA_TRANS_CMD);
 
+	timeout = jiffies + msec_to_jiffies(20);
+
 	do {
 		status = readl(base + S5PC110_DMA_TRANS_STATUS);
-	} while (!(status & S5PC110_DMA_TRANS_STATUS_TD));
-
-	if (status & S5PC110_DMA_TRANS_STATUS_TE) {
-		writel(S5PC110_DMA_TRANS_CMD_TEC, base + S5PC110_DMA_TRANS_CMD);
-		writel(S5PC110_DMA_TRANS_CMD_TDC, base + S5PC110_DMA_TRANS_CMD);
-		return -EIO;
-	}
+		if (status & S5PC110_DMA_TRANS_STATUS_TE) {
+			writel(S5PC110_DMA_TRANS_CMD_TEC,
+					base + S5PC110_DMA_TRANS_CMD);
+			return -EIO;
+		}
+	} while (!(status & S5PC110_DMA_TRANS_STATUS_TD) &&
+		time_before(jiffies, timeout));
 
 	writel(S5PC110_DMA_TRANS_CMD_TDC, base + S5PC110_DMA_TRANS_CMD);
 
-- 
1.5.3.3