[PATCH 4/7] spi: s3c64xx: Use jiffies instead of loops for timeout

[sjg@chromium.org (Simon Glass)]

The current timeout uses loops, but does not actually use an empty loop. In
fact it checks SPI registers which are pretty slow to read. As a result the
timeout ends up being several seconds most of the time.

Change this to use jiffies instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
---
 drivers/spi/spi-s3c64xx.c |   37 ++++++++++++++++++++++---------------
 1 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 95a1bfc..db79d87 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -427,6 +427,7 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
 static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 				struct spi_transfer *xfer, int dma_mode)
 {
+	struct device *dev = &sdd->pdev->dev;
 	void __iomem *regs = sdd->regs;
 	unsigned long val;
 	int ms;
@@ -439,16 +440,21 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 		val = msecs_to_jiffies(ms) + 10;
 		val = wait_for_completion_timeout(&sdd->xfer_completion, val);
 	} else {
+		ulong deadline;
 		u32 status;
-		val = msecs_to_loops(ms);
+
+		deadline = jiffies + msecs_to_jiffies(ms);
 		do {
 			status = readl(regs + S3C64XX_SPI_STATUS);
-		} while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
+			if (time_after(jiffies, deadline)) {
+				dev_warn(dev, "RX timeout level=%d, need=%d\n",
+					RX_FIFO_LVL(status, sdd), xfer->len);
+				return -EIO;
+			}
+			cpu_relax();
+		} while (RX_FIFO_LVL(status, sdd) < xfer->len);
 	}
 
-	if (!val)
-		return -EIO;
-
 	if (dma_mode) {
 		u32 status;
 
@@ -460,17 +466,18 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
 		 * Xfer involved Rx(with or without Tx).
 		 */
 		if (xfer->rx_buf == NULL) {
-			val = msecs_to_loops(10);
-			status = readl(regs + S3C64XX_SPI_STATUS);
-			while ((TX_FIFO_LVL(status, sdd)
-				|| !S3C64XX_SPI_ST_TX_DONE(status, sdd))
-					&& --val) {
-				cpu_relax();
-				status = readl(regs + S3C64XX_SPI_STATUS);
-			}
+			ulong deadline;
 
-			if (!val)
-				return -EIO;
+			deadline = jiffies + msecs_to_jiffies(10);
+			do {
+				status = readl(regs + S3C64XX_SPI_STATUS);
+				if (time_after(jiffies, deadline)) {
+					dev_warn(dev, "TX timeout level=%d\n",
+						TX_FIFO_LVL(status, sdd));
+					return -EIO;
+				}
+			} while (TX_FIFO_LVL(status, sdd) ||
+					!S3C64XX_SPI_ST_TX_DONE(status, sdd));
 		}
 	} else {
 		/* If it was only Tx */
-- 
1.7.7.3