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 <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
