[PATCH 13/20] Blackfin SPI Driver: add timeout while waiting for SPIF in dma irq handler

Bryan Wu
2009-02-06T07:15:49Z

The "while" endless loop will cause the system hang if hardware error, so we add
timeout control to make the system alive.

Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
---
drivers/spi/spi_bfin5xx.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 83398b3..748e98f 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -557,6 +557,7 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
struct driver_data *drv_data = dev_id;
struct chip_data *chip = drv_data->cur_chip;
struct spi_message *msg = drv_data->cur_msg;
+ unsigned long timeout;
unsigned short dmastat = get_dma_curr_irqstat(drv_data->dma_channel);
u16 spistat = read_STAT(drv_data);

@@ -582,8 +583,17 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
cpu_relax();
}

+ dev_dbg(&drv_data->pdev->dev,
+ "in dma_irq_handler dmastat:0x%x spistat:0x%x\n",
+ dmastat, read_STAT(drv_data));
+
+ timeout = jiffies + HZ;
while (!(read_STAT(drv_data) & SPIF))
- cpu_relax();
+ if (!time_before(jiffies, timeout)) {
+ dev_warn(&drv_data->pdev->dev, "timeout waiting for SPIF");
+ break;
+ } else
+ cpu_relax();

if ((dmastat & DMA_ERR) && (spistat & RBSY)) {
msg->state = ERROR_STATE;
--
1.5.6.3