From aaaf939c573b783398b6af863576322256352f64 Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier.adi@gmail.com>
Date: Mon, 6 Apr 2009 19:00:42 -0700
Subject: Blackfin SPI Driver: add timeout while waiting for SPIF in dma irq
 handler

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>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 88dee87..e706de1 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;
-- 
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