From e9f59b9c9bc5730152b6a94c47dd90b730a07e35 Mon Sep 17 00:00:00 2001
From: Alexander Shishkin <virtuoso@slind.org>
Date: Tue, 11 May 2010 11:35:17 -0700
Subject: [PATCH] omap: i2c: add a timeout to the busy waiting
The errata 1.153 workaround is busy waiting on XUDF bit in interrupt
context, which may lead to kernel hangs. The problem can be reproduced
by running the bus with wrong (too high) speed.
Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
---
drivers/i2c/busses/i2c-omap.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index ef73483efb846d..00fd02ec1b6500 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -763,17 +763,25 @@ omap_i2c_rev1_isr(int this_irq, void *dev_id)
*/
static int errata_omap3_1p153(struct omap_i2c_dev *dev, u16 *stat, int *err)
{
- while (!(*stat & OMAP_I2C_STAT_XUDF)) {
+ unsigned long timeout = 10000;
+
+ while (--timeout && !(*stat & OMAP_I2C_STAT_XUDF)) {
if (*stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
omap_i2c_ack_stat(dev, *stat & (OMAP_I2C_STAT_XRDY |
OMAP_I2C_STAT_XDR));
*err |= OMAP_I2C_STAT_XUDF;
return -ETIMEDOUT;
}
+
cpu_relax();
*stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
}
+ if (!timeout) {
+ dev_err(dev->dev, "timeout waiting on XUDF bit\n");
+ return 0;
+ }
+
return 0;
}
--
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