From 63415e0eea739a32833a0bcb55216468f4bc0d3a Mon Sep 17 00:00:00 2001 From: Alexander Shishkin 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 Signed-off-by: Tony Lindgren Signed-off-by: Ben Dooks --- 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 ef73483efb846..00fd02ec1b650 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; } -- 2.39.5