From: Dmitry Osipenko digetx@gmail.com
[ Upstream commit a900aeac253729411cf33c6cb598c152e9e4137f ]
Boot CPU0 always handle I2C interrupt and under some rare circumstances (like running KASAN + NFS root) it may stuck in uninterruptible state for a significant time. In this case we will get timeout if I2C transfer is running on a sibling CPU, despite of IRQ being raised. In order to handle this rare condition, the IRQ status needs to be checked after completion timeout.
Signed-off-by: Dmitry Osipenko digetx@gmail.com Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-tegra.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index cbc2ad49043e4..0daa863fb26f2 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -1000,14 +1000,13 @@ tegra_i2c_poll_completion_timeout(struct tegra_i2c_dev *i2c_dev, do { u32 status = i2c_readl(i2c_dev, I2C_INT_STATUS);
- if (status) { + if (status) tegra_i2c_isr(i2c_dev->irq, i2c_dev);
- if (completion_done(complete)) { - s64 delta = ktime_ms_delta(ktimeout, ktime); + if (completion_done(complete)) { + s64 delta = ktime_ms_delta(ktimeout, ktime);
- return msecs_to_jiffies(delta) ?: 1; - } + return msecs_to_jiffies(delta) ?: 1; }
ktime = ktime_get(); @@ -1034,14 +1033,18 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev, disable_irq(i2c_dev->irq);
/* - * There is a chance that completion may happen after IRQ - * synchronization, which is done by disable_irq(). + * Under some rare circumstances (like running KASAN + + * NFS root) CPU, which handles interrupt, may stuck in + * uninterruptible state for a significant time. In this + * case we will get timeout if I2C transfer is running on + * a sibling CPU, despite of IRQ being raised. + * + * In order to handle this rare condition, the IRQ status + * needs to be checked after timeout. */ - if (ret == 0 && completion_done(complete)) { - dev_warn(i2c_dev->dev, - "completion done after timeout\n"); - ret = 1; - } + if (ret == 0) + ret = tegra_i2c_poll_completion_timeout(i2c_dev, + complete, 0); }
return ret;