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authorDmitry Osipenko <digetx@gmail.com>2020-03-24 20:12:16 +0100
committerWolfram Sang <wsa@the-dreams.de>2020-04-15 18:27:25 +0200
commita900aeac253729411cf33c6cb598c152e9e4137f (patch)
tree6da7d9aa0522bc6423900ba220f7a2b4baf94939 /drivers
parenti2c: remove i2c_new_probed_device API (diff)
downloadlinux-a900aeac253729411cf33c6cb598c152e9e4137f.tar.xz
linux-a900aeac253729411cf33c6cb598c152e9e4137f.zip
i2c: tegra: Better handle case where CPU0 is busy for a long time
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/i2c/busses/i2c-tegra.c27
1 files changed, 15 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 4c4d17ddc96b..a795b4e278b1 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -996,14 +996,13 @@ 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();
@@ -1030,14 +1029,18 @@ 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;