Revert "i2c: tegra: Better handle case where CPU0 is busy for a long time"

This reverts commit a900aeac253729411cf33c6cb598c152e9e4137f because
regressions were showing up.

Suggested-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/dmaengine/20200319201140.17451-1-digetx@gmail.com/
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index a795b4e278b1fcd9b964b9bd556a31eadfcf2fd2..4c4d17ddc96b964125f89b49c13dd1f44f8bc457 100644 (file)
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -996,13 +996,14 @@ 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();
@@ -1029,18 +1030,14 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
                disable_irq(i2c_dev->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.
+                * There is a chance that completion may happen after IRQ
+                * synchronization, which is done by disable_irq().
                 */
-               if (ret == 0)
-                       ret = tegra_i2c_poll_completion_timeout(i2c_dev,
-                                                               complete, 0);
+               if (ret == 0 && completion_done(complete)) {
+                       dev_warn(i2c_dev->dev,
+                                "completion done after timeout\n");
+                       ret = 1;
+               }
        }
 
        return ret;