[PATCH 04/15] thermal/drivers/samsung: acpm-tmu: Disable IRQ across system suspend/resume

[Tudor Ambarus]

The PM core masks device IRQs in dpm_suspend_noirq() and unmasks them in
dpm_resume_noirq(), leaving the TMU interrupt enabled after
acpm_tmu_suspend() and before acpm_tmu_resume() while runtime PM is
disabled and PCLK is gated:

1. If acpm_tmu_thread_fn() runs in that window,
   pm_runtime_resume_and_get() fails with -EACCES and returns IRQ_NONE
   without clearing the level-high hardware interrupt, triggering an
   unhandled IRQF_ONESHOT interrupt storm when the line is unmasked.
2. If acpm_tmu_thread_fn() is already running when acpm_tmu_suspend()
   executes, pm_runtime_force_suspend() ignores usage_count and gates
   PCLK underneath MMIO INTPEND reads.

Call disable_irq() at the start of acpm_tmu_suspend() to mask and
synchronize the interrupt before tearing down sensors and runtime PM,
and re-enable it with enable_irq() on acpm_tmu_suspend() rollback and
before returning from acpm_tmu_resume().

Fixes: 50a2c5d4062a ("thermal/drivers/samsung: Add Exynos ACPM TMU driver GS101")
Reported-by: Sashiko <sashiko-bot at kernel.org>
Link: https://sashiko.dev/#/patchset/20260603-acpm-tmu-v8-0-0f1810a356e6@linaro.org?part=2
Signed-off-by: Tudor Ambarus <tudor.ambarus at linaro.org>
---
 drivers/thermal/samsung/acpm-tmu.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/samsung/acpm-tmu.c b/drivers/thermal/samsung/acpm-tmu.c
index f490551de69a..55ee97218f47 100644
--- a/drivers/thermal/samsung/acpm-tmu.c
+++ b/drivers/thermal/samsung/acpm-tmu.c
@@ -541,6 +541,8 @@ static int acpm_tmu_suspend(struct device *dev)
 	const struct acpm_tmu_ops *ops = &handle->ops->tmu;
 	int ret, restore_ret;
 
+	disable_irq(priv->irq);
+
 	ret = acpm_tmu_control(priv, false);
 	if (ret)
 		goto err_restore_sensors;
@@ -568,6 +570,8 @@ static int acpm_tmu_suspend(struct device *dev)
 		dev_err(dev, "Failed to re-enable TMU after suspend failure: %d\n",
 			restore_ret);
 
+	enable_irq(priv->irq);
+
 	return ret;
 }
 
@@ -580,14 +584,19 @@ static int acpm_tmu_resume(struct device *dev)
 
 	ret = pm_runtime_force_resume(dev);
 	if (ret)
-		return ret;
+		goto out_enable_irq;
 
 	/* APB clock not required for this specific msg */
 	ret = ops->resume(handle, priv->mbox_chan_id);
 	if (ret)
-		return ret;
+		goto out_enable_irq;
+
+	ret = acpm_tmu_control(priv, true);
 
-	return acpm_tmu_control(priv, true);
+out_enable_irq:
+	enable_irq(priv->irq);
+
+	return ret;
 }
 
 static int acpm_tmu_runtime_suspend(struct device *dev)

-- 
2.56.0.257.gf7497c7d27-goog