Re: [PATCH v1 1/1] thermal: rcar_gen3_thermal: request IRQ after device initialization

From: Jiada Wang
Date: Thu Apr 18 2019 - 07:37:25 EST


Hi Daniel

Thanks for your comments

On 2019/04/17 17:05, Daniel Lezcano wrote:
On 17/04/2019 05:01, Jiada Wang wrote:
Hi Daniel

On 2019/04/17 4:22, Daniel Lezcano wrote:
On 11/04/2019 12:03, Jiada Wang wrote:
Currently IRQ is remain enabled after .remove, later if device is
probed,
IRQ is requested before .thermal_init, this may cause IRQ function be
triggered but not able to clear IRQ status, thus cause system to hang.

this patch by moving request of IRQ after device initialization to
avoid this issue.

Why not disable the interrupt and clear the irq status in the .remove
callback, so the place is clean when probing again?


ÂÂÂÂÂÂÂÂ struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);

ÂÂÂÂÂÂÂÂ rcar_thermal_irq_set(priv, false);

should do the trick no ?

yes, this issue also can be addressed by disable the interrupt in .remove.

But there is race condition between .remove and irq thread function,
(which enables IRQ)
so driver need to ensure threaded irq has been disabled before call
rcar_thermal_irq_set(priv, false) in .remove.
this adds additional complexity.

I am fine with both solutions,
what is your opinion?

My opinion is it is the tree hiding the forest.

After a quick look at the irq setup and handling, it appears the
implementation is cumbersome. This part should be fixed before the rest:

- check IRQF_ONESHOT flag
- remove the lock in the interrupt handlers
- remove rcar_gen3_thermal_irq() which is pointless
- check the IRQF_SHARED flag is correct (I doubt)


yes, I think rather than IRQF_SHARED, IRQF_ONESHOT flag need to be used.
these suggestions make sense, I will add these changes in v2 patch-set

As the function devm_request_threaded_irq() is called 3 times, you
should add the priv->tscs[i]->zone in the private data and the irq
thread handler should look like:

static irqreturn_t rcar_gen3_thermal_irq_thread(int irq, void *data)
{
struct thermal_zone_device *tz = data;

thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);

[ ... ]

return IRQ_HANDLED;
}

hmmm, IRQ is requested 2 times to monitor low and high temperature of all tzs.

Thanks,
Jiada

When the implementation is fixed, then we can take care of the .remove

Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
 drivers/thermal/rcar_gen3_thermal.c | 48 ++++++++++++++++-------------
 1 file changed, 26 insertions(+), 22 deletions(-)

diff --git a/drivers/thermal/rcar_gen3_thermal.c
b/drivers/thermal/rcar_gen3_thermal.c
index 88fa41cf16e8..4d095d7f9763 100644
--- a/drivers/thermal/rcar_gen3_thermal.c
+++ b/drivers/thermal/rcar_gen3_thermal.c
@@ -375,28 +375,6 @@ static int rcar_gen3_thermal_probe(struct
platform_device *pdev)
 Â platform_set_drvdata(pdev, priv);
 - /*
-ÂÂÂÂ * Request 2 (of the 3 possible) IRQs, the driver only needs to
-ÂÂÂÂ * to trigger on the low and high trip points of the current
-ÂÂÂÂ * temp window at this point.
-ÂÂÂÂ */
-ÂÂÂ for (i = 0; i < 2; i++) {
-ÂÂÂÂÂÂÂ irq = platform_get_irq(pdev, i);
-ÂÂÂÂÂÂÂ if (irq < 0)
-ÂÂÂÂÂÂÂÂÂÂÂ return irq;
-
-ÂÂÂÂÂÂÂ irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev_name(dev), i);
-ÂÂÂÂÂÂÂ if (!irqname)
-ÂÂÂÂÂÂÂÂÂÂÂ return -ENOMEM;
-
-ÂÂÂÂÂÂÂ ret = devm_request_threaded_irq(dev, irq,
rcar_gen3_thermal_irq,
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ rcar_gen3_thermal_irq_thread,
-ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ IRQF_SHARED, irqname, priv);
-ÂÂÂÂÂÂÂ if (ret)
-ÂÂÂÂÂÂÂÂÂÂÂ return ret;
-ÂÂÂ }
-
ÂÂÂÂÂ pm_runtime_enable(dev);
ÂÂÂÂÂ pm_runtime_get_sync(dev);
 @@ -458,6 +436,32 @@ static int rcar_gen3_thermal_probe(struct
platform_device *pdev)
ÂÂÂÂÂÂÂÂÂ goto error_unregister;
ÂÂÂÂÂ }
 + /*
+ÂÂÂÂ * Request 2 (of the 3 possible) IRQs, the driver only needs to
+ÂÂÂÂ * to trigger on the low and high trip points of the current
+ÂÂÂÂ * temp window at this point.
+ÂÂÂÂ */
+ÂÂÂ for (i = 0; i < 2; i++) {
+ÂÂÂÂÂÂÂ irq = platform_get_irq(pdev, i);
+ÂÂÂÂÂÂÂ if (irq < 0) {
+ÂÂÂÂÂÂÂÂÂÂÂ ret = irq;
+ÂÂÂÂÂÂÂÂÂÂÂ goto error_unregister;
+ÂÂÂÂÂÂÂ }
+
+ÂÂÂÂÂÂÂ irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ dev_name(dev), i);
+ÂÂÂÂÂÂÂ if (!irqname) {
+ÂÂÂÂÂÂÂÂÂÂÂ ret = -ENOMEM;
+ÂÂÂÂÂÂÂÂÂÂÂ goto error_unregister;
+ÂÂÂÂÂÂÂ }
+
+ÂÂÂÂÂÂÂ ret = devm_request_threaded_irq(dev, irq,
rcar_gen3_thermal_irq,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ rcar_gen3_thermal_irq_thread,
+ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ IRQF_SHARED, irqname, priv);
+ÂÂÂÂÂÂÂ if (ret)
+ÂÂÂÂÂÂÂÂÂÂÂ goto error_unregister;
+ÂÂÂ }
+
ÂÂÂÂÂ rcar_thermal_irq_set(priv, true);
 Â return 0;