[PATCH 6.6] mailbox: mtk-cmdq: Move devm_mbox_controller_register() after devm_pm_runtime_enable()

[PATCH 6.6] mailbox: mtk-cmdq: Move devm_mbox_controller_register() after devm_pm_runtime_enable()

[bin.lan.cn]

From: "Jason-JH.Lin" <jason-jh.lin@mediatek.com>

[ Upstream commit a8bd68e4329f9a0ad1b878733e0f80be6a971649 ]

When mtk-cmdq unbinds, a WARN_ON message with condition
pm_runtime_get_sync() < 0 occurs.

According to the call tracei below:
  cmdq_mbox_shutdown
  mbox_free_channel
  mbox_controller_unregister
  __devm_mbox_controller_unregister
  ...

The root cause can be deduced to be calling pm_runtime_get_sync() after
calling pm_runtime_disable() as observed below:
1. CMDQ driver uses devm_mbox_controller_register() in cmdq_probe()
   to bind the cmdq device to the mbox_controller, so
   devm_mbox_controller_unregister() will automatically unregister
   the device bound to the mailbox controller when the device-managed
   resource is removed. That means devm_mbox_controller_unregister()
   and cmdq_mbox_shoutdown() will be called after cmdq_remove().
2. CMDQ driver also uses devm_pm_runtime_enable() in cmdq_probe() after
   devm_mbox_controller_register(), so that devm_pm_runtime_disable()
   will be called after cmdq_remove(), but before
   devm_mbox_controller_unregister().

To fix this problem, cmdq_probe() needs to move
devm_mbox_controller_register() after devm_pm_runtime_enable() to make
devm_pm_runtime_disable() be called after
devm_mbox_controller_unregister().

Fixes: 623a6143a845 ("mailbox: mediatek: Add Mediatek CMDQ driver")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
---
 drivers/mailbox/mtk-cmdq-mailbox.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index 4d62b07c1411..d5f5606585f4 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c
@@ -623,12 +623,6 @@ static int cmdq_probe(struct platform_device *pdev)
 		cmdq->mbox.chans[i].con_priv = (void *)&cmdq->thread[i];
 	}
 
-	err = devm_mbox_controller_register(dev, &cmdq->mbox);
-	if (err < 0) {
-		dev_err(dev, "failed to register mailbox: %d\n", err);
-		return err;
-	}
-
 	platform_set_drvdata(pdev, cmdq);
 
 	WARN_ON(clk_bulk_prepare(cmdq->pdata->gce_num, cmdq->clocks));
@@ -642,6 +636,12 @@ static int cmdq_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	err = devm_mbox_controller_register(dev, &cmdq->mbox);
+	if (err < 0) {
+		dev_err(dev, "failed to register mailbox: %d\n", err);
+		return err;
+	}
+
 	return 0;
 }
 
-- 
2.34.1

Re: [PATCH 6.6] mailbox: mtk-cmdq: Move devm_mbox_controller_register() after devm_pm_runtime_enable()

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: a8bd68e4329f9a0ad1b878733e0f80be6a971649

WARNING: Author mismatch between patch and upstream commit:
Backport author: bin.lan.cn@eng.windriver.com
Commit author: Jason-JH.Lin <jason-jh.lin@mediatek.com>


Status in newer kernel trees:
6.12.y | Present (exact SHA1)
6.11.y | Present (exact SHA1)
6.6.y | Not found

Note: The patch differs from the upstream commit:
---
--- -	2024-11-28 07:03:31.668427430 -0500
+++ /tmp/tmp.wAGCAEZAC5	2024-11-28 07:03:31.661714582 -0500
@@ -1,3 +1,5 @@
+[ Upstream commit a8bd68e4329f9a0ad1b878733e0f80be6a971649 ]
+
 When mtk-cmdq unbinds, a WARN_ON message with condition
 pm_runtime_get_sync() < 0 occurs.
 
@@ -30,15 +32,16 @@
 Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
 Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
 Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>
+Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
 ---
  drivers/mailbox/mtk-cmdq-mailbox.c | 12 ++++++------
  1 file changed, 6 insertions(+), 6 deletions(-)
 
 diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
-index f1dfce9e27f5e..4bff73532085b 100644
+index 4d62b07c1411..d5f5606585f4 100644
 --- a/drivers/mailbox/mtk-cmdq-mailbox.c
 +++ b/drivers/mailbox/mtk-cmdq-mailbox.c
-@@ -689,12 +689,6 @@ static int cmdq_probe(struct platform_device *pdev)
+@@ -623,12 +623,6 @@ static int cmdq_probe(struct platform_device *pdev)
  		cmdq->mbox.chans[i].con_priv = (void *)&cmdq->thread[i];
  	}
  
@@ -51,9 +54,9 @@
  	platform_set_drvdata(pdev, cmdq);
  
  	WARN_ON(clk_bulk_prepare(cmdq->pdata->gce_num, cmdq->clocks));
-@@ -722,6 +716,12 @@ static int cmdq_probe(struct platform_device *pdev)
- 	pm_runtime_set_autosuspend_delay(dev, CMDQ_MBOX_AUTOSUSPEND_DELAY_MS);
- 	pm_runtime_use_autosuspend(dev);
+@@ -642,6 +636,12 @@ static int cmdq_probe(struct platform_device *pdev)
+ 		return err;
+ 	}
  
 +	err = devm_mbox_controller_register(dev, &cmdq->mbox);
 +	if (err < 0) {
@@ -64,3 +67,6 @@
  	return 0;
  }
  
+-- 
+2.34.1
+
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.6.y        |  Success    |  Success   |