[PATCH v2 0/8] firmware: imx: scu: Misc update

[PATCH v2 0/8] firmware: imx: scu: Misc update

[Peng Fan]

various misc update for imx-scu.c and imx-scu-irq.c.
Patch 1 is a bug fix, but not critical.
For other patches, there is no real issue reported, I just reviewed
the code again and see some potential risk, so patch 2-4 is to
avoid potential issues. Other patches are misc patches, regarding
error code update, use devm_x API, suppress bind attr.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
Changes in v2:
- Update commit log for patch 2 per Frank.
- Keep free at one place for patch 2 per Frank
- Add R-b from Frank
- Link to v1: https://lore.kernel.org/r/20251014-imx-firmware-v1-0-ba00220613ca@nxp.com

---
Peng Fan (8):
      firmware: imx: scu-irq: fix OF node leak in
      firmware: imx: scu-irq: Free mailbox client on failure at imx_scu_enable_general_irq_channel()
      firmware: imx: scu-irq: Init workqueue before request mbox channel
      firmware: imx: scu-irq: Set mu_resource_id before get handle
      firmware: imx: scu-irq: Remove unused export of imx_scu_enable_general_irq_channel
      firmware: imx: scu: Update error code
      firmware: imx: scu: Suppress bind attrs
      firmware: imx: scu: Use devm_mutex_init

 drivers/firmware/imx/imx-scu-irq.c | 32 +++++++++++++++++---------------
 drivers/firmware/imx/imx-scu.c     | 11 +++++++----
 2 files changed, 24 insertions(+), 19 deletions(-)
---
base-commit: 2b763d4652393c90eaa771a5164502ec9dd965ae
change-id: 20251012-imx-firmware-492ba9230ef2

Best regards,
-- 
Peng Fan <peng.fan@nxp.com>

[PATCH v2 1/8] firmware: imx: scu-irq: fix OF node leak in

[Peng Fan]

imx_scu_enable_general_irq_channel() calls of_parse_phandle_with_args(),
but does not release the OF node reference. Add a of_node_put() call
to release the reference.

Fixes: 851826c7566e ("firmware: imx: enable imx scu general irq function")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu-irq.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 6125cccc9ba79cd3445a720935b5c0b276c83d73..f2b902e95b738fae90af9cbe54da4f488219906f 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -226,8 +226,10 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
 
 	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
-				       "#mbox-cells", 0, &spec))
+				       "#mbox-cells", 0, &spec)) {
 		i = of_alias_get_id(spec.np, "mu");
+		of_node_put(spec.np);
+	}
 
 	/* use mu1 as general mu irq channel if failed */
 	if (i < 0)

-- 
2.37.1

[PATCH v2 2/8] firmware: imx: scu-irq: Free mailbox client on failure at imx_scu_enable_general_irq_channel()

[Peng Fan]

The IRQ mailbox is an optional channel and does not need to be kept until
driver removal when an error occurs. Free the allocated memory in the
error path.

Add 'goto free_cl' when mbox_request_channel_byname() fails, to keep free
at one place.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu-irq.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index f2b902e95b738fae90af9cbe54da4f488219906f..d6fd04404e2a3113a6d22b1a580e6c0ac48f5975 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -219,8 +219,7 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 	if (IS_ERR(ch)) {
 		ret = PTR_ERR(ch);
 		dev_err(dev, "failed to request mbox chan gip3, ret %d\n", ret);
-		devm_kfree(dev, cl);
-		return ret;
+		goto free_cl;
 	}
 
 	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
@@ -255,6 +254,8 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 
 free_ch:
 	mbox_free_channel(ch);
+free_cl:
+	devm_kfree(dev, cl);
 
 	return ret;
 }

-- 
2.37.1

Re: [PATCH v2 2/8] firmware: imx: scu-irq: Free mailbox client on failure at imx_scu_enable_general_irq_channel()

[Frank Li]

On Fri, Oct 17, 2025 at 09:56:25AM +0800, Peng Fan wrote:
> The IRQ mailbox is an optional channel and does not need to be kept until
> driver removal when an error occurs. Free the allocated memory in the
> error path.
>
> Add 'goto free_cl' when mbox_request_channel_byname() fails, to keep free
> at one place.
>
> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>

>  drivers/firmware/imx/imx-scu-irq.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
> index f2b902e95b738fae90af9cbe54da4f488219906f..d6fd04404e2a3113a6d22b1a580e6c0ac48f5975 100644
> --- a/drivers/firmware/imx/imx-scu-irq.c
> +++ b/drivers/firmware/imx/imx-scu-irq.c
> @@ -219,8 +219,7 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
>  	if (IS_ERR(ch)) {
>  		ret = PTR_ERR(ch);
>  		dev_err(dev, "failed to request mbox chan gip3, ret %d\n", ret);
> -		devm_kfree(dev, cl);
> -		return ret;
> +		goto free_cl;
>  	}
>
>  	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
> @@ -255,6 +254,8 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
>
>  free_ch:
>  	mbox_free_channel(ch);
> +free_cl:
> +	devm_kfree(dev, cl);
>
>  	return ret;
>  }
>
> --
> 2.37.1
>

[PATCH v2 3/8] firmware: imx: scu-irq: Init workqueue before request mbox channel

[Peng Fan]

With mailbox channel requested, there is possibility that interrupts may
come in, so need to make sure the workqueue is initialized before
the queue is scheduled by mailbox rx callback.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu-irq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index d6fd04404e2a3113a6d22b1a580e6c0ac48f5975..2d7237188932632ffd4960796c7e73b69ceac7d5 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -214,6 +214,8 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 	cl->dev = dev;
 	cl->rx_callback = imx_scu_irq_callback;
 
+	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
+
 	/* SCU general IRQ uses general interrupt channel 3 */
 	ch = mbox_request_channel_byname(cl, "gip3");
 	if (IS_ERR(ch)) {
@@ -222,8 +224,6 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 		goto free_cl;
 	}
 
-	INIT_WORK(&imx_sc_irq_work, imx_scu_irq_work_handler);
-
 	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
 				       "#mbox-cells", 0, &spec)) {
 		i = of_alias_get_id(spec.np, "mu");

-- 
2.37.1

[PATCH v2 4/8] firmware: imx: scu-irq: Set mu_resource_id before get handle

[Peng Fan]

mu_resource_id is referenced in imx_scu_irq_get_status() and
imx_scu_irq_group_enable() which could be used by other modules, so
need to set correct value before using imx_sc_irq_ipc_handle in
SCU API call.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu-irq.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 2d7237188932632ffd4960796c7e73b69ceac7d5..3dda42be4e6b9a0df0b2b1ddcfb64dd112007e02 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -203,6 +203,18 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 	struct mbox_chan *ch;
 	int ret = 0, i = 0;
 
+	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
+				       "#mbox-cells", 0, &spec)) {
+		i = of_alias_get_id(spec.np, "mu");
+		of_node_put(spec.np);
+	}
+
+	/* use mu1 as general mu irq channel if failed */
+	if (i < 0)
+		i = 1;
+
+	mu_resource_id = IMX_SC_R_MU_0A + i;
+
 	ret = imx_scu_get_handle(&imx_sc_irq_ipc_handle);
 	if (ret)
 		return ret;
@@ -224,18 +236,6 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 		goto free_cl;
 	}
 
-	if (!of_parse_phandle_with_args(dev->of_node, "mboxes",
-				       "#mbox-cells", 0, &spec)) {
-		i = of_alias_get_id(spec.np, "mu");
-		of_node_put(spec.np);
-	}
-
-	/* use mu1 as general mu irq channel if failed */
-	if (i < 0)
-		i = 1;
-
-	mu_resource_id = IMX_SC_R_MU_0A + i;
-
 	/* Create directory under /sysfs/firmware */
 	wakeup_obj = kobject_create_and_add("scu_wakeup_source", firmware_kobj);
 	if (!wakeup_obj) {

-- 
2.37.1

[PATCH v2 5/8] firmware: imx: scu-irq: Remove unused export of imx_scu_enable_general_irq_channel

[Peng Fan]

Since its introduction, this symbol has not been used by any loadable
modules. It remains only referenced within imx-scu.c, which is always built
together with imx-scu-irq.c

As such, exporting imx_scu_enable_general_irq_channel is unnecessary, so
remove the export.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu-irq.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index 3dda42be4e6b9a0df0b2b1ddcfb64dd112007e02..a68d38f89254438c33588c3e17ce2f811eff0840 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -259,4 +259,3 @@ int imx_scu_enable_general_irq_channel(struct device *dev)
 
 	return ret;
 }
-EXPORT_SYMBOL(imx_scu_enable_general_irq_channel);

-- 
2.37.1

[PATCH v2 6/8] firmware: imx: scu: Update error code

[Peng Fan]

IMX_SC_ERR_NOTFOUND should map with -ENOENT, not -EEXIST. -ENODEV makes
more sense for IMX_SC_ERR_NOPOWER, and -ECOMM makes more sense for
IMX_SC_ERR_IPC.

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 8c28e25ddc8a650d2d191c40193cf1fb5e70bc35..6046156bc3c9abcd8f62b46f04571b1a9decc0eb 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -73,9 +73,9 @@ static int imx_sc_linux_errmap[IMX_SC_ERR_LAST] = {
 	-EACCES, /* IMX_SC_ERR_NOACCESS */
 	-EACCES, /* IMX_SC_ERR_LOCKED */
 	-ERANGE, /* IMX_SC_ERR_UNAVAILABLE */
-	-EEXIST, /* IMX_SC_ERR_NOTFOUND */
-	-EPERM,	 /* IMX_SC_ERR_NOPOWER */
-	-EPIPE,	 /* IMX_SC_ERR_IPC */
+	-ENOENT, /* IMX_SC_ERR_NOTFOUND */
+	-ENODEV, /* IMX_SC_ERR_NOPOWER */
+	-ECOMM,	 /* IMX_SC_ERR_IPC */
 	-EBUSY,	 /* IMX_SC_ERR_BUSY */
 	-EIO,	 /* IMX_SC_ERR_FAIL */
 };

-- 
2.37.1

[PATCH v2 7/8] firmware: imx: scu: Suppress bind attrs

[Peng Fan]

The SCU driver is critical for system working properly, it should
never be removed and binded again. So suppress the bind attrs

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 6046156bc3c9abcd8f62b46f04571b1a9decc0eb..630e3dba4db15961ae4d77273af6248be614145e 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -352,6 +352,7 @@ static struct platform_driver imx_scu_driver = {
 	.driver = {
 		.name = "imx-scu",
 		.of_match_table = imx_scu_match,
+		.suppress_bind_attrs = true,
 	},
 	.probe = imx_scu_probe,
 };

-- 
2.37.1

[PATCH v2 8/8] firmware: imx: scu: Use devm_mutex_init

[Peng Fan]

In normal case, there is no need to invoke mutex_destroy in error path,
but it is useful when CONFIG_DEBUG_MUTEXES, so use devm_mutex_init().

Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/firmware/imx/imx-scu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/imx/imx-scu.c b/drivers/firmware/imx/imx-scu.c
index 630e3dba4db15961ae4d77273af6248be614145e..67b267a7408a12deed77d2c8f52d5f64b239a408 100644
--- a/drivers/firmware/imx/imx-scu.c
+++ b/drivers/firmware/imx/imx-scu.c
@@ -324,7 +324,9 @@ static int imx_scu_probe(struct platform_device *pdev)
 	}
 
 	sc_ipc->dev = dev;
-	mutex_init(&sc_ipc->lock);
+	ret = devm_mutex_init(dev, &sc_ipc->lock);
+	if (ret)
+		return ret;
 	init_completion(&sc_ipc->done);
 
 	imx_sc_ipc_handle = sc_ipc;

-- 
2.37.1

Re: [PATCH v2 0/8] firmware: imx: scu: Misc update

[Shawn Guo]

On Fri, Oct 17, 2025 at 09:56:23AM +0800, Peng Fan wrote:
> Peng Fan (8):
>       firmware: imx: scu-irq: fix OF node leak in
>       firmware: imx: scu-irq: Free mailbox client on failure at imx_scu_enable_general_irq_channel()
>       firmware: imx: scu-irq: Init workqueue before request mbox channel
>       firmware: imx: scu-irq: Set mu_resource_id before get handle
>       firmware: imx: scu-irq: Remove unused export of imx_scu_enable_general_irq_channel
>       firmware: imx: scu: Update error code
>       firmware: imx: scu: Suppress bind attrs
>       firmware: imx: scu: Use devm_mutex_init

Applied all, thanks!