[PATCH v2] wifi: ath10k: Drop of_get_property() call

[PATCH v2] wifi: ath10k: Drop of_get_property() call

[Rob Herring (Arm)]

There's no need to check the property presence and length before calling
of_property_read_u8_array() as it will return an error if the property
is missing or the length is too small. The return errno doesn't matter
to the caller, so no change in behavior there.

Change of_property_read_u8_array() to of_property_read_variable_u8_array()
as the former allows properties to be longer than the requested length.
Now the property has to be the exact length requested as the removed
check required.

This part of a larger effort to remove DT functions like
of_get_property() and of_find_property() which return raw DT data
having no reference counting.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
---
v2:
 - Add check that cal_data_len is non-zero
---
 drivers/net/wireless/ath/ath10k/core.c | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
index b3294287bce1..47206b171aa5 100644
--- a/drivers/net/wireless/ath/ath10k/core.c
+++ b/drivers/net/wireless/ath/ath10k/core.c
@@ -1889,39 +1889,29 @@ static int ath10k_download_cal_file(struct ath10k *ar,
 static int ath10k_download_cal_dt(struct ath10k *ar, const char *dt_name)
 {
 	struct device_node *node;
-	int data_len;
+	int data_len = ar->hw_params.cal_data_len;
 	void *data;
 	int ret;
 
 	node = ar->dev->of_node;
-	if (!node)
+	if (!node || !data_len)
 		/* Device Tree is optional, don't print any warnings if
 		 * there's no node for ath10k.
 		 */
 		return -ENOENT;
 
-	if (!of_get_property(node, dt_name, &data_len)) {
-		/* The calibration data node is optional */
-		return -ENOENT;
-	}
-
-	if (data_len != ar->hw_params.cal_data_len) {
-		ath10k_warn(ar, "invalid calibration data length in DT: %d\n",
-			    data_len);
-		ret = -EMSGSIZE;
-		goto out;
-	}
-
 	data = kmalloc(data_len, GFP_KERNEL);
 	if (!data) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
-	ret = of_property_read_u8_array(node, dt_name, data, data_len);
+	ret = of_property_read_variable_u8_array(node, dt_name, data, data_len, data_len);
 	if (ret) {
-		ath10k_warn(ar, "failed to read calibration data from DT: %d\n",
-			    ret);
+		/* Don't warn if optional property not found  */
+		if (ret != -EINVAL)
+			ath10k_warn(ar, "failed to read calibration data from DT: %d\n",
+				    ret);
 		goto out_free;
 	}
 
-- 
2.47.2

Re: [PATCH v2] wifi: ath10k: Drop of_get_property() call

[Jonas Gorski]

Hi,

On Sat, Mar 15, 2025 at 12:39 AM Rob Herring (Arm) <robh@kernel.org> wrote:
>
> There's no need to check the property presence and length before calling
> of_property_read_u8_array() as it will return an error if the property
> is missing or the length is too small. The return errno doesn't matter
> to the caller, so no change in behavior there.
>
> Change of_property_read_u8_array() to of_property_read_variable_u8_array()
> as the former allows properties to be longer than the requested length.
> Now the property has to be the exact length requested as the removed
> check required.
>
> This part of a larger effort to remove DT functions like
> of_get_property() and of_find_property() which return raw DT data
> having no reference counting.
>
> Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> ---
> v2:
>  - Add check that cal_data_len is non-zero
> ---
>  drivers/net/wireless/ath/ath10k/core.c | 24 +++++++-----------------
>  1 file changed, 7 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index b3294287bce1..47206b171aa5 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -1889,39 +1889,29 @@ static int ath10k_download_cal_file(struct ath10k *ar,
>  static int ath10k_download_cal_dt(struct ath10k *ar, const char *dt_name)
>  {
>         struct device_node *node;
> -       int data_len;
> +       int data_len = ar->hw_params.cal_data_len;
>         void *data;
>         int ret;
>
>         node = ar->dev->of_node;
> -       if (!node)
> +       if (!node || !data_len)
>                 /* Device Tree is optional, don't print any warnings if
>                  * there's no node for ath10k.
>                  */
>                 return -ENOENT;
>
> -       if (!of_get_property(node, dt_name, &data_len)) {
> -               /* The calibration data node is optional */
> -               return -ENOENT;
> -       }
> -
> -       if (data_len != ar->hw_params.cal_data_len) {
> -               ath10k_warn(ar, "invalid calibration data length in DT: %d\n",
> -                           data_len);
> -               ret = -EMSGSIZE;
> -               goto out;
> -       }
> -
>         data = kmalloc(data_len, GFP_KERNEL);
>         if (!data) {
>                 ret = -ENOMEM;
>                 goto out;
>         }
>
> -       ret = of_property_read_u8_array(node, dt_name, data, data_len);
> +       ret = of_property_read_variable_u8_array(node, dt_name, data, data_len, data_len);
>         if (ret) {

of_property_read_u8_array() returns 0 on success, but
of_property_read_variable_u8_array() returns the number of elements
read on success, so this check needs to be ret < 0 now.

> -               ath10k_warn(ar, "failed to read calibration data from DT: %d\n",
> -                           ret);
> +               /* Don't warn if optional property not found  */
> +               if (ret != -EINVAL)
> +                       ath10k_warn(ar, "failed to read calibration data from DT: %d\n",
> +                                   ret);

Best regards,
Jonas

Re: [PATCH v2] wifi: ath10k: Drop of_get_property() call

[Rob Herring]

On Sat, Mar 15, 2025 at 5:07 AM Jonas Gorski <jonas.gorski@gmail.com> wrote:
>
> Hi,
>
> On Sat, Mar 15, 2025 at 12:39 AM Rob Herring (Arm) <robh@kernel.org> wrote:
> >
> > There's no need to check the property presence and length before calling
> > of_property_read_u8_array() as it will return an error if the property
> > is missing or the length is too small. The return errno doesn't matter
> > to the caller, so no change in behavior there.
> >
> > Change of_property_read_u8_array() to of_property_read_variable_u8_array()
> > as the former allows properties to be longer than the requested length.
> > Now the property has to be the exact length requested as the removed
> > check required.
> >
> > This part of a larger effort to remove DT functions like
> > of_get_property() and of_find_property() which return raw DT data
> > having no reference counting.
> >
> > Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
> > ---
> > v2:
> >  - Add check that cal_data_len is non-zero
> > ---
> >  drivers/net/wireless/ath/ath10k/core.c | 24 +++++++-----------------
> >  1 file changed, 7 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> > index b3294287bce1..47206b171aa5 100644
> > --- a/drivers/net/wireless/ath/ath10k/core.c
> > +++ b/drivers/net/wireless/ath/ath10k/core.c
> > @@ -1889,39 +1889,29 @@ static int ath10k_download_cal_file(struct ath10k *ar,
> >  static int ath10k_download_cal_dt(struct ath10k *ar, const char *dt_name)
> >  {
> >         struct device_node *node;
> > -       int data_len;
> > +       int data_len = ar->hw_params.cal_data_len;
> >         void *data;
> >         int ret;
> >
> >         node = ar->dev->of_node;
> > -       if (!node)
> > +       if (!node || !data_len)
> >                 /* Device Tree is optional, don't print any warnings if
> >                  * there's no node for ath10k.
> >                  */
> >                 return -ENOENT;
> >
> > -       if (!of_get_property(node, dt_name, &data_len)) {
> > -               /* The calibration data node is optional */
> > -               return -ENOENT;
> > -       }
> > -
> > -       if (data_len != ar->hw_params.cal_data_len) {
> > -               ath10k_warn(ar, "invalid calibration data length in DT: %d\n",
> > -                           data_len);
> > -               ret = -EMSGSIZE;
> > -               goto out;
> > -       }
> > -
> >         data = kmalloc(data_len, GFP_KERNEL);
> >         if (!data) {
> >                 ret = -ENOMEM;
> >                 goto out;
> >         }
> >
> > -       ret = of_property_read_u8_array(node, dt_name, data, data_len);
> > +       ret = of_property_read_variable_u8_array(node, dt_name, data, data_len, data_len);
> >         if (ret) {
>
> of_property_read_u8_array() returns 0 on success, but
> of_property_read_variable_u8_array() returns the number of elements
> read on success, so this check needs to be ret < 0 now.

Indeed. Thanks for catching that.

Rob

Re: [PATCH v2] wifi: ath10k: Drop of_get_property() call

[Jeff Johnson]

On 3/17/2025 10:19 AM, Rob Herring wrote:
> On Sat, Mar 15, 2025 at 5:07 AM Jonas Gorski <jonas.gorski@gmail.com> wrote:
>> of_property_read_u8_array() returns 0 on success, but
>> of_property_read_variable_u8_array() returns the number of elements
>> read on success, so this check needs to be ret < 0 now.
> 
> Indeed. Thanks for catching that.

cleaning up patchwork. was there ever a v3?