[PATCH 0/2] platform/x86: Allow retrieving the number of WMI object instances

[PATCH 0/2] platform/x86: Allow retrieving the number of WMI object instances

[Armin Wolf]

This patch series allows WMI drivers to retrieve the number of
WMI object instances. This functionality benefits several current
and upcoming WMI drivers, the dell-wmi-sysman driver is converted
to use this new API as an example.

The changes are compile-tested only, the change to the dell-wmi-sysman
driver also needs to be tested on real hardware.

Changes since RFC v2:
- modify wmi_instance_count() to return an integer

Armin Wolf (2):
  platform/x86: wmi: Allow retrieving the number of WMI object instances
  platform/x86: dell-sysman: Improve instance detection

 .../x86/dell/dell-wmi-sysman/sysman.c         | 13 +++---
 drivers/platform/x86/wmi.c                    | 41 +++++++++++++++++++
 include/linux/acpi.h                          |  2 +
 include/linux/wmi.h                           |  2 +
 4 files changed, 50 insertions(+), 8 deletions(-)

--
2.30.2

[PATCH 1/2] platform/x86: wmi: Allow retrieving the number of WMI object instances

[Armin Wolf]

Currently, the WMI driver core knows how many instances of a given
WMI object exist, but WMI drivers cannot access this information.
At the same time, some current and upcoming WMI drivers want to
have access to this information. Add wmi_instance_count() and
wmidev_instance_count() to allow WMI drivers to get the number of
WMI object instances.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/wmi.c | 41 ++++++++++++++++++++++++++++++++++++++
 include/linux/acpi.h       |  2 ++
 include/linux/wmi.h        |  2 ++
 3 files changed, 45 insertions(+)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index c226dd4163a1..5b95d7aa5c2f 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -263,6 +263,47 @@ int set_required_buffer_size(struct wmi_device *wdev, u64 length)
 }
 EXPORT_SYMBOL_GPL(set_required_buffer_size);

+/**
+ * wmi_instance_count - Get number of WMI object instances
+ * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
+ *
+ * Get the number of WMI object instances.
+ *
+ * Returns: Number of WMI object instances or negative error code.
+ */
+int wmi_instance_count(const char *guid_string)
+{
+	struct wmi_block *wblock;
+	acpi_status status;
+
+	status = find_guid(guid_string, &wblock);
+	if (ACPI_FAILURE(status)) {
+		if (status == AE_BAD_PARAMETER)
+			return -EINVAL;
+
+		return -ENODEV;
+	}
+
+	return wmidev_instance_count(&wblock->dev);
+}
+EXPORT_SYMBOL_GPL(wmi_instance_count);
+
+/**
+ * wmidev_instance_count - Get number of WMI object instances
+ * @wdev: A wmi bus device from a driver
+ *
+ * Get the number of WMI object instances.
+ *
+ * Returns: Number of WMI object instances.
+ */
+u8 wmidev_instance_count(struct wmi_device *wdev)
+{
+	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
+
+	return wblock->gblock.instance_count;
+}
+EXPORT_SYMBOL_GPL(wmidev_instance_count);
+
 /**
  * wmi_evaluate_method - Evaluate a WMI method (deprecated)
  * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index efff750f326d..e52bf2742eaf 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -412,6 +412,8 @@ extern bool acpi_is_pnp_device(struct acpi_device *);

 typedef void (*wmi_notify_handler) (u32 value, void *context);

+int wmi_instance_count(const char *guid);
+
 extern acpi_status wmi_evaluate_method(const char *guid, u8 instance,
 					u32 method_id,
 					const struct acpi_buffer *in,
diff --git a/include/linux/wmi.h b/include/linux/wmi.h
index c1a3bd4e4838..763bd382cf2d 100644
--- a/include/linux/wmi.h
+++ b/include/linux/wmi.h
@@ -35,6 +35,8 @@ extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev,
 extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
 					     u8 instance);

+u8 wmidev_instance_count(struct wmi_device *wdev);
+
 extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);

 /**
--
2.30.2

Re: [PATCH 1/2] platform/x86: wmi: Allow retrieving the number of WMI object instances

[Hans de Goede]

Hi Armin,

On 4/30/23 22:31, Armin Wolf wrote:
> Currently, the WMI driver core knows how many instances of a given
> WMI object exist, but WMI drivers cannot access this information.
> At the same time, some current and upcoming WMI drivers want to
> have access to this information. Add wmi_instance_count() and
> wmidev_instance_count() to allow WMI drivers to get the number of
> WMI object instances.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>

Thank you for your work on this.

> ---
>  drivers/platform/x86/wmi.c | 41 ++++++++++++++++++++++++++++++++++++++
>  include/linux/acpi.h       |  2 ++
>  include/linux/wmi.h        |  2 ++
>  3 files changed, 45 insertions(+)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index c226dd4163a1..5b95d7aa5c2f 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -263,6 +263,47 @@ int set_required_buffer_size(struct wmi_device *wdev, u64 length)
>  }
>  EXPORT_SYMBOL_GPL(set_required_buffer_size);
> 
> +/**
> + * wmi_instance_count - Get number of WMI object instances
> + * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
> + *
> + * Get the number of WMI object instances.
> + *
> + * Returns: Number of WMI object instances or negative error code.
> + */
> +int wmi_instance_count(const char *guid_string)
> +{
> +	struct wmi_block *wblock;
> +	acpi_status status;
> +
> +	status = find_guid(guid_string, &wblock);
> +	if (ACPI_FAILURE(status)) {
> +		if (status == AE_BAD_PARAMETER)
> +			return -EINVAL;
> +
> +		return -ENODEV;

Maybe just return 0 here ?

The GUID not existing at all does not seem like
an error to me, but rather a case of there
being 0 instances.

This will also allow patch 2/2 to completely
drop the get_instance_count() function and
replace its callers with direct calls to
wmi_instance_count() as the code is known
to always pass a valid GUID, so it won't hit
the -EINVAL path.

Regards,

Hans



> +	}
> +
> +	return wmidev_instance_count(&wblock->dev);
> +}
> +EXPORT_SYMBOL_GPL(wmi_instance_count);
> +
> +/**
> + * wmidev_instance_count - Get number of WMI object instances
> + * @wdev: A wmi bus device from a driver
> + *
> + * Get the number of WMI object instances.
> + *
> + * Returns: Number of WMI object instances.
> + */
> +u8 wmidev_instance_count(struct wmi_device *wdev)
> +{
> +	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
> +
> +	return wblock->gblock.instance_count;
> +}
> +EXPORT_SYMBOL_GPL(wmidev_instance_count);
> +
>  /**
>   * wmi_evaluate_method - Evaluate a WMI method (deprecated)
>   * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index efff750f326d..e52bf2742eaf 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -412,6 +412,8 @@ extern bool acpi_is_pnp_device(struct acpi_device *);
> 
>  typedef void (*wmi_notify_handler) (u32 value, void *context);
> 
> +int wmi_instance_count(const char *guid);
> +
>  extern acpi_status wmi_evaluate_method(const char *guid, u8 instance,
>  					u32 method_id,
>  					const struct acpi_buffer *in,
> diff --git a/include/linux/wmi.h b/include/linux/wmi.h
> index c1a3bd4e4838..763bd382cf2d 100644
> --- a/include/linux/wmi.h
> +++ b/include/linux/wmi.h
> @@ -35,6 +35,8 @@ extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev,
>  extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
>  					     u8 instance);
> 
> +u8 wmidev_instance_count(struct wmi_device *wdev);
> +
>  extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
> 
>  /**
> --
> 2.30.2
> 

Re: [PATCH 1/2] platform/x86: wmi: Allow retrieving the number of WMI object instances

[Armin Wolf]

Am 30.04.23 um 22:41 schrieb Hans de Goede:

> Hi Armin,
>
> On 4/30/23 22:31, Armin Wolf wrote:
>> Currently, the WMI driver core knows how many instances of a given
>> WMI object exist, but WMI drivers cannot access this information.
>> At the same time, some current and upcoming WMI drivers want to
>> have access to this information. Add wmi_instance_count() and
>> wmidev_instance_count() to allow WMI drivers to get the number of
>> WMI object instances.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> Thank you for your work on this.
>
>> ---
>>   drivers/platform/x86/wmi.c | 41 ++++++++++++++++++++++++++++++++++++++
>>   include/linux/acpi.h       |  2 ++
>>   include/linux/wmi.h        |  2 ++
>>   3 files changed, 45 insertions(+)
>>
>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>> index c226dd4163a1..5b95d7aa5c2f 100644
>> --- a/drivers/platform/x86/wmi.c
>> +++ b/drivers/platform/x86/wmi.c
>> @@ -263,6 +263,47 @@ int set_required_buffer_size(struct wmi_device *wdev, u64 length)
>>   }
>>   EXPORT_SYMBOL_GPL(set_required_buffer_size);
>>
>> +/**
>> + * wmi_instance_count - Get number of WMI object instances
>> + * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>> + *
>> + * Get the number of WMI object instances.
>> + *
>> + * Returns: Number of WMI object instances or negative error code.
>> + */
>> +int wmi_instance_count(const char *guid_string)
>> +{
>> +	struct wmi_block *wblock;
>> +	acpi_status status;
>> +
>> +	status = find_guid(guid_string, &wblock);
>> +	if (ACPI_FAILURE(status)) {
>> +		if (status == AE_BAD_PARAMETER)
>> +			return -EINVAL;
>> +
>> +		return -ENODEV;
> Maybe just return 0 here ?
>
> The GUID not existing at all does not seem like
> an error to me, but rather a case of there
> being 0 instances.
>
> This will also allow patch 2/2 to completely
> drop the get_instance_count() function and
> replace its callers with direct calls to
> wmi_instance_count() as the code is known
> to always pass a valid GUID, so it won't hit
> the -EINVAL path.
>
> Regards,
>
> Hans
>
Hi,

i would prefer returning -ENODEV instead of 0, so WMI drivers can
distinguish between "not found" and "zero instances". Also i do not
think that relying on the parameter of get_instance_count() always
being a valid GUID is a good idea, just in case wmi_instance_count()
is later modified to be able to encounter runtime errors.

Armin Wolf

>
>> +	}
>> +
>> +	return wmidev_instance_count(&wblock->dev);
>> +}
>> +EXPORT_SYMBOL_GPL(wmi_instance_count);
>> +
>> +/**
>> + * wmidev_instance_count - Get number of WMI object instances
>> + * @wdev: A wmi bus device from a driver
>> + *
>> + * Get the number of WMI object instances.
>> + *
>> + * Returns: Number of WMI object instances.
>> + */
>> +u8 wmidev_instance_count(struct wmi_device *wdev)
>> +{
>> +	struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
>> +
>> +	return wblock->gblock.instance_count;
>> +}
>> +EXPORT_SYMBOL_GPL(wmidev_instance_count);
>> +
>>   /**
>>    * wmi_evaluate_method - Evaluate a WMI method (deprecated)
>>    * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>> index efff750f326d..e52bf2742eaf 100644
>> --- a/include/linux/acpi.h
>> +++ b/include/linux/acpi.h
>> @@ -412,6 +412,8 @@ extern bool acpi_is_pnp_device(struct acpi_device *);
>>
>>   typedef void (*wmi_notify_handler) (u32 value, void *context);
>>
>> +int wmi_instance_count(const char *guid);
>> +
>>   extern acpi_status wmi_evaluate_method(const char *guid, u8 instance,
>>   					u32 method_id,
>>   					const struct acpi_buffer *in,
>> diff --git a/include/linux/wmi.h b/include/linux/wmi.h
>> index c1a3bd4e4838..763bd382cf2d 100644
>> --- a/include/linux/wmi.h
>> +++ b/include/linux/wmi.h
>> @@ -35,6 +35,8 @@ extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev,
>>   extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
>>   					     u8 instance);
>>
>> +u8 wmidev_instance_count(struct wmi_device *wdev);
>> +
>>   extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
>>
>>   /**
>> --
>> 2.30.2
>>

Re: [PATCH 1/2] platform/x86: wmi: Allow retrieving the number of WMI object instances

[Hans de Goede]

Hi,

On 4/30/23 23:01, Armin Wolf wrote:
> Am 30.04.23 um 22:41 schrieb Hans de Goede:
> 
>> Hi Armin,
>>
>> On 4/30/23 22:31, Armin Wolf wrote:
>>> Currently, the WMI driver core knows how many instances of a given
>>> WMI object exist, but WMI drivers cannot access this information.
>>> At the same time, some current and upcoming WMI drivers want to
>>> have access to this information. Add wmi_instance_count() and
>>> wmidev_instance_count() to allow WMI drivers to get the number of
>>> WMI object instances.
>>>
>>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> Thank you for your work on this.
>>
>>> ---
>>>   drivers/platform/x86/wmi.c | 41 ++++++++++++++++++++++++++++++++++++++
>>>   include/linux/acpi.h       |  2 ++
>>>   include/linux/wmi.h        |  2 ++
>>>   3 files changed, 45 insertions(+)
>>>
>>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>>> index c226dd4163a1..5b95d7aa5c2f 100644
>>> --- a/drivers/platform/x86/wmi.c
>>> +++ b/drivers/platform/x86/wmi.c
>>> @@ -263,6 +263,47 @@ int set_required_buffer_size(struct wmi_device *wdev, u64 length)
>>>   }
>>>   EXPORT_SYMBOL_GPL(set_required_buffer_size);
>>>
>>> +/**
>>> + * wmi_instance_count - Get number of WMI object instances
>>> + * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>> + *
>>> + * Get the number of WMI object instances.
>>> + *
>>> + * Returns: Number of WMI object instances or negative error code.
>>> + */
>>> +int wmi_instance_count(const char *guid_string)
>>> +{
>>> +    struct wmi_block *wblock;
>>> +    acpi_status status;
>>> +
>>> +    status = find_guid(guid_string, &wblock);
>>> +    if (ACPI_FAILURE(status)) {
>>> +        if (status == AE_BAD_PARAMETER)
>>> +            return -EINVAL;
>>> +
>>> +        return -ENODEV;
>> Maybe just return 0 here ?
>>
>> The GUID not existing at all does not seem like
>> an error to me, but rather a case of there
>> being 0 instances.
>>
>> This will also allow patch 2/2 to completely
>> drop the get_instance_count() function and
>> replace its callers with direct calls to
>> wmi_instance_count() as the code is known
>> to always pass a valid GUID, so it won't hit
>> the -EINVAL path.
>>
>> Regards,
>>
>> Hans
>>
> Hi,
> 
> i would prefer returning -ENODEV instead of 0, so WMI drivers can
> distinguish between "not found" and "zero instances".

Ah right, that is a good point, ok lets keep this as is then.

Regards,

Hans




> Also i do not
> think that relying on the parameter of get_instance_count() always
> being a valid GUID is a good idea, just in case wmi_instance_count()
> is later modified to be able to encounter runtime errors.
> 
> Armin Wolf
> 
>>
>>> +    }
>>> +
>>> +    return wmidev_instance_count(&wblock->dev);
>>> +}
>>> +EXPORT_SYMBOL_GPL(wmi_instance_count);
>>> +
>>> +/**
>>> + * wmidev_instance_count - Get number of WMI object instances
>>> + * @wdev: A wmi bus device from a driver
>>> + *
>>> + * Get the number of WMI object instances.
>>> + *
>>> + * Returns: Number of WMI object instances.
>>> + */
>>> +u8 wmidev_instance_count(struct wmi_device *wdev)
>>> +{
>>> +    struct wmi_block *wblock = container_of(wdev, struct wmi_block, dev);
>>> +
>>> +    return wblock->gblock.instance_count;
>>> +}
>>> +EXPORT_SYMBOL_GPL(wmidev_instance_count);
>>> +
>>>   /**
>>>    * wmi_evaluate_method - Evaluate a WMI method (deprecated)
>>>    * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
>>> index efff750f326d..e52bf2742eaf 100644
>>> --- a/include/linux/acpi.h
>>> +++ b/include/linux/acpi.h
>>> @@ -412,6 +412,8 @@ extern bool acpi_is_pnp_device(struct acpi_device *);
>>>
>>>   typedef void (*wmi_notify_handler) (u32 value, void *context);
>>>
>>> +int wmi_instance_count(const char *guid);
>>> +
>>>   extern acpi_status wmi_evaluate_method(const char *guid, u8 instance,
>>>                       u32 method_id,
>>>                       const struct acpi_buffer *in,
>>> diff --git a/include/linux/wmi.h b/include/linux/wmi.h
>>> index c1a3bd4e4838..763bd382cf2d 100644
>>> --- a/include/linux/wmi.h
>>> +++ b/include/linux/wmi.h
>>> @@ -35,6 +35,8 @@ extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev,
>>>   extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
>>>                            u8 instance);
>>>
>>> +u8 wmidev_instance_count(struct wmi_device *wdev);
>>> +
>>>   extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
>>>
>>>   /**
>>> -- 
>>> 2.30.2
>>>
> 

[PATCH 2/2] platform/x86: dell-sysman: Improve instance detection

[Armin Wolf]

The WMI driver core already knows how many WMI object instances
are available, use this information instead of probing the WMI object
manually.

Compile-tested only.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/dell/dell-wmi-sysman/sysman.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
index 0285b47d99d1..b68dd11cb892 100644
--- a/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
+++ b/drivers/platform/x86/dell/dell-wmi-sysman/sysman.c
@@ -303,16 +303,13 @@ union acpi_object *get_wmiobj_pointer(int instance_id, const char *guid_string)
  */
 int get_instance_count(const char *guid_string)
 {
-	union acpi_object *wmi_obj = NULL;
-	int i = 0;
+	int ret;

-	do {
-		kfree(wmi_obj);
-		wmi_obj = get_wmiobj_pointer(i, guid_string);
-		i++;
-	} while (wmi_obj);
+	ret = wmi_instance_count(guid_string);
+	if (ret < 0)
+		return 0;

-	return (i-1);
+	return ret;
 }

 /**
--
2.30.2

Re: [PATCH 0/2] platform/x86: Allow retrieving the number of WMI object instances

[Hans de Goede]

Hi,

On 4/30/23 22:31, Armin Wolf wrote:
> This patch series allows WMI drivers to retrieve the number of
> WMI object instances. This functionality benefits several current
> and upcoming WMI drivers, the dell-wmi-sysman driver is converted
> to use this new API as an example.
> 
> The changes are compile-tested only, the change to the dell-wmi-sysman
> driver also needs to be tested on real hardware.
> 
> Changes since RFC v2:
> - modify wmi_instance_count() to return an integer

Thank you for your patch-series, I've applied the series to my
review-hans branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans




> Armin Wolf (2):
>   platform/x86: wmi: Allow retrieving the number of WMI object instances
>   platform/x86: dell-sysman: Improve instance detection
> 
>  .../x86/dell/dell-wmi-sysman/sysman.c         | 13 +++---
>  drivers/platform/x86/wmi.c                    | 41 +++++++++++++++++++
>  include/linux/acpi.h                          |  2 +
>  include/linux/wmi.h                           |  2 +
>  4 files changed, 50 insertions(+), 8 deletions(-)
> 
> --
> 2.30.2
>