linux-kernel - RE: [RFC] platform/x86: wmi: Allow retrieving the number of WMI object instances

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Message-ID: <MN0PR12MB6101B03167C55AA342FE69F8E2659@MN0PR12MB6101.namprd12.prod.outlook.com>
Date:   Wed, 26 Apr 2023 21:06:57 +0000
From:   "Limonciello, Mario" <Mario.Limonciello@....com>
To:     Armin Wolf <W_Armin@....de>,
        "hdegoede@...hat.com" <hdegoede@...hat.com>,
        "markgross@...nel.org" <markgross@...nel.org>
CC:     "prasanth.ksr@...l.com" <prasanth.ksr@...l.com>,
        "jorgealtxwork@...il.com" <jorgealtxwork@...il.com>,
        "james@...iv.tech" <james@...iv.tech>,
        "Dell.Client.Kernel@...l.com" <Dell.Client.Kernel@...l.com>,
        "platform-driver-x86@...r.kernel.org" 
        <platform-driver-x86@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [RFC] platform/x86: wmi: Allow retrieving the number of WMI
 object instances

[Public]



> -----Original Message-----
> From: Armin Wolf <W_Armin@....de>
> Sent: Wednesday, April 26, 2023 16:04
> To: hdegoede@...hat.com; markgross@...nel.org
> Cc: Limonciello, Mario <Mario.Limonciello@....com>;
> prasanth.ksr@...l.com; jorgealtxwork@...il.com; james@...iv.tech;
> Dell.Client.Kernel@...l.com; platform-driver-x86@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: [RFC] platform/x86: wmi: Allow retrieving the number of WMI
> object instances
> 
> 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.
> 

Makes sense to me.  I think that you'll want to also update the dell driver
in the same series to use this instead.

> Signed-off-by: Armin Wolf <W_Armin@....de>
> ---
>  drivers/platform/x86/wmi.c | 40
> ++++++++++++++++++++++++++++++++++++++
>  include/linux/acpi.h       |  2 ++
>  include/linux/wmi.h        |  2 ++
>  3 files changed, 44 insertions(+)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index c226dd4163a1..7c1a904dec5f 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -263,6 +263,46 @@ 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
> + * @instance_count: variable to hold the instance count
> + *
> + * Get the number of WMI object instances.
> + *
> + * Returns: acpi_status signaling success or error.
> + */
> +acpi_status wmi_instance_count(const char *guid_string, u8
> *instance_count)
> +{
> +	struct wmi_block *wblock;
> +	acpi_status status;
> +
> +	status = find_guid(guid_string, &wblock);
> +	if (ACPI_FAILURE(status))
> +		return status;
> +
> +	*instance_count = wmidev_instance_count(&wblock->dev);
> +
> +	return AE_OK;
> +}
> +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..ab2a4b23e7a3 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);
> 
> +acpi_status wmi_instance_count(const char *guid, u8 *instance_count);
> +
>  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