Hi Armin,
Thank you for your work on this.
On 4/26/23 23:28, 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@xxxxxx>
> ---
> 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);
I would prefer this to have a normal kernel function prototype
which returns -errno rather then returning an acpi_status. E.g. :
/**
* 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: The number of WMI object instances, 0 if the GUID is not found.
*/
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))
return 0;
return wmidev_instance_count(&wblock->dev);
}
EXPORT_SYMBOL_GPL(wmi_instance_count);
This will also allow this to completely replace
the get_instance_count() function in dell-wmi-sysman.
Note I have just gone with always returning 0 here
on error. I guess you could look at the status and
return 0 for not-found and -errno for other errors
but I don't think any callers will care for the difference,
so just always returning 0 seems easier for callers to
deal with.
As always this is just a suggestion, let me know if
you think this is a bad idea.
Regards,
Hans
> +
> +/**
> + * 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
>
