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@xxxxxx>
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
