platform/x86: dell-descriptor: Use new buffer-based WMI API

Use the new buffer-based WMI API to also support ACPI firmware
implementations that do not use ACPI buffers for the descriptor.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20260610203453.816254-2-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

diff --git a/drivers/platform/x86/dell/dell-wmi-descriptor.c b/drivers/platform/x86/dell/dell-wmi-descriptor.c
index c2a1802027190186cc364991a100515266a925a1..179d5678b3ad376589a081f57464cbba732f9e5b 100644 (file)
--- a/drivers/platform/x86/dell/dell-wmi-descriptor.c
+++ b/drivers/platform/x86/dell/dell-wmi-descriptor.c
@@ -7,14 +7,35 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/acpi.h>
+#include <linux/cleanup.h>
+#include <linux/compiler_attributes.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/types.h>
 #include <linux/wmi.h>
 #include "dell-wmi-descriptor.h"
 
 #define DELL_WMI_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
 
+/*
+ * Descriptor buffer is 128 byte long and contains:
+ *
+ *       Name             Offset  Length  Value
+ * Vendor Signature          0       4    "DELL"
+ * Object Signature          4       4    " WMI"
+ * WMI Interface Version     8       4    <version>
+ * WMI buffer length        12       4    <length>
+ * WMI hotfix number        16       4    <hotfix>
+ */
+struct descriptor {
+       /* Both fields are NOT null-terminated */
+       char vendor_signature[4] __nonstring;
+       char object_signature[4] __nonstring;
+       __le32 interface_version;
+       __le32 buffer_length;
+       __le32 hotfix_number;
+} __packed;
+
 struct descriptor_priv {
        struct list_head list;
        u32 interface_version;
@@ -88,77 +109,46 @@ bool dell_wmi_get_hotfix(u32 *hotfix)
 }
 EXPORT_SYMBOL_GPL(dell_wmi_get_hotfix);
 
-/*
- * Descriptor buffer is 128 byte long and contains:
- *
- *       Name             Offset  Length  Value
- * Vendor Signature          0       4    "DELL"
- * Object Signature          4       4    " WMI"
- * WMI Interface Version     8       4    <version>
- * WMI buffer length        12       4    <length>
- * WMI hotfix number        16       4    <hotfix>
- */
-static int dell_wmi_descriptor_probe(struct wmi_device *wdev,
-                                    const void *context)
+static int dell_wmi_descriptor_probe(struct wmi_device *wdev, const void *context)
 {
-       union acpi_object *obj = NULL;
        struct descriptor_priv *priv;
-       u32 *buffer;
+       struct wmi_buffer buffer;
        int ret;
 
-       obj = wmidev_block_query(wdev, 0);
-       if (!obj) {
-               dev_err(&wdev->dev, "failed to read Dell WMI descriptor\n");
-               ret = -EIO;
-               goto out;
-       }
-
-       if (obj->type != ACPI_TYPE_BUFFER) {
-               dev_err(&wdev->dev, "Dell descriptor has wrong type\n");
-               ret = -EINVAL;
+       ret = wmidev_query_block(wdev, 0, &buffer, sizeof(struct descriptor));
+       if (ret < 0) {
                descriptor_valid = ret;
-               goto out;
+               return ret;
        }
 
-       /* Although it's not technically a failure, this would lead to
-        * unexpected behavior
-        */
-       if (obj->buffer.length != 128) {
-               dev_err(&wdev->dev,
-                       "Dell descriptor buffer has unexpected length (%d)\n",
-                       obj->buffer.length);
-               ret = -EINVAL;
-               descriptor_valid = ret;
-               goto out;
-       }
+       struct descriptor *desc __free(kfree) = buffer.data;
 
-       buffer = (u32 *)obj->buffer.pointer;
+       if (strncmp(desc->vendor_signature, "DELL", sizeof(desc->vendor_signature))) {
+               dev_err(&wdev->dev, "Dell descriptor buffer has invalid vendor signature (%4ph)\n",
+                       desc->vendor_signature);
+               descriptor_valid = -ENOMSG;
+               return -ENOMSG;
+       }
 
-       if (strncmp(obj->string.pointer, "DELL WMI", 8) != 0) {
-               dev_err(&wdev->dev, "Dell descriptor buffer has invalid signature (%8ph)\n",
-                       buffer);
-               ret = -EINVAL;
-               descriptor_valid = ret;
-               goto out;
+       if (strncmp(desc->object_signature, " WMI", sizeof(desc->object_signature))) {
+               dev_err(&wdev->dev, "Dell descriptor buffer has invalid object signature (%4ph)\n",
+                       desc->object_signature);
+               descriptor_valid = -ENOMSG;
+               return -ENOMSG;
        }
        descriptor_valid = 0;
 
-       if (buffer[2] != 0 && buffer[2] != 1)
-               dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%lu)\n",
-                       (unsigned long) buffer[2]);
-
-       priv = devm_kzalloc(&wdev->dev, sizeof(struct descriptor_priv),
-       GFP_KERNEL);
+       if (le32_to_cpu(desc->interface_version) > 1)
+               dev_warn(&wdev->dev, "Dell descriptor buffer has unknown version (%u)\n",
+                        le32_to_cpu(desc->interface_version));
 
-       if (!priv) {
-               ret = -ENOMEM;
-               goto out;
-       }
+       priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
+       if (!priv)
+               return -ENOMEM;
 
-       priv->interface_version = buffer[2];
-       priv->size = buffer[3];
-       priv->hotfix = buffer[4];
-       ret = 0;
+       priv->interface_version = le32_to_cpu(desc->interface_version);
+       priv->size = le32_to_cpu(desc->buffer_length);
+       priv->hotfix = le32_to_cpu(desc->hotfix_number);
        dev_set_drvdata(&wdev->dev, priv);
        mutex_lock(&list_mutex);
        list_add_tail(&priv->list, &wmi_list);
@@ -169,8 +159,6 @@ static int dell_wmi_descriptor_probe(struct wmi_device *wdev,
                (unsigned long) priv->size,
                (unsigned long) priv->hotfix);
 
-out:
-       kfree(obj);
        return ret;
 }