platform/x86: dell-smbios-wmi: Disable userspace interface if missing hotfix

The Dell SMBIOS WMI interface will fail for some more complex calls unless
a WMI hotfix has been included.  Most platforms have this fix available in
a maintenance BIOS release.  In the case the driver is loaded on a
platform without this fix, disable the userspace interface.

A hotfix indicator is present in the dell-wmi-descriptor that represents
whether or not more complex calls will work properly.

"Simple" calls such as those used by dell-laptop and dell-wmi will continue
to work properly so dell-smbios-wmi should not be blocked from binding and
being used as the dell-smbios dispatcher.

Suggested-by: Girish Prakash <girish.prakash@dell.com>
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/platform/x86/dell-smbios-wmi.c b/drivers/platform/x86/dell-smbios-wmi.c
index 0cab1f9c35af..609557aa5868 100644
--- a/drivers/platform/x86/dell-smbios-wmi.c
+++ b/drivers/platform/x86/dell-smbios-wmi.c
@@ -147,7 +147,10 @@ fail_smbios_cmd:
 
 static int dell_smbios_wmi_probe(struct wmi_device *wdev)
 {
+	struct wmi_driver *wdriver =
+		container_of(wdev->dev.driver, struct wmi_driver, driver);
 	struct wmi_smbios_priv *priv;
+	u32 hotfix;
 	int count;
 	int ret;
 
@@ -164,6 +167,16 @@ static int dell_smbios_wmi_probe(struct wmi_device *wdev)
 	if (!dell_wmi_get_size(&priv->req_buf_size))
 		return -EPROBE_DEFER;
 
+	/* some SMBIOS calls fail unless BIOS contains hotfix */
+	if (!dell_wmi_get_hotfix(&hotfix))
+		return -EPROBE_DEFER;
+	if (!hotfix) {
+		dev_warn(&wdev->dev,
+			"WMI SMBIOS userspace interface not supported(%u), try upgrading to a newer BIOS\n",
+			hotfix);
+		wdriver->filter_callback = NULL;
+	}
+
 	/* add in the length object we will use internally with ioctl */
 	priv->req_buf_size += sizeof(u64);
 	ret = set_required_buffer_size(wdev, priv->req_buf_size);