[embassy-usb-dfu] support function level WinUSB GUIDs

This commit makes it possible to provide function level msos GUIDs to usb_dfu. This helps to ensure that composite DFU devices automatically get assigned the WinUSB driver on Windows.

2 files changed, 30 insertions, 2 deletions

diff --git a/embassy-usb-dfu/src/application.rs b/embassy-usb-dfu/src/application.rs
index 6ad07a78c..52a7ca951 100644
--- a/embassy-usb-dfu/src/application.rs
+++ b/embassy-usb-dfu/src/application.rs
@@ -2,7 +2,7 @@ use embassy_boot::BlockingFirmwareState;
 use embassy_time::{Duration, Instant};
 use embassy_usb::control::{InResponse, OutResponse, Recipient, RequestType};
 use embassy_usb::driver::Driver;
-use embassy_usb::{Builder, Handler};
+use embassy_usb::{msos, Builder, Handler};
 use embedded_storage::nor_flash::NorFlash;
 
 use crate::consts::{
@@ -130,8 +130,22 @@ pub fn usb_dfu<'d, D: Driver<'d>, MARK: DfuMarker, RST: Reset>(
     builder: &mut Builder<'d, D>,
     handler: &'d mut Control<MARK, RST>,
     timeout: Duration,
+    winusb_guids: Option<&'d [&str]>,
 ) {
     let mut func = builder.function(0x00, 0x00, 0x00);
+    if let Some(winusb_guids) = winusb_guids {
+        // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
+        // Otherwise users need to do this manually using a tool like Zadig.
+        //
+        // Adding them here on the function level appears to only work for compositive devices though.
+        // For non-composite devices they should be placed on the device level instead.
+        func.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
+        func.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
+            "DeviceInterfaceGUIDs",
+            msos::PropertyData::RegMultiSz(winusb_guids),
+        ));
+    }
+
     let mut iface = func.interface();
     let mut alt = iface.alt_setting(USB_CLASS_APPN_SPEC, APPN_SPEC_SUBCLASS_DFU, DFU_PROTOCOL_RT, None);
     let timeout = timeout.as_millis() as u16;
diff --git a/embassy-usb-dfu/src/dfu.rs b/embassy-usb-dfu/src/dfu.rs
index a98d6ab40..83feacaf8 100644
--- a/embassy-usb-dfu/src/dfu.rs
+++ b/embassy-usb-dfu/src/dfu.rs
@@ -1,7 +1,7 @@
 use embassy_boot::{AlignedBuffer, BlockingFirmwareUpdater, FirmwareUpdaterError};
 use embassy_usb::control::{InResponse, OutResponse, Recipient, RequestType};
 use embassy_usb::driver::Driver;
-use embassy_usb::{Builder, Handler};
+use embassy_usb::{msos, Builder, Handler};
 use embedded_storage::nor_flash::{NorFlash, NorFlashErrorKind};
 
 use crate::consts::{
@@ -186,8 +186,22 @@ impl<'d, DFU: NorFlash, STATE: NorFlash, RST: Reset, const BLOCK_SIZE: usize> Ha
 pub fn usb_dfu<'d, D: Driver<'d>, DFU: NorFlash, STATE: NorFlash, RST: Reset, const BLOCK_SIZE: usize>(
     builder: &mut Builder<'d, D>,
     handler: &'d mut Control<'d, DFU, STATE, RST, BLOCK_SIZE>,
+    winusb_guids: Option<&'d [&str]>,
 ) {
     let mut func = builder.function(USB_CLASS_APPN_SPEC, APPN_SPEC_SUBCLASS_DFU, DFU_PROTOCOL_DFU);
+    if let Some(winusb_guids) = winusb_guids {
+        // We add MSOS headers so that the device automatically gets assigned the WinUSB driver on Windows.
+        // Otherwise users need to do this manually using a tool like Zadig.
+        //
+        // Adding them here on the function level appears to only work for compositive devices though.
+        // For non-composite devices they should be placed on the device level instead.
+        func.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
+        func.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
+            "DeviceInterfaceGUIDs",
+            msos::PropertyData::RegMultiSz(winusb_guids),
+        ));
+    }
+
     let mut iface = func.interface();
     let mut alt = iface.alt_setting(USB_CLASS_APPN_SPEC, APPN_SPEC_SUBCLASS_DFU, DFU_PROTOCOL_DFU, None);
     alt.descriptor(