[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.

4 files changed, 65 insertions, 8 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(
diff --git a/examples/boot/application/stm32wb-dfu/src/main.rs b/examples/boot/application/stm32wb-dfu/src/main.rs
index dda2b795b..68e9bc3f6 100644
--- a/examples/boot/application/stm32wb-dfu/src/main.rs
+++ b/examples/boot/application/stm32wb-dfu/src/main.rs
@@ -13,7 +13,7 @@ use embassy_stm32::usb::{self, Driver};
 use embassy_stm32::{bind_interrupts, peripherals};
 use embassy_sync::blocking_mutex::Mutex;
 use embassy_time::Duration;
-use embassy_usb::Builder;
+use embassy_usb::{msos, Builder};
 use embassy_usb_dfu::consts::DfuAttributes;
 use embassy_usb_dfu::{usb_dfu, Control, ResetImmediate};
 use panic_reset as _;
@@ -22,6 +22,9 @@ bind_interrupts!(struct Irqs {
     USB_LP => usb::InterruptHandler<peripherals::USB>;
 });
 
+// This is a randomly generated GUID to allow clients on Windows to find our device
+const DEVICE_INTERFACE_GUIDS: &[&str] = &["{EAA9A5DC-30BA-44BC-9232-606CDC875321}"];
+
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     let mut config = embassy_stm32::Config::default();
@@ -54,7 +57,26 @@ async fn main(_spawner: Spawner) {
         &mut control_buf,
     );
 
-    usb_dfu(&mut builder, &mut state, Duration::from_millis(2500));
+    // 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.
+    builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
+
+    // In the case of non-composite devices, it seems that feature headers need to be on the device level.
+    // (As is implemented here)
+    //
+    // For composite devices however, they should be on the function level instead.
+    // (This is achieved by passing a GUID to the "usb_dfu" function)
+    builder.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
+    builder.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
+        "DeviceInterfaceGUIDs",
+        msos::PropertyData::RegMultiSz(DEVICE_INTERFACE_GUIDS),
+    ));
+
+    // For non-composite devices:
+    usb_dfu(&mut builder, &mut state, Duration::from_millis(2500), None);
+
+    // Or for composite devices:
+    // usb_dfu(&mut builder, &mut state, Duration::from_millis(2500), Some(DEVICE_INTERFACE_GUIDS));
 
     let mut dev = builder.build();
     dev.run().await
diff --git a/examples/boot/bootloader/stm32wb-dfu/src/main.rs b/examples/boot/bootloader/stm32wb-dfu/src/main.rs
index 28216806e..2cd7f859d 100644
--- a/examples/boot/bootloader/stm32wb-dfu/src/main.rs
+++ b/examples/boot/bootloader/stm32wb-dfu/src/main.rs
@@ -67,17 +67,24 @@ fn main() -> ! {
 
         // 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.
-        //
-        // It seems it is important for the DFU class that these headers be on the Device level.
-        //
         builder.msos_descriptor(msos::windows_version::WIN8_1, 2);
+
+        // In the case of non-composite devices, it seems that feature headers need to be on the device level.
+        // (As is implemented here)
+        //
+        // For composite devices however, they should be on the function level instead.
+        // (This is achieved by passing a GUID to the "usb_dfu" function)
         builder.msos_feature(msos::CompatibleIdFeatureDescriptor::new("WINUSB", ""));
         builder.msos_feature(msos::RegistryPropertyFeatureDescriptor::new(
             "DeviceInterfaceGUIDs",
             msos::PropertyData::RegMultiSz(DEVICE_INTERFACE_GUIDS),
         ));
 
-        usb_dfu::<_, _, _, _, 4096>(&mut builder, &mut state);
+        // For non-composite devices:
+        usb_dfu::<_, _, _, _, 4096>(&mut builder, &mut state, None);
+
+        // Or for composite devices:
+        // usb_dfu::<_, _, _, _, 4096>(&mut builder, &mut state, Some(DEVICE_INTERFACE_GUIDS));
 
         let mut dev = builder.build();
         embassy_futures::block_on(dev.run());