Add embassy-usb-dfu

embassy-boot/boot/src/boot_loader.rs

@@ -5,7 +5,7 @@ use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use embassy_sync::blocking_mutex::Mutex;
 use embedded_storage::nor_flash::{NorFlash, NorFlashError, NorFlashErrorKind};
 
-use crate::{State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC};
+use crate::{State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC, DFU_DETACH_MAGIC};
 
 /// Errors returned by bootloader
 #[derive(PartialEq, Eq, Debug)]
@@ -371,6 +371,8 @@ impl<ACTIVE: NorFlash, DFU: NorFlash, STATE: NorFlash> BootLoader<ACTIVE, DFU, S
 
         if !state_word.iter().any(|&b| b != SWAP_MAGIC) {
             Ok(State::Swap)
+        } else if !state_word.iter().any(|&b| b != DFU_DETACH_MAGIC) {
+            Ok(State::DfuDetach)
         } else {
             Ok(State::Boot)
         }

embassy-boot/boot/src/firmware_updater/asynch.rs

@@ -6,7 +6,7 @@ use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use embedded_storage_async::nor_flash::NorFlash;
 
 use super::FirmwareUpdaterConfig;
-use crate::{FirmwareUpdaterError, State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC};
+use crate::{FirmwareUpdaterError, State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC, DFU_DETACH_MAGIC};
 
 /// FirmwareUpdater is an application API for interacting with the BootLoader without the ability to
 /// 'mess up' the internal bootloader state
@@ -161,6 +161,12 @@ impl<'d, DFU: NorFlash, STATE: NorFlash> FirmwareUpdater<'d, DFU, STATE> {
         self.state.mark_updated().await
     }
 
+    /// Mark to trigger USB DFU on next boot.
+    pub async fn mark_dfu(&mut self) -> Result<(), FirmwareUpdaterError> {
+        self.state.verify_booted().await?;
+        self.state.mark_dfu().await
+    }
+
     /// Mark firmware boot successful and stop rollback on reset.
     pub async fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
         self.state.mark_booted().await
@@ -247,6 +253,11 @@ impl<'d, STATE: NorFlash> FirmwareState<'d, STATE> {
         self.set_magic(SWAP_MAGIC).await
     }
 
+    /// Mark to trigger USB DFU on next boot.
+    pub async fn mark_dfu(&mut self) -> Result<(), FirmwareUpdaterError> {
+        self.set_magic(DFU_DETACH_MAGIC).await
+    }
+
     /// Mark firmware boot successful and stop rollback on reset.
     pub async fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
         self.set_magic(BOOT_MAGIC).await

embassy-boot/boot/src/firmware_updater/blocking.rs

@@ -6,7 +6,7 @@ use embassy_sync::blocking_mutex::raw::NoopRawMutex;
 use embedded_storage::nor_flash::NorFlash;
 
 use super::FirmwareUpdaterConfig;
-use crate::{FirmwareUpdaterError, State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC};
+use crate::{FirmwareUpdaterError, State, BOOT_MAGIC, STATE_ERASE_VALUE, SWAP_MAGIC, DFU_DETACH_MAGIC};
 
 /// Blocking FirmwareUpdater is an application API for interacting with the BootLoader without the ability to
 /// 'mess up' the internal bootloader state
@@ -168,6 +168,12 @@ impl<'d, DFU: NorFlash, STATE: NorFlash> BlockingFirmwareUpdater<'d, DFU, STATE>
         self.state.mark_updated()
     }
 
+    /// Mark to trigger USB DFU device on next boot.
+    pub fn mark_dfu(&mut self) -> Result<(), FirmwareUpdaterError> {
+        self.state.verify_booted()?;
+        self.state.mark_dfu()
+    }
+
     /// Mark firmware boot successful and stop rollback on reset.
     pub fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
         self.state.mark_booted()
@@ -226,7 +232,7 @@ impl<'d, STATE: NorFlash> BlockingFirmwareState<'d, STATE> {
 
     // Make sure we are running a booted firmware to avoid reverting to a bad state.
     fn verify_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
-        if self.get_state()? == State::Boot {
+        if self.get_state()? == State::Boot || self.get_state()? == State::DfuDetach {
             Ok(())
         } else {
             Err(FirmwareUpdaterError::BadState)
@@ -243,6 +249,8 @@ impl<'d, STATE: NorFlash> BlockingFirmwareState<'d, STATE> {
 
         if !self.aligned.iter().any(|&b| b != SWAP_MAGIC) {
             Ok(State::Swap)
+        } else if !self.aligned.iter().any(|&b| b != DFU_DETACH_MAGIC) {
+            Ok(State::DfuDetach)
         } else {
             Ok(State::Boot)
         }
@@ -253,6 +261,11 @@ impl<'d, STATE: NorFlash> BlockingFirmwareState<'d, STATE> {
         self.set_magic(SWAP_MAGIC)
     }
 
+    /// Mark to trigger USB DFU on next boot.
+    pub fn mark_dfu(&mut self) -> Result<(), FirmwareUpdaterError> {
+        self.set_magic(DFU_DETACH_MAGIC)
+    }
+
     /// Mark firmware boot successful and stop rollback on reset.
     pub fn mark_booted(&mut self) -> Result<(), FirmwareUpdaterError> {
         self.set_magic(BOOT_MAGIC)

embassy-boot/boot/src/lib.rs

@@ -23,6 +23,7 @@ pub use firmware_updater::{
 
 pub(crate) const BOOT_MAGIC: u8 = 0xD0;
 pub(crate) const SWAP_MAGIC: u8 = 0xF0;
+pub(crate) const DFU_DETACH_MAGIC: u8 = 0xE0;
 
 /// The state of the bootloader after running prepare.
 #[derive(PartialEq, Eq, Debug)]
@@ -32,6 +33,8 @@ pub enum State {
     Boot,
     /// Bootloader has swapped the active partition with the dfu partition and will attempt boot.
     Swap,
+    /// Application has received a DFU_DETACH request over USB, and is rebooting into the bootloader to apply a DFU.
+    DfuDetach,
 }
 
 /// Buffer aligned to 32 byte boundary, largest known alignment requirement for embassy-boot.

embassy-boot/stm32/src/lib.rs

@@ -10,7 +10,10 @@ pub use embassy_boot::{
 use embedded_storage::nor_flash::NorFlash;
 
 /// A bootloader for STM32 devices.
-pub struct BootLoader;
+pub struct BootLoader {
+    /// The reported state of the bootloader after preparing for boot
+    pub state: State,
+}
 
 impl BootLoader {
     /// Inspect the bootloader state and perform actions required before booting, such as swapping firmware
@@ -19,8 +22,8 @@ impl BootLoader {
     ) -> Self {
         let mut aligned_buf = AlignedBuffer([0; BUFFER_SIZE]);
         let mut boot = embassy_boot::BootLoader::new(config);
-        boot.prepare_boot(aligned_buf.as_mut()).expect("Boot prepare error");
+        let state = boot.prepare_boot(aligned_buf.as_mut()).expect("Boot prepare error");
-        Self
+        Self { state }
     }
 
     /// Boots the application.

embassy-usb-dfu/Cargo.toml

@@ -0,0 +1,31 @@
+[package]
+edition = "2021"
+name = "embassy-usb-dfu"
+version = "0.1.0"
+description = "An implementation of the USB DFU 1.1 protocol, using embassy-boot"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/embassy-rs/embassy"
+categories = [
+    "embedded",
+    "no-std",
+    "asynchronous"
+]
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+bitflags = "2.4.1"
+cortex-m = { version = "0.7.7", features = ["inline-asm"] }
+defmt = { version = "0.3.5", optional = true }
+embassy-boot = { version = "0.1.1", path = "../embassy-boot/boot" }
+embassy-embedded-hal = { version = "0.1.0", path = "../embassy-embedded-hal" }
+embassy-futures = { version = "0.1.1", path = "../embassy-futures" }
+embassy-sync = { version = "0.5.0", path = "../embassy-sync" }
+embassy-time = { version = "0.2.0", path = "../embassy-time" }
+embassy-usb = { version = "0.1.0", path = "../embassy-usb", default-features = false }
+embedded-storage = { version = "0.3.1" }
+
+[features]
+bootloader = []
+application = []
+defmt = ["dep:defmt"]

embassy-usb-dfu/src/application.rs

@@ -0,0 +1,114 @@
+
+use embassy_boot::BlockingFirmwareUpdater;
+use embassy_time::{Instant, Duration};
+use embassy_usb::{Handler, control::{RequestType, Recipient, OutResponse, InResponse}, Builder, driver::Driver};
+use embedded_storage::nor_flash::NorFlash;
+
+use crate::consts::{DfuAttributes, Request, Status, State, USB_CLASS_APPN_SPEC, APPN_SPEC_SUBCLASS_DFU, DESC_DFU_FUNCTIONAL, DFU_PROTOCOL_RT};
+
+/// Internal state for the DFU class
+pub struct Control<'d, DFU: NorFlash, STATE: NorFlash> {
+    updater: BlockingFirmwareUpdater<'d, DFU, STATE>,
+    attrs: DfuAttributes,
+    state: State,
+    timeout: Option<Duration>,
+    detach_start: Option<Instant>,
+}
+
+impl<'d, DFU: NorFlash, STATE: NorFlash> Control<'d, DFU, STATE> {
+    pub fn new(updater: BlockingFirmwareUpdater<'d, DFU, STATE>, attrs: DfuAttributes) -> Self {
+        Control { updater, attrs, state: State::AppIdle, detach_start: None, timeout: None }
+    }
+}
+
+impl<'d, DFU: NorFlash, STATE: NorFlash> Handler for Control<'d, DFU, STATE> {
+    fn reset(&mut self) {
+        if let Some(start) = self.detach_start {
+            let delta = Instant::now() - start;
+            let timeout = self.timeout.unwrap();
+            #[cfg(feature = "defmt")]
+            defmt::info!("Received RESET with delta = {}, timeout = {}", delta.as_millis(), timeout.as_millis());
+            if delta < timeout {
+                self.updater.mark_dfu().expect("Failed to mark DFU mode in bootloader");
+                cortex_m::asm::dsb();
+                cortex_m::peripheral::SCB::sys_reset();
+            }
+        }
+    }
+
+    fn control_out(&mut self, req: embassy_usb::control::Request, _: &[u8]) -> Option<embassy_usb::control::OutResponse> {
+        if (req.request_type, req.recipient) != (RequestType::Class, Recipient::Interface) {
+            return None;
+        }
+
+        #[cfg(feature = "defmt")]
+        defmt::info!("Received request {}", req);
+
+        match Request::try_from(req.request) {
+            Ok(Request::Detach) => {
+                #[cfg(feature = "defmt")]
+                defmt::info!("Received DETACH, awaiting USB reset");
+                self.detach_start = Some(Instant::now());
+                self.timeout = Some(Duration::from_millis(req.value as u64));
+                self.state = State::AppDetach;
+                Some(OutResponse::Accepted)
+            }
+            _ => {
+                None
+            }
+        }
+    }
+
+    fn control_in<'a>(&'a mut self, req: embassy_usb::control::Request, buf: &'a mut [u8]) -> Option<embassy_usb::control::InResponse<'a>> {
+        if (req.request_type, req.recipient) != (RequestType::Class, Recipient::Interface) {
+            return None;
+        }
+
+        #[cfg(feature = "defmt")]
+        defmt::info!("Received request {}", req);
+
+        match Request::try_from(req.request) {
+            Ok(Request::GetStatus) => {
+                buf[0..6].copy_from_slice(&[Status::Ok as u8, 0x32, 0x00, 0x00, self.state as u8, 0x00]);
+                Some(InResponse::Accepted(buf))
+            }
+            _ => None
+        }
+    }
+}
+
+/// An implementation of the USB DFU 1.1 runtime protocol
+/// 
+/// This function will add a DFU interface descriptor to the provided Builder, and register the provided Control as a handler for the USB device. The USB builder can be used as normal once this is complete.
+/// The handler is responsive to DFU GetStatus and Detach commands. 
+/// 
+/// Once a detach command, followed by a USB reset is received by the host, a magic number will be written into the bootloader state partition to indicate that
+/// it should expose a DFU device, and a software reset will be issued.
+/// 
+/// To apply USB DFU updates, the bootloader must be capable of recognizing the DFU magic and exposing a device to handle the full DFU transaction with the host.
+pub fn usb_dfu<'d, D: Driver<'d>, DFU: NorFlash, STATE: NorFlash>(builder: &mut Builder<'d, D>, handler: &'d mut Control<'d, DFU, STATE>, timeout: Duration) {
+    #[cfg(feature = "defmt")]
+    defmt::info!("Application USB DFU initializing");
+    let mut func = builder.function(0x00, 0x00, 0x00);
+    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;
+    alt.descriptor(
+        DESC_DFU_FUNCTIONAL,
+        &[
+            handler.attrs.bits(),
+            (timeout & 0xff) as u8,
+            ((timeout >> 8) & 0xff) as u8,
+            0x40, 0x00, // 64B control buffer size for application side
+            0x10, 0x01, // DFU 1.1
+        ],
+    );
+
+    drop(func);
+    builder.handler(handler); 
+}

embassy-usb-dfu/src/bootloader.rs

@@ -0,0 +1,196 @@
+use embassy_boot::BlockingFirmwareUpdater;
+use embassy_usb::{
+    control::{InResponse, OutResponse, Recipient, RequestType},
+    driver::Driver,
+    Builder, Handler,
+};
+use embedded_storage::nor_flash::{NorFlashErrorKind, NorFlash};
+
+use crate::consts::{DfuAttributes, Request, State, Status, USB_CLASS_APPN_SPEC, APPN_SPEC_SUBCLASS_DFU, DFU_PROTOCOL_DFU, DESC_DFU_FUNCTIONAL};
+
+/// Internal state for USB DFU
+pub struct Control<'d, DFU: NorFlash, STATE: NorFlash, const BLOCK_SIZE: usize> {
+    updater: BlockingFirmwareUpdater<'d, DFU, STATE>,
+    attrs: DfuAttributes,
+    state: State,
+    status: Status,
+    offset: usize,
+}
+
+impl<'d, DFU: NorFlash, STATE: NorFlash, const BLOCK_SIZE: usize> Control<'d, DFU, STATE, BLOCK_SIZE> {
+    pub fn new(updater: BlockingFirmwareUpdater<'d, DFU, STATE>, attrs: DfuAttributes) -> Self {
+        Self {
+            updater,
+            attrs,
+            state: State::DfuIdle,
+            status: Status::Ok,
+            offset: 0,
+        }
+    }
+
+    fn reset_state(&mut self) {
+        self.offset = 0;
+        self.state = State::DfuIdle;
+        self.status = Status::Ok;
+    }
+}
+
+impl<'d, DFU: NorFlash, STATE: NorFlash, const BLOCK_SIZE: usize> Handler for Control<'d, DFU, STATE, BLOCK_SIZE> {
+    fn control_out(
+        &mut self,
+        req: embassy_usb::control::Request,
+        data: &[u8],
+    ) -> Option<embassy_usb::control::OutResponse> {
+        if (req.request_type, req.recipient) != (RequestType::Class, Recipient::Interface) {
+            return None;
+        }
+        match Request::try_from(req.request) {
+            Ok(Request::Abort) => {
+                self.reset_state();
+                Some(OutResponse::Accepted)
+            }
+            Ok(Request::Dnload) if self.attrs.contains(DfuAttributes::CAN_DOWNLOAD) => {
+                if req.value == 0 {
+                    self.state = State::Download;
+                    self.offset = 0;
+                }
+
+                let mut buf = [0; BLOCK_SIZE];
+                buf[..data.len()].copy_from_slice(data);
+
+                if req.length == 0 {
+                    match self.updater.mark_updated() {
+                        Ok(_) => {
+                            self.status = Status::Ok;
+                            self.state = State::ManifestSync;
+                        }
+                        Err(e) => {
+                            self.state = State::Error;
+                            match e {
+                                embassy_boot::FirmwareUpdaterError::Flash(e) => match e {
+                                    NorFlashErrorKind::NotAligned => self.status = Status::ErrWrite,
+                                    NorFlashErrorKind::OutOfBounds => {
+                                        self.status = Status::ErrAddress
+                                    }
+                                    _ => self.status = Status::ErrUnknown,
+                                },
+                                embassy_boot::FirmwareUpdaterError::Signature(_) => {
+                                    self.status = Status::ErrVerify
+                                }
+                                embassy_boot::FirmwareUpdaterError::BadState => {
+                                    self.status = Status::ErrUnknown
+                                }
+                            }
+                        }
+                    }
+                } else {
+                    if self.state != State::Download {
+                        // Unexpected DNLOAD while chip is waiting for a GETSTATUS
+                        self.status = Status::ErrUnknown;
+                        self.state = State::Error;
+                        return Some(OutResponse::Rejected);
+                    }
+                    match self.updater.write_firmware(self.offset, &buf[..]) {
+                        Ok(_) => {
+                            self.status = Status::Ok;
+                            self.state = State::DlSync;
+                            self.offset += data.len();
+                        }
+                        Err(e) => {
+                            self.state = State::Error;
+                            match e {
+                                embassy_boot::FirmwareUpdaterError::Flash(e) => match e {
+                                    NorFlashErrorKind::NotAligned => self.status = Status::ErrWrite,
+                                    NorFlashErrorKind::OutOfBounds => {
+                                        self.status = Status::ErrAddress
+                                    }
+                                    _ => self.status = Status::ErrUnknown,
+                                },
+                                embassy_boot::FirmwareUpdaterError::Signature(_) => {
+                                    self.status = Status::ErrVerify
+                                }
+                                embassy_boot::FirmwareUpdaterError::BadState => {
+                                    self.status = Status::ErrUnknown
+                                }
+                            }
+                        }
+                    }
+                }
+
+                Some(OutResponse::Accepted)
+            }
+            Ok(Request::Detach) => Some(OutResponse::Accepted), // Device is already in DFU mode
+            Ok(Request::ClrStatus) => {
+                self.reset_state();
+                Some(OutResponse::Accepted)
+            }
+            _ => None,
+        }
+    }
+
+    fn control_in<'a>(
+        &'a mut self,
+        req: embassy_usb::control::Request,
+        buf: &'a mut [u8],
+    ) -> Option<embassy_usb::control::InResponse<'a>> {
+        if (req.request_type, req.recipient) != (RequestType::Class, Recipient::Interface) {
+            return None;
+        }
+        match Request::try_from(req.request) {
+            Ok(Request::GetStatus) => {
+                //TODO: Configurable poll timeout, ability to add string for Vendor error
+                buf[0..6].copy_from_slice(&[self.status as u8, 0x32, 0x00, 0x00, self.state as u8, 0x00]);
+                match self.state {
+                    State::DlSync => self.state = State::Download,
+                    State::ManifestSync => cortex_m::peripheral::SCB::sys_reset(),
+                    _ => {}
+                }
+
+                Some(InResponse::Accepted(&buf[0..6]))
+            }
+            Ok(Request::GetState) => {
+                buf[0] = self.state as u8;
+                Some(InResponse::Accepted(&buf[0..1]))
+            }
+            Ok(Request::Upload) if self.attrs.contains(DfuAttributes::CAN_UPLOAD) => {
+                //TODO: FirmwareUpdater does not provide a way of reading the active partition, can't upload.
+                Some(InResponse::Rejected)
+            }
+            _ => None,
+        }
+    }
+}
+
+/// An implementation of the USB DFU 1.1 protocol
+/// 
+/// This function will add a DFU interface descriptor to the provided Builder, and register the provided Control as a handler for the USB device
+/// The handler is responsive to DFU GetState, GetStatus, Abort, and ClrStatus commands, as well as Download if configured by the user.
+/// 
+/// Once the host has initiated a DFU download operation, the chunks sent by the host will be written to the DFU partition.
+/// Once the final sync in the manifestation phase has been received, the handler will trigger a system reset to swap the new firmware.
+pub fn usb_dfu<'d, D: Driver<'d>, DFU: NorFlash, STATE: NorFlash, const BLOCK_SIZE: usize>(
+    builder: &mut Builder<'d, D>,
+    handler: &'d mut Control<'d, DFU, STATE, BLOCK_SIZE>,
+) {
+    let mut func = builder.function(0x00, 0x00, 0x00);
+    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(
+        DESC_DFU_FUNCTIONAL,
+        &[
+            handler.attrs.bits(),
+            0xc4, 0x09, // 2500ms timeout, doesn't affect operation as DETACH not necessary in bootloader code
+            (BLOCK_SIZE & 0xff) as u8,
+            ((BLOCK_SIZE & 0xff00) >> 8) as u8,
+            0x10, 0x01, // DFU 1.1
+        ],
+    );
+
+    drop(func);
+    builder.handler(handler);
+}

embassy-usb-dfu/src/consts.rs

@@ -0,0 +1,96 @@
+
+pub(crate) const USB_CLASS_APPN_SPEC: u8 = 0xFE;
+pub(crate) const APPN_SPEC_SUBCLASS_DFU: u8 = 0x01;
+#[allow(unused)]
+pub(crate) const DFU_PROTOCOL_DFU: u8 = 0x02;
+#[allow(unused)]
+pub(crate) const DFU_PROTOCOL_RT: u8 = 0x01;
+pub(crate) const DESC_DFU_FUNCTIONAL: u8 = 0x21;
+
+#[cfg(feature = "defmt")]
+defmt::bitflags! {
+    pub struct DfuAttributes: u8 {
+        const WILL_DETACH = 0b0000_1000;
+        const MANIFESTATION_TOLERANT = 0b0000_0100;
+        const CAN_UPLOAD = 0b0000_0010;
+        const CAN_DOWNLOAD = 0b0000_0001;
+    }
+}
+
+#[cfg(not(feature = "defmt"))]
+bitflags::bitflags! {
+    pub struct DfuAttributes: u8 {
+        const WILL_DETACH = 0b0000_1000;
+        const MANIFESTATION_TOLERANT = 0b0000_0100;
+        const CAN_UPLOAD = 0b0000_0010;
+        const CAN_DOWNLOAD = 0b0000_0001;
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+#[repr(u8)]
+#[allow(unused)]
+pub enum State {
+    AppIdle = 0,
+    AppDetach = 1,
+    DfuIdle = 2,
+    DlSync = 3,
+    DlBusy = 4,
+    Download = 5,
+    ManifestSync = 6,
+    Manifest = 7,
+    ManifestWaitReset = 8,
+    UploadIdle = 9,
+    Error = 10,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+#[repr(u8)]
+#[allow(unused)]
+pub enum Status {
+    Ok = 0x00,
+    ErrTarget = 0x01,
+    ErrFile = 0x02,
+    ErrWrite = 0x03,
+    ErrErase = 0x04,
+    ErrCheckErased = 0x05,
+    ErrProg = 0x06,
+    ErrVerify = 0x07,
+    ErrAddress = 0x08,
+    ErrNotDone = 0x09,
+    ErrFirmware = 0x0A,
+    ErrVendor = 0x0B,
+    ErrUsbr = 0x0C,
+    ErrPor = 0x0D,
+    ErrUnknown = 0x0E,
+    ErrStalledPkt = 0x0F,
+}
+
+#[derive(Copy, Clone, PartialEq, Eq)]
+#[repr(u8)]
+pub enum Request {
+    Detach = 0,
+    Dnload = 1,
+    Upload = 2,
+    GetStatus = 3,
+    ClrStatus = 4,
+    GetState = 5,
+    Abort = 6,
+}
+
+impl TryFrom<u8> for Request {
+    type Error = ();
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            0 => Ok(Request::Detach),
+            1 => Ok(Request::Dnload),
+            2 => Ok(Request::Upload),
+            3 => Ok(Request::GetStatus),
+            4 => Ok(Request::ClrStatus),
+            5 => Ok(Request::GetState),
+            6 => Ok(Request::Abort),
+            _ => Err(()),
+        }
+    }
+}

embassy-usb-dfu/src/lib.rs

@@ -0,0 +1,16 @@
+#![no_std]
+
+pub mod consts;
+
+#[cfg(feature = "bootloader")]
+mod bootloader;
+#[cfg(feature = "bootloader")]
+pub use self::bootloader::*;
+
+#[cfg(feature = "application")]
+mod application;
+#[cfg(feature = "application")]
+pub use self::application::*;
+
+#[cfg(any(all(feature = "bootloader", feature = "application"), not(any(feature = "bootloader", feature = "application"))))]
+compile_error!("usb-dfu must be compiled with exactly one of `bootloader`, or `application` features");