Merge branch 'embassy-rs:master' into qdec

21 files changed, 317 insertions, 399 deletions

diff --git a/ci.sh b/ci.sh
index c6fe9c4aa..00dc8cb9c 100755
--- a/ci.sh
+++ b/ci.sh
@@ -58,6 +58,7 @@ cargo batch  \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv8m.main-none-eabihf --features nightly,stm32l552ze,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv6m-none-eabi --features nightly,stm32wl54jc-cm0p,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32wle5ub,defmt,exti,time-driver-any,unstable-traits \
+    --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7m-none-eabi --features nightly,stm32f107vc,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-boot/nrf/Cargo.toml --target thumbv7em-none-eabi --features embassy-nrf/nrf52840 \
     --- build --release --manifest-path embassy-boot/stm32/Cargo.toml --target thumbv7em-none-eabi --features embassy-stm32/stm32wl55jc-cm4 \
     --- build --release --manifest-path docs/modules/ROOT/examples/basic/Cargo.toml --target thumbv7em-none-eabi \
diff --git a/embassy-nrf/src/usb.rs b/embassy-nrf/src/usb.rs
index c032b2cc5..1162946a9 100644
--- a/embassy-nrf/src/usb.rs
+++ b/embassy-nrf/src/usb.rs
@@ -143,58 +143,46 @@ impl<'d, T: Instance> driver::Driver<'d> for Driver<'d, T> {
 
     fn alloc_endpoint_in(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
-        max_packet_size: u16,
+        packet_size: u16,
         interval: u8,
     ) -> Result<Self::EndpointIn, driver::EndpointAllocError> {
-        let index = self
-            .alloc_in
-            .allocate(ep_addr, ep_type, max_packet_size, interval)?;
+        let index = self.alloc_in.allocate(ep_type)?;
         let ep_addr = EndpointAddress::from_parts(index, UsbDirection::In);
         Ok(Endpoint::new(EndpointInfo {
             addr: ep_addr,
             ep_type,
-            max_packet_size,
+            max_packet_size: packet_size,
             interval,
         }))
     }
 
     fn alloc_endpoint_out(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
-        max_packet_size: u16,
+        packet_size: u16,
         interval: u8,
     ) -> Result<Self::EndpointOut, driver::EndpointAllocError> {
-        let index = self
-            .alloc_out
-            .allocate(ep_addr, ep_type, max_packet_size, interval)?;
+        let index = self.alloc_out.allocate(ep_type)?;
         let ep_addr = EndpointAddress::from_parts(index, UsbDirection::Out);
         Ok(Endpoint::new(EndpointInfo {
             addr: ep_addr,
             ep_type,
-            max_packet_size,
+            max_packet_size: packet_size,
             interval,
         }))
     }
 
-    fn alloc_control_pipe(
-        &mut self,
-        max_packet_size: u16,
-    ) -> Result<Self::ControlPipe, driver::EndpointAllocError> {
-        self.alloc_endpoint_out(Some(0x00.into()), EndpointType::Control, max_packet_size, 0)?;
-        self.alloc_endpoint_in(Some(0x80.into()), EndpointType::Control, max_packet_size, 0)?;
-        Ok(ControlPipe {
-            _phantom: PhantomData,
-            max_packet_size,
-        })
-    }
-
-    fn into_bus(self) -> Self::Bus {
-        Bus {
-            phantom: PhantomData,
-        }
+    fn start(self, control_max_packet_size: u16) -> (Self::Bus, Self::ControlPipe) {
+        (
+            Bus {
+                phantom: PhantomData,
+            },
+            ControlPipe {
+                _phantom: PhantomData,
+                max_packet_size: control_max_packet_size,
+            },
+        )
     }
 }
 
@@ -681,8 +669,7 @@ impl<'d, T: Instance> driver::ControlPipe for ControlPipe<'d, T> {
             .await;
 
             // Reset shorts
-            regs.shorts
-                .modify(|_, w| w.ep0datadone_ep0status().clear_bit());
+            regs.shorts.write(|w| w);
             regs.events_ep0setup.reset();
 
             let mut buf = [0; 8];
@@ -746,7 +733,7 @@ impl<'d, T: Instance> driver::ControlPipe for ControlPipe<'d, T> {
             }
 
             regs.shorts
-                .modify(|_, w| w.ep0datadone_ep0status().bit(last_packet));
+                .write(|w| w.ep0datadone_ep0status().bit(last_packet));
 
             regs.intenset.write(|w| {
                 w.usbreset().set();
@@ -796,25 +783,14 @@ fn dma_end() {
 
 struct Allocator {
     used: u16,
-    // Buffers can be up to 64 Bytes since this is a Full-Speed implementation.
-    lens: [u8; 9],
 }
 
 impl Allocator {
     fn new() -> Self {
-        Self {
-            used: 0,
-            lens: [0; 9],
-        }
+        Self { used: 0 }
     }
 
-    fn allocate(
-        &mut self,
-        ep_addr: Option<EndpointAddress>,
-        ep_type: EndpointType,
-        max_packet_size: u16,
-        _interval: u8,
-    ) -> Result<usize, driver::EndpointAllocError> {
+    fn allocate(&mut self, ep_type: EndpointType) -> Result<usize, driver::EndpointAllocError> {
         // Endpoint addresses are fixed in hardware:
         // - 0x80 / 0x00 - Control        EP0
         // - 0x81 / 0x01 - Bulk/Interrupt EP1
@@ -828,27 +804,16 @@ impl Allocator {
 
         // Endpoint directions are allocated individually.
 
-        let alloc_index = if let Some(ep_addr) = ep_addr {
-            match (ep_addr.index(), ep_type) {
-                (0, EndpointType::Control) => {}
-                (8, EndpointType::Isochronous) => {}
-                (n, EndpointType::Bulk) | (n, EndpointType::Interrupt) if n >= 1 && n <= 7 => {}
-                _ => return Err(driver::EndpointAllocError),
-            }
-
-            ep_addr.index()
-        } else {
-            match ep_type {
-                EndpointType::Isochronous => 8,
-                EndpointType::Control => 0,
-                EndpointType::Interrupt | EndpointType::Bulk => {
-                    // Find rightmost zero bit in 1..=7
-                    let ones = (self.used >> 1).trailing_ones() as usize;
-                    if ones >= 7 {
-                        return Err(driver::EndpointAllocError);
-                    }
-                    ones + 1
+        let alloc_index = match ep_type {
+            EndpointType::Isochronous => 8,
+            EndpointType::Control => return Err(driver::EndpointAllocError),
+            EndpointType::Interrupt | EndpointType::Bulk => {
+                // Find rightmost zero bit in 1..=7
+                let ones = (self.used >> 1).trailing_ones() as usize;
+                if ones >= 7 {
+                    return Err(driver::EndpointAllocError);
                 }
+                ones + 1
             }
         };
 
@@ -857,7 +822,6 @@ impl Allocator {
         }
 
         self.used |= 1 << alloc_index;
-        self.lens[alloc_index] = max_packet_size as u8;
 
         Ok(alloc_index)
     }
diff --git a/embassy-rp/Cargo.toml b/embassy-rp/Cargo.toml
index 17fce54e5..9f295c759 100644
--- a/embassy-rp/Cargo.toml
+++ b/embassy-rp/Cargo.toml
@@ -15,7 +15,7 @@ flavors = [
 [features]
 
 # Reexport the PAC for the currently enabled chip at `embassy_rp::pac`.
-# This is unstable because semver-minor (non-breaking) releases of embassy-nrf may major-bump (breaking) the PAC version.
+# This is unstable because semver-minor (non-breaking) releases of embassy-rp may major-bump (breaking) the PAC version.
 # If this is an issue for you, you're encouraged to directly depend on a fixed version of the PAC.
 # There are no plans to make this stable.
 unstable-pac = []
diff --git a/embassy-rp/src/gpio.rs b/embassy-rp/src/gpio.rs
index 598759036..28dfce476 100644
--- a/embassy-rp/src/gpio.rs
+++ b/embassy-rp/src/gpio.rs
@@ -127,8 +127,9 @@ impl<'d, T: Pin> Output<'d, T> {
 
     /// Is the output pin set as low?
     pub fn is_set_low(&self) -> bool {
-        // todo
-        true
+        // Reading from SIO: GPIO_OUT gives the last value written.
+        let val = 1 << self.pin.pin();
+        unsafe { (self.pin.sio_out().value().read() & val) == 0 }
     }
 }
 
diff --git a/embassy-stm32/src/exti.rs b/embassy-stm32/src/exti.rs
index 957a1ca55..d065a5557 100644
--- a/embassy-stm32/src/exti.rs
+++ b/embassy-stm32/src/exti.rs
@@ -371,7 +371,7 @@ pub(crate) unsafe fn init() {
 
     foreach_exti_irq!(enable_irq);
 
-    #[cfg(not(any(rcc_wb, rcc_wl5, rcc_wle, rcc_f1)))]
+    #[cfg(not(any(rcc_wb, rcc_wl5, rcc_wle, stm32f1)))]
     <crate::peripherals::SYSCFG as crate::rcc::sealed::RccPeripheral>::enable();
     #[cfg(stm32f1)]
     <crate::peripherals::AFIO as crate::rcc::sealed::RccPeripheral>::enable();
diff --git a/embassy-stm32/src/gpio.rs b/embassy-stm32/src/gpio.rs
index 30f900316..b6982e91a 100644
--- a/embassy-stm32/src/gpio.rs
+++ b/embassy-stm32/src/gpio.rs
@@ -511,10 +511,19 @@ pub(crate) mod sealed {
             self.set_as_analog();
         }
 
-        #[cfg(gpio_v2)]
         #[inline]
         unsafe fn set_speed(&self, speed: Speed) {
             let pin = self._pin() as usize;
+
+            #[cfg(gpio_v1)]
+            {
+                let crlh = if pin < 8 { 0 } else { 1 };
+                self.block().cr(crlh).modify(|w| {
+                    w.set_mode(pin % 8, speed.into());
+                });
+            }
+
+            #[cfg(gpio_v2)]
             self.block()
                 .ospeedr()
                 .modify(|w| w.set_ospeedr(pin, speed.into()));
diff --git a/embassy-stm32/src/rcc/f3.rs b/embassy-stm32/src/rcc/f3.rs
index ababc4f90..c2aec04c4 100644
--- a/embassy-stm32/src/rcc/f3.rs
+++ b/embassy-stm32/src/rcc/f3.rs
@@ -93,7 +93,10 @@ pub(crate) unsafe fn init(config: Config) {
     assert!(pclk2 <= 72_000_000);
 
     // Set latency based on HCLK frquency
-    FLASH.acr().write(|w| {
+    // RM0316: "The prefetch buffer must be kept on when using a prescaler
+    // different from 1 on the AHB clock.", "Half-cycle access cannot be
+    // used when there is a prescaler different from 1 on the AHB clock"
+    FLASH.acr().modify(|w| {
         w.set_latency(if hclk <= 24_000_000 {
             Latency::WS0
         } else if hclk <= 48_000_000 {
@@ -101,11 +104,16 @@ pub(crate) unsafe fn init(config: Config) {
         } else {
             Latency::WS2
         });
+        if hpre_div != 1 {
+            w.set_hlfcya(false);
+            w.set_prftbe(true);
+        }
     });
 
     // Enable HSE
+    // RM0316: "Bits 31:26 Reserved, must be kept at reset value."
     if config.hse.is_some() {
-        RCC.cr().write(|w| {
+        RCC.cr().modify(|w| {
             w.set_hsebyp(config.bypass_hse);
             // We turn on clock security to switch to HSI when HSE fails
             w.set_csson(true);
@@ -115,27 +123,30 @@ pub(crate) unsafe fn init(config: Config) {
     }
 
     // Enable PLL
+    // RM0316: "Reserved, must be kept at reset value."
     if let Some(ref pll_config) = pll_config {
-        RCC.cfgr().write(|w| {
+        RCC.cfgr().modify(|w| {
             w.set_pllmul(pll_config.pll_mul);
             w.set_pllsrc(pll_config.pll_src);
         });
         if let Some(pll_div) = pll_config.pll_div {
-            RCC.cfgr2().write(|w| w.set_prediv(pll_div));
+            RCC.cfgr2().modify(|w| w.set_prediv(pll_div));
         }
         RCC.cr().modify(|w| w.set_pllon(true));
         while !RCC.cr().read().pllrdy() {}
     }
 
+    // CFGR has been written before (PLL) don't overwrite these settings
     if config.pll48 {
         let usb_pre = get_usb_pre(&config, sysclk, pclk1, &pll_config);
-        RCC.cfgr().write(|w| {
+        RCC.cfgr().modify(|w| {
             w.set_usbpre(usb_pre);
         });
     }
 
     // Set prescalers
-    RCC.cfgr().write(|w| {
+    // CFGR has been written before (PLL, PLL48) don't overwrite these settings
+    RCC.cfgr().modify(|w| {
         w.set_ppre2(ppre2_bits);
         w.set_ppre1(ppre1_bits);
         w.set_hpre(hpre_bits);
@@ -146,7 +157,8 @@ pub(crate) unsafe fn init(config: Config) {
     //  1 to 16 AHB cycles after write"
     cortex_m::asm::delay(16);
 
-    RCC.cfgr().write(|w| {
+    // CFGR has been written before (PLL, PLL48, clock divider) don't overwrite these settings
+    RCC.cfgr().modify(|w| {
         w.set_sw(match (pll_config, config.hse) {
             (Some(_), _) => Sw::PLL,
             (None, Some(_)) => Sw::HSE,
diff --git a/embassy-stm32/src/rcc/f7.rs b/embassy-stm32/src/rcc/f7.rs
index 9f2c63c16..f45a725ce 100644
--- a/embassy-stm32/src/rcc/f7.rs
+++ b/embassy-stm32/src/rcc/f7.rs
@@ -170,7 +170,7 @@ pub(crate) unsafe fn init(config: Config) {
     // Calculate real AHB clock
     let hclk = sysclk / hpre_div;
 
-    assert!(hclk < max::HCLK_MAX);
+    assert!(hclk <= max::HCLK_MAX);
 
     let pclk1 = config
         .pclk1
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index d3710b8c3..959e59265 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -4,7 +4,7 @@ use crate::time::Hertz;
 use core::mem::MaybeUninit;
 
 #[cfg_attr(rcc_f0, path = "f0.rs")]
-#[cfg_attr(rcc_f1, path = "f1.rs")]
+#[cfg_attr(any(rcc_f1, rcc_f1cl), path = "f1.rs")]
 #[cfg_attr(rcc_f2, path = "f2.rs")]
 #[cfg_attr(rcc_f3, path = "f3.rs")]
 #[cfg_attr(any(rcc_f4, rcc_f410), path = "f4.rs")]
@@ -56,7 +56,7 @@ pub struct Clocks {
     #[cfg(any(rcc_f2, rcc_f4, rcc_f410, rcc_f7))]
     pub pll48: Option<Hertz>,
 
-    #[cfg(rcc_f1)]
+    #[cfg(stm32f1)]
     pub adc: Hertz,
 
     #[cfg(any(rcc_h7, rcc_h7ab))]
diff --git a/embassy-stm32/src/usart/mod.rs b/embassy-stm32/src/usart/mod.rs
index 6feecd184..472680113 100644
--- a/embassy-stm32/src/usart/mod.rs
+++ b/embassy-stm32/src/usart/mod.rs
@@ -219,7 +219,11 @@ impl<'d, T: Instance, TxDma, RxDma> Uart<'d, T, TxDma, RxDma> {
                 w.set_ue(true);
                 w.set_te(true);
                 w.set_re(true);
-                w.set_m0(vals::M0::BIT8);
+                w.set_m0(if config.parity != Parity::ParityNone {
+                    vals::M0::BIT9
+                } else {
+                    vals::M0::BIT8
+                });
                 w.set_pce(config.parity != Parity::ParityNone);
                 w.set_ps(match config.parity {
                     Parity::ParityOdd => vals::Ps::ODD,
diff --git a/embassy-stm32/src/usb_otg.rs b/embassy-stm32/src/usb_otg.rs
index 21b890d7c..c3cd776ca 100644
--- a/embassy-stm32/src/usb_otg.rs
+++ b/embassy-stm32/src/usb_otg.rs
@@ -3,7 +3,6 @@ use embassy::util::Unborrow;
 use embassy_hal_common::unborrow;
 
 use crate::gpio::sealed::AFType;
-use crate::gpio::Speed;
 use crate::{peripherals, rcc::RccPeripheral};
 
 macro_rules! config_ulpi_pins {
@@ -13,7 +12,8 @@ macro_rules! config_ulpi_pins {
         critical_section::with(|_| unsafe {
             $(
                 $pin.set_as_af($pin.af_num(), AFType::OutputPushPull);
-                $pin.set_speed(Speed::VeryHigh);
+                #[cfg(gpio_v2)]
+                $pin.set_speed(crate::gpio::Speed::VeryHigh);
             )*
         })
     };
diff --git a/embassy-usb-ncm/src/lib.rs b/embassy-usb-ncm/src/lib.rs
index 3a5abee8d..71d0691d4 100644
--- a/embassy-usb-ncm/src/lib.rs
+++ b/embassy-usb-ncm/src/lib.rs
@@ -133,6 +133,7 @@ impl Default for ControlShared {
 struct CommControl<'a> {
     mac_addr_string: StringIndex,
     shared: &'a ControlShared,
+    mac_addr_str: [u8; 12],
 }
 
 impl<'d> ControlHandler for CommControl<'d> {
@@ -178,24 +179,20 @@ impl<'d> ControlHandler for CommControl<'d> {
         }
     }
 
-    fn get_string<'a>(
-        &'a mut self,
-        index: StringIndex,
-        _lang_id: u16,
-        buf: &'a mut [u8],
-    ) -> Option<&'a str> {
+    fn get_string(&mut self, index: StringIndex, _lang_id: u16) -> Option<&str> {
         if index == self.mac_addr_string {
             let mac_addr = self.shared.mac_addr.get();
+            let s = &mut self.mac_addr_str;
             for i in 0..12 {
                 let n = (mac_addr[i / 2] >> ((1 - i % 2) * 4)) & 0xF;
-                buf[i] = match n {
+                s[i] = match n {
                     0x0..=0x9 => b'0' + n,
                     0xA..=0xF => b'A' + n - 0xA,
                     _ => unreachable!(),
                 }
             }
 
-            Some(unsafe { core::str::from_utf8_unchecked(&buf[..12]) })
+            Some(unsafe { core::str::from_utf8_unchecked(s) })
         } else {
             warn!("unknown string index requested");
             None
@@ -244,6 +241,7 @@ impl<'d, D: Driver<'d>> CdcNcmClass<'d, D> {
         iface.handler(state.comm_control.write(CommControl {
             mac_addr_string,
             shared: &control_shared,
+            mac_addr_str: [0; 12],
         }));
         let comm_if = iface.interface_number();
         let mut alt = iface.alt_setting(USB_CLASS_CDC, CDC_SUBCLASS_NCM, CDC_PROTOCOL_NONE);
diff --git a/embassy-usb/src/builder.rs b/embassy-usb/src/builder.rs
index 8cf9c82a9..698a5f765 100644
--- a/embassy-usb/src/builder.rs
+++ b/embassy-usb/src/builder.rs
@@ -372,7 +372,6 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
 
     fn endpoint_in(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
         max_packet_size: u16,
         interval: u8,
@@ -380,7 +379,7 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
         let ep = self
             .builder
             .driver
-            .alloc_endpoint_in(ep_addr, ep_type, max_packet_size, interval)
+            .alloc_endpoint_in(ep_type, max_packet_size, interval)
             .expect("alloc_endpoint_in failed");
 
         self.builder.config_descriptor.endpoint(ep.info());
@@ -390,7 +389,6 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
 
     fn endpoint_out(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
         max_packet_size: u16,
         interval: u8,
@@ -398,7 +396,7 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
         let ep = self
             .builder
             .driver
-            .alloc_endpoint_out(ep_addr, ep_type, max_packet_size, interval)
+            .alloc_endpoint_out(ep_type, max_packet_size, interval)
             .expect("alloc_endpoint_out failed");
 
         self.builder.config_descriptor.endpoint(ep.info());
@@ -411,7 +409,7 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
     /// Descriptors are written in the order builder functions are called. Note that some
     /// classes care about the order.
     pub fn endpoint_bulk_in(&mut self, max_packet_size: u16) -> D::EndpointIn {
-        self.endpoint_in(None, EndpointType::Bulk, max_packet_size, 0)
+        self.endpoint_in(EndpointType::Bulk, max_packet_size, 0)
     }
 
     /// Allocate a BULK OUT endpoint and write its descriptor.
@@ -419,7 +417,7 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
     /// Descriptors are written in the order builder functions are called. Note that some
     /// classes care about the order.
     pub fn endpoint_bulk_out(&mut self, max_packet_size: u16) -> D::EndpointOut {
-        self.endpoint_out(None, EndpointType::Bulk, max_packet_size, 0)
+        self.endpoint_out(EndpointType::Bulk, max_packet_size, 0)
     }
 
     /// Allocate a INTERRUPT IN endpoint and write its descriptor.
@@ -427,11 +425,11 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> {
     /// Descriptors are written in the order builder functions are called. Note that some
     /// classes care about the order.
     pub fn endpoint_interrupt_in(&mut self, max_packet_size: u16, interval: u8) -> D::EndpointIn {
-        self.endpoint_in(None, EndpointType::Interrupt, max_packet_size, interval)
+        self.endpoint_in(EndpointType::Interrupt, max_packet_size, interval)
     }
 
     /// Allocate a INTERRUPT OUT endpoint and write its descriptor.
     pub fn endpoint_interrupt_out(&mut self, max_packet_size: u16, interval: u8) -> D::EndpointOut {
-        self.endpoint_out(None, EndpointType::Interrupt, max_packet_size, interval)
+        self.endpoint_out(EndpointType::Interrupt, max_packet_size, interval)
     }
 }
diff --git a/embassy-usb/src/control.rs b/embassy-usb/src/control.rs
index ff42f9d78..12e5303c3 100644
--- a/embassy-usb/src/control.rs
+++ b/embassy-usb/src/control.rs
@@ -1,8 +1,5 @@
 use core::mem;
 
-use crate::descriptor::DescriptorWriter;
-use crate::driver::{self, EndpointError};
-
 use super::types::*;
 
 /// Control request type.
@@ -191,151 +188,8 @@ pub trait ControlHandler {
     }
 
     /// Called when a GET_DESCRIPTOR STRING control request is received.
-    ///
-    /// Write the response string somewhere (usually to `buf`, but you may use another buffer
-    /// owned by yourself, or a static buffer), then return it.
-    fn get_string<'a>(
-        &'a mut self,
-        index: StringIndex,
-        lang_id: u16,
-        buf: &'a mut [u8],
-    ) -> Option<&'a str> {
-        let _ = (index, lang_id, buf);
+    fn get_string(&mut self, index: StringIndex, lang_id: u16) -> Option<&str> {
+        let _ = (index, lang_id);
         None
     }
 }
-
-/// Typestate representing a ControlPipe in the DATA IN stage
-#[derive(Debug)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub(crate) struct DataInStage {
-    pub(crate) length: usize,
-}
-
-/// Typestate representing a ControlPipe in the DATA OUT stage
-#[derive(Debug)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub(crate) struct DataOutStage {
-    length: usize,
-}
-
-/// Typestate representing a ControlPipe in the STATUS stage
-#[derive(Debug)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub(crate) struct StatusStage {}
-
-#[derive(Debug)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub(crate) enum Setup {
-    DataIn(Request, DataInStage),
-    DataOut(Request, DataOutStage),
-}
-
-pub(crate) struct ControlPipe<C: driver::ControlPipe> {
-    control: C,
-}
-
-impl<C: driver::ControlPipe> ControlPipe<C> {
-    pub(crate) fn new(control: C) -> Self {
-        ControlPipe { control }
-    }
-
-    pub(crate) async fn setup(&mut self) -> Setup {
-        let req = self.control.setup().await;
-        trace!("control request: {:02x}", req);
-
-        match (req.direction, req.length) {
-            (UsbDirection::Out, n) => Setup::DataOut(
-                req,
-                DataOutStage {
-                    length: usize::from(n),
-                },
-            ),
-            (UsbDirection::In, n) => Setup::DataIn(
-                req,
-                DataInStage {
-                    length: usize::from(n),
-                },
-            ),
-        }
-    }
-
-    pub(crate) async fn data_out<'a>(
-        &mut self,
-        buf: &'a mut [u8],
-        stage: DataOutStage,
-    ) -> Result<(&'a [u8], StatusStage), EndpointError> {
-        if stage.length == 0 {
-            Ok((&[], StatusStage {}))
-        } else {
-            let req_length = stage.length;
-            let max_packet_size = self.control.max_packet_size();
-            let mut total = 0;
-
-            for chunk in buf.chunks_mut(max_packet_size) {
-                let size = self.control.data_out(chunk).await?;
-                total += size;
-                if size < max_packet_size || total == req_length {
-                    break;
-                }
-            }
-
-            let res = &buf[0..total];
-            #[cfg(feature = "defmt")]
-            trace!("  control out data: {:02x}", res);
-            #[cfg(not(feature = "defmt"))]
-            trace!("  control out data: {:02x?}", res);
-
-            Ok((res, StatusStage {}))
-        }
-    }
-
-    pub(crate) async fn accept_in(&mut self, buf: &[u8], stage: DataInStage) {
-        #[cfg(feature = "defmt")]
-        trace!("  control in accept {:02x}", buf);
-        #[cfg(not(feature = "defmt"))]
-        trace!("  control in accept {:02x?}", buf);
-
-        let req_len = stage.length;
-        let len = buf.len().min(req_len);
-        let max_packet_size = self.control.max_packet_size();
-        let need_zlp = len != req_len && (len % usize::from(max_packet_size)) == 0;
-
-        let mut chunks = buf[0..len]
-            .chunks(max_packet_size)
-            .chain(need_zlp.then(|| -> &[u8] { &[] }));
-
-        while let Some(chunk) = chunks.next() {
-            match self.control.data_in(chunk, chunks.size_hint().0 == 0).await {
-                Ok(()) => {}
-                Err(e) => {
-                    warn!("control accept_in failed: {:?}", e);
-                    return;
-                }
-            }
-        }
-    }
-
-    pub(crate) async fn accept_in_writer(
-        &mut self,
-        req: Request,
-        stage: DataInStage,
-        f: impl FnOnce(&mut DescriptorWriter),
-    ) {
-        let mut buf = [0; 256];
-        let mut w = DescriptorWriter::new(&mut buf);
-        f(&mut w);
-        let pos = w.position().min(usize::from(req.length));
-        self.accept_in(&buf[..pos], stage).await
-    }
-
-    pub(crate) fn accept(&mut self, _: StatusStage) {
-        trace!("  control accept");
-        self.control.accept();
-    }
-
-    pub(crate) fn reject(&mut self) {
-        trace!("  control reject");
-        self.control.reject();
-    }
-}
diff --git a/embassy-usb/src/descriptor.rs b/embassy-usb/src/descriptor.rs
index dce326780..7f23fd921 100644
--- a/embassy-usb/src/descriptor.rs
+++ b/embassy-usb/src/descriptor.rs
@@ -244,6 +244,7 @@ impl<'a> DescriptorWriter<'a> {
     }
 
     /// Writes a string descriptor.
+    #[allow(unused)]
     pub(crate) fn string(&mut self, string: &str) {
         let mut pos = self.position;
 
diff --git a/embassy-usb/src/driver.rs b/embassy-usb/src/driver.rs
index e552dc7b6..57f2b0656 100644
--- a/embassy-usb/src/driver.rs
+++ b/embassy-usb/src/driver.rs
@@ -14,7 +14,7 @@ pub trait Driver<'a> {
 
     /// Allocates an endpoint and specified endpoint parameters. This method is called by the device
     /// and class implementations to allocate endpoints, and can only be called before
-    /// [`enable`](UsbBus::enable) is called.
+    /// [`start`](UsbBus::start) is called.
     ///
     /// # Arguments
     ///
@@ -25,7 +25,6 @@ pub trait Driver<'a> {
     /// * `interval` - Polling interval parameter for interrupt endpoints.
     fn alloc_endpoint_out(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
         max_packet_size: u16,
         interval: u8,
@@ -33,20 +32,20 @@ pub trait Driver<'a> {
 
     fn alloc_endpoint_in(
         &mut self,
-        ep_addr: Option<EndpointAddress>,
         ep_type: EndpointType,
         max_packet_size: u16,
         interval: u8,
     ) -> Result<Self::EndpointIn, EndpointAllocError>;
 
-    fn alloc_control_pipe(
-        &mut self,
-        max_packet_size: u16,
-    ) -> Result<Self::ControlPipe, EndpointAllocError>;
-
-    /// Enables and initializes the USB peripheral. Soon after enabling the device will be reset, so
-    /// there is no need to perform a USB reset in this method.
-    fn into_bus(self) -> Self::Bus;
+    /// Start operation of the USB device.
+    ///
+    /// This returns the `Bus` and `ControlPipe` instances that are used to operate
+    /// the USB device. Additionally, this makes all the previously allocated endpoints
+    /// start operating.
+    ///
+    /// This consumes the `Driver` instance, so it's no longer possible to allocate more
+    /// endpoints.
+    fn start(self, control_max_packet_size: u16) -> (Self::Bus, Self::ControlPipe);
 
     /// Indicates that `set_device_address` must be called before accepting the corresponding
     /// control transfer, not after.
diff --git a/embassy-usb/src/lib.rs b/embassy-usb/src/lib.rs
index 3bfedc048..b135f5eb3 100644
--- a/embassy-usb/src/lib.rs
+++ b/embassy-usb/src/lib.rs
@@ -16,6 +16,7 @@ use embassy::util::{select, Either};
 use heapless::Vec;
 
 use crate::descriptor_reader::foreach_endpoint;
+use crate::driver::ControlPipe;
 
 use self::control::*;
 use self::descriptor::*;
@@ -100,15 +101,19 @@ struct Interface<'d> {
 }
 
 pub struct UsbDevice<'d, D: Driver<'d>> {
+    control_buf: &'d mut [u8],
+    control: D::ControlPipe,
+    inner: Inner<'d, D>,
+}
+
+struct Inner<'d, D: Driver<'d>> {
     bus: D::Bus,
     handler: Option<&'d dyn DeviceStateHandler>,
-    control: ControlPipe<D::ControlPipe>,
 
     config: Config<'d>,
     device_descriptor: &'d [u8],
     config_descriptor: &'d [u8],
     bos_descriptor: &'d [u8],
-    control_buf: &'d mut [u8],
 
     device_state: UsbDeviceState,
     suspended: bool,
@@ -121,7 +126,7 @@ pub struct UsbDevice<'d, D: Driver<'d>> {
 
 impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     pub(crate) fn build(
-        mut driver: D,
+        driver: D,
         config: Config<'d>,
         handler: Option<&'d dyn DeviceStateHandler>,
         device_descriptor: &'d [u8],
@@ -130,29 +135,28 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         interfaces: Vec<Interface<'d>, MAX_INTERFACE_COUNT>,
         control_buf: &'d mut [u8],
     ) -> UsbDevice<'d, D> {
-        let control = driver
-            .alloc_control_pipe(config.max_packet_size_0 as u16)
-            .expect("failed to alloc control endpoint");
-
-        // Enable the USB bus.
+        // Start the USB bus.
         // This prevent further allocation by consuming the driver.
-        let bus = driver.into_bus();
+        let (bus, control) = driver.start(config.max_packet_size_0 as u16);
 
         Self {
-            bus,
-            config,
-            handler,
-            control: ControlPipe::new(control),
-            device_descriptor,
-            config_descriptor,
-            bos_descriptor,
             control_buf,
-            device_state: UsbDeviceState::Disabled,
-            suspended: false,
-            remote_wakeup_enabled: false,
-            self_powered: false,
-            pending_address: 0,
-            interfaces,
+            control,
+            inner: Inner {
+                bus,
+                config,
+                handler,
+                device_descriptor,
+                config_descriptor,
+                bos_descriptor,
+
+                device_state: UsbDeviceState::Disabled,
+                suspended: false,
+                remote_wakeup_enabled: false,
+                self_powered: false,
+                pending_address: 0,
+                interfaces,
+            },
         }
     }
 
@@ -176,42 +180,34 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     /// before calling any other `UsbDevice` methods to fully reset the
     /// peripheral.
     pub async fn run_until_suspend(&mut self) -> () {
-        if self.device_state == UsbDeviceState::Disabled {
-            self.bus.enable().await;
-            self.device_state = UsbDeviceState::Default;
+        if self.inner.device_state == UsbDeviceState::Disabled {
+            self.inner.bus.enable().await;
+            self.inner.device_state = UsbDeviceState::Default;
 
-            if let Some(h) = &self.handler {
+            if let Some(h) = &self.inner.handler {
                 h.enabled(true);
             }
         }
 
-        loop {
+        while !self.inner.suspended {
             let control_fut = self.control.setup();
-            let bus_fut = self.bus.poll();
+            let bus_fut = self.inner.bus.poll();
             match select(bus_fut, control_fut).await {
-                Either::First(evt) => {
-                    self.handle_bus_event(evt);
-                    if self.suspended {
-                        return;
-                    }
-                }
-                Either::Second(req) => match req {
-                    Setup::DataIn(req, stage) => self.handle_control_in(req, stage).await,
-                    Setup::DataOut(req, stage) => self.handle_control_out(req, stage).await,
-                },
+                Either::First(evt) => self.inner.handle_bus_event(evt),
+                Either::Second(req) => self.handle_control(req).await,
             }
         }
     }
 
     /// Disables the USB peripheral.
     pub async fn disable(&mut self) {
-        if self.device_state != UsbDeviceState::Disabled {
-            self.bus.disable().await;
-            self.device_state = UsbDeviceState::Disabled;
-            self.suspended = false;
-            self.remote_wakeup_enabled = false;
+        if self.inner.device_state != UsbDeviceState::Disabled {
+            self.inner.bus.disable().await;
+            self.inner.device_state = UsbDeviceState::Disabled;
+            self.inner.suspended = false;
+            self.inner.remote_wakeup_enabled = false;
 
-            if let Some(h) = &self.handler {
+            if let Some(h) = &self.inner.handler {
                 h.enabled(false);
             }
         }
@@ -221,9 +217,9 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     ///
     /// This future is cancel-safe.
     pub async fn wait_resume(&mut self) {
-        while self.suspended {
-            let evt = self.bus.poll().await;
-            self.handle_bus_event(evt);
+        while self.inner.suspended {
+            let evt = self.inner.bus.poll().await;
+            self.inner.handle_bus_event(evt);
         }
     }
 
@@ -236,11 +232,11 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
     /// After dropping the future, [`UsbDevice::disable()`] should be called
     /// before calling any other `UsbDevice` methods to fully reset the peripheral.
     pub async fn remote_wakeup(&mut self) -> Result<(), RemoteWakeupError> {
-        if self.suspended && self.remote_wakeup_enabled {
-            self.bus.remote_wakeup().await?;
-            self.suspended = false;
+        if self.inner.suspended && self.inner.remote_wakeup_enabled {
+            self.inner.bus.remote_wakeup().await?;
+            self.inner.suspended = false;
 
-            if let Some(h) = &self.handler {
+            if let Some(h) = &self.inner.handler {
                 h.suspended(false);
             }
 
@@ -250,6 +246,88 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         }
     }
 
+    async fn handle_control(&mut self, req: Request) {
+        trace!("control request: {:02x}", req);
+
+        match req.direction {
+            UsbDirection::In => self.handle_control_in(req).await,
+            UsbDirection::Out => self.handle_control_out(req).await,
+        }
+    }
+
+    async fn handle_control_in(&mut self, req: Request) {
+        let mut resp_length = req.length as usize;
+        let max_packet_size = self.control.max_packet_size();
+
+        // If we don't have an address yet, respond with max 1 packet.
+        // The host doesn't know our EP0 max packet size yet, and might assume
+        // a full-length packet is a short packet, thinking we're done sending data.
+        // See https://github.com/hathach/tinyusb/issues/184
+        const DEVICE_DESCRIPTOR_LEN: usize = 18;
+        if self.inner.pending_address == 0
+            && max_packet_size < DEVICE_DESCRIPTOR_LEN
+            && (max_packet_size as usize) < resp_length
+        {
+            trace!("received control req while not addressed: capping response to 1 packet.");
+            resp_length = max_packet_size;
+        }
+
+        match self.inner.handle_control_in(req, &mut self.control_buf) {
+            InResponse::Accepted(data) => {
+                let len = data.len().min(resp_length);
+                let need_zlp = len != resp_length && (len % usize::from(max_packet_size)) == 0;
+
+                let mut chunks = data[0..len]
+                    .chunks(max_packet_size)
+                    .chain(need_zlp.then(|| -> &[u8] { &[] }));
+
+                while let Some(chunk) = chunks.next() {
+                    match self.control.data_in(chunk, chunks.size_hint().0 == 0).await {
+                        Ok(()) => {}
+                        Err(e) => {
+                            warn!("control accept_in failed: {:?}", e);
+                            return;
+                        }
+                    }
+                }
+            }
+            InResponse::Rejected => self.control.reject(),
+        }
+    }
+
+    async fn handle_control_out(&mut self, req: Request) {
+        let req_length = req.length as usize;
+        let max_packet_size = self.control.max_packet_size();
+        let mut total = 0;
+
+        for chunk in self.control_buf[..req_length].chunks_mut(max_packet_size) {
+            let size = match self.control.data_out(chunk).await {
+                Ok(x) => x,
+                Err(e) => {
+                    warn!("usb: failed to read CONTROL OUT data stage: {:?}", e);
+                    return;
+                }
+            };
+            total += size;
+            if size < max_packet_size || total == req_length {
+                break;
+            }
+        }
+
+        let data = &self.control_buf[0..total];
+        #[cfg(feature = "defmt")]
+        trace!("  control out data: {:02x}", data);
+        #[cfg(not(feature = "defmt"))]
+        trace!("  control out data: {:02x?}", data);
+
+        match self.inner.handle_control_out(req, data) {
+            OutResponse::Accepted => self.control.accept(),
+            OutResponse::Rejected => self.control.reject(),
+        }
+    }
+}
+
+impl<'d, D: Driver<'d>> Inner<'d, D> {
     fn handle_bus_event(&mut self, evt: Event) {
         match evt {
             Event::Reset => {
@@ -288,18 +366,10 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
         }
     }
 
-    async fn handle_control_out(&mut self, req: Request, stage: DataOutStage) {
+    fn handle_control_out(&mut self, req: Request, data: &[u8]) -> OutResponse {
         const CONFIGURATION_NONE_U16: u16 = CONFIGURATION_NONE as u16;
         const CONFIGURATION_VALUE_U16: u16 = CONFIGURATION_VALUE as u16;
 
-        let (data, stage) = match self.control.data_out(self.control_buf, stage).await {
-            Ok(data) => data,
-            Err(_) => {
-                warn!("usb: failed to read CONTROL OUT data stage.");
-                return;
-            }
-        };
-
         match (req.request_type, req.recipient) {
             (RequestType::Standard, Recipient::Device) => match (req.request, req.value) {
                 (Request::CLEAR_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
@@ -307,14 +377,14 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if let Some(h) = &self.handler {
                         h.remote_wakeup_enabled(false);
                     }
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
                 (Request::SET_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
                     self.remote_wakeup_enabled = true;
                     if let Some(h) = &self.handler {
                         h.remote_wakeup_enabled(true);
                     }
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
                 (Request::SET_ADDRESS, addr @ 1..=127) => {
                     self.pending_address = addr as u8;
@@ -323,7 +393,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if let Some(h) = &self.handler {
                         h.addressed(self.pending_address);
                     }
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
                 (Request::SET_CONFIGURATION, CONFIGURATION_VALUE_U16) => {
                     debug!("SET_CONFIGURATION: configured");
@@ -344,10 +414,10 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         h.configured(true);
                     }
 
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
                 (Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => match self.device_state {
-                    UsbDeviceState::Default => self.control.accept(stage),
+                    UsbDeviceState::Default => OutResponse::Accepted,
                     _ => {
                         debug!("SET_CONFIGURATION: unconfigured");
                         self.device_state = UsbDeviceState::Addressed;
@@ -363,15 +433,15 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                             h.configured(false);
                         }
 
-                        self.control.accept(stage)
+                        OutResponse::Accepted
                     }
                 },
-                _ => self.control.reject(),
+                _ => OutResponse::Rejected,
             },
             (RequestType::Standard, Recipient::Interface) => {
                 let iface = match self.interfaces.get_mut(req.index as usize) {
                     Some(iface) => iface,
-                    None => return self.control.reject(),
+                    None => return OutResponse::Rejected,
                 };
 
                 match req.request {
@@ -380,7 +450,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
 
                         if new_altsetting >= iface.num_alt_settings {
                             warn!("SET_INTERFACE: trying to select alt setting out of range.");
-                            return self.control.reject();
+                            return OutResponse::Rejected;
                         }
 
                         iface.current_alt_setting = new_altsetting;
@@ -402,55 +472,39 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                         if let Some(handler) = &mut iface.handler {
                             handler.set_alternate_setting(new_altsetting);
                         }
-                        self.control.accept(stage)
+                        OutResponse::Accepted
                     }
-                    _ => self.control.reject(),
+                    _ => OutResponse::Rejected,
                 }
             }
             (RequestType::Standard, Recipient::Endpoint) => match (req.request, req.value) {
                 (Request::SET_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
                     let ep_addr = ((req.index as u8) & 0x8f).into();
                     self.bus.endpoint_set_stalled(ep_addr, true);
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
                 (Request::CLEAR_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
                     let ep_addr = ((req.index as u8) & 0x8f).into();
                     self.bus.endpoint_set_stalled(ep_addr, false);
-                    self.control.accept(stage)
+                    OutResponse::Accepted
                 }
-                _ => self.control.reject(),
+                _ => OutResponse::Rejected,
             },
             (RequestType::Class, Recipient::Interface) => {
                 let iface = match self.interfaces.get_mut(req.index as usize) {
                     Some(iface) => iface,
-                    None => return self.control.reject(),
+                    None => return OutResponse::Rejected,
                 };
                 match &mut iface.handler {
-                    Some(handler) => match handler.control_out(req, data) {
-                        OutResponse::Accepted => self.control.accept(stage),
-                        OutResponse::Rejected => self.control.reject(),
-                    },
-                    None => self.control.reject(),
+                    Some(handler) => handler.control_out(req, data),
+                    None => OutResponse::Rejected,
                 }
             }
-            _ => self.control.reject(),
+            _ => OutResponse::Rejected,
         }
     }
 
-    async fn handle_control_in(&mut self, req: Request, mut stage: DataInStage) {
-        // If we don't have an address yet, respond with max 1 packet.
-        // The host doesn't know our EP0 max packet size yet, and might assume
-        // a full-length packet is a short packet, thinking we're done sending data.
-        // See https://github.com/hathach/tinyusb/issues/184
-        const DEVICE_DESCRIPTOR_LEN: u8 = 18;
-        if self.pending_address == 0
-            && self.config.max_packet_size_0 < DEVICE_DESCRIPTOR_LEN
-            && (self.config.max_packet_size_0 as usize) < stage.length
-        {
-            trace!("received control req while not addressed: capping response to 1 packet.");
-            stage.length = self.config.max_packet_size_0 as _;
-        }
-
+    fn handle_control_in<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
         match (req.request_type, req.recipient) {
             (RequestType::Standard, Recipient::Device) => match req.request {
                 Request::GET_STATUS => {
@@ -461,42 +515,41 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if self.remote_wakeup_enabled {
                         status |= 0x0002;
                     }
-                    self.control.accept_in(&status.to_le_bytes(), stage).await
+                    buf[..2].copy_from_slice(&status.to_le_bytes());
+                    InResponse::Accepted(&buf[..2])
                 }
-                Request::GET_DESCRIPTOR => self.handle_get_descriptor(req, stage).await,
+                Request::GET_DESCRIPTOR => self.handle_get_descriptor(req, buf),
                 Request::GET_CONFIGURATION => {
                     let status = match self.device_state {
                         UsbDeviceState::Configured => CONFIGURATION_VALUE,
                         _ => CONFIGURATION_NONE,
                     };
-                    self.control.accept_in(&status.to_le_bytes(), stage).await
+                    buf[0] = status;
+                    InResponse::Accepted(&buf[..1])
                 }
-                _ => self.control.reject(),
+                _ => InResponse::Rejected,
             },
             (RequestType::Standard, Recipient::Interface) => {
                 let iface = match self.interfaces.get_mut(req.index as usize) {
                     Some(iface) => iface,
-                    None => return self.control.reject(),
+                    None => return InResponse::Rejected,
                 };
 
                 match req.request {
                     Request::GET_STATUS => {
                         let status: u16 = 0;
-                        self.control.accept_in(&status.to_le_bytes(), stage).await
+                        buf[..2].copy_from_slice(&status.to_le_bytes());
+                        InResponse::Accepted(&buf[..2])
                     }
                     Request::GET_INTERFACE => {
-                        self.control
-                            .accept_in(&[iface.current_alt_setting], stage)
-                            .await;
+                        buf[0] = iface.current_alt_setting;
+                        InResponse::Accepted(&buf[..1])
                     }
                     Request::GET_DESCRIPTOR => match &mut iface.handler {
-                        Some(handler) => match handler.get_descriptor(req, self.control_buf) {
-                            InResponse::Accepted(data) => self.control.accept_in(data, stage).await,
-                            InResponse::Rejected => self.control.reject(),
-                        },
-                        None => self.control.reject(),
+                        Some(handler) => handler.get_descriptor(req, buf),
+                        None => InResponse::Rejected,
                     },
-                    _ => self.control.reject(),
+                    _ => InResponse::Rejected,
                 }
             }
             (RequestType::Standard, Recipient::Endpoint) => match req.request {
@@ -506,44 +559,40 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     if self.bus.endpoint_is_stalled(ep_addr) {
                         status |= 0x0001;
                     }
-                    self.control.accept_in(&status.to_le_bytes(), stage).await
+                    buf[..2].copy_from_slice(&status.to_le_bytes());
+                    InResponse::Accepted(&buf[..2])
                 }
-                _ => self.control.reject(),
+                _ => InResponse::Rejected,
             },
             (RequestType::Class, Recipient::Interface) => {
                 let iface = match self.interfaces.get_mut(req.index as usize) {
                     Some(iface) => iface,
-                    None => return self.control.reject(),
+                    None => return InResponse::Rejected,
                 };
 
                 match &mut iface.handler {
-                    Some(handler) => match handler.control_in(req, self.control_buf) {
-                        InResponse::Accepted(data) => self.control.accept_in(data, stage).await,
-                        InResponse::Rejected => self.control.reject(),
-                    },
-                    None => self.control.reject(),
+                    Some(handler) => handler.control_in(req, buf),
+                    None => InResponse::Rejected,
                 }
             }
-            _ => self.control.reject(),
+            _ => InResponse::Rejected,
         }
     }
 
-    async fn handle_get_descriptor(&mut self, req: Request, stage: DataInStage) {
+    fn handle_get_descriptor<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
         let (dtype, index) = req.descriptor_type_index();
 
         match dtype {
-            descriptor_type::BOS => self.control.accept_in(self.bos_descriptor, stage).await,
-            descriptor_type::DEVICE => self.control.accept_in(self.device_descriptor, stage).await,
-            descriptor_type::CONFIGURATION => {
-                self.control.accept_in(self.config_descriptor, stage).await
-            }
+            descriptor_type::BOS => InResponse::Accepted(self.bos_descriptor),
+            descriptor_type::DEVICE => InResponse::Accepted(self.device_descriptor),
+            descriptor_type::CONFIGURATION => InResponse::Accepted(self.config_descriptor),
             descriptor_type::STRING => {
                 if index == 0 {
-                    self.control
-                        .accept_in_writer(req, stage, |w| {
-                            w.write(descriptor_type::STRING, &lang_id::ENGLISH_US.to_le_bytes());
-                        })
-                        .await
+                    buf[0] = 4; // len
+                    buf[1] = descriptor_type::STRING;
+                    buf[2] = lang_id::ENGLISH_US as u8;
+                    buf[3] = (lang_id::ENGLISH_US >> 8) as u8;
+                    InResponse::Accepted(&buf[..4])
                 } else {
                     let s = match index {
                         STRING_INDEX_MANUFACTURER => self.config.manufacturer,
@@ -565,7 +614,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                                 if let Some(handler) = &mut iface.handler {
                                     let index = StringIndex::new(index);
                                     let lang_id = req.index;
-                                    handler.get_string(index, lang_id, self.control_buf)
+                                    handler.get_string(index, lang_id)
                                 } else {
                                     warn!("String requested to an interface with no handler.");
                                     None
@@ -578,15 +627,29 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
                     };
 
                     if let Some(s) = s {
-                        self.control
-                            .accept_in_writer(req, stage, |w| w.string(s))
-                            .await
+                        if buf.len() < 2 {
+                            panic!("control buffer too small");
+                        }
+
+                        buf[1] = descriptor_type::STRING;
+                        let mut pos = 2;
+                        for c in s.encode_utf16() {
+                            if pos >= buf.len() {
+                                panic!("control buffer too small");
+                            }
+
+                            buf[pos..pos + 2].copy_from_slice(&c.to_le_bytes());
+                            pos += 2;
+                        }
+
+                        buf[0] = pos as u8;
+                        InResponse::Accepted(&buf[..pos])
                     } else {
-                        self.control.reject()
+                        InResponse::Rejected
                     }
                 }
             }
-            _ => self.control.reject(),
+            _ => InResponse::Rejected,
         }
     }
 }
diff --git a/examples/nrf/src/bin/usb_hid_keyboard.rs b/examples/nrf/src/bin/usb_hid_keyboard.rs
index 3852dd8da..d855a3a57 100644
--- a/examples/nrf/src/bin/usb_hid_keyboard.rs
+++ b/examples/nrf/src/bin/usb_hid_keyboard.rs
@@ -71,7 +71,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     let mut device_descriptor = [0; 256];
     let mut config_descriptor = [0; 256];
     let mut bos_descriptor = [0; 256];
-    let mut control_buf = [0; 16];
+    let mut control_buf = [0; 64];
     let request_handler = MyRequestHandler {};
     let device_state_handler = MyDeviceStateHandler::new();
 
diff --git a/examples/nrf/src/bin/usb_hid_mouse.rs b/examples/nrf/src/bin/usb_hid_mouse.rs
index e70dc51a5..c526c1c6f 100644
--- a/examples/nrf/src/bin/usb_hid_mouse.rs
+++ b/examples/nrf/src/bin/usb_hid_mouse.rs
@@ -50,7 +50,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     let mut device_descriptor = [0; 256];
     let mut config_descriptor = [0; 256];
     let mut bos_descriptor = [0; 256];
-    let mut control_buf = [0; 16];
+    let mut control_buf = [0; 64];
     let request_handler = MyRequestHandler {};
 
     let mut state = State::new();
diff --git a/examples/nrf/src/bin/usb_serial.rs b/examples/nrf/src/bin/usb_serial.rs
index bc41c2acf..2551c4ba1 100644
--- a/examples/nrf/src/bin/usb_serial.rs
+++ b/examples/nrf/src/bin/usb_serial.rs
@@ -43,12 +43,19 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     config.max_power = 100;
     config.max_packet_size_0 = 64;
 
+    // Required for windows compatiblity.
+    // https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/kconfig/CONFIG_CDC_ACM_IAD.html#help
+    config.device_class = 0xEF;
+    config.device_sub_class = 0x02;
+    config.device_protocol = 0x01;
+    config.composite_with_iads = true;
+
     // Create embassy-usb DeviceBuilder using the driver and config.
     // It needs some buffers for building the descriptors.
     let mut device_descriptor = [0; 256];
     let mut config_descriptor = [0; 256];
     let mut bos_descriptor = [0; 256];
-    let mut control_buf = [0; 7];
+    let mut control_buf = [0; 64];
 
     let mut state = State::new();
 
diff --git a/examples/nrf/src/bin/usb_serial_multitask.rs b/examples/nrf/src/bin/usb_serial_multitask.rs
index 31e0af483..0e82ba313 100644
--- a/examples/nrf/src/bin/usb_serial_multitask.rs
+++ b/examples/nrf/src/bin/usb_serial_multitask.rs
@@ -60,11 +60,18 @@ async fn main(spawner: Spawner, p: Peripherals) {
     config.max_power = 100;
     config.max_packet_size_0 = 64;
 
+    // Required for windows compatiblity.
+    // https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.9.1/kconfig/CONFIG_CDC_ACM_IAD.html#help
+    config.device_class = 0xEF;
+    config.device_sub_class = 0x02;
+    config.device_protocol = 0x01;
+    config.composite_with_iads = true;
+
     struct Resources {
         device_descriptor: [u8; 256],
         config_descriptor: [u8; 256],
         bos_descriptor: [u8; 256],
-        control_buf: [u8; 7],
+        control_buf: [u8; 64],
         serial_state: State<'static>,
     }
     static RESOURCES: Forever<Resources> = Forever::new();
@@ -72,7 +79,7 @@ async fn main(spawner: Spawner, p: Peripherals) {
         device_descriptor: [0; 256],
         config_descriptor: [0; 256],
         bos_descriptor: [0; 256],
-        control_buf: [0; 7],
+        control_buf: [0; 64],
         serial_state: State::new(),
     });