721: USB HID: simplify API r=Dirbaio a=Dirbaio

Following the discussion from #720  and [matrix](https://matrix.to/#/!YoLPkieCYHGzdjUhOK:matrix.org/$PcPr8E_JbodEPuUUKI2PzIC9sx7nF3y0kV2T5O4UWj8?via=matrix.org&via=converser.eu&via=braun-odw.eu), this is a second take on simplifying the HID API.

Split into a separate PR so it can be reviewed separately.

See individual commit messages for details.

cc `@alexmoon` 

Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>
This commit is contained in:
bors[bot] 2022-04-16 01:55:21 +00:00 committed by GitHub
commit 1c9adec3c5
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4 changed files with 178 additions and 164 deletions

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@ -41,6 +41,24 @@ const HID_REQ_SET_REPORT: u8 = 0x09;
const HID_REQ_GET_PROTOCOL: u8 = 0x03;
const HID_REQ_SET_PROTOCOL: u8 = 0x0b;
pub struct Config<'d> {
/// HID report descriptor.
pub report_descriptor: &'d [u8],
/// Handler for control requests.
pub request_handler: Option<&'d dyn RequestHandler>,
/// Configures how frequently the host should poll for reading/writing HID reports.
///
/// A lower value means better throughput & latency, at the expense
/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
/// high performance uses, and a value of 255 is good for best-effort usecases.
pub poll_ms: u8,
/// Max packet size for both the IN and OUT endpoints.
pub max_packet_size: u16,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub enum ReportId {
@ -60,12 +78,12 @@ impl ReportId {
}
}
pub struct State<'a, const IN_N: usize, const OUT_N: usize> {
control: MaybeUninit<Control<'a>>,
pub struct State<'d> {
control: MaybeUninit<Control<'d>>,
out_report_offset: AtomicUsize,
}
impl<'a, const IN_N: usize, const OUT_N: usize> State<'a, IN_N, OUT_N> {
impl<'d> State<'d> {
pub fn new() -> Self {
State {
control: MaybeUninit::uninit(),
@ -74,107 +92,128 @@ impl<'a, const IN_N: usize, const OUT_N: usize> State<'a, IN_N, OUT_N> {
}
}
pub struct HidClass<'d, D: Driver<'d>, T, const IN_N: usize> {
input: ReportWriter<'d, D, IN_N>,
output: T,
pub struct HidReaderWriter<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize> {
reader: HidReader<'d, D, READ_N>,
writer: HidWriter<'d, D, WRITE_N>,
}
impl<'d, D: Driver<'d>, const IN_N: usize> HidClass<'d, D, (), IN_N> {
/// Creates a new HidClass.
///
/// poll_ms configures how frequently the host should poll for reading/writing
/// HID reports. A lower value means better throughput & latency, at the expense
/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
/// high performance uses, and a value of 255 is good for best-effort usecases.
///
/// This allocates an IN endpoint only.
pub fn new<const OUT_N: usize>(
builder: &mut UsbDeviceBuilder<'d, D>,
state: &'d mut State<'d, IN_N, OUT_N>,
report_descriptor: &'static [u8],
request_handler: Option<&'d dyn RequestHandler>,
poll_ms: u8,
max_packet_size: u16,
) -> Self {
let ep_in = builder.alloc_interrupt_endpoint_in(max_packet_size, poll_ms);
let control = state.control.write(Control::new(
report_descriptor,
request_handler,
&state.out_report_offset,
));
control.build(builder, None, &ep_in);
fn build<'d, D: Driver<'d>>(
builder: &mut UsbDeviceBuilder<'d, D>,
state: &'d mut State<'d>,
config: Config<'d>,
with_out_endpoint: bool,
) -> (Option<D::EndpointOut>, D::EndpointIn, &'d AtomicUsize) {
let control = state.control.write(Control::new(
config.report_descriptor,
config.request_handler,
&state.out_report_offset,
));
Self {
input: ReportWriter { ep_in },
output: (),
}
let len = config.report_descriptor.len();
let if_num = builder.alloc_interface_with_handler(control);
let ep_in = builder.alloc_interrupt_endpoint_in(config.max_packet_size, config.poll_ms);
let ep_out = if with_out_endpoint {
Some(builder.alloc_interrupt_endpoint_out(config.max_packet_size, config.poll_ms))
} else {
None
};
builder.config_descriptor.interface(
if_num,
USB_CLASS_HID,
USB_SUBCLASS_NONE,
USB_PROTOCOL_NONE,
);
// HID descriptor
builder.config_descriptor.write(
HID_DESC_DESCTYPE_HID,
&[
// HID Class spec version
HID_DESC_SPEC_1_10[0],
HID_DESC_SPEC_1_10[1],
// Country code not supported
HID_DESC_COUNTRY_UNSPEC,
// Number of following descriptors
1,
// We have a HID report descriptor the host should read
HID_DESC_DESCTYPE_HID_REPORT,
// HID report descriptor size,
(len & 0xFF) as u8,
(len >> 8 & 0xFF) as u8,
],
);
builder.config_descriptor.endpoint(ep_in.info());
if let Some(ep_out) = &ep_out {
builder.config_descriptor.endpoint(ep_out.info());
}
(ep_out, ep_in, &state.out_report_offset)
}
impl<'d, D: Driver<'d>, T, const IN_N: usize> HidClass<'d, D, T, IN_N> {
/// Gets the [`ReportWriter`] for input reports.
///
/// **Note:** If the `HidClass` was created with [`new_ep_out()`](Self::new_ep_out)
/// this writer will be useless as no endpoint is availabe to send reports.
pub fn input(&mut self) -> &mut ReportWriter<'d, D, IN_N> {
&mut self.input
}
}
impl<'d, D: Driver<'d>, const IN_N: usize, const OUT_N: usize>
HidClass<'d, D, ReportReader<'d, D, OUT_N>, IN_N>
impl<'d, D: Driver<'d>, const READ_N: usize, const WRITE_N: usize>
HidReaderWriter<'d, D, READ_N, WRITE_N>
{
/// Creates a new HidClass.
/// Creates a new HidReaderWriter.
///
/// poll_ms configures how frequently the host should poll for reading/writing
/// HID reports. A lower value means better throughput & latency, at the expense
/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
/// high performance uses, and a value of 255 is good for best-effort usecases.
/// This will allocate one IN and one OUT endpoints. If you only need writing (sending)
/// HID reports, consider using [`HidWriter::new`] instead, which allocates an IN endpoint only.
///
/// This allocates two endpoints (IN and OUT).
pub fn with_output_ep(
pub fn new(
builder: &mut UsbDeviceBuilder<'d, D>,
state: &'d mut State<'d, IN_N, OUT_N>,
report_descriptor: &'static [u8],
request_handler: Option<&'d dyn RequestHandler>,
poll_ms: u8,
max_packet_size: u16,
state: &'d mut State<'d>,
config: Config<'d>,
) -> Self {
let ep_out = builder.alloc_interrupt_endpoint_out(max_packet_size, poll_ms);
let ep_in = builder.alloc_interrupt_endpoint_in(max_packet_size, poll_ms);
let control = state.control.write(Control::new(
report_descriptor,
request_handler,
&state.out_report_offset,
));
control.build(builder, Some(&ep_out), &ep_in);
let (ep_out, ep_in, offset) = build(builder, state, config, true);
Self {
input: ReportWriter { ep_in },
output: ReportReader {
ep_out,
offset: &state.out_report_offset,
reader: HidReader {
ep_out: ep_out.unwrap(),
offset,
},
writer: HidWriter { ep_in },
}
}
/// Gets the [`ReportReader`] for output reports.
pub fn output(&mut self) -> &mut ReportReader<'d, D, OUT_N> {
&mut self.output
/// Splits into seperate readers/writers for input and output reports.
pub fn split(self) -> (HidReader<'d, D, READ_N>, HidWriter<'d, D, WRITE_N>) {
(self.reader, self.writer)
}
/// Splits this `HidClass` into seperate readers/writers for input and output reports.
pub fn split(self) -> (ReportWriter<'d, D, IN_N>, ReportReader<'d, D, OUT_N>) {
(self.input, self.output)
/// Waits for both IN and OUT endpoints to be enabled.
pub async fn ready(&mut self) -> () {
self.reader.ready().await;
self.writer.ready().await;
}
/// Writes an input report by serializing the given report structure.
#[cfg(feature = "usbd-hid")]
pub async fn write_serialize<IR: AsInputReport>(
&mut self,
r: &IR,
) -> Result<(), EndpointError> {
self.writer.write_serialize(r).await
}
/// Writes `report` to its interrupt endpoint.
pub async fn write(&mut self, report: &[u8]) -> Result<(), EndpointError> {
self.writer.write(report).await
}
/// Reads an output report from the Interrupt Out pipe.
///
/// See [`HidReader::read`].
pub async fn read(&mut self, buf: &mut [u8]) -> Result<usize, ReadError> {
self.reader.read(buf).await
}
}
pub struct ReportWriter<'d, D: Driver<'d>, const N: usize> {
pub struct HidWriter<'d, D: Driver<'d>, const N: usize> {
ep_in: D::EndpointIn,
}
pub struct ReportReader<'d, D: Driver<'d>, const N: usize> {
pub struct HidReader<'d, D: Driver<'d>, const N: usize> {
ep_out: D::EndpointOut,
offset: &'d AtomicUsize,
}
@ -197,17 +236,39 @@ impl From<embassy_usb::driver::EndpointError> for ReadError {
}
}
impl<'d, D: Driver<'d>, const N: usize> ReportWriter<'d, D, N> {
impl<'d, D: Driver<'d>, const N: usize> HidWriter<'d, D, N> {
/// Creates a new HidWriter.
///
/// This will allocate one IN endpoint only, so the host won't be able to send
/// reports to us. If you need that, consider using [`HidReaderWriter::new`] instead.
///
/// poll_ms configures how frequently the host should poll for reading/writing
/// HID reports. A lower value means better throughput & latency, at the expense
/// of CPU on the device & bandwidth on the bus. A value of 10 is reasonable for
/// high performance uses, and a value of 255 is good for best-effort usecases.
pub fn new(
builder: &mut UsbDeviceBuilder<'d, D>,
state: &'d mut State<'d>,
config: Config<'d>,
) -> Self {
let (ep_out, ep_in, _offset) = build(builder, state, config, false);
assert!(ep_out.is_none());
Self { ep_in }
}
/// Waits for the interrupt in endpoint to be enabled.
pub async fn ready(&mut self) -> () {
self.ep_in.wait_enabled().await
}
/// Tries to write an input report by serializing the given report structure.
///
/// Panics if no endpoint is available.
/// Writes an input report by serializing the given report structure.
#[cfg(feature = "usbd-hid")]
pub async fn serialize<IR: AsInputReport>(&mut self, r: &IR) -> Result<(), EndpointError> {
pub async fn write_serialize<IR: AsInputReport>(
&mut self,
r: &IR,
) -> Result<(), EndpointError> {
let mut buf: [u8; N] = [0; N];
let size = match serialize(&mut buf, r) {
Ok(size) => size,
@ -217,8 +278,6 @@ impl<'d, D: Driver<'d>, const N: usize> ReportWriter<'d, D, N> {
}
/// Writes `report` to its interrupt endpoint.
///
/// Panics if no endpoint is available.
pub async fn write(&mut self, report: &[u8]) -> Result<(), EndpointError> {
assert!(report.len() <= N);
@ -236,16 +295,13 @@ impl<'d, D: Driver<'d>, const N: usize> ReportWriter<'d, D, N> {
}
}
impl<'d, D: Driver<'d>, const N: usize> ReportReader<'d, D, N> {
impl<'d, D: Driver<'d>, const N: usize> HidReader<'d, D, N> {
/// Waits for the interrupt out endpoint to be enabled.
pub async fn ready(&mut self) -> () {
self.ep_out.wait_enabled().await
}
/// Starts a task to deliver output reports from the Interrupt Out pipe to
/// `handler`.
///
/// Terminates when the interface becomes disabled.
/// Delivers output reports from the Interrupt Out pipe to `handler`.
///
/// If `use_report_ids` is true, the first byte of the report will be used as
/// the `ReportId` value. Otherwise the `ReportId` value will be 0.
@ -355,17 +411,17 @@ pub trait RequestHandler {
}
struct Control<'d> {
report_descriptor: &'static [u8],
report_descriptor: &'d [u8],
request_handler: Option<&'d dyn RequestHandler>,
out_report_offset: &'d AtomicUsize,
hid_descriptor: [u8; 9],
}
impl<'a> Control<'a> {
impl<'d> Control<'d> {
fn new(
report_descriptor: &'static [u8],
request_handler: Option<&'a dyn RequestHandler>,
out_report_offset: &'a AtomicUsize,
report_descriptor: &'d [u8],
request_handler: Option<&'d dyn RequestHandler>,
out_report_offset: &'d AtomicUsize,
) -> Self {
Control {
report_descriptor,
@ -391,47 +447,6 @@ impl<'a> Control<'a> {
],
}
}
fn build<'d, D: Driver<'d>>(
&'d mut self,
builder: &mut UsbDeviceBuilder<'d, D>,
ep_out: Option<&D::EndpointOut>,
ep_in: &D::EndpointIn,
) {
let len = self.report_descriptor.len();
let if_num = builder.alloc_interface_with_handler(self);
builder.config_descriptor.interface(
if_num,
USB_CLASS_HID,
USB_SUBCLASS_NONE,
USB_PROTOCOL_NONE,
);
// HID descriptor
builder.config_descriptor.write(
HID_DESC_DESCTYPE_HID,
&[
// HID Class spec version
HID_DESC_SPEC_1_10[0],
HID_DESC_SPEC_1_10[1],
// Country code not supported
HID_DESC_COUNTRY_UNSPEC,
// Number of following descriptors
1,
// We have a HID report descriptor the host should read
HID_DESC_DESCTYPE_HID_REPORT,
// HID report descriptor size,
(len & 0xFF) as u8,
(len >> 8 & 0xFF) as u8,
],
);
builder.config_descriptor.endpoint(ep_in.info());
if let Some(ep) = ep_out {
builder.config_descriptor.endpoint(ep.info());
}
}
}
impl<'d> ControlHandler for Control<'d> {

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@ -271,9 +271,9 @@ impl<C: driver::ControlPipe> ControlPipe<C> {
let res = &buf[0..total];
#[cfg(feature = "defmt")]
trace!(" control out data: {:02x}", buf);
trace!(" control out data: {:02x}", res);
#[cfg(not(feature = "defmt"))]
trace!(" control out data: {:02x?}", buf);
trace!(" control out data: {:02x?}", res);
Ok((res, StatusStage {}))
}

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@ -18,7 +18,7 @@ use embassy_nrf::usb::Driver;
use embassy_nrf::Peripherals;
use embassy_usb::control::OutResponse;
use embassy_usb::{Config, DeviceStateHandler, UsbDeviceBuilder};
use embassy_usb_hid::{HidClass, ReportId, RequestHandler, State};
use embassy_usb_hid::{HidReaderWriter, ReportId, RequestHandler, State};
use futures::future::join;
use usbd_hid::descriptor::{KeyboardReport, SerializedDescriptor};
@ -75,7 +75,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
let request_handler = MyRequestHandler {};
let device_state_handler = MyDeviceStateHandler::new();
let mut state = State::<8, 1>::new();
let mut state = State::new();
let mut builder = UsbDeviceBuilder::new(
driver,
@ -88,14 +88,13 @@ async fn main(_spawner: Spawner, p: Peripherals) {
);
// Create classes on the builder.
let hid = HidClass::with_output_ep(
&mut builder,
&mut state,
KeyboardReport::desc(),
Some(&request_handler),
60,
64,
);
let config = embassy_usb_hid::Config {
report_descriptor: KeyboardReport::desc(),
request_handler: Some(&request_handler),
poll_ms: 60,
max_packet_size: 64,
};
let hid = HidReaderWriter::<_, 1, 8>::new(&mut builder, &mut state, config);
// Build the builder.
let mut usb = builder.build();
@ -135,7 +134,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
let mut button = Input::new(p.P0_11.degrade(), Pull::Up);
let (mut hid_in, hid_out) = hid.split();
let (reader, mut writer) = hid.split();
// Do stuff with the class!
let in_fut = async {
@ -153,7 +152,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
modifier: 0,
reserved: 0,
};
match hid_in.serialize(&report).await {
match writer.write_serialize(&report).await {
Ok(()) => {}
Err(e) => warn!("Failed to send report: {:?}", e),
};
@ -167,7 +166,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
modifier: 0,
reserved: 0,
};
match hid_in.serialize(&report).await {
match writer.write_serialize(&report).await {
Ok(()) => {}
Err(e) => warn!("Failed to send report: {:?}", e),
};
@ -175,7 +174,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
};
let out_fut = async {
hid_out.run(false, &request_handler).await;
reader.run(false, &request_handler).await;
};
let power_irq = interrupt::take!(POWER_CLOCK);

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@ -13,7 +13,7 @@ use embassy_nrf::usb::Driver;
use embassy_nrf::Peripherals;
use embassy_usb::control::OutResponse;
use embassy_usb::{Config, UsbDeviceBuilder};
use embassy_usb_hid::{HidClass, ReportId, RequestHandler, State};
use embassy_usb_hid::{HidWriter, ReportId, RequestHandler, State};
use futures::future::join;
use usbd_hid::descriptor::{MouseReport, SerializedDescriptor};
@ -52,7 +52,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
let mut control_buf = [0; 16];
let request_handler = MyRequestHandler {};
let mut control = State::<5, 0>::new();
let mut state = State::new();
let mut builder = UsbDeviceBuilder::new(
driver,
@ -65,14 +65,14 @@ async fn main(_spawner: Spawner, p: Peripherals) {
);
// Create classes on the builder.
let mut hid = HidClass::new(
&mut builder,
&mut control,
MouseReport::desc(),
Some(&request_handler),
60,
8,
);
let config = embassy_usb_hid::Config {
report_descriptor: MouseReport::desc(),
request_handler: Some(&request_handler),
poll_ms: 60,
max_packet_size: 8,
};
let mut writer = HidWriter::<_, 5>::new(&mut builder, &mut state, config);
// Build the builder.
let mut usb = builder.build();
@ -94,7 +94,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
wheel: 0,
pan: 0,
};
match hid.input().serialize(&report).await {
match writer.write_serialize(&report).await {
Ok(()) => {}
Err(e) => warn!("Failed to send report: {:?}", e),
}