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Refactor ControlPipe to use the typestate pattern for safety

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This commit is contained in:
alexmoon 2022-03-30 14:17:15 -04:00 committed by Dario Nieuwenhuis
parent 77e0aca03b
commit f5ba022257
2 changed files with 157 additions and 122 deletions
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121
embassy-usb/src/control.rs
View File

@ -1,5 +1,7 @@
use core::mem;
use crate::descriptor::DescriptorWriter;
use crate::driver::{self, ReadError};
use crate::DEFAULT_ALTERNATE_SETTING;
use super::types::*;
@ -191,3 +193,122 @@ pub trait ControlHandler {
InResponse::Accepted(&buf[0..2])
}
}
/// Typestate representing a ControlPipe in the DATA IN stage
#[derive(Debug)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
pub(crate) struct DataInStage {
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;
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), ReadError> {
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;
}
}
Ok((&buf[0..total], StatusStage {}))
}
}
pub(crate) async fn accept_in(&mut self, buf: &[u8], stage: DataInStage) {
#[cfg(feature = "defmt")]
debug!("control in accept {:x}", buf);
#[cfg(not(feature = "defmt"))]
debug!("control in accept {:x?}", 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() {
self.control.data_in(chunk, chunks.size_hint().0 == 0).await;
}
}
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) {
self.control.accept();
}
pub(crate) fn reject(&mut self) {
self.control.reject();
}
}

158
embassy-usb/src/lib.rs
View File

@ -16,7 +16,7 @@ use heapless::Vec;
use self::control::*;
use self::descriptor::*;
use self::driver::*;
use self::driver::{Bus, Driver, Event};
use self::types::*;
use self::util::*;
@ -92,10 +92,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
Self {
bus: driver,
config,
control: ControlPipe {
control,
request: None,
},
control: ControlPipe::new(control),
device_descriptor,
config_descriptor,
bos_descriptor,
@ -134,57 +131,50 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
Either::Right(req) => {
debug!("control request: {:x}", req);
match req.direction {
UsbDirection::In => self.handle_control_in(req).await,
UsbDirection::Out => self.handle_control_out(req).await,
match req {
Setup::DataIn(req, stage) => self.handle_control_in(req, stage).await,
Setup::DataOut(req, stage) => self.handle_control_out(req, stage).await,
}
}
}
}
}
async fn handle_control_out(&mut self, req: Request) {
async fn handle_control_out(&mut self, req: Request, stage: DataOutStage) {
const CONFIGURATION_NONE_U16: u16 = CONFIGURATION_NONE as u16;
const CONFIGURATION_VALUE_U16: u16 = CONFIGURATION_VALUE as u16;
// If the request has a data state, we must read it.
let data = if req.length > 0 {
match self.control.data_out(self.control_buf).await {
Ok(data) => data,
Err(_) => {
warn!("usb: failed to read CONTROL OUT data stage.");
return;
}
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;
}
} else {
&[]
};
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match (req.request, req.value) {
(Request::CLEAR_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
self.remote_wakeup_enabled = false;
self.control.accept();
self.control.accept(stage)
}
(Request::SET_FEATURE, Request::FEATURE_DEVICE_REMOTE_WAKEUP) => {
self.remote_wakeup_enabled = true;
self.control.accept();
self.control.accept(stage)
}
(Request::SET_ADDRESS, 1..=127) => {
self.pending_address = req.value as u8;
self.control.accept();
self.control.accept(stage)
}
(Request::SET_CONFIGURATION, CONFIGURATION_VALUE_U16) => {
self.device_state = UsbDeviceState::Configured;
self.control.accept();
self.control.accept(stage)
}
(Request::SET_CONFIGURATION, CONFIGURATION_NONE_U16) => match self.device_state {
UsbDeviceState::Default => {
self.control.accept();
}
UsbDeviceState::Default => self.control.accept(stage),
_ => {
self.device_state = UsbDeviceState::Addressed;
self.control.accept();
self.control.accept(stage)
}
},
_ => self.control.reject(),
@ -193,12 +183,12 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
(Request::SET_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.set_stalled(ep_addr, true);
self.control.accept();
self.control.accept(stage)
}
(Request::CLEAR_FEATURE, Request::FEATURE_ENDPOINT_HALT) => {
let ep_addr = ((req.index as u8) & 0x8f).into();
self.bus.set_stalled(ep_addr, false);
self.control.accept();
self.control.accept(stage)
}
_ => self.control.reject(),
},
@ -218,7 +208,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
_ => handler.control_out(req, data),
};
match response {
OutResponse::Accepted => self.control.accept(),
OutResponse::Accepted => self.control.accept(stage),
OutResponse::Rejected => self.control.reject(),
}
}
@ -229,7 +219,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
}
}
async fn handle_control_in(&mut self, req: Request) {
async fn handle_control_in(&mut self, req: Request, stage: DataInStage) {
match (req.request_type, req.recipient) {
(RequestType::Standard, Recipient::Device) => match req.request {
Request::GET_STATUS => {
@ -240,17 +230,15 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
if self.remote_wakeup_enabled {
status |= 0x0002;
}
self.control.accept_in(&status.to_le_bytes()).await;
}
Request::GET_DESCRIPTOR => {
self.handle_get_descriptor(req).await;
self.control.accept_in(&status.to_le_bytes(), stage).await
}
Request::GET_DESCRIPTOR => self.handle_get_descriptor(req, stage).await,
Request::GET_CONFIGURATION => {
let status = match self.device_state {
UsbDeviceState::Configured => CONFIGURATION_VALUE,
_ => CONFIGURATION_NONE,
};
self.control.accept_in(&status.to_le_bytes()).await;
self.control.accept_in(&status.to_le_bytes(), stage).await
}
_ => self.control.reject(),
},
@ -261,7 +249,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
if self.bus.is_stalled(ep_addr) {
status |= 0x0001;
}
self.control.accept_in(&status.to_le_bytes()).await;
self.control.accept_in(&status.to_le_bytes(), stage).await
}
_ => self.control.reject(),
},
@ -285,7 +273,7 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
};
match response {
InResponse::Accepted(data) => self.control.accept_in(data).await,
InResponse::Accepted(data) => self.control.accept_in(data, stage).await,
InResponse::Rejected => self.control.reject(),
}
}
@ -296,17 +284,19 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
}
}
async fn handle_get_descriptor(&mut self, req: Request) {
async fn handle_get_descriptor(&mut self, req: Request, stage: DataInStage) {
let (dtype, index) = req.descriptor_type_index();
match dtype {
descriptor_type::BOS => self.control.accept_in(self.bos_descriptor).await,
descriptor_type::DEVICE => self.control.accept_in(self.device_descriptor).await,
descriptor_type::CONFIGURATION => self.control.accept_in(self.config_descriptor).await,
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::STRING => {
if index == 0 {
self.control
.accept_in_writer(req, |w| {
.accept_in_writer(req, stage, |w| {
w.write(descriptor_type::STRING, &lang_id::ENGLISH_US.to_le_bytes());
})
.await
@ -324,7 +314,9 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
};
if let Some(s) = s {
self.control.accept_in_writer(req, |w| w.string(s)).await;
self.control
.accept_in_writer(req, stage, |w| w.string(s))
.await
} else {
self.control.reject()
}
@ -334,81 +326,3 @@ impl<'d, D: Driver<'d>> UsbDevice<'d, D> {
}
}
}
struct ControlPipe<C: driver::ControlPipe> {
control: C,
request: Option<Request>,
}
impl<C: driver::ControlPipe> ControlPipe<C> {
async fn setup(&mut self) -> Request {
assert!(self.request.is_none());
let req = self.control.setup().await;
self.request = Some(req);
req
}
async fn data_out<'a>(&mut self, buf: &'a mut [u8]) -> Result<&'a [u8], ReadError> {
let req = self.request.unwrap();
assert_eq!(req.direction, UsbDirection::Out);
assert!(req.length > 0);
let req_length = usize::from(req.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;
}
}
Ok(&buf[0..total])
}
async fn accept_in(&mut self, buf: &[u8]) -> () {
#[cfg(feature = "defmt")]
debug!("control in accept {:x}", buf);
#[cfg(not(feature = "defmt"))]
debug!("control in accept {:x?}", buf);
let req = unwrap!(self.request);
assert!(req.direction == UsbDirection::In);
let req_len = usize::from(req.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() {
self.control.data_in(chunk, chunks.size_hint().0 == 0).await;
}
self.request = None;
}
async fn accept_in_writer(&mut self, req: Request, 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]).await;
}
fn accept(&mut self) {
assert!(self.request.is_some());
self.control.accept();
self.request = None;
}
fn reject(&mut self) {
assert!(self.request.is_some());
self.control.reject();
self.request = None;
}
}