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usb: builtin handling of interface alternate settings

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The stack reads its own descriptors to figure out which endpoints
are used in which alt settings, and enables/disables them as needed.

The ControlHandler has a callback so it can get notified of alternate
setting changes, which is purely informative (it doesn't have to do anything).
This commit is contained in:
Dario Nieuwenhuis
2022-04-16 04:47:27 +02:00
parent ea0a701ebd
commit 092c2b7dfe
9 changed files with 357 additions and 146 deletions
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37
embassy-usb/src/control.rs
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@ -2,7 +2,6 @@ use core::mem;
use crate::descriptor::DescriptorWriter;
use crate::driver::{self, EndpointError};
use crate::DEFAULT_ALTERNATE_SETTING;
use super::types::*;
@ -150,6 +149,10 @@ pub trait ControlHandler {
/// Called after a USB reset after the bus reset sequence is complete.
fn reset(&mut self) {}
fn set_alternate_setting(&mut self, alternate_setting: u8) {
let _ = alternate_setting;
}
/// Called when a control request is received with direction HostToDevice.
///
/// # Arguments
@ -163,8 +166,8 @@ pub trait ControlHandler {
/// Called when a control request is received with direction DeviceToHost.
///
/// You should write the response to `resp`, then return `InResponse::Accepted(len)`
/// with the length of the response.
/// You should write the response somewhere (usually to `buf`, but you may use another buffer
/// owned by yourself, or a static buffer), then return `InResponse::Accepted(data)`.
///
/// # Arguments
///
@ -174,23 +177,17 @@ pub trait ControlHandler {
InResponse::Rejected
}
fn set_interface(&mut self, alternate_setting: u16) -> OutResponse {
if alternate_setting == u16::from(DEFAULT_ALTERNATE_SETTING) {
OutResponse::Accepted
} else {
OutResponse::Rejected
}
}
fn get_interface<'a>(&'a mut self, buf: &'a mut [u8]) -> InResponse<'a> {
buf[0] = DEFAULT_ALTERNATE_SETTING;
InResponse::Accepted(&buf[0..1])
}
fn get_status<'a>(&'a mut self, buf: &'a mut [u8]) -> InResponse {
let status: u16 = 0;
buf[0..2].copy_from_slice(&status.to_le_bytes());
InResponse::Accepted(&buf[0..2])
/// Called when a GET DESCRIPTOR control request is received on the interface.
///
/// You should write the response somewhere (usually to `buf`, but you may use another buffer
/// owned by yourself, or a static buffer), then return `InResponse::Accepted(data)`.
///
/// # Arguments
///
/// * `req` - The request from the SETUP packet.
fn get_descriptor<'a>(&'a mut self, req: Request, buf: &'a mut [u8]) -> InResponse<'a> {
let _ = (req, buf);
InResponse::Rejected
}
}