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use crate::bus::HostBus;
use crate::descriptor;
use crate::driver::Driver;
use crate::types::DeviceAddress;
use crate::{Event, UsbHost};
use usb_device::control::Recipient;
use defmt::trace;
#[derive(Copy, Clone)]
pub enum DiscoveryState {
// get device descriptor
DeviceDesc,
// get configuration descriptor length n of m
ConfigDescLen(u8, u8),
// get full configuration descriptor n of m
ConfigDesc(u8, u8),
// finished discovery.
Done,
// failed to parse one of the descriptors
ParseError,
}
/// Begin discovery, by requesting the device descriptor
pub fn start_discovery<B: HostBus>(
dev_addr: DeviceAddress,
host: &mut UsbHost<B>,
) -> DiscoveryState {
// Unwrap safety: it is up to the UsbHost to start discovery only when no other transfer is in progress.
host.get_descriptor(
Some(dev_addr),
None,
Recipient::Device,
descriptor::TYPE_DEVICE,
0,
18,
)
.ok()
.unwrap();
DiscoveryState::DeviceDesc
}
pub fn process_discovery<B: HostBus>(
event: Event,
dev_addr: DeviceAddress,
state: DiscoveryState,
drivers: &mut [&mut dyn Driver<B>],
host: &mut UsbHost<B>,
) -> DiscoveryState {
match state {
DiscoveryState::DeviceDesc => {
match event {
Event::ControlInData(_, length) => {
let data = unsafe { host.bus.control_buffer(length as usize) };
let Ok((_, descriptor)) = descriptor::parse::any_descriptor(data) else {
trace!("Failed to parse descriptor frame: {}", data);
return DiscoveryState::ParseError
};
for driver in drivers {
driver.descriptor(dev_addr, descriptor.descriptor_type, descriptor.data);
}
let Ok((_, device_descriptor)) = descriptor::parse::device_descriptor(descriptor.data) else {
trace!("Failed to parse device descriptor: {}", descriptor.data);
return DiscoveryState::ParseError
};
// Unwrap safety: when a `Control*` event is emitted, the host is idle and a transfer can be started
host.get_descriptor(
Some(dev_addr),
None,
Recipient::Device,
descriptor::TYPE_CONFIGURATION,
0,
9,
)
.ok()
.unwrap();
trace!("-> ConfigDescLen(0, {})", device_descriptor.num_configurations);
DiscoveryState::ConfigDescLen(0, device_descriptor.num_configurations)
}
_ => state,
}
}
DiscoveryState::ConfigDescLen(n, m) => {
match event {
Event::ControlInData(_, length) => {
let data = unsafe { host.bus.control_buffer(length as usize) };
let Ok((_, descriptor)) = descriptor::parse::any_descriptor(data) else {
trace!("Failed to parse descriptor frame: {}", data);
return DiscoveryState::ParseError
};
let Ok((_, total_length)) = descriptor::parse::configuration_descriptor_length(descriptor.data) else {
trace!("Failed to extract length from configuration descriptor: {}", descriptor.data);
return DiscoveryState::ParseError
};
// Unwrap safety: when a `Control*` event is emitted, the host is idle and a transfer can be started
host.get_descriptor(
Some(dev_addr),
None,
Recipient::Device,
descriptor::TYPE_CONFIGURATION,
n,
total_length,
)
.ok()
.unwrap();
trace!("-> ConfigDesc({}, {})", n, m);
DiscoveryState::ConfigDesc(n, m)
}
_ => state,
}
}
DiscoveryState::ConfigDesc(n, m) => {
match event {
Event::ControlInData(_, length) => {
let mut data = unsafe { host.bus.control_buffer(length as usize) };
loop {
let Ok((rest, descriptor)) = descriptor::parse::any_descriptor(data) else {
trace!("Failed to parse descriptor frame: {}", data);
return DiscoveryState::ParseError
};
for driver in &mut *drivers {
driver.descriptor(
dev_addr,
descriptor.descriptor_type,
descriptor.data,
);
}
if rest.len() > 0 {
data = rest;
} else {
break;
}
}
if (n + 1) < m {
// Unwrap safety: when a `Control*` event is emitted, the host is idle and a transfer can be started
host.get_descriptor(
Some(dev_addr),
None,
Recipient::Device,
descriptor::TYPE_CONFIGURATION,
n + 1,
9,
)
.ok()
.unwrap();
trace!("-> ConfigDescLen({}, {})", n + 1, m);
DiscoveryState::ConfigDescLen(n + 1, m)
} else {
// NOTE: do not start a transfer here, the UsbHost code expects the bus to stay idle.
trace!("-> Done");
DiscoveryState::Done
}
}
_ => state,
}
}
DiscoveryState::Done | DiscoveryState::ParseError => unreachable!(),
}
}