serenity/Kernel/Bus/USB/USBEndpoint.h

62 lines
3 KiB
C++

/*
* Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <Kernel/Bus/USB/USBDescriptors.h>
#include <Kernel/Bus/USB/USBPipe.h>
namespace Kernel::USB {
//
// An endpoint is the "end point" of communication of a USB device. That is, data is read from and written
// to an endpoint via a USB pipe. As an example, during device enumeration (where we assign an address to the
// device), we communicate with the device over the default endpoint, endpoint0, which all devices _must_
// contain to be compliant with the USB specification.
//
// And endpoint describes characteristics about the transfer between the host and the device, such as:
// - The endpoint number
// - Max packet size of send/recv of the endpoint
// - Transfer type (bulk, interrupt, isochronous etc)
//
// Take for example a USB multifunction device, such as a keyboard/mouse combination. The mouse
// may need to be polled every n milliseconds, meaning the transfer may be isochronous (streamed),
// while the keyboard part would only generate data once we push a key (hence an interrupt transfer).
// Each of these data sources would be a _different_ endpoint on the device that we read from.
class USBEndpoint {
public:
static constexpr u8 ENDPOINT_ADDRESS_NUMBER_MASK = 0x0f;
static constexpr u8 ENDPOINT_ADDRESS_DIRECTION_MASK = 0x80;
static constexpr u8 ENDPOINT_ADDRESS_DIRECTION_OUT = 0x00;
static constexpr u8 ENDPOINT_ADDRESS_DIRECTION_IN = 0x80;
static constexpr u8 ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_MASK = 0x03;
static constexpr u8 ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_CONTROL = 0x00;
static constexpr u8 ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_ISOCHRONOUS = 0x01;
static constexpr u8 ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_BULK = 0x02;
static constexpr u8 ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_INTERRUPT = 0x03;
static constexpr u8 ENDPOINT_ATTRIBUTES_ISO_MODE_SYNC_TYPE = 0x0c;
static constexpr u8 ENDPOINT_ATTRIBUTES_ISO_MODE_USAGE_TYPE = 0x30;
USBEndpointDescriptor const& descriptor() const { return m_descriptor; }
bool is_control() const { return (m_descriptor.endpoint_attributes_bitmap & ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_MASK) == ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_CONTROL; }
bool is_isochronous() const { return (m_descriptor.endpoint_attributes_bitmap & ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_MASK) == ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_ISOCHRONOUS; }
bool is_bulk() const { return (m_descriptor.endpoint_attributes_bitmap & ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_MASK) == ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_BULK; }
bool is_interrupt() const { return (m_descriptor.endpoint_attributes_bitmap & ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_MASK) == ENDPOINT_ATTRIBUTES_TRANSFER_TYPE_INTERRUPT; }
u16 max_packet_size() const { return m_descriptor.max_packet_size; }
u8 polling_interval() const { return m_descriptor.poll_interval_in_frames; }
private:
USBEndpointDescriptor m_descriptor;
Pipe m_pipe;
};
}