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pbio/drv/usb/usb_ch9.h: Add definitions for USB data types
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‎lib/pbio/drv/usb/usb_ch9.h‎

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// SPDX-License-Identifier: MIT
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// Copyright (c) 2025 The Pybricks Authors
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// Various bits of USB "Chapter 9" types
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// A number of these types additionally define a union with uint32_t.
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// This serves two functions:
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// 1. Aligns the data to a 4-byte boundary
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// 2. Explicitly enables type punning without violating strict aliasing
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//
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// The latter is important for drivers which want to efficiently copy data
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// multiple bytes at a time. The C standard considers it undefined to access
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// data behind a struct pointer by casting it to a uint32_t pointer,
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// and doing so can cause miscompiles. In order to get what we actually want,
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// GCC explicitly allows type punning via unions. This is documented in the manual:
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// https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#Type-punning
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#ifndef _INTERNAL_PBDRV_USB_CH9_H_
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#define _INTERNAL_PBDRV_USB_CH9_H_
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#include <stdint.h>
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// SETUP transaction packet structure
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typedef struct {
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uint8_t bmRequestType;
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uint8_t bRequest;
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uint16_t wValue;
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uint16_t wIndex;
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uint16_t wLength;
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} usb_setup_packet;
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typedef union {
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usb_setup_packet s;
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uint32_t u[2];
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} usb_setup_packet_u;
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// Bitfields in bmRequestType
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#define BM_REQ_DIR_MASK 0x80
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#define BM_REQ_DIR_H2D 0x00
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#define BM_REQ_DIR_D2H 0x80
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#define BM_REQ_TYPE_MASK 0x60
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#define BM_REQ_TYPE_STANDARD (0 << 5)
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#define BM_REQ_TYPE_CLASS (1 << 5)
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#define BM_REQ_TYPE_VENDOR (2 << 5)
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#define BM_REQ_RECIP_MASK 0x1f
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#define BM_REQ_RECIP_DEV 0
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#define BM_REQ_RECIP_IF 1
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#define BM_REQ_RECIP_EP 2
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#define BM_REQ_RECIP_OTHER 3
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// Standard USB requests
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#define GET_STATUS 0
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#define CLEAR_FEATURE 1
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#define SET_FEATURE 3
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#define SET_ADDRESS 5
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#define GET_DESCRIPTOR 6
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#define SET_DESCRIPTOR 7
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#define GET_CONFIGURATION 8
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#define SET_CONFIGURATION 9
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#define GET_INTERFACE 10
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#define SET_INTERFACE 11
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#define SYNCH_FRAME 12
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// Standard descriptor types
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#define DESC_TYPE_DEVICE 1
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#define DESC_TYPE_CONFIGURATION 2
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#define DESC_TYPE_STRING 3
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#define DESC_TYPE_INTERFACE 4
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#define DESC_TYPE_ENDPOINT 5
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#define DESC_TYPE_DEVICE_QUALIFIER 6
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#define DESC_TYPE_OTHER_SPEED_CONFIGURATION 7
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#define DESC_TYPE_INTERFACE_POWER 8
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// Device descriptor
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typedef struct __attribute__((packed)) {
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uint8_t bLength;
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uint8_t bDescriptorType;
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uint16_t bcdUSB;
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uint8_t bDeviceClass;
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uint8_t bDeviceSubClass;
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uint8_t bDeviceProtocol;
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uint8_t bMaxPacketSize0;
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uint16_t idVendor;
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uint16_t idProduct;
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uint16_t bcdDevice;
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uint8_t iManufacturer;
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uint8_t iProduct;
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uint8_t iSerialNumber;
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uint8_t bNumConfigurations;
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} usb_dev_desc;
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typedef union {
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usb_dev_desc s;
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uint32_t u[(sizeof(usb_dev_desc) + 3) / 4];
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} usb_dev_desc_u;
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// Configuration descriptor
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typedef struct __attribute__((packed)) {
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uint8_t bLength;
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uint8_t bDescriptorType;
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uint16_t wTotalLength;
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uint8_t bNumInterfaces;
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uint8_t bConfigurationValue;
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uint8_t iConfiguration;
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uint8_t bmAttributes;
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uint8_t bMaxPower;
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} usb_conf_desc;
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#define USB_CONF_DESC_BM_ATTR_MUST_BE_SET 0x80
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#define USB_CONF_DESC_BM_ATTR_SELF_POWERED 0x40
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#define USB_CONF_DESC_BM_ATTR_REMOTE_WAKEUP 0x20
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// Interface descriptor
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typedef struct __attribute__((packed)) {
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uint8_t bLength;
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uint8_t bDescriptorType;
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uint8_t bInterfaceNumber;
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uint8_t bAlternateSetting;
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uint8_t bNumEndpoints;
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uint8_t bInterfaceClass;
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uint8_t bInterfaceSubClass;
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uint8_t bInterfaceProtocol;
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uint8_t iInterface;
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} usb_iface_desc;
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// Endpoint descriptor
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typedef struct __attribute__((packed)) {
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uint8_t bLength;
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uint8_t bDescriptorType;
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uint8_t bEndpointAddress;
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uint8_t bmAttributes;
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uint16_t wMaxPacketSize;
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uint8_t bInterval;
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} usb_ep_desc;
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// Endpoint types for bmAttributes
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#define EP_TYPE_CTRL 0
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#define EP_TYPE_ISOC 1
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#define EP_TYPE_BULK 2
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#define EP_TYPE_INTR 3
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// Device qualifier descriptor
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typedef struct __attribute__((packed)) {
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uint8_t bLength;
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uint8_t bDescriptorType;
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uint16_t bcdUSB;
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uint8_t bDeviceClass;
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uint8_t bDeviceSubClass;
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uint8_t bDeviceProtocol;
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uint8_t bMaxPacketSize0;
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uint8_t bNumConfigurations;
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uint8_t bReserved;
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} usb_dev_qualifier_desc;
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typedef union {
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usb_dev_qualifier_desc s;
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uint32_t u[(sizeof(usb_dev_qualifier_desc) + 3) / 4];
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} usb_dev_qualifier_desc_u;
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#endif // _INTERNAL_PBDRV_USB_CH9_H_

‎lib/pbio/drv/usb/usb_ev3.c‎

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#include <pbdrv/clock.h>
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#include "usb_ch9.h"
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#define INTR_BIT_USB_RESET (1 << 18)
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#define INTR_BIT_EP1_OUT (1 << 9)
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#define INTR_BIT_EP1_IN (1 << 1)

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