esp-idf/components/usb/usb_helpers.c
Darian Leung 963836f491 Add USB Host Library API docs
- This commit adds the API documentation for the USB Host Library.
- Warnings about the beta API are also added.
- usb_host_misc.h renamed to usb_helpers.h
2021-09-02 18:40:24 +08:00

169 lines
7.0 KiB
C

/*
* SPDX-FileCopyrightText: 2015-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <assert.h>
#include "usb/usb_helpers.h"
#include "usb/usb_types_ch9.h"
// ---------------------------------------- Configuration Descriptor Parsing -------------------------------------------
const usb_standard_desc_t *usb_parse_next_descriptor(const usb_standard_desc_t *cur_desc, uint16_t wTotalLength, int *offset)
{
assert(cur_desc != NULL && offset != NULL);
if (*offset >= wTotalLength) {
return NULL; //We have traversed the entire configuration descriptor
}
if (*offset + cur_desc->bLength >= wTotalLength) {
return NULL; //Next descriptor is out of bounds
}
//Return the next descriptor, update offset
const usb_standard_desc_t *ret_desc = (const usb_standard_desc_t *)(((uint32_t)cur_desc) + cur_desc->bLength);
*offset += cur_desc->bLength;
return ret_desc;
}
const usb_standard_desc_t *usb_parse_next_descriptor_of_type(const usb_standard_desc_t *cur_desc, uint16_t wTotalLength, uint8_t bDescriptorType, int *offset)
{
assert(cur_desc != NULL && offset != NULL);
int offset_temp = *offset; //We only want to update offset if we've actually found a descriptor
//Keep stepping over descriptors until we find one of bDescriptorType or until we go out of bounds
const usb_standard_desc_t *ret_desc = usb_parse_next_descriptor(cur_desc, wTotalLength, &offset_temp);
while (ret_desc != NULL) {
if (ret_desc->bDescriptorType == bDescriptorType) {
break;
}
ret_desc = usb_parse_next_descriptor(ret_desc, wTotalLength, &offset_temp);
}
if (ret_desc != NULL) {
//We've found a descriptor. Update the offset
*offset = offset_temp;
}
return ret_desc;
}
int usb_parse_interface_number_of_alternate(const usb_config_desc_t *config_desc, uint8_t bInterfaceNumber)
{
assert(config_desc != NULL);
int offset = 0;
//Find the first interface descriptor of bInterfaceNumber
const usb_intf_desc_t *first_intf_desc = usb_parse_interface_descriptor(config_desc, bInterfaceNumber, 0, &offset);
if (first_intf_desc == NULL) {
return -1; //bInterfaceNumber not found
}
int num_alt_setting = 0;
const usb_intf_desc_t *next_intf_desc = (const usb_intf_desc_t *)usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)first_intf_desc, config_desc->wTotalLength, USB_B_DESCRIPTOR_TYPE_INTERFACE, &offset);
while (next_intf_desc != NULL) {
if (next_intf_desc->bInterfaceNumber != bInterfaceNumber) {
break;
}
num_alt_setting++;
next_intf_desc = (const usb_intf_desc_t *)usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)next_intf_desc, config_desc->wTotalLength, USB_B_DESCRIPTOR_TYPE_INTERFACE, &offset);
}
return num_alt_setting;
}
const usb_intf_desc_t *usb_parse_interface_descriptor(const usb_config_desc_t *config_desc, uint8_t bInterfaceNumber, uint8_t bAlternateSetting, int *offset)
{
assert(config_desc != NULL);
if (bInterfaceNumber >= config_desc->bNumInterfaces) {
return NULL; //bInterfaceNumber is out of range
}
//Walk to first interface descriptor of bInterfaceNumber
int offset_temp = 0;
const usb_intf_desc_t *next_intf_desc = (const usb_intf_desc_t *)usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)config_desc, config_desc->wTotalLength, USB_B_DESCRIPTOR_TYPE_INTERFACE, &offset_temp);
while (next_intf_desc != NULL) {
if (next_intf_desc->bInterfaceNumber == bInterfaceNumber) {
break; //We found the first interface descriptor with matching bInterfaceNumber
}
next_intf_desc = (const usb_intf_desc_t *)usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)next_intf_desc, config_desc->wTotalLength, USB_B_DESCRIPTOR_TYPE_INTERFACE, &offset_temp);
}
if (next_intf_desc == NULL) {
return NULL; //Couldn't find a interface with bInterfaceNumber
}
//Keep walking until an interface descriptor matching bInterfaceNumber and bAlternateSetting is found
while (next_intf_desc != NULL) {
if (next_intf_desc->bInterfaceNumber == bInterfaceNumber + 1) {
//We've walked past our target bInterfaceNumber
next_intf_desc = NULL;
break;
}
if (next_intf_desc->bAlternateSetting == bAlternateSetting) {
//We've found our target interface descriptor
break;
}
//Get the next interface descriptor
next_intf_desc = (const usb_intf_desc_t *)usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)next_intf_desc, config_desc->wTotalLength, USB_B_DESCRIPTOR_TYPE_INTERFACE, &offset_temp);
}
if (next_intf_desc != NULL && offset != NULL) {
*offset = offset_temp;
}
return next_intf_desc;
}
const usb_ep_desc_t *usb_parse_endpoint_descriptor_by_index(const usb_intf_desc_t *intf_desc, int index, uint16_t wTotalLength, int *offset)
{
assert(intf_desc != NULL && offset != NULL);
if (index >= intf_desc->bNumEndpoints) {
return NULL; //Index is out of range
}
//Walk to the Nth endpoint descriptor we find
int offset_temp = *offset;
bool ep_found = true;
const usb_standard_desc_t *next_desc = (const usb_standard_desc_t *)intf_desc;
for (int i = 0; i <= index; i++) {
next_desc = usb_parse_next_descriptor_of_type((const usb_standard_desc_t *)next_desc, wTotalLength, USB_B_DESCRIPTOR_TYPE_ENDPOINT, &offset_temp);
if (next_desc == NULL) {
ep_found = false;
break;
}
}
if (ep_found) {
*offset = offset_temp;
return (const usb_ep_desc_t *)next_desc;
}
return NULL;
}
const usb_ep_desc_t *usb_parse_endpoint_descriptor_by_address(const usb_config_desc_t *config_desc, uint8_t bInterfaceNumber, uint8_t bAlternateSetting, uint8_t bEndpointAddress, int *offset)
{
assert(config_desc != NULL);
//Find the interface descriptor
int offset_intf;
const usb_intf_desc_t *intf_desc = usb_parse_interface_descriptor(config_desc, bInterfaceNumber, bAlternateSetting, &offset_intf);
if (intf_desc == NULL) {
return NULL;
}
//Walk endpoint descriptors until one matching bEndpointAddress is found
int offset_ep;
bool ep_found = false;
const usb_ep_desc_t *ep_desc = NULL;
for (int index = 0; index < intf_desc->bNumEndpoints; index++) {
offset_ep = offset_intf;
ep_desc = usb_parse_endpoint_descriptor_by_index(intf_desc, index, config_desc->wTotalLength, &offset_ep);
if (ep_desc == NULL) {
break;
}
if (ep_desc->bEndpointAddress == bEndpointAddress) {
ep_found = true;
break;
}
}
if (ep_found && offset != NULL) {
*offset = offset_ep;
}
return ep_desc;
}
// ------------------------------------------------------ Misc ---------------------------------------------------------