/* * SPDX-FileCopyrightText: 2020-2022 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #include <string.h> #include "esp32s2/rom/usb/usb_common.h" #include "soc/soc.h" #include "hal/efuse_hal.h" /* USB CDC descriptor. * Note that we aren't using the one in ROM since it doesn't * set "serial" to the MAC address. * However overriding the descriptor is cheap - we can reuse most * of its components from ROM. */ /* This is not const, since the MAC address is only known at run time */ static struct string_descriptor s_str_serial_descr = { .bLength = 2 + 2 * 17, .bDescriptorType = 0x03, .bString={'0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0', ':', '0', '0'} }; static const struct rom_usb_descriptors s_acm_usb_descriptors_override = { .device_descr = &general_device_descr, .config_descr = { &acm_config_descr }, .string_count = 4, .string0_descr = &string0_descr, .string_descrs = { &str_manu_descr, &str_prod_descr, &s_str_serial_descr } }; static inline uint16_t nibble_to_hex_u16(uint8_t b) { if (b < 0xa) { return '0' + b; } else { return 'a' + b - 0xa; } } void rom_usb_cdc_set_descriptor_patch(void) { uint8_t mac_bytes[6]; efuse_hal_get_mac(mac_bytes); /* Convert to UTF16 string */ #pragma GCC diagnostic push #if __GNUC__ >= 9 #pragma GCC diagnostic ignored "-Waddress-of-packed-member" #endif uint16_t* dst = s_str_serial_descr.bString; for (int i = 0; i < 6; ++i) { uint8_t b = mac_bytes[5 - i]; /* printing from the MSB */ *dst++ = nibble_to_hex_u16(b >> 4); *dst++ = nibble_to_hex_u16(b & 0xf); dst++; } #pragma GCC diagnostic pop /* Override the pointer to descriptors structure */ rom_usb_curr_desc = &s_acm_usb_descriptors_override; }