cpu/esp32: wrong XTAL frequency resulting in serial rubbish on ESP32 board with custom frequency

[jmgraeffe]

Description

Applications output rubbish through UART which seems to be the result of a mismatching XTAL frequency while building the bootloader. I've a board that has an XTAL frequency of 26 MHz but the bootloader is being built with 40 MHz configured fixed.

Steps to reproduce the issue

I built and flashed examples/hello-world to my ESP32 board using:

make flash term BOARD=esp32-wroom-32

Expected results

Serial output over UART:

2022-11-01 03:13:27,000 # ets Jul 29 2019 12:21:46
2022-11-01 03:13:27,000 # 
2022-11-01 03:13:27,005 # rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
2022-11-01 03:13:27,007 # configsip: 0, SPIWP:0xee
2022-11-01 03:13:27,013 # clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
2022-11-01 03:13:27,016 # mode:DOUT, clock div:2
2022-11-01 03:13:27,018 # load:0x3fff0030,len:1428
2022-11-01 03:13:27,020 # load:0x40078000,len:12788
2022-11-01 03:13:27,022 # load:0x40080400,len:2840
2022-11-01 03:13:27,024 # entry 0x40080410
2022-11-01 03:13:27,069 # Pro cpu up.
2022-11-01 03:13:27,070 # Single core mode
2022-11-01 03:13:27,125 # 
2022-11-01 03:13:27,132 # main(): This is RIOT! (Version: 2023.01-devel-219-g240cc)
2022-11-01 03:13:27,133 # Hello World!
2022-11-01 03:13:27,138 # You are running RIOT on a(n) esp32-wroom-32 board.
2022-11-01 03:13:27,141 # This board features a(n) esp32 MCU.

Actual results

Serial output over UART:

2022-11-01 03:09:39,720 # �#���l��l�n���N|$no�`lrn#$�
                                                     �n�lo|��$�
                                                               b�Nn���l$b�ܒ�oo�lld"���"`��noN�"�o� l�N�l"����o����l$��Nl#Nll�|�{�$b�|~�o���pb���o�����������{$co$l�|�s�ll �bets Jul 29 2019 12:21:46
2022-11-01 03:09:39,721 # 
2022-11-01 03:09:39,725 # rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
2022-11-01 03:09:39,727 # configsip: 0, SPIWP:0xee
2022-11-01 03:09:39,734 # clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
2022-11-01 03:09:39,736 # mode:DOUT, clock div:2
2022-11-01 03:09:39,738 # load:0x3fff0030,len:1428
2022-11-01 03:09:39,740 # load:0x40078000,len:12788

Versions

Operating System Environment
----------------------------
         Operating System: "Ubuntu" "20.04.4 LTS (Focal Fossa)"
                   Kernel: Linux 5.15.0-46-generic x86_64 x86_64
             System shell: /usr/bin/dash (probably dash)
             make's shell: /usr/bin/dash (probably dash)

Installed compiler toolchains
-----------------------------
               native gcc: gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0
        arm-none-eabi-gcc: missing
                  avr-gcc: avr-gcc (GCC) 5.4.0
           msp430-elf-gcc: missing
       riscv-none-elf-gcc: missing
  riscv64-unknown-elf-gcc: missing
     riscv-none-embed-gcc: missing
     xtensa-esp32-elf-gcc: missing
   xtensa-esp8266-elf-gcc: missing
                    clang: missing

Installed compiler libs
-----------------------
     arm-none-eabi-newlib: missing
        msp430-elf-newlib: missing
    riscv-none-elf-newlib: missing
riscv64-unknown-elf-newlib: missing
  riscv-none-embed-newlib: missing
  xtensa-esp32-elf-newlib: missing
xtensa-esp8266-elf-newlib: missing
                 avr-libc: "2.0.0" ("20150208")

Installed development tools
---------------------------
                   ccache: missing
                    cmake: cmake version 3.16.3
                 cppcheck: missing
                  doxygen: missing
                      git: git version 2.25.1
                     make: GNU Make 4.2.1
                  openocd: missing
                   python: Python 3.8.10
                  python2: Python 2.7.18
                  python3: Python 3.8.10
                   flake8: error: /usr/bin/python3: No module named flake8
               coccinelle: missing