This commit implements a workaround that allows ESP32-C5 to run at 240MHz CPU frequency
normally, while automatically reducing CPU frequency during encrypted flash writes to
ensure correct operation. The frequency limit is chip revision dependent:
- v1.2 and above: limited to 160MHz during encrypted writes
- v1.0 and below: limited to 80MHz during encrypted writes
Key implementation details:
- Frequency limiting is triggered automatically when esp_flash_write_encrypted() is called
- Uses start() flags (ESP_FLASH_START_FLAG_LIMIT_CPU_FREQ) to integrate with OS layer
- Works with both PM enabled and disabled configurations
- Frequency is automatically restored after encrypted write completes
- For ESP32-C5 with 120MHz flash, Flash clock and timing registers are adjusted when
CPU frequency is reduced to 80MHz
- SPI1 timing registers are configured during frequency switching since encrypted writes
use SPI1 and must work correctly at reduced CPU frequencies
Code improvements:
- Use SOC_MSPI_FREQ_AXI_CONSTRAINED capability macro instead of hardcoded chip checks
- Control workaround via Kconfig (CONFIG_PM_WORKAROUND_FREQ_LIMIT_ENABLED) instead of
hardcoded macros
- Add comprehensive test cases covering various PM configurations and edge cases
This workaround enables ESP32-C5 applications to benefit from 240MHz CPU performance
while maintaining reliable encrypted flash write functionality.
For RAM loadable ELF case, there is no application or the bootloader on
the flash. And hence the check for getting current running OTA partition
or looking up partition table fails during dangerous writes option.
We are disabling the dangerous writes option for RAM loadable ELF case
and allowing writes to entire flash memory.
- Adds arbitration between the erase and write in suspend mode
(If the flash memory is suspended then only a read operation can be performed.)
- espcoredump: Dump does not use suspend feature, just resume before continue.
- spi_flash: Add release_cpu() to do suspend/release_cpu/resume
Xiao Xufeng
armando
C.S.M
Krzysztof
wanlei
gaoxu
Mahavir Jain
wuzhenghui
jiangguangming
KonstantinKondrashov
Ivan Grokhotkov
Angus Gratton