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.
If LDO1 is used by spi flash, then we recommend to give the ownership to
the hardware. Software just read the parameters from the efuse and set
to PMU.
Common spi functionality for sharing the SPI bus between modules is moved from esp_driver_spi to
a more fitting location in esp_hw_support (shared HW resource control).
This also allows us to decouple the spi_flash driver from esp_driver_spi, removing
esp_driver_spi and esp_ringbuf from G1 builds.
For some of the MSPI high frequency setting (e.g. 80M DDR mode Flash or PSRAM), timing tuning is required.
Certain delays will be added to the MSPI RX direction. When system clock switches down, the delays should be
cleared. When system clock switches up, the delays should be restored.
