XIP: Need help with enabling execute in place in esp-idf

[bembite]

Hello. I have seen that esp32 support XIP (https://open4tech.com/execute-place-xip-memory-model/). And I also found that some changes to the linker script can enable it (https://github.com/zephyrproject-rtos/zephyr/pull/30424 as it was done here).

I am interested how to do this with esp-idf. Maybe there is flag in menuconfig to enable it. I would be grateful if you could provide me any additional info. Thank you.

[ESP_Sprite]

ESP-IDF already uses XIP for the large majority of the code generated. Is there anything specific that you want to achieve with this?

[bembite]

ESP-IDF already uses XIP for the large majority of the code generated. Is there anything specific that you want to achieve with this?

Thank you for replying. How to detect that XIP is enabled?

[ESP_Sprite]

Well, if you build your program using esp-idf, it always uses XIP for most of the code because otherwise most programs wouldn't fit in memory. But if you want specifics, run 'idf.py size', the part where it says 'flash code' will be executed as XIP. (Something similar goes for 'flash data' but it's not executed... it's directly loaded from flash, though.)

[bembite]

Well, if you build your program using esp-idf, it always uses XIP for most of the code because otherwise most programs wouldn't fit in memory. But if you want specifics, run 'idf.py size', the part where it says 'flash code' will be executed as XIP. (Something similar goes for 'flash data' but it's not executed... it's directly loaded from flash, though.)

So most of the time we cannot use external SPI-connected RAM, as it it is using same SPI. Thank you!

[ESP_Sprite]

Define "cannot use"? If you mean the PSRAM that sits on the same bus in e.g. the Wrover modules; it's accessed via the same mechanism XIP uses so outside of the times you need to do something bypassing that mechanism (specifically flash erases and writes, in which case most code is suspended anyway), RAM is perfectly usable. Same goes for user-defined stuff you talk to via the SPI driver: while you're accessing any other SPI device on that bus, code execution is mostly suspended, but it will happily resume after you're done.

[bembite]

"cannot use"

Define "cannot use"? If you mean the PSRAM that sits on the same bus in e.g. the Wrover modules; it's accessed via the same mechanism XIP uses so outside of the times you need to do something bypassing that mechanism (specifically flash erases and writes, in which case most code is suspended anyway), RAM is perfectly usable. Same goes for user-defined stuff you talk to via the SPI driver: while you're accessing any other SPI device on that bus, code execution is mostly suspended, but it will happily resume after you're done.

Thank you!
"cannot use" - I thought that in XIP mode this SPI buss is used for reading instructions from extflash and cannot suspend.

My fault, need more doc reading...