cpu/esp*: Tracking refactoring of ESP MCU implementations

[gschorcht]

Description

There are already parts of MCU implementations for ESP8266 and ESP32 SoCs which are almost identical or at least very similar. Examples are the implementations of

• context handling, context switching and low level interrupt handling (cpu/esp*/vendor/xtensa/*)
• ESP-NOW netdev driver and interface (cpu/esp*/esp-now)

All other parts are completely different at the moment, since ESP32 and ESP8266 use SDKs with libraries which are completely different. However, with the ESP8266 RTOS SDK version under development, it seems that upcoming SDK versions for the ESP8266 will be at least partially compatible with the ESP-IDF for ESP32.

Therefore, it is very likely that both MCUs can use more and more the same code base. This issue is intended to track the modules that can be refactored designed to use the same code base and their progress.

Update With the reimplementation of the ESP8266 port based on the ESP8266 RTOS SDK in PR #11108 it became possible to deduplicate a lot. The code in PR #11108 was already prepared for this deduplication.

Refactored modules

• cpu/esp*/vendor/xtensa (PR cpu/esp*: Xtensa vendor code moved to esp_common #10883)
• cpu/esp*/esp-now
• common definitions

Refactoring prerequisites / steps

• adapt makefiles for ESP32 to use cpu/common/esp/* (PR cpu: esp_common added for common modules of ESP SoCs #10663)
• adapt makefiles for ESP8266 to use cpu/common/esp/* (PR cpu: esp_common added for common modules of ESP SoCs #10663)
• remove SDK interrupt handling from ESP8266 (PR cpu/esp8266: change of ETS task handling  #10656)
• adapt cpu/esp*/vendor/xtensa/* to use architecture specific data in thread control block
• adapt cpu/esp32/vendor/xtensa/* (PR cpu/esp*: Xtensa vendor code moved to esp_common #10883)
• adapt cpu/esp8266/vendor/xtensa/* (PR cpu/esp*: Xtensa vendor code moved to esp_common #10883)
• move cpu/esp*/vendor/xtensa/* to cpu/esp_common/vendor (PR cpu/esp*: Xtensa vendor code moved to esp_common #10883)
• create common Makefile* in cpu/esp_common and include them (PR cpu/esp*: code deduplication and cleanup #12955)
• move common definitions in cpu/esp*/Makefile* to cpu/esp_common/Makefile* (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/vendor/esp/* to cpu/esp_common/vendor (PR cpu/esp*: code deduplication and cleanup #12955)
• move gen_esp32part.py to cpu/esp_common/vendor/esp-idf/partition_table (PR cpu/esp*: code deduplication and cleanup #12955)
• move common definitions (cpu.h, esp_common.h, and to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move LOG_TAG* macros (log_module.h, esp_common_log.h) to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/exceptions to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/events to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/thread_arch to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/tools to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/irq_arch to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/irq_arch to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/syscalls to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/periph/flash to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/periph/hrwng to cpu/esp_common/periph (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/periph/i2c to cpu/esp_common/periph (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/periph/spi to cpu/esp_common/periph (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/periph/uart to cpu/esp_common/periph (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/freertos to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move cpu/esp*/esp_wifi to cpu/esp_common (PR cpu/esp*: code deduplication and cleanup #12955)
• move boards/common/esp*/board_common to board/common/esp

PR dependencies

cpu/esp*/esp-now depends on #10581, #9917

[phillaverdiere]

I am triaging older issues. Can this one be closed?

[gschorcht]

Now that PR #11108 has been merged, there are a lot of other possible code deduplications that are not listed here yet. I have to update the list and would leave the tracking issue open.