esp32: is broken for the latest esp-idf version

[SebastianBoe]

Following the ESP32's instructions for installing and using the espressif SDK resulted in a broken build.

Specifically, I get the below error message when building hello_world.

Git blame shows that the offending line was added in mid-august, so I am guessing that the latest ESP-IDF SDK is not compatible with Zephyr. Haven't confirmed this by going back in time yet though ...

Solution suggestions

1. Put a specific git revision in the SDK installation instructions.
2. Fix the latest ESP-IDF version to be compatible with Zephyr and then set up CI to ensure the latest ESP-IDF is always compatible with Zephyr.

Make output

  /home/sebo/workspace_zephyr/esp/xtensa-esp32-elf/bin/xtensa-esp32-elf-gcc -Wp,-MD,drivers/gpio/.gpio_esp32.o.d  -nostdinc -isystem /home/sebo/workspace_zephyr/esp/xtensa-esp32-elf/bin/../lib/gcc/xtensa-esp32-elf/5.2.0/include -isystem /home/sebo/workspace_zephyr/esp/xtensa-esp32-elf/bin/../lib/gcc/xtensa-esp32-elf/5.2.0/include-fixed -I/home/sebo/zephyr/kernel/include -I/home/sebo/zephyr/arch/xtensa/include -I/home/sebo/zephyr/arch/xtensa/soc/esp32 -I/home/sebo/zephyr/boards/xtensa/esp32  -I/home/sebo/zephyr/include -I/home/sebo/zephyr/include -I/home/sebo/workspace_zephyr/zephyr/samples/hello_world/outdir/esp32/include/generated -include /home/sebo/workspace_zephyr/zephyr/samples/hello_world/outdir/esp32/include/generated/autoconf.h  -I/home/sebo/workspace_zephyr/esp/esp-idf/components/esp32/include -I/home/sebo/workspace_zephyr/esp/esp-idf/components/soc/esp32/include -I/home/sebo/zephyr/lib/libc/minimal/include  -I/home/sebo/zephyr/drivers/gpio -Idrivers/gpio -DKERNEL -D__ZEPHYR__=1 -c -g -std=c99 -Wall -Wformat -Wformat-security -D_FORTIFY_SOURCE=2 -Wno-format-zero-length -Wno-main -ffreestanding -Os -fno-asynchronous-unwind-tables -fno-pie -fno-pic -fno-stack-protector -ffunction-sections -fdata-sections -fms-extensions -Wno-unused-but-set-variable -fno-reorder-functions -fno-defer-pop -Wno-pointer-sign -fno-strict-overflow -Werror=implicit-int   -I/home/sebo/zephyr/include/drivers   -I/home/sebo/zephyr/drivers    -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(gpio_esp32)"  -D"KBUILD_MODNAME=KBUILD_STR(gpio_esp32)" -c -o drivers/gpio/gpio_esp32.o /home/sebo/zephyr/drivers/gpio/gpio_esp32.c
In file included from /home/sebo/workspace_zephyr/esp/esp-idf/components/soc/esp32/include/soc/dport_access.h:20:0,
                 from /home/sebo/workspace_zephyr/esp/esp-idf/components/soc/esp32/include/soc/dport_reg.h:20,
                 from /home/sebo/zephyr/drivers/gpio/gpio_esp32.c:9:
/home/sebo/workspace_zephyr/esp/esp-idf/components/esp32/include/esp_dport_access.h:15:23: fatal error: sdkconfig.h: No such file or directory

[SebastianBoe]

Can confirm that it is a regression from commit cb31222e in the esp-idf repo.

git checkout cb31222e~1

resolves the issue.

[pfalcon]

Don't we pin esp-idf to a specific revision? Everybody does, it's still largely WIP and incompatible changes happen regularly (from what I heard).

[SebastianBoe]

No.

The board's documentation says this:

Two components are required in order to build this port: the toolchain_
and the SDK_. Both are provided by the SoC manufacturer.

The SDK contains headers and a hardware abstraction layer library
(provided only as object files) that are required for the port to
function.

The toolchain is available for Linux, Windows, and Mac hosts and
instructions to obtain and set them up are available in the ESP-IDF
repository, using the toolchain and SDK links above.

Following the SDK link eventually gives you:

git clone --recursive https://github.com/espressif/esp-idf.git

So latest master of esp-idf.

I would suggest pinning the version.

[SebastianBoe]

Could you elaborate on it being WIP? Is there anything I should expect to be broken with esp32?

Specifically, is it expected that

sanitycheck -p esp32

will have 0 failures?

[lpereira]

I believe that @pfalcon was saying that esp-idf is WIP, so likely to break every now and then. I agree with the suggestion to pin to a particular revision, as we don't really care about esp-idf itself: we only need it for some headers and libhal.a, which are unlikely to significantly change.

[pfalcon]

I believe that @pfalcon was saying that esp-idf is WIP

Yes, that's what I meant.

[andrewboie]

I would be not at all opposed to checking in a 'known good' version of ESP-IDF directly into the Zephyr tree, along with our other HALs in ext/ if there are no license issues.

[SebastianBoe]

For source code this is OK IMHO, but not for the 452K binary libhal.a.

I worry it would bloat git over time.

[lpereira]

Yeah. The whole repository for esp-idf is licensed under an Apache License 2.0 (IIRC), so in theory we could do that. But I'm not keen on distributing a binary blob with Zephyr.

[pfalcon]

@nashif already raised (or mentioned) an issue that 90% (if not 95%) of Zephyr's "weight" are existing vendor libs in ext/ . So, if esp32 doesn't have that, it can be a fresh breath and start of something new (I for example would really ponder of using git submodules).