pkg/tinyusb: implement stdio via CDC ACM

[benpicco]

Contribution description

This hooks up tinyUSB CDC ACM to stdio.
Some more work is needed so this can be used as default stdio on e.g. esp32s2-mini:

• [ ] Use XFA for common usb_descriptors.c

So we can use application unmodified without providing a custom usb_descriptors.c.

Testing procedure

Flash the tests/pkg_tinyusb_cdc_acm_stdio application on any supported board.

Issues/PRs references

[gschorcht]

Funny, I was working on the same feature in my branch pkg/tinyusb_stdio commit a3048979f18372fc67117989ac3f026d92a4de41 😉 I would drop my work in favor of yours because yours seems to be finished while mine was still in progress.

[gschorcht]

So we can use application unmodified without providing a custom usb_descriptors.c.

BTW, I'm working on a pkg/contrib/tinyusb_descriptors.c implementation which defines the descriptors and handles them for standard cases according to used device classes (defined by the tinyusb_class_* modules) so that an application hasn't to define any usb_descriptors.c.

[gschorcht]

Regarding this file, it makes little sense to redefine it again, since most of the parts are always the same. Furthermore, an application can't use other device classes if module tinyusb_cdc_acm_stdio is used.

That's why I'm working on a common tinyusb_descriptors.c file that uses the configuration and the Kconfig CONFIG_* symbols from the usbus to implement the descriptors. Once I have finished that work, we should be able to drop this file and it should be possible to use tinyusb_stdio together with other device class just by enabling the according tinyusb_class_* modules.

[benpicco]

If you already have a common tinyusb_descriptors.c in the works, I'll just wait for that 😃

Moving this to XFA seems to be a bit tricky, you'll likely be faster with providing a generic solution as you already have experience with this package.

[benpicco]

I renamed the module stdio_tinyusb_cdc_acm for consistency, but now I'm getting

Error - using unknown modules: stdio_tinyusb_cdc_acm
make: *** [/home/benpicco/dev/RIOT/tests/pkg_tinyusb_cdc_acm_stdio/../../Makefile.include:734: ..module-check] Error 1
make: *** Waiting for unfinished jobs....
/usr/lib/gcc/arm-none-eabi/10.3.1/../../../arm-none-eabi/bin/ld: /home/benpicco/dev/RIOT/tests/pkg_tinyusb_cdc_acm_stdio/bin/same54-xpro/cpu/cpu.o: in function `cpu_init':
/home/benpicco/dev/RIOT/cpu/samd5x/cpu.c:386: undefined reference to `stdio_init'
/usr/lib/gcc/arm-none-eabi/10.3.1/../../../arm-none-eabi/bin/ld: /home/benpicco/dev/RIOT/tests/pkg_tinyusb_cdc_acm_stdio/bin/same54-xpro/newlib_syscalls_default/syscalls.o: in function `_read_r':
/home/benpicco/dev/RIOT/sys/newlib_syscalls_default/syscalls.c:507: undefined reference to `stdio_read'
/usr/lib/gcc/arm-none-eabi/10.3.1/../../../arm-none-eabi/bin/ld: /home/benpicco/dev/RIOT/tests/pkg_tinyusb_cdc_acm_stdio/bin/same54-xpro/newlib_syscalls_default/syscalls.o: in function `_write_r':
/home/benpicco/dev/RIOT/sys/newlib_syscalls_default/syscalls.c:520: undefined reference to `stdio_write'
collect2: error: ld returned 1 exit status

what kind of auto-magic am I missing?

[gschorcht]

Target stdio_tinyusb_cdc_acm is not build because it is not in the list of filtered modules in target all.

diff --git a/pkg/tinyusb/Makefile b/pkg/tinyusb/Makefile
index 770f956d1a..6bc7c7afd7 100644
--- a/pkg/tinyusb/Makefile
+++ b/pkg/tinyusb/Makefile
@@ -11,7 +11,7 @@ PSRC = $(PKG_SOURCE_DIR)/src
 
 .PHONY: all
 
-all: $(filter tinyusb_%,$(USEMODULE))
+all: $(filter stdio_tinyusb_cdc_acm tinyusb_%,$(USEMODULE))
        $(QQ)"$(MAKE)" -C $(PSRC) -f $(RIOTBASE)/Makefile.base MODULE=tinyusb
 
 stdio_tinyusb_cdc_acm:

[gschorcht]

@benpicco

BOARD=native make -j8 -C examples/hello-world/

fails due to multiple definitions of several stdio symbols.

[riot-ci]

Murdock results

✔️ PASSED

ea0cf85 tests/pkg_tinyusb_cdc_acm_stdio: add test for stdio via CDC ACM

Success	Failures	Total	Runtime
2002	0	2002	07m:05s

Artifacts

• Documentation preview

This only reflects a subset of all builds from https://ci-prod.riot-os.org. Please refer to https://ci.riot-os.org for a complete build for now.

[gschorcht]

Feel free to squash it directly.

[benpicco]

thank you for the common USB descriptors!

[gschorcht]

Next task on my ToDo list is a tinyUSB netdev driver for CDC ECM.

[gschorcht]

@benpicco Now that we have the stdio implementation for tinyUSB, we could theoretically enable the tinyusb_device feature even for boards that have only one USB interface and use stdio_cdc_acm when the highlevel_stdio feature is enabled.

Before this PR, we couldn't enable tinyUSB for such boards due to the conflict between periph_usbdev and tinusb_device. Now we could select

• stdio_tinyusb_cdc_acm if highlevel_stdio and tinyusb_device are enabled or
• stdio_cdc_acm if highlevel_stdio and periph_usbdev are enable

What do you think?

[benpicco]

Sounds good!

[gschorcht]

Sounds good!

I will provide a PR in next few days.