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zephyrproject-rtos / zephyr

Primary Git Repository for the Zephyr Project. Zephyr is a new generation, scalable, optimized, secure RTOS for multiple hardware architectures.
https://docs.zephyrproject.org
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Shell module broken on LiteX/VexRiscv after release zephyr-v2.1.0 #30702

Closed lindemer closed 3 years ago

lindemer commented 3 years ago

Description In releases after zephyr-v2.1.0 the shell module no longer accepts input on LiteX/VexRiscv running on an Arty A7 FPGA.

To reproduce Steps to reproduce the behavior:

  1. Clone and follow the installation steps in https://github.com/litex-hub/zephyr-on-litex-vexriscv.
  2. Load the FPGA bitstream according to those same instructions.
  3. From the Zephyr repository
    • git checkout zephyr-v2.1.0
    • cd samples/subsys/shell/shell_module
    • west build -b litex_vexriscv
    • lxterm /dev/ttyUSB1 --kernel build/zephyr/zephyr.bin --serial-boot OR flterm --port /dev/ttyUSB1 --kernel build/zephyr/zephyr.bin --kernel-adr 0x40000000

This should flash the firmware onto the soft CPU and bring up the Zephyr shell. Repeating the above with any release after zephyr-v2.1.0 will display the shell prompt but it does not accept any user input.

Environment

lindemer commented 3 years ago

This may be unrelated, but Zephyr's memory footprint appears to have increased significantly after that release. Here's the RAM usage for two samples on litex_vexriscv:

zephyr-v2.1.0 zephyr-v2.2.0
hello_world 13024 B 80560 B
shell_module 73584 B 138672 B
tgorochowik commented 3 years ago

The problem here was that the ethernet driver was getting stuck waiting for buffers to be ready with interrupts disabled. This appeared as a problem with broken shell because the serial driver needed those interrupts to work. This has been resolved by #31152.

In addition the underlying problem in the platform that caused the ethernet driver to get stuck has been resolved in the platform as well (as noted here: https://github.com/litex-hub/zephyr-on-litex-vexriscv/issues/3).

I think this can be closed too.