sof/zephyr

SOF with Zephyr RTOS
====================

SOF currently uses the Cadence Xtos/HAL and it's own kernel functions as
its RTOS. SOF is moving to use Zephyr as it's RTOS in parallel to current
releases using xtos.

The initial "alpha" of SOF on Zephyr will use the Zephyr RTOS for boot, IRQs,
scheduling and memory allocation. Subsequent release will use more Zephyr
functionality as code is moved from SOF to Zephyr (i.e. EDF scheduler updates
copied from SOF to Zephyr).

Building SOF on Zephyr
======================

Section promoted to
https://thesofproject.github.io/latest/getting_started/build-guide/build-with-zephyr.html

Testing on Qemu
===============

Get the SOF qemu sof-v4.2 branch here.

git@github.com:thesofproject/qemu.git

Configure as

./configure' '--prefix=.' '--target-list=xtensa-softmmu,x86_64-softmmu' \
             '--enable-gtk' '--enable-sdl' '--enable-spice' \
             '--audio-drv-list=alsa' '--enable-libusb' \
             '--enable-usb-redir' '--enable-coroutine-pool' \
             '--disable-opengl' '--enable-fdt'

 Then run make.

FW can be tested as follows using the qemu helper script.

 ./xtensa-host.sh apl \
     -r ../../sof/sof/build_apl_gcc/src/arch/xtensa/rom-apl.bin \
     -k ../../zephyrproject/zephyr/build/zephyr/zephyr.ri

Where -r and -k are used to specify the ROM and kernel files.

The ROMS can be built from the SOF repo by running

./scripts/xtensa-build-all.sh  -r -a

Using console
-------------

Using logging and simulator backend with processing printk (LOG_PRINTK)
can bring console in qemu.

 - Enable xtensa simulator logging backend (LOG_BACKEND_XTENSA_SIM).
 - Enable printk processing(LOG_PRINTK)
 - Add "-semihosting" to qemu command line. Make sure it goes through scripts to real qemu.