OpenBMC on the OpenWRT

[Anton D. Kachalov]

Hello everybody.

I'm working on a separate project for rack solution which utilize many portions of OpenBMC:

   https://github.com/ya-mouse/openbmc-target

As a system base we choose OpenWRT (flexible kernel-style configurations, package manager,
wide and experienced support for embedded systems with limited resources).
We still use old u-boot that came from OpenSource release of AMI SDK.
Have plans to move to the OpenBMC's version to start using of DTS.
And a few modifications over OpenBMC kernel tree:

1. I2C slave support for the aspeed adapter (it is ugly a bit).
2. I2C slave support for MUX switch (pca954x).
3. DTS overlay support ported from Raspberry Pi with userspace dtoverlay/dtparam/dtmerge tools to manage configs.
4. LuaJIT + Nginx as a HTTP API backend instead of python/micropython.
    We're on internal dissccusion of the API as a mainstream replacement for IPMB/IPMI.
    We use local memcached for fast serving data.
5. Transparent master/slave i2c based IPMB driver with OpenIPMI interface
    (works with regular ipmitool/freeipmi) to send requests to the Nodes.
    To work in a daemon mode kernel part of ipmi_msghandler should be modified a bit
    to receive incoming requests and store it separately while user (opener of the /dev/ipmiX)
    assigned by the outgoing SeqId. For unwanted (from current module's point of view)
    incoming packets there is currently no way to proper store such messages.

Just for reference.
We've compared performance of the several dynamic HTTP configurations such as
python/micropython/lua (LuCI) and embeeded lua within nginx and discover that last one has almost
maximum RPS comparing to the static pages serving.
Static is about 350 RPS while dynamic nginx+luajit with auth checking is at 220RPS.
Simple python's http serves at 40 RPS. LuCI variant is 4-6 RPS.
First request to authentication service occurs via https and the result stored in the
local nginx shared memory storage for the further use (configured for one minute).

-- 
Anton D. Kachalov