README


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skiboot
-------

Firmware for OpenPower systems

Source:
https://github.com/open-power/skiboot

Mailing list: skiboot@lists.ozlabs.org
Info/subscribe: https://lists.ozlabs.org/listinfo/skiboot
Archives: https://lists.ozlabs.org/pipermail/skiboot/

Patchwork:
http://patchwork.ozlabs.org/project/skiboot/list/

Overview
--------
OPAL firmware (OpenPower Abstraction Layer) comes in several parts.

A simplified flow of what happens when the power button is pressed is:

 1) The baseboard management controller (BMC) powers the system on.
 2) The BMC selects the master chip and releases the self-boot engines (SBEs)
    on the POWER8 chips, master last.
 3) The BMC relinquishes control of the flexible service interface (FSI)
    SCAN/SCOM engines.
 4) The hostboot firmware IPLs the system. It initiates a secondary power-on
    sequence through a digital power systems sweep (DPSS).
 5) The hostboot firmware loads the OPAL image and moves all processors to
    their execution starting points.

Here, the OPAL image is three parts:
 1) skiboot (includes OPAL runtime services)
 2) skiroot - the bootloader environment
    a) kernel
    b) initramfs (containing petitboot bootloader)

They may be all part of one payload or three separate images (depending on
platform).

The bootloader will kexec a host kernel (probably linux). The host OS can
make OPAL calls. A TODO item is to extensively document this API.

See doc/overview.txt for a more in depth overview of skiboot.


Hacking
-------
You will need a C compiler (gcc 4.8) for ppc64 (big endian).
You will need a POWER8 system that you can deploy new firmware to.

You may also use the IBM POWER8 Functional Simulator to test on.
http://www-304.ibm.com/support/customercare/sas/f/pwrfs/home.html

Qemu (as of 2.2.0) is not suitable as it does not (yet) implement
the HyperVisor mode of the POWER8 processor.

All patches should be sent to the mailing list with linux-kernel style
'Signed-Off-By'.

You probably want to read the linux documentation/SubmittingPatches as
much of it applies to skiboot.

License
-------
See LICENSE