doc: Add links in Introduction to firmware components
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
diff --git a/doc/introduction.rst b/doc/introduction.rst
index 5ae846b..9fde475 100644
--- a/doc/introduction.rst
+++ b/doc/introduction.rst
@@ -7,30 +7,40 @@
Firmware Components
-------------------
-Buildroot
+Buildroot_
We use http://buildroot.net/ as the build system for assembling a firmware
image. `op-build` is a "Buildroot overlay". We build a kernel and initramfs
- using buildroot to run the Petitboot boot loader in.
-SBE
+ using buildroot to run the Petitboot boot loader in. We maintain a branch
+ with a minimum number of patches on top of upstream buildroot.
+SBE_
the Self Boot Engine is the first unit inside the POWER processor to start
executing. It's job is to set up a core and load Hostboot.
-Hostboot
+Hostboot_
Low level system boot firmware. It brings up CPU cores, the OCC, Memory
and hands control over to OPAL (skiboot)
-OCC
+OCC_
The On Chip Controller is responsible for thermal limits and frequency
management.
OPAL
The OpenPOWER Abstraction Layer, provided by skiboot
-skiboot
+skiboot_
skiboot implements OPAL (the OpenPOWER Abstraction Layer). Skiboot is
boot and runtime firmware and is responsible for bringing up PCI and
providing runtime abstractions to the running OS.
-Linux
+Linux_
Once skiboot has finished setting up the machine, it hands control over
to a Linux kernel. This kernel provides device drivers and userspace to
- run the bootloader, Petitboot
-Petitboot
+ run the bootloader, Petitboot. We maintain our own branch with a minimal
+ number of patches on top of the latest upstream stable release.
+Petitboot_
The bootloader. It is a normal user-space process running on Linux that
searches the system for disks and network devices that it can boot the
OS from.
+
+.. _Buildroot: https://github.com/open-power/buildroot
+.. _SBE: https://github.com/open-power/sbe
+.. _OCC: https://github.com/open-power/occ
+.. _Hostboot: https://github.com/open-power/hostboot
+.. _skiboot: https://open-power.github.io/skiboot/
+.. _Linux: https://github.com/open-power/linux
+.. _Petitboot: https://github.com/open-power/petitboot/