Add links to PCIe-related specifications

Signed-off-by: Sergii Dmytruk <[email protected]>

Author: SergiiDmytruk

README.md

@@ -38,7 +38,8 @@ programming guides:
 - [POWER9 Registers vol3](https://ibm.ent.box.com/s/flt3hs6eiwd9glq3yzzff0flnup2j7p0)
 - [POWER ISA v3.0B](https://ibm.ent.box.com/s/1hzcwkwf8rbju5h9iyf44wm94amnlcrv)
 - [POWER9 processor errata](https://ibm.ent.box.com/s/0ixfserqjzjmt3q6vabotz9arxzs59md)
-- [POWER9 IPL flow](https://wiki.raptorcs.com/w/images/b/bd/IPL-Flow-POWER9.pdf)
+- [Power9 PCIe Controller](https://ibm.box.com/s/07dfe69jbaavct70a642f0bhrqhlhgze)
+- [PHB4 Specification (PCIe related)](https://ibm.ent.box.com/s/jftnfhceul07qjh9jtn91xwjmclabc71)
 
 Other useful information extracted form documents aboive may be found in
 [ppc.md](devnotes/ppc.md).

devnotes/pci.md

@@ -1,3 +1,9 @@
+## Specifications
+
+[POWER9 PCIe Controller (Functional Specification)](https://wiki.raptorcs.com/w/images/a/a5/POWER9_PCIe_controller_v11_27JUL2018_pub.pdf)
+
+[Power Systems Host Bridge 4 (PHB4) Specification](https://wiki.raptorcs.com/w/images/a/ad/P9_PHB_version1.0_27July2018_pub.pdf)
+
 ## Terms
 
 PEC - PCI Express Controller (probably)