Fix documentation links

Change-Id: Ic09e74f22b43fba51ee17cd02b5e1dc5d8e0bb63
Signed-off-by: John Tsichritzis <john.tsichritzis@arm.com>
diff --git a/docs/change-log.rst b/docs/change-log.rst
index 5941a8b..22effb1 100644
--- a/docs/change-log.rst
+++ b/docs/change-log.rst
@@ -2428,6 +2428,7 @@
 .. _Contribution Guide: ./contributing.rst
 .. _Authentication framework: ./design/auth-framework.rst
 .. _Firmware Update: ./design/firmware-update.rst
+.. _Firmware Design: ./design/firmware-design.rst
 .. _TF-A Reset Design: ./design/reset-design.rst
 .. _Power Domain Topology Design: ./design/psci-pd-tree.rst
 .. _TF-A wiki on GitHub: https://github.com/ARM-software/arm-trusted-firmware/wiki/ARM-Trusted-Firmware-Image-Terminology
diff --git a/docs/components/sdei.rst b/docs/components/sdei.rst
index 845a295..6d0e156 100644
--- a/docs/components/sdei.rst
+++ b/docs/components/sdei.rst
@@ -41,7 +41,7 @@
 original EL2 execution [13]. Note that the SDEI interrupt remains active until
 the client handler completes, at which point EL3 does EOI [12].
 
-Other than events bound to interrupts (as depicted in the sequence above, SDEI
+Other than events bound to interrupts, as depicted in the sequence above, SDEI
 events can be explicitly dispatched in response to other exceptions, for
 example, upon receiving an *SError* or *Synchronous External Abort*. See
 `Explicit dispatch of events`_.
@@ -370,3 +370,4 @@
 
 .. _SDEI specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0054a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf
 .. _SDEI porting requirements: ../getting_started/porting-guide.rst#sdei-porting-requirements
+.. _Software Delegated Exception Interface: `SDEI specification`_
diff --git a/readme.rst b/readme.rst
index 02aa392..378982f 100644
--- a/readme.rst
+++ b/readme.rst
@@ -341,8 +341,8 @@
 .. _Acknowledgments: ./docs/acknowledgements.rst
 .. _Firmware Design: ./docs/design/firmware-design.rst
 .. _Change Log: ./docs/change-log.rst
-.. _User Guide: ./docs/getting-started/user-guide.rst
-.. _Porting Guide: ./docs/getting-started/porting-guide.rst
+.. _User Guide: ./docs/getting_started/user-guide.rst
+.. _Porting Guide: ./docs/getting_started/porting-guide.rst
 .. _FreeBSD: http://www.freebsd.org
 .. _SCC: http://www.simple-cc.org/
 .. _Security Advisory TFV-1: ./docs/security_advisories/security-advisory-tfv-1.rst