TBB: add mbedTLS authentication related libraries

This patch adds the following mbedTLS based libraries:

* Cryptographic library

It is used by the crypto module to verify a digital signature
and a hash. This library relies on mbedTLS to perform the
cryptographic operations. mbedTLS sources must be obtained
separately.

Two key algorithms are currently supported:

    * RSA-2048
    * ECDSA-SECP256R1

The platform is responsible for picking up the required
algorithm by defining the 'MBEDTLS_KEY_ALG' variable in the
platform makefile. Available options are:

    * 'rsa' (for RSA-2048) (default option)
    * 'ecdsa' (for ECDSA-SECP256R1)

Hash algorithm currently supported is SHA-256.

* Image parser library

Used by the image parser module to extract the authentication
parameters stored in X509v3 certificates.

Change-Id: I597c4be3d29287f2f18b82846973afc142ee0bf0
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
new file mode 100644
index 0000000..b71bbc9
--- /dev/null
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -0,0 +1,60 @@
+#
+# Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# Redistributions of source code must retain the above copyright notice, this
+# list of conditions and the following disclaimer.
+#
+# Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# Neither the name of ARM nor the names of its contributors may be used
+# to endorse or promote products derived from this software without specific
+# prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+ifneq (${MBEDTLS_COMMON_MK},1)
+MBEDTLS_COMMON_MK	:=	1
+
+# MBEDTLS_DIR must be set to the mbedTLS main directory (it must contain
+# the 'include' and 'library' subdirectories).
+ifeq (${MBEDTLS_DIR},)
+  $(error Error: MBEDTLS_DIR not set)
+endif
+
+INCLUDES		+=	-I${MBEDTLS_DIR}/include		\
+				-Iinclude/drivers/auth/mbedtls
+
+# Specify mbedTLS configuration file
+POLARSSL_CONFIG_FILE	:=	"<mbedtls_config.h>"
+$(eval $(call add_define,POLARSSL_CONFIG_FILE))
+
+MBEDTLS_COMMON_SOURCES	:=	drivers/auth/mbedtls/mbedtls_common.c	\
+				$(addprefix ${MBEDTLS_DIR}/library/,	\
+				asn1parse.c 				\
+				asn1write.c 				\
+				memory_buffer_alloc.c			\
+				oid.c 					\
+				platform.c 				\
+				)
+
+BL1_SOURCES		+=	${MBEDTLS_COMMON_SOURCES}
+BL2_SOURCES		+=	${MBEDTLS_COMMON_SOURCES}
+DISABLE_PEDANTIC	:=	1
+
+endif