Build: Correct the description of Crypto config

This patch corrects the description of crypto service
config parameters and also sets the correct default for
CRYPTO_ENGINE_BUF_SIZE config.

Signed-off-by: Soby Mathew <soby.mathew@arm.com>
Change-Id: I5552ab0ce0bafaf14752fdca4714d41956c7bb43
diff --git a/config/config_default.cmake b/config/config_default.cmake
index b5b32f5..2364c8e 100644
--- a/config/config_default.cmake
+++ b/config/config_default.cmake
@@ -83,17 +83,17 @@
 set(ITS_BUF_SIZE                        ""          CACHE STRING    "Size of the ITS internal data transfer buffer (defaults to ITS_MAX_ASSET_SIZE if not set)")
 
 set(TFM_PARTITION_CRYPTO                ON          CACHE BOOL      "Enable Crypto partition")
-set(CRYPTO_ENGINE_BUF_SIZE              0x2000      CACHE STRING    "TODO Soby Matthew")
-set(CRYPTO_CONC_OPER_NUM                8           CACHE STRING    "TODO Soby Matthew")
-set(CRYPTO_KEY_MODULE_DISABLED          FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_AEAD_MODULE_DISABLED         FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_MAC_MODULE_DISABLED          FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_HASH_MODULE_DISABLED         FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_CIPHER_MODULE_DISABLED       FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_GENERATOR_MODULE_DISABLED    FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_GENERATOR_MODULE_DISABLED    TRUE        CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_ASYMMETRIC_MODULE_DISABLED   FALSE       CACHE BOOL      "TODO Soby Matthew")
-set(CRYPTO_IOVEC_BUFFER_SIZE            5120        CACHE BOOL      "TODO Soby Matthew")
+# CRYPTO_ENGINE_BUF_SIZE needs to be >8KB for EC signing by attest module.
+set(CRYPTO_ENGINE_BUF_SIZE              0x2040      CACHE STRING    "Heap size for the crypto backend")
+set(CRYPTO_CONC_OPER_NUM                8           CACHE STRING    "The max number of concurrent operations that can be active (allocated) at any time in Crypto")
+set(CRYPTO_KEY_MODULE_DISABLED          FALSE       CACHE BOOL      "Disable PSA Crypto Key module")
+set(CRYPTO_AEAD_MODULE_DISABLED         FALSE       CACHE BOOL      "Disable PSA Crypto AEAD module")
+set(CRYPTO_MAC_MODULE_DISABLED          FALSE       CACHE BOOL      "Disable PSA Crypto MAC module")
+set(CRYPTO_HASH_MODULE_DISABLED         FALSE       CACHE BOOL      "Disable PSA Crypto Hash module")
+set(CRYPTO_CIPHER_MODULE_DISABLED       FALSE       CACHE BOOL      "Disable PSA Crypto Cipher module")
+set(CRYPTO_GENERATOR_MODULE_DISABLED    FALSE       CACHE BOOL      "Disable PSA Crypto Key Derivation module")
+set(CRYPTO_ASYMMETRIC_MODULE_DISABLED   FALSE       CACHE BOOL      "Disable PSA Crypto Asymmetric key module")
+set(CRYPTO_IOVEC_BUFFER_SIZE            5120        CACHE STRING    "Default size of the internal scratch buffer used for PSA FF IOVec allocations")
 
 set(TFM_PARTITION_INITIAL_ATTESTATION   ON          CACHE BOOL      "Enable Initial Attestation partition")
 set(SYMMETRIC_INITIAL_ATTESTATION       OFF         CACHE BOOL      "Use symmetric crypto for inital attestation")