Add documentation for HKDF functions. Improve param comments for devId.

Author: dgarske

doc/dox_comments/header_files/aes.h

@@ -668,13 +668,13 @@ int  wc_AesCcmDecrypt(Aes* aes, byte* out,
 
     \param aes   AES keys for encrypt/decrypt process
     \param heap  heap hint to use for memory. Can be NULL
-    \param devId id to use with async crypto. Can be 0
+    \param devId ID to use with crypto callbacks or async hardware. Set to INVALID_DEVID (-2) if not used
 
     _Example_
     \code
     XtsAes aes;
 
-    if(wc_AesXtsInit(&aes, NULL, 0) != 0)
+    if(wc_AesXtsInit(&aes, NULL, INVALID_DEVID) != 0)
     {
         // Handle error
     }
@@ -749,13 +749,13 @@ int wc_AesXtsSetKeyNoInit(XtsAes* aes, const byte* key,
                  i.e. 32 for a 16 byte key.
     \param dir   direction, either AES_ENCRYPTION or AES_DECRYPTION
     \param heap  heap hint to use for memory. Can be NULL
-    \param devId id to use with async crypto. Can be 0
+    \param devId ID to use with crypto callbacks or async hardware. Set to INVALID_DEVID (-2) if not used
 
     _Example_
     \code
     XtsAes aes;
 
-    if(wc_AesXtsSetKey(&aes, key, sizeof(key), AES_ENCRYPTION, NULL, 0) != 0)
+    if(wc_AesXtsSetKey(&aes, key, sizeof(key), AES_ENCRYPTION, NULL, INVALID_DEVID) != 0)
     {
         // Handle error
     }
@@ -974,7 +974,7 @@ int wc_AesXtsFree(XtsAes* aes);
 
     \param aes aes structure in to initialize
     \param heap heap hint to use for malloc / free if needed
-    \param devId ID to use with async hardware
+    \param devId ID to use with crypto callbacks or async hardware. Set to INVALID_DEVID (-2) if not used
 
     _Example_
     \code
@@ -1455,7 +1455,7 @@ WOLFSSL_API int  wc_AesEaxEncryptUpdate(AesEax* eax, byte* out,
     This argument should be NULL if not used
     \param authInSz size in bytes of the input authentication data
 
-    
+
     _Example_
     \code
     AesEax eax;
@@ -1571,8 +1571,8 @@ WOLFSSL_API int  wc_AesEaxAuthDataUpdate(AesEax* eax,
 
 /*!
     \ingroup AES
-    \brief This function finalizes the encrypt AEAD operation, producing an auth 
-    tag over the current authentication stream. \c eax must have been previously 
+    \brief This function finalizes the encrypt AEAD operation, producing an auth
+    tag over the current authentication stream. \c eax must have been previously
     initialized with a call to \ref wc_AesEaxInit. When done using the \c AesEax
     context structure, make sure to free it using \ref wc_AesEaxFree.
 
@@ -1632,10 +1632,10 @@ WOLFSSL_API int wc_AesEaxEncryptFinal(AesEax* eax,
 
 /*!
     \ingroup AES
-    \brief This function finalizes the decrypt AEAD operation, finalizing the 
+    \brief This function finalizes the decrypt AEAD operation, finalizing the
     auth tag computation and checking it for validity against the user supplied
-    tag. \c eax must have been previously initialized with a call to 
-    \ref wc_AesEaxInit. When done using the \c AesEax context structure, make 
+    tag. \c eax must have been previously initialized with a call to
+    \ref wc_AesEaxInit. When done using the \c AesEax context structure, make
     sure to free it using \ref wc_AesEaxFree.
 
     \return 0 if data is authenticated successfully

doc/dox_comments/header_files/cmac.h

@@ -40,7 +40,7 @@ int wc_InitCmac(Cmac* cmac,
     \param type Always WC_CMAC_AES = 1
     \param unused not used, exists for potential future use around compatibility
     \param heap pointer to the heap hint used for dynamic allocation. Typically used with our static memory option. Can be NULL.
-    \param devId ID to use with async hardware. Set to INVALID_DEVID if not using async hardware.
+    \param devId ID to use with crypto callbacks or async hardware. Set to INVALID_DEVID (-2) if not used
 
     _Example_
     \code

doc/dox_comments/header_files/ecc.h

@@ -572,8 +572,8 @@ int wc_ecc_init(ecc_key* key);
     \return MEMORY_E Returned if there is an error allocating memory
 
     \param key pointer to the ecc_key object to initialize
-    \param devId ID to use with async hardware
     \param heap pointer to a heap identifier
+    \param devId ID to use with crypto callbacks or async hardware. Set to INVALID_DEVID (-2) if not used
 
     _Example_
     \code
@@ -1968,7 +1968,7 @@ int wc_ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
 /*!
     \ingroup ECC
 
-    \brief Enable ECC support for non-blocking operations. Supported for 
+    \brief Enable ECC support for non-blocking operations. Supported for
         Single Precision (SP) math with the following build options:
             WOLFSSL_SP_NONBLOCK
             WOLFSSL_SP_SMALL
@@ -1978,7 +1978,7 @@ int wc_ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
     \return 0 Returned upon successfully setting the callback context the input message
 
     \param key pointer to the ecc_key object
-    \param ctx pointer to ecc_nb_ctx_t structure with stack data cache for SP 
+    \param ctx pointer to ecc_nb_ctx_t structure with stack data cache for SP
 
     _Example_
     \code
@@ -1998,7 +1998,7 @@ int wc_ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                     &key
                 );
 
-                // TODO: Real-time work can be called here 
+                // TODO: Real-time work can be called here
             } while (ret == FP_WOULDBLOCK);
         }
         wc_ecc_free(&key);