Add documentation + reformat the code

Author: adustm

hal/targets/hal/TARGET_STM/TARGET_STM32F4/entropy_hardware_poll.c

@@ -30,21 +30,27 @@
 /* RNG handler declaration */
 RNG_HandleTypeDef RngHandle;
 
-/*
- * Get one byte of entropy from the RNG, assuming it is up and running.
+
+/** rng_get_byte
+ *  @brief Get one byte of entropy from the RNG, assuming it is up and running.
+ *  @param pointer to the hardware generated random byte.
  */
 static void rng_get_byte( unsigned char *byte )
 {
     *byte = (unsigned char)HAL_RNG_GetRandomNumber(&RngHandle);
 }
 
-/*
- * Get len bytes of entropy from the hardware RNG.
+
+/** mbedtls_hardware_poll
+ *  @brief Get len bytes of entropy from the hardware RNG.
+ *  @param data pointer will be NULL
+ *  @param output pointer to the random generated bytes buffer
+ *  @param len input is the requested length of bytes to be generated
+ *  @param olen is the pointer to the length of bytes effectively generated
+ *  @returns 0 if the generation went well. -1 in case of error
  */
-int mbedtls_hardware_poll( void *data,
-                    unsigned char *output, size_t len, size_t *olen )
+int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t *olen )
 {
-    size_t i;
     int ret;
     ((void) data);
 
@@ -56,22 +62,17 @@ int mbedtls_hardware_poll( void *data,
     HAL_RNG_Init(&RngHandle);
 
     /* Get Random byte */
-    for( i = 0; i < len; i++ ){
+    for( uint32_t i = 0; i < len; i++ ){
         rng_get_byte( output + i );
-        printf("output %i: %i\n",i,(int)*(output+i));
 
     }
+    *olen = len;
     /* Just be extra sure that we didn't do it wrong */
-    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 )
-    {
+    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 ) {
         ret = -1;
-        goto cleanup;
+    } else {
+        ret = 0;
     }
-
-    *olen = len;
-    ret = 0;
-
-cleanup:
     /*Disable the RNG peripheral */
     HAL_RNG_DeInit(&RngHandle);
     /* RNG Peripheral clock disable - assume we're the only users of RNG  */

hal/targets/hal/TARGET_STM/TARGET_STM32F7/entropy_hardware_poll.c

@@ -25,21 +25,27 @@
 /* RNG handler declaration */
 RNG_HandleTypeDef RngHandle;
 
-/*
- * Get one byte of entropy from the RNG, assuming it is up and running.
+
+/** rng_get_byte
+ *  @brief Get one byte of entropy from the RNG, assuming it is up and running.
+ *  @param pointer to the hardware generated random byte.
  */
 static void rng_get_byte( unsigned char *byte )
 {
     *byte = (unsigned char)HAL_RNG_GetRandomNumber(&RngHandle);
 }
 
-/*
- * Get len bytes of entropy from the hardware RNG.
+
+/** mbedtls_hardware_poll
+ *  @brief Get len bytes of entropy from the hardware RNG.
+ *  @param data pointer will be NULL
+ *  @param output pointer to the random generated bytes buffer
+ *  @param len input is the requested length of bytes to be generated
+ *  @param olen is the pointer to the length of bytes effectively generated
+ *  @returns 0 if the generation went well. -1 in case of error
  */
-int mbedtls_hardware_poll( void *data,
-                    unsigned char *output, size_t len, size_t *olen )
+int mbedtls_hardware_poll( void *data, unsigned char *output, size_t len, size_t *olen )
 {
-    size_t i;
     int ret;
     ((void) data);
 
@@ -50,22 +56,18 @@ int mbedtls_hardware_poll( void *data,
     RngHandle.Instance = RNG;
     HAL_RNG_Init(&RngHandle);
 
-
     /* Get Random byte */
-    for( i = 0; i < len; i++ )
+    for( uint32_t i = 0; i < len; i++ ){
         rng_get_byte( output + i );
 
+    }
+    *olen = len;
     /* Just be extra sure that we didn't do it wrong */
-    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 )
-    {
+    if( ( __HAL_RNG_GET_FLAG(&RngHandle, (RNG_FLAG_CECS|RNG_FLAG_SECS)) ) != 0 ) {
         ret = -1;
-        goto cleanup;
+    } else {
+        ret = 0;
     }
-
-    *olen = len;
-    ret = 0;
-
-cleanup:
     /*Disable the RNG peripheral */
     HAL_RNG_DeInit(&RngHandle);
     /* RNG Peripheral clock disable - assume we're the only users of RNG  */