I am using mbedTLS library and below API for initilaisation, i got stuck at adding entropy source to seed the PRNG. how can i proceed on this, any suggestions on this? Below is my code.

##
this is the error message i got :

**Failed to seed PRNG: mbedTLSError = : CTR_DRBG - The Entropy source failed**

```
/* Initialize contexts for random number generation. */
mbedtls_entropy_init( pEntropyContext );
mbedtls_ctr_drbg_init( pCtrDrgbContext );
/* Add a strong entropy source. At least one is required. */
mbedtlsError = mbedtls_entropy_add_source( pEntropyContext,
mbedtls_platform_entropy_poll,
NULL,
32,
MBEDTLS_ENTROPY_SOURCE_STRONG );
if( mbedtlsError != 0 )
{
LogError( ( "Failed to add entropy source: mbedTLSError= %s : %s.",
mbedtlsHighLevelCodeOrDefault( mbedtlsError ),
mbedtlsLowLevelCodeOrDefault( mbedtlsError ) ) );
returnStatus = TLS_TRANSPORT_INTERNAL_ERROR;
}
if( returnStatus == TLS_TRANSPORT_SUCCESS )
{
/* Seed the random number generator. */
mbedtlsError = mbedtls_ctr_drbg_seed( pCtrDrgbContext,
mbedtls_entropy_func,
pEntropyContext,
NULL,
0 );
```