/* Choose SHA S/W or H/W context and initialize it
*
* try_hw:
* 0: Initialize S/W context
* 1: Try acquiring SHA H/W resource first and initialize its H/W context if successful. If failed, initialize S/W context.
*/
static void mbedtls_sha256_init_internal(mbedtls_sha256_context *ctx, int try_hw)
{
if (try_hw && crypto_sha_acquire()) {
ctx->active_ctx = &ctx->hw_ctx;
mbedtls_sha256_hw_init(&ctx->hw_ctx);
} else {
ctx->active_ctx = &ctx->sw_ctx;
mbedtls_sha256_sw_init(&ctx->sw_ctx);
}
}
void mbedtls_sha256_init(mbedtls_sha256_context *ctx)
{
if (crypto_sha_acquire()) {
ctx->ishw = 1;
mbedtls_sha256_hw_init(&ctx->hw_ctx);
}
else {
ctx->ishw = 0;
mbedtls_sha256_sw_init(&ctx->sw_ctx);
}
}
void mbedtls_sha256_hw_finish(crypto_sha_context *ctx, unsigned char output[32])
{
// H/W SHA cannot handle zero data well. Fall back to S/W SHA.
if (ctx->total) {
crypto_sha_update_nobuf(ctx, ctx->buffer, ctx->buffer_left, 1);
ctx->buffer_left = 0;
crypto_sha_getinternstate(output, ctx->is224 ? 28 : 32);
CRPT->SHA_CTL |= CRPT_SHA_CTL_STOP_Msk;
}
else {
mbedtls_sha256_sw_context ctx_sw;
mbedtls_sha256_sw_init(&ctx_sw);
mbedtls_sha256_sw_starts(&ctx_sw, ctx->is224);
mbedtls_sha256_sw_finish(&ctx_sw, output);
mbedtls_sha256_sw_free(&ctx_sw);
}
}