Updated the code with the review feedback

sw/device/tests/BUILD

@@ -6279,3 +6279,61 @@ opentitan_test(
         "//sw/device/lib/testing/test_framework:ottf_utils",
     ],
 )
+
+opentitan_test(
+    name = "aes_force_prng_reseed_test",
+    srcs = ["aes_force_prng_reseed_test.c"],
+    exec_env = dicts.add(
+        {
+            "//hw/top_earlgrey:sim_verilator": None,
+            "//hw/top_earlgrey:fpga_cw340_sival": None,
+        },
+    ),
+    verilator = verilator_params(
+        timeout = "long",
+    ),
+    deps = [
+        "//hw/ip/aes:model",
+        "//hw/top_earlgrey/sw/autogen:top_earlgrey",
+        "//sw/device/lib/base:memory",
+        "//sw/device/lib/base:mmio",
+        "//sw/device/lib/dif:aes",
+        "//sw/device/lib/dif:edn",
+        "//sw/device/lib/dif:entropy_src",
+        "//sw/device/lib/runtime:log",
+        "//sw/device/lib/testing:aes_testutils",
+        "//sw/device/lib/testing:entropy_testutils",
+        "//sw/device/lib/testing/test_framework:ottf_main",
+        "//sw/device/sca/lib:simple_serial",
+    ],
+)
+
+opentitan_test(
+    name = "aes_prng_reseed_test",
+    srcs = ["aes_prng_reseed_test.c"],
+    exec_env = dicts.add(
+        {
+            "//hw/top_earlgrey:sim_verilator": None,
+            "//hw/top_earlgrey:fpga_cw340_sival": None,
+        },
+    ),
+    verilator = verilator_params(
+        timeout = "long",
+    ),
+    deps = [
+        "//hw/ip/aes:model",
+        "//hw/top_earlgrey/sw/autogen:top_earlgrey",
+        "//sw/device/lib/base:memory",
+        "//sw/device/lib/base:mmio",
+        "//sw/device/lib/dif:aes",
+        "//sw/device/lib/dif:edn",
+        "//sw/device/lib/dif:entropy_src",
+        "//sw/device/lib/runtime:log",
+        "//sw/device/lib/testing:aes_testutils",
+        "//sw/device/lib/testing:entropy_testutils",
+        "//sw/device/lib/testing/test_framework:check",
+        "//sw/device/lib/testing/test_framework:ottf_main",
+        "//sw/device/lib/testing/test_framework:ottf_utils",
+        "//sw/device/sca/lib:simple_serial",
+    ],
+)

sw/device/tests/aes_force_prng_reseed_test.c

@@ -0,0 +1,274 @@
+// Copyright lowRISC contributors (OpenTitan project).
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "sw/device/lib/base/bitfield.h"
+#include "sw/device/lib/base/mmio.h"
+#include "sw/device/lib/base/multibits.h"
+#include "sw/device/lib/dif/dif_aes.h"
+#include "sw/device/lib/dif/dif_csrng.h"
+#include "sw/device/lib/dif/dif_csrng_shared.h"
+#include "sw/device/lib/dif/dif_edn.h"
+#include "sw/device/lib/dif/dif_entropy_src.h"
+#include "sw/device/lib/runtime/hart.h"
+#include "sw/device/lib/runtime/log.h"
+#include "sw/device/lib/testing/aes_testutils.h"
+#include "sw/device/lib/testing/csrng_testutils.h"
+#include "sw/device/lib/testing/entropy_testutils.h"
+#include "sw/device/lib/testing/test_framework/check.h"
+#include "sw/device/lib/testing/test_framework/ottf_main.h"
+#include "sw/device/sca/lib/simple_serial.h"
+
+#include "hw/top_earlgrey/sw/autogen/top_earlgrey.h"
+
+OTTF_DEFINE_TEST_CONFIG();
+
+enum {
+  kTestTimeout = 1000 * 1000,  // Timeout for waiting for AES operations
+};
+
+static dif_aes_t aes;
+static dif_edn_t edn0, edn1;
+static dif_csrng_t csrng;
+static dif_entropy_src_t entropy_src;
+
+// Function to fetch and log CSRNG internal state
+static void log_csrng_internal_state(const dif_csrng_t *csrng) {
+  dif_csrng_internal_state_t csrng_state;
+  dif_csrng_internal_state_id_t instance_id = kCsrngInternalStateIdSw;
+
+  CHECK_DIF_OK(dif_csrng_get_internal_state(csrng, instance_id, &csrng_state));
+
+  LOG_INFO("CSRNG internal state: 0x%x", csrng_state);
+}
+
+void monitor_entropy_sources(void) {
+  // EDN status monitoring
+  bool edn_status0, edn_status1;
+  CHECK_DIF_OK(dif_edn_get_status(&edn0, kDifEdnStatusReady, &edn_status0));
+  CHECK_DIF_OK(dif_edn_get_status(&edn1, kDifEdnStatusReady, &edn_status1));
+  LOG_INFO("EDN0 status: 0x%x", edn_status0);
+  LOG_INFO("EDN1 status: 0x%x", edn_status1);
+}
+
+// Function to check the status of EDN
+static void monitor_edn_status(const dif_edn_t *edn0, const dif_edn_t *edn1) {
+  bool edn_status0, edn_status1;
+
+  // Check EDN0 status using kDifEdnStatusReady flag
+  CHECK_DIF_OK(dif_edn_get_status(edn0, kDifEdnStatusReady, &edn_status0));
+  LOG_INFO("EDN0 status (Ready): 0x%x", edn_status0);
+
+  // Check EDN1 status using kDifEdnStatusReady flag
+  CHECK_DIF_OK(dif_edn_get_status(edn1, kDifEdnStatusReady, &edn_status1));
+  LOG_INFO("EDN1 status (Ready): 0x%x", edn_status1);
+}
+
+// AES key used for the test
+static const unsigned char kAesModesKey128[16] = {
+    0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
+    0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c};
+
+static const unsigned char kAesModesPlainText[16] = {
+    0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
+    0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
+};
+
+static const unsigned char kAesModesCipherTextEcb128[16] = {
+    0x3a, 0xd7, 0x7b, 0xb4, 0x0d, 0x7a, 0x36, 0x60,
+    0xa8, 0x9e, 0xca, 0xf3, 0x24, 0x66, 0xef, 0x97};
+
+/*
+The mask share, used to mask kKey. Note that the masking should not be done
+manually. Software is expected to get the key in two shares right from the
+beginning.
+*/
+static const uint8_t kKeyShare1[] = {
+    0x0f, 0x1f, 0x2f, 0x3F, 0x4f, 0x5f, 0x6f, 0x7f, 0x8f, 0x9f, 0xaf,
+    0xbf, 0xcf, 0xdf, 0xef, 0xff, 0x0a, 0x1a, 0x2a, 0x3a, 0x4a, 0x5a,
+    0x6a, 0x7a, 0x8a, 0x9a, 0xaa, 0xba, 0xca, 0xda, 0xea, 0xfa,
+};
+
+// Function to print AES blocks key and data
+static void aes_print_block(const unsigned char *data, const int num_bytes) {
+  for (int i = 0; i < num_bytes; i++) {
+    LOG_INFO("%02x ", data[i]);
+  }
+  LOG_INFO("");
+}
+
+status_t disable_entropy_complex(void) {
+  // Use the entropy test utility to stop all EDN0, EDN1, CSRNG, and the Entropy
+  // Source
+  TRY(entropy_testutils_stop_all());
+  LOG_INFO("The entire entropy complex is stopped");
+  return OK_STATUS();
+}
+
+status_t enable_entropy_complex(void) {
+  // Use the entropy test utility to enable all EDN0, EDN1, CSRNG, and the
+  // Entropy Source
+  TRY(entropy_testutils_auto_mode_init());
+  LOG_INFO("The entire entropy complex is enabled");
+  return OK_STATUS();
+}
+
+status_t execute_test(void) {
+  // Initialize AES, EDN, CSRNG, and Entropy Source
+
+  // Initialize all modules
+  LOG_INFO("Initializing AES unit.");
+  CHECK_DIF_OK(
+      dif_aes_init(mmio_region_from_addr(TOP_EARLGREY_AES_BASE_ADDR), &aes));
+  CHECK_DIF_OK(dif_aes_reset(&aes));
+  LOG_INFO("Module initialized: AES");
+  LOG_INFO("Starting AES PRNG reseed stall test...");
+  CHECK_DIF_OK(
+      dif_edn_init(mmio_region_from_addr(TOP_EARLGREY_EDN0_BASE_ADDR), &edn0));
+  CHECK_DIF_OK(
+      dif_edn_init(mmio_region_from_addr(TOP_EARLGREY_EDN1_BASE_ADDR), &edn1));
+  CHECK_DIF_OK(dif_csrng_init(
+      mmio_region_from_addr(TOP_EARLGREY_CSRNG_BASE_ADDR), &csrng));
+  CHECK_DIF_OK(dif_entropy_src_init(
+      mmio_region_from_addr(TOP_EARLGREY_ENTROPY_SRC_BASE_ADDR), &entropy_src));
+  LOG_INFO("Modules initialized: EDN0, EDN1, CSRNG, Entropy Source");
+
+  // Configure AES for ECB mode, 128-bit key, and manual operation
+  dif_aes_transaction_t transaction = {
+      .operation = kDifAesOperationEncrypt,
+      .mode = kDifAesModeEcb,
+      .key_len = kDifAesKey128,
+      .key_provider = kDifAesKeySoftwareProvided,
+      .mask_reseeding = kDifAesReseedPerBlock,
+      .manual_operation = kDifAesManualOperationManual,
+      .reseed_on_key_change = true,
+      .force_masks = false,
+      .ctrl_aux_lock = false,
+  };
+
+  LOG_INFO(
+      "AES transaction configured: ECB mode, 128-bit key, manual operation.");
+
+  // Disable EDN and CSRNG to simulate stalling
+  LOG_INFO(
+      "Disabling entropy complex- EDN0, EDN1, CSRNG, and the Entropy Source "
+      "...");
+  disable_entropy_complex();
+  busy_spin_micros(500);
+
+  // Expanding aes_testutils_setup_encryption T1 to T8:
+  // T: Start of aes_testutils_setup_encryption function steps
+  // T1: Mask the key. Note that this should not be done manually. Software is
+  // expected to get the key in two shares right from the beginning.
+  uint8_t key_share0[sizeof(kAesModesKey128)];
+  for (int i = 0; i < sizeof(kAesModesKey128); ++i) {
+    key_share0[i] = kAesModesKey128[i] ^ kKeyShare1[i];
+  }
+
+  // T2: "Convert" key share byte arrays to `dif_aes_key_share_t`.
+  dif_aes_key_share_t key;
+  memcpy(key.share0, key_share0, sizeof(key.share0));
+  memcpy(key.share1, kKeyShare1, sizeof(key.share1));
+
+  // T3:  Wait for status kDifAesStatusIdle
+  // Start AES with the given transaction
+  AES_TESTUTILS_WAIT_FOR_STATUS(&aes, kDifAesStatusIdle, true, kTestTimeout);
+
+  // T4: dif_aes_start
+  CHECK_DIF_OK(dif_aes_start(&aes, &transaction, &key, NULL));
+
+  // Trigger PRNG reseed for the first key
+  CHECK_DIF_OK(dif_aes_trigger(&aes, kDifAesTriggerPrngReseed));
+
+  // Generate the second key key2 by slightly modifying the first key to ensure
+  // difference (adding 1) Declare second key shares (ensure it's a new
+  // declaration)
+  uint8_t key2_share0[sizeof(kAesModesKey128)];
+
+  // Generate the second key by modifying the first key (to ensure it’s
+  // different)
+  for (int i = 0; i < sizeof(kAesModesKey128); ++i) {
+    key2_share0[i] = (kAesModesKey128[i] ^ kKeyShare1[i]) + 1;
+  }
+
+  // Load the second key
+  dif_aes_key_share_t key2;
+  memcpy(key2.share0, key2_share0, sizeof(key2_share0));
+  memcpy(key2.share1, kKeyShare1, sizeof(key2.share1));
+
+  LOG_INFO("Conditionally checking AES status after stopping EDN and CSRNG.");
+  LOG_INFO("Waiting for AES to stall after PRNG reseed request...");
+  bool stall = false;
+  CHECK_DIF_OK(dif_aes_get_status(&aes, kDifAesStatusStall, &stall));
+
+  if (stall) {
+    LOG_INFO("AES encryption has stalled as expected.");
+  } else {
+    LOG_ERROR(
+        "ERROR:AES encryption did not stall as expected after EDN stop! Lets "
+        "proceed "
+        "for now to verify further steps...");
+  }
+
+  log_csrng_internal_state(&csrng);
+  monitor_entropy_sources();
+
+  LOG_INFO(
+      "Enabling entropy complex- EDN0, EDN1, CSRNG, and the Entropy Source "
+      "...");
+  enable_entropy_complex();
+  monitor_edn_status(&edn0, &edn1);
+
+  // Trigger PRNG reseed request
+  LOG_INFO("Triggering PRNG reseed...");
+  CHECK_DIF_OK(dif_aes_trigger(&aes, kDifAesTriggerPrngReseed));
+
+  // T5: "Convert" plain data byte arrays to `dif_aes_data_t`
+  dif_aes_data_t in_data_plain;
+  memcpy(in_data_plain.data, kAesModesPlainText, sizeof(in_data_plain.data));
+
+  // T6: Wait ofr Status kDifAesStatusIdle
+  LOG_INFO(
+      "Now Starting AES encryption process firstly by observing if AES is in "
+      "Idle state");
+  AES_TESTUTILS_WAIT_FOR_STATUS(&aes, kDifAesStatusIdle, true, kTestTimeout);
+
+  // T7: Wait for Status input DifAesStatusInputReady
+  LOG_INFO("AES started: ECB encryption, waiting for input ready.");
+  AES_TESTUTILS_WAIT_FOR_STATUS(&aes, kDifAesStatusInputReady, true,
+                                kTestTimeout);
+  // T8: Load the plain text to trigger the encryption operation
+  CHECK_DIF_OK(dif_aes_load_data(&aes, in_data_plain));
+
+  // Load the second key into AES (key2)
+  CHECK_DIF_OK(dif_aes_start(&aes, &transaction, &key2, NULL));
+
+  // Trigger AES reseed request, specific for manual operation case
+  LOG_INFO("AES encryption started.");
+  CHECK_DIF_OK(dif_aes_trigger(&aes, kDifAesTriggerStart));
+
+  busy_spin_micros(500);
+
+  // LOG_INFO("Setting EDN to auto mode...");
+  // TRY(entropy_testutils_auto_mode_init());
+  //// CHECK_DIF_OK(entropy_testutils_auto_mode_init());
+  // monitor_edn_status(&edn0, &edn1);
+
+  // Read out the produced cipher text.
+  dif_aes_data_t out_data;
+  LOG_INFO("AES dif_aes_read_output:");
+  CHECK_DIF_OK(dif_aes_read_output(&aes, &out_data));
+
+  LOG_INFO("Encrypted text:");
+  aes_print_block((const unsigned char *)out_data.data, 16);
+
+  // Finish the ECB encryption transaction.
+  CHECK_DIF_OK(dif_aes_end(&aes));
+  LOG_INFO("AES comparison out_data with CipherText:");
+  CHECK_ARRAYS_EQ((uint8_t *)out_data.data, kAesModesCipherTextEcb128,
+                  sizeof(out_data.data));
+
+  return OK_STATUS();
+}
+
+bool test_main(void) { return status_ok(execute_test()); }