3.8.3.1.3 Workflow

  1. Define sample data from NIST-800-38A appendix F for ECB mode. 
    #define AES_EXAMPLE_REFBUF_SIZE 4

uint32_t ref_plain_text[AES_EXAMPLE_REFBUF_SIZE] = {
    0xe2bec16b,
    0x969f402e,
    0x117e3de9,
    0x2a179373
};

uint32_t ref_cipher_text_ecb[AES_EXAMPLE_REFBUF_SIZE] = {
    0xb47bd73a,
    0x60367a0d,
    0xf3ca9ea8,
    0x97ef6624
};

const uint32_t key128[4] = {
    0x16157e2b,
    0xa6d2ae28,
    0x8815f7ab,
    0x3c4fcf09
};
  2. Create related module variable and software instance structure. 
    
/* Output data array */
static uint32_t output_data[AES_EXAMPLE_REFBUF_SIZE];
/* State indicate */
volatile bool state = false;
struct aes_config g_aes_cfg;
struct aes_module aes_instance;
struct usart_module usart_instance;
  3. Create DMA resource struct and descriptor. 
    struct dma_resource example_resource_tx;
struct dma_resource example_resource_rx;
COMPILER_ALIGNED(16)
DmacDescriptor example_descriptor_tx SECTION_DMAC_DESCRIPTOR;
DmacDescriptor example_descriptor_rx SECTION_DMAC_DESCRIPTOR;
  4. Configure, initialize, and enable AES module.
    1. Configuration AES DMA module, which can be used for AES. 
      /* Configure AES DMA and enable callback */
configure_dma_aes_wr();
configure_dma_aes_rd();

dma_register_callback(&example_resource_tx, transfer_tx_rx_done,
        DMA_CALLBACK_TRANSFER_DONE);
dma_enable_callback(&example_resource_tx, DMA_CALLBACK_TRANSFER_DONE);

dma_register_callback(&example_resource_rx, transfer_tx_rx_done,
        DMA_CALLBACK_TRANSFER_DONE);
dma_enable_callback(&example_resource_rx, DMA_CALLBACK_TRANSFER_DONE);
    2. Configuration AES struct, which can be filled out to adjust the configuration of a physical AES peripheral. 
      aes_get_config_defaults(&g_aes_cfg);
    3. Initialize the AES configuration struct with the module's default values. 
      aes_init(&aes_instance,AES, &g_aes_cfg);
    4. Enable the AES module. 
      aes_enable(&aes_instance);