/******************************************************************************
* Send a string over UART.
*****************************************************************************/
RAMFUNC void BLUART_sendString(char *str)
{
while (1) {
if ( *str == 0 )
break;
BLUART_send((uint8_t)*str++);
}
while ( !(UART->STATUS & USART_STATUS_TXC) );
}
/**************************************************************************//**
* @brief Starts a XMODEM download.
*****************************************************************************/
RAMFUNC bool XMODEM_download(void)
{
XMODEM_packet *pkt;
uint32_t i;
uint32_t byte;
uint32_t sequenceNumber = 1;
uint32_t writeAddress, endAddress;
uint8_t *decryptedBuffer;
if ( USE_TEMP_STORAGE ) {
writeAddress = TEMP_START_ADDRESS;
endAddress = TEMP_END_ADDRESS;
} else {
writeAddress = FIRMWARE_START_ADDRESS;
endAddress = FIRMWARE_END_ADDRESS;
}
/* Initialize AES for decryption */
startDecryptCBC256();
/* Send one start transmission packet. Wait for a response. If there is no
* response, we resend the start transmission packet. */
while (1)
{
BLUART_send(XMODEM_NCG);
i = 10000000;
/* Wait until we receive a packet */
while ( !(UART->STATUS & USART_STATUS_RXDATAV) ) {
/* Time out */
if ( --i == 0 )
break;
}
/* We have received a packet */
if ( UART->STATUS & USART_STATUS_RXDATAV ) {
break;
}
}
/* Start receiving XMODEM packets */
while (1)
{
/* Swap buffer for packet buffer */
pkt = (XMODEM_packet *) rawPacket[sequenceNumber & 1];
decryptedBuffer = rawBuffer[sequenceNumber & 1];
/* Fetch the first byte of the packet explicitly, as it defines the
* rest of the packet */
pkt->header = BLUART_receive();
/* Check for end of transfer */
if (pkt->header == XMODEM_EOT)
{
/* Acknowledge End of transfer */
BLUART_send(XMODEM_ACK);
break;
}
/* If header is cancel message, then cancel the transfer */
if (pkt->header == XMODEM_CAN)
{
return false;
}
/* If the header is not a start of header (SOH), then cancel *
* the transfer. */
if (pkt->header != XMODEM_SOH)
{
BLUART_send(XMODEM_CAN);
return false;
}
/* If the received file is larger than the allocated memory
* for the firmware, cancel the transfer. */
if ( writeAddress > endAddress ) {
BLUART_send(XMODEM_CAN);
return false;
}
/* Fill the remaining bytes packet */
/* Byte 0 is padding, byte 1 is header */
for (byte = 2; byte < sizeof(XMODEM_packet); byte++)
{
*((uint8_t *)pkt + byte) = BLUART_receive();
}
/* Verify that the packet is valid */
if (XMODEM_verifyPacketChecksum(pkt, sequenceNumber) != 0)
{
/* On a malformed packet, send a NAK and start over */
BLUART_send(XMODEM_NAK);
continue;
}
/* If we have reached a new page, first erase it */
if ( writeAddress % FLASH_PAGE_SIZE == 0 ) {
FLASH_erasePage(writeAddress);
}
/* Decrypt one XMODEM packet(32 words) */
for ( i=0; i<XMODEM_DATA_SIZE/AES_BLOCKSIZE; i++ ) {
/* Decrypt one AES block (4 words) */
decryptBlockCBC256(&(pkt->data[i * AES_BLOCKSIZE]), &(decryptedBuffer[i * AES_BLOCKSIZE]));
}
/* Check if this is the header packet */
if ( sequenceNumber == 1 ) {
/* Get the header */
FirmwareHeader *header = (FirmwareHeader *)decryptedBuffer;
/* Set the state to not verified initially */
header->verified = FW_NOT_VERIFIED;
/* Write the header to flash */
FLASH_write((uint32_t *)writeAddress, (uint32_t *)header, sizeof(FirmwareHeader) / 4);
/* Start at the boot address for the next packet */
writeAddress = writeAddress + FIRMWARE_HEADER_SIZE;
} else {
/* Write decrypted packet to flash */
FLASH_write((uint32_t *)writeAddress, (uint32_t *)decryptedBuffer, XMODEM_DATA_SIZE / 4);
writeAddress += XMODEM_DATA_SIZE;
}
sequenceNumber++;
/* Send ACK */
BLUART_send(XMODEM_ACK);
}
endDecryptCBC256();
/* Wait for the last DMA transfer to finish. */
while (DMA->CHENS & DMA_CHENS_CH0ENS) ;
/* Return success */
return true;
}
