MCU-PLUS-SDK-AM243X: Custom PRU bootloader

I was able to implement this and it is working now, I will spend more time cleaning up this code and add error handling in the future.

Here is what I'm doing:

1) RF5 downloads new PRU HEX file over UART port and stores it in an char* array
2) All the HEX values from the array are parsed out and put into an uint32 array, the first element of the array is the array length
3) The OSPI FLASH Block at location 0x200000 is erased, (I couldn't get Sector erase to work using TI APIs)
4) The uint32 array of PRU HEX data is then written to the OSPI FLASH at 0x200000
4) The array is then read back from the OSPI FLASH and compared to what was written, an error could be thrown if it doesn't match
5) The pru_init() function was then modified to read the OSPI_FLASH at location 0x200000 to determine length of PRU HEX array
6) Then entire length of PRU HEX image is read back from OSPI FLASH into an array
7) PRU then starts to run new code, also if board is rebooted the new PRU code in OSPI FLASH starts running

Here is main code doing the work:

char buffer[4096];
UART_Transaction_init(&trans);
gNumBytesRead = 0U;
trans.buf = &buffer[0];
trans.count = 4096;
trans.timeout = 4000; //Wait up to 4000 ms
transferOK = UART_read(gUartHandle[CONFIG_UART_LOG], &trans);

uint32_t* data=(uint32_t*)gOspiTxBuf;
uint32_t* data_ver=(uint32_t*)gOspiRxBuf;
const char* bufferp = buffer;
uint32_t* hexArray = data;
size_t bufferSize = strlen(bufferp);
size_t hexArraySize=1; //First location will be for array size so reserve first location b starting with 1 instead of 0

// Skip characters until newline since first line in PRU HEX file doesn't have data
while (*bufferp != '\n') bufferp++;

//Read all the hexadecimal values from the PRU HEX file and put them into an array of 32bit integers
while (*bufferp && hexArraySize < bufferSize)
{
// Skip non-hexadecimal characters
while (*bufferp && !isxdigit(*bufferp)) bufferp++;

if (*bufferp)
{
// Convert hexadecimal character(s) to unsigned int
char* endptr;
hexArray[hexArraySize] = strtoul(bufferp, &endptr, 16);
hexArraySize++;
bufferp = endptr; // Move buffer pointer to the next character
}
}
data[0]=hexArraySize; //Set first element of array to the array length
ospi_flash_write((uint8_t *) data, hexArraySize*4); //Write the PRU HEX data to the OSPI FLASH 0x200000
//Read the data back from the OSPI FLASH to validate it is correct
ospi_flash_read((uint8_t *) data_ver, 4); //Read length of data array
ospi_flash_read((uint8_t *) data_ver, data_ver[0]*4); //Use length to read entire array
//Compare original array written to FLASH with array read from FLASH
for(i=0;i<hexArraySize;i++)
{
if(data[i]!=data_ver[i])
{
status = SystemP_FAILURE;
DebugP_logError("OSPI FLASH programming error!\r\n");
break;
}
}
pru_init(); //Reload PRU with new code in OSPI FLASH

Change to pru_int() function

uint32_t data[1024];
uint32_t size=0;
ospi_flash_read((uint8_t*) &size, 4); //Read the size of the uint32 array that holds the PRU program, the first location of the array is the length of the array
ospi_flash_read((uint8_t*) data, size*4); //Now that size is known we can read the entire PRU program array

status = PRUICSS_writeMemory(gPruIcss0Handle, PRUICSS_IRAM_PRU(PRUICSS_PRUx), 0, data+1, (size-1)*4); //Skip over first element since it is the size of the array