In the fsl_flash.c library in the MKE02z64 SDK, why does the FLASH_EepromWrite function throw an InvalidArgument status when given more than 4 bytes? Some of the code is written as if it assumes you must only give it 4 bytes, but it's almost written such that it can accept any number of bytes (within a valid range).
It starts by checking that there are not more than 4 bytes given
if ((lengthInBytes > 4UL) || (0UL == lengthInBytes))
{
return kStatus_FLASH_InvalidArgument;
}
then enters a while loop if there are more than 3 bytes. But why is this a "while" loop, instead of an "if" statement, if we KNOW we're never going to his this loop more than once (because we know we will only ever have either 4 bytes, or fewer than 4 bytes)?
If we simply remove the check for more than 4 bytes, and change this:
for (i = 0UL; i < lengthInBytes; i++
{
flash_set_command(0x02UL + i, *src++, 0UL);
}
to this:
for (i = 0UL; i < 4; i++
{
flash_set_command(0x02UL + i, *src++, 0UL);
}
we could send any number of bytes, and it would loop through internally, instead of having to call this function in a loop.
EXCEPT that, there is seems to be another error. As we loop through each byte in the above "for" loop, we increment src. By the time we are done, src will have incremented by 4. However, after we finish doing that (and checking that there are no other errors), we hit this code:
/* update start address for next iteration */
start += 4U;
src += 4U
/* update lengthInBytes for next iteration */
lengthInBytes -= 4UL;
Which ends up incrementing src by an additional 4.
So if we remove the first check from more than 4 bytes, make the change to the bounds of the "for" loop as suggested above, and get rid of the redundant incrementation of src at the end, we should be able to send any number of bytes (within a valid range) and the code will handle it until all bytes are written. I have, in fact, made this changes myself and it seems to work just fine. The code even states that it is incrementing/decrementing variables for "next iteration", which (if we only accept 4 bytes), we know is never going to happen.
Am I missing something? Is there a reason this was not done?
-Josiah
