Micron Q Flash support

This note is addressed to those that use "bootldr" for custom boards. If you
plan to use Micron Q Flash devices, such MT28F640J3, replacing intel chips,
in your project with "bootldr" you have to modify the btflash.c file: after
each write command (word or block) a Read Array command (0xff) must be used
to go back to read state. The following stub of code illustrates the patch.

/*
 * Programs value at flashAddress
 * Sectors must be erased before they can be programmed.
 */
static int intelFlashProgramWord(unsigned long flashAddress, unsigned long
value)
{
   unsigned long flashWordOffset = (flashAddress&flash_address_mask) >> 2;
   long timeout = FLASH_TIMEOUT;
   unsigned long flashContents = flashword[flashWordOffset];
   unsigned long status = 0;

   /* see if we can program the value without erasing */
   if ((flashContents & value) != value) {
      putstr("the flash sector needs to be erased first!\r\n");
      putLabeledWord("  flashAddress=", flashAddress);
      putLabeledWord("  flashWordOffset=", flashWordOffset);
      putLabeledWord("  &flashword[flashWordOffset]=",
       (dword)&flashword[flashWordOffset]);
      putLabeledWord("  flashContents=", flashContents);
      return -1;
   }

   /* send flash the program word command */
   flashword[0x55] = bothbanks(0x40);
   flashword[flashWordOffset] = value;
   /* now wait for it to be programmed */
   while (timeout > 0) {
      status = flashword[flashWordOffset];
      if ((status & bothbanks(0x80)) == bothbanks(0x80))
         break;
      timeout--;
   }
   intelFlashClearStatus();
   flashword[0x55] = bothbanks(0xff); // back to read array

   if ((timeout <= 0) || (status & bothbanks(0x7f))) {
      putstr("programFlashWord error\r\n");
      putLabeledWord("  flashAddress=", flashAddress);
      putLabeledWord("  value=", value);
      putLabeledWord("  flashContents=", flashContents);
      putLabeledWord("  status=", status);
      return(-1);
   }
   return 0;
}

/* each flash chip has 32B block, 64B block for chip array */
static int intelFlashProgramBlock(unsigned long flashAddress, unsigned long
*values, int nbytes)
{
   unsigned long flashWordOffset = (flashAddress&flash_address_mask) >> 2;
   unsigned long blockOffset = (flashWordOffset & 0xFFFFFFC0);
   int nwords = nbytes >> 2;
   int result = 0;
   long timeout = FLASH_TIMEOUT;
   unsigned long status = 0;
   int i;

   if (0) putLabeledWord("intelFlashProgramFlashBlock\r\n", flashAddress);

   /* send the "write to buffer" command and read the extended status
register */
   timeout = FLASH_TIMEOUT;
   do {
      flashword[flashWordOffset] = bothbanks(0xE8);
      status = flashword[flashWordOffset];
      if (0) putLabeledWord("  XSR=", status);
   if (--timeout <= 0)
  goto endprg;
   } while ((status & 0x00800080) != 0x00800080);

   /* write word count at block start address */
   flashword[blockOffset] = bothbanks(nwords-1); /* length minus one */

   /* send the data */
   for (i = 0; i < nwords; i++) {
      flashword[flashWordOffset+i] = values[i];
      if (0) putLabeledWord(" sr=", flashword[blockOffset]);
   }

   /* send the confirmation to program */
   flashword[blockOffset] = bothbanks(0xD0);

   /* now wait for it to be programmed */
   timeout = FLASH_TIMEOUT;
   while (timeout > 0) {
      status = flashword[blockOffset];
      if (0) putLabeledWord("  status=", status);
      if ((status & bothbanks(0x80)) == bothbanks(0x80))
         break;
      timeout--;
   }
   status = intelFlashReadStatus();
   if (0) putLabeledWord("final status=", status);

endprg:
   intelFlashClearStatus();
   flashword[0x55] = bothbanks(0xff); // back to read array

   if ((timeout <= 0) || (status & bothbanks(0x7f))) {
      putstr("programFlashBlock error\r\n");
      putLabeledWord("  flashAddress=", flashAddress);
      putLabeledWord("  status=", status);
      return(-1);
   }
   return 0;
}

Hope this helps.
Michele