nand_compute_ecc
nand_compute_ecc(bptr, ecc);
nand_compute_ecc(bptr + (pagesize / 2), ecc);
nand_compute_ecc(bptr, ecc);
nand_compute_ecc(bptr + (pagesize / 2), ecc);
nand_compute_ecc(bptr, ecc);
nand_compute_ecc(bptr+(info->pagesize / 2), ecc);
nand_compute_ecc(bptr, ecc);
nand_compute_ecc(bptr+(info->pagesize / 2), ecc);