ref: 8dcf65f21e079f471eef6d3b3d0360c7beac4cd6
dir: /sys/src/9/port/nandecc.h/
typedef enum NandEccError { NandEccErrorBad, NandEccErrorGood, NandEccErrorOneBit, NandEccErrorOneBitInEcc, } NandEccError; ulong nandecc(uchar buf[256]); NandEccError nandecccorrect(uchar buf[256], ulong calcecc, ulong *storedecc, int reportbad);