The author begins by discussing their experience optimizing the linux mtd/nand Hamming software ECC engine driver. They state that they were able to increase the speed by 35-40%, but felt there was still room for improvement. They then explain the problem with NAND flash and the need for error detection and correction using a Hamming code. The author goes on to provide a detailed explanation of how parity is calculated for each row and column. They then present their first attempt at implementing the parity calculation in C pseudocode. The author acknowledges that this code is not efficient and mentions the need for improvement.
https://docs.kernel.org/driver-api/mtd/nand_ecc.html