int yflash2_WriteChunkWithTagsToNAND(struct yaffs_dev *dev,int nand_chunk,const u8 *data, const struct yaffs_ext_tags *tags);
int yflash2_ReadChunkFromNAND(struct yaffs_dev *dev,int nand_chunk, u8 *data, struct yaffs_spare *spare);
int yflash2_ReadChunkWithTagsFromNAND(struct yaffs_dev *dev,int nand_chunk, u8 *data, struct yaffs_ext_tags *tags);
-int yflash2_EraseBlockInNAND(struct yaffs_dev *dev, int blockNumber);
int yflash2_InitialiseNAND(struct yaffs_dev *dev);
int yflash2_MarkNANDBlockBad(struct yaffs_dev *dev, int block_no);
int yflash2_QueryNANDBlock(struct yaffs_dev *dev, int block_no, enum yaffs_block_state *state, u32 *seq_number);