The init function allocates memory and sets up all the board specific parameters and function pointers. When everything is set up nand_scan() is called. This function tries to detect and identify then chip. If a chip is found all the internal data fields are initialized accordingly. The structure(s) have to be zeroed out first and then filled with the neccecary information about the device.

int __init board_init (void)
{
	struct nand_chip *this;
	int err = 0;

	/* Allocate memory for MTD device structure and private data */
	board_mtd = kmalloc (sizeof(struct mtd_info) + sizeof (struct nand_chip), GFP_KERNEL);
	if (!board_mtd) {
		printk ("Unable to allocate NAND MTD device structure.\n");
		err = -ENOMEM;
		goto out;
	}

	/* Initialize structures */
	memset ((char *) board_mtd, 0, sizeof(struct mtd_info) + sizeof(struct nand_chip));

	/* map physical adress */
	baseaddr = (unsigned long)ioremap(CHIP_PHYSICAL_ADDRESS, 1024);
	if(!baseaddr){
		printk("Ioremap to access NAND chip failed\n");
		err = -EIO;
		goto out_mtd;
	}

	/* Get pointer to private data */
	this = (struct nand_chip *) ();
	/* Link the private data with the MTD structure */
	board_mtd->priv = this;

	/* Set address of NAND IO lines */
	this->IO_ADDR_R = baseaddr;
	this->IO_ADDR_W = baseaddr;
	/* Reference hardware control function */
	this->hwcontrol = board_hwcontrol;
	/* Set command delay time, see datasheet for correct value */
	this->chip_delay = CHIP_DEPENDEND_COMMAND_DELAY;
	/* Assign the device ready function, if available */
	this->dev_ready = board_dev_ready;
	this->eccmode = NAND_ECC_SOFT;

	/* Scan to find existance of the device */
	if (nand_scan (board_mtd, 1)) {
		err = -ENXIO;
		goto out_ior;
	}
	
	add_mtd_partitions(board_mtd, partition_info, NUM_PARTITIONS);
	goto out;

out_ior:
	iounmap((void *)baseaddr);
out_mtd:
	kfree (board_mtd);
out:
	return err;
}
module_init(board_init);