mtd: add init_size hook for NAND driver

Not all the NAND devices have all the information in additional
id bytes.

So add a hook in the nand_chip{} is a good method to calculate the
right value of oobsize, erasesize and so on.

Without the hook,you will get the wrong value, and you have to hack
in the ->scan_bbt() to change the wrong value which make the code
mess.
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/nand/nand_base.c

@@ -2976,8 +2976,10 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 
 	chip->chipsize = (uint64_t)type->chipsize << 20;
 
-	/* Newer devices have all the information in additional id bytes */
-	if (!type->pagesize) {
+	if (!type->pagesize && chip->init_size) {
+		/* set the pagesize, oobsize, erasesize by the driver*/
+		busw = chip->init_size(mtd, chip, id_data);
+	} else if (!type->pagesize) {
 		int extid;
 		/* The 3rd id byte holds MLC / multichip data */
 		chip->cellinfo = id_data[2];

include/linux/mtd/nand.h

@@ -396,6 +396,10 @@ struct nand_buffers {
  * @block_markbad:	[REPLACEABLE] mark the block bad
  * @cmd_ctrl:		[BOARDSPECIFIC] hardwarespecific funtion for controlling
  *			ALE/CLE/nCE. Also used to write command and address
+ * @init_size:		[BOARDSPECIFIC] hardwarespecific funtion for setting
+ *			mtd->oobsize, mtd->writesize and so on.
+ *			@id_data contains the 8 bytes values of NAND_CMD_READID.
+ *			Return with the bus width.
  * @dev_ready:		[BOARDSPECIFIC] hardwarespecific function for accesing device ready/busy line
  *			If set to NULL no access to ready/busy is available and the ready/busy information
  *			is read from the chip status register
@@ -452,6 +456,8 @@ struct nand_chip {
 	int		(*block_markbad)(struct mtd_info *mtd, loff_t ofs);
 	void		(*cmd_ctrl)(struct mtd_info *mtd, int dat,
 				    unsigned int ctrl);
+	int		(*init_size)(struct mtd_info *mtd,
+					struct nand_chip *this, u8 *id_data);
 	int		(*dev_ready)(struct mtd_info *mtd);
 	void		(*cmdfunc)(struct mtd_info *mtd, unsigned command, int column, int page_addr);
 	int		(*waitfunc)(struct mtd_info *mtd, struct nand_chip *this);