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Commit fc09bbc0 authored by Brian Norris's avatar Brian Norris Committed by David Woodhouse
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mtd: nand: split extended ID decoding into its own function 



When detecting NAND parameters, the code gets a little ugly so that the
logic is obscured. Try to remedy that by moving code to separate functions
that have well-defined purposes.

This patch splits out the extended ID decode functionality, which handles
decoding the 3rd-8th ID bytes to determine NAND device parameters.

Signed-off-by: default avatarBrian Norris <computersforpeace@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 7e74c2d7

drivers/mtd/nand/nand_base.c

+67 −55
Original line number Diff line number Diff line
@@ -2905,6 +2905,71 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip, 
	return 1;

}



/*

 * Many new NAND share similar device ID codes, which represent the size of the

 * chip. The rest of the parameters must be decoded according to generic or

 * manufacturer-specific "extended ID" decoding patterns.

 */

static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,

				u8 id_data[8], int *busw)

{

	int extid;

	/* The 3rd id byte holds MLC / multichip data */

	chip->cellinfo = id_data[2];

	/* The 4th id byte is the important one */

	extid = id_data[3];



	/*

	 * Field definitions are in the following datasheets:

	 * Old style (4,5 byte ID): Samsung K9GAG08U0M (p.32)

	 * New style   (6 byte ID): Samsung K9GBG08U0M (p.40)

	 *

	 * Check for wraparound + Samsung ID + nonzero 6th byte

	 * to decide what to do.

	 */

	if (id_data[0] == id_data[6] && id_data[1] == id_data[7] &&

			id_data[0] == NAND_MFR_SAMSUNG &&

			(chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&

			id_data[5] != 0x00) {

		/* Calc pagesize */

		mtd->writesize = 2048 << (extid & 0x03);

		extid >>= 2;

		/* Calc oobsize */

		switch (extid & 0x03) {

		case 1:

			mtd->oobsize = 128;

			break;

		case 2:

			mtd->oobsize = 218;

			break;

		case 3:

			mtd->oobsize = 400;

			break;

		default:

			mtd->oobsize = 436;

			break;

		}

		extid >>= 2;

		/* Calc blocksize */

		mtd->erasesize = (128 * 1024) <<

			(((extid >> 1) & 0x04) | (extid & 0x03));

		*busw = 0;

	} else {

		/* Calc pagesize */

		mtd->writesize = 1024 << (extid & 0x03);

		extid >>= 2;

		/* Calc oobsize */

		mtd->oobsize = (8 << (extid & 0x01)) *

			(mtd->writesize >> 9);

		extid >>= 2;

		/* Calc blocksize. Blocksize is multiples of 64KiB */

		mtd->erasesize = (64 * 1024) << (extid & 0x03);

		extid >>= 2;

		/* Get buswidth information */

		*busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;

	}

}



/*

 * Set the bad block marker/indicator (BBM/BBI) patterns according to some

 * heuristic patterns using various detected parameters (e.g., manufacturer,
@@ -3016,61 +3081,8 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd, 
		/* 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];

		/* The 4th id byte is the important one */

		extid = id_data[3];



		/*

		 * Field definitions are in the following datasheets:

		 * Old style (4,5 byte ID): Samsung K9GAG08U0M (p.32)

		 * New style   (6 byte ID): Samsung K9GBG08U0M (p.40)

		 *

		 * Check for wraparound + Samsung ID + nonzero 6th byte

		 * to decide what to do.

		 */

		if (id_data[0] == id_data[6] && id_data[1] == id_data[7] &&

				id_data[0] == NAND_MFR_SAMSUNG &&

				(chip->cellinfo & NAND_CI_CELLTYPE_MSK) &&

				id_data[5] != 0x00) {

			/* Calc pagesize */

			mtd->writesize = 2048 << (extid & 0x03);

			extid >>= 2;

			/* Calc oobsize */

			switch (extid & 0x03) {

			case 1:

				mtd->oobsize = 128;

				break;

			case 2:

				mtd->oobsize = 218;

				break;

			case 3:

				mtd->oobsize = 400;

				break;

			default:

				mtd->oobsize = 436;

				break;

			}

			extid >>= 2;

			/* Calc blocksize */

			mtd->erasesize = (128 * 1024) <<

				(((extid >> 1) & 0x04) | (extid & 0x03));

			busw = 0;

		} else {

			/* Calc pagesize */

			mtd->writesize = 1024 << (extid & 0x03);

			extid >>= 2;

			/* Calc oobsize */

			mtd->oobsize = (8 << (extid & 0x01)) *

				(mtd->writesize >> 9);

			extid >>= 2;

			/* Calc blocksize. Blocksize is multiples of 64KiB */

			mtd->erasesize = (64 * 1024) << (extid & 0x03);

			extid >>= 2;

			/* Get buswidth information */

			busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;

		}

		/* Decode parameters from extended ID */

		nand_decode_ext_id(mtd, chip, id_data, &busw);

	} else {

		/*

		 * Old devices have chip data hardcoded in the device id table.