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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: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Brian Norris 2012-09-24 20:40:50 -07:00 committed by David Woodhouse
parent 7e74c2d714
commit fc09bbc04c
1 changed files with 67 additions and 55 deletions
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122
drivers/mtd/nand/nand_base.c
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@ -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.