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mtd: nand: split simple ID decode into its own function
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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 simple ID decode functionality, where all the
information regarding NAND size/blocksize/pagesize/oobsize/busw is encoded in
the first two bytes of the ID string.

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>
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Brian Norris authored and David Woodhouse committed Sep 29, 2012
1 parent fc09bbc commit f23a481
Showing 1 changed file with 31 additions and 20 deletions.
51 changes: 31 additions & 20 deletions drivers/mtd/nand/nand_base.c
Original file line number Diff line number Diff line change
@@ -2970,6 +2970,36 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
}
}

/*
* Old devices have chip data hardcoded in the device ID table. nand_decode_id
* decodes a matching ID table entry and assigns the MTD size parameters for
* the chip.
*/
static void nand_decode_id(struct mtd_info *mtd, struct nand_chip *chip,
struct nand_flash_dev *type, u8 id_data[8],
int *busw)
{
int maf_id = id_data[0];

mtd->erasesize = type->erasesize;
mtd->writesize = type->pagesize;
mtd->oobsize = mtd->writesize / 32;
*busw = type->options & NAND_BUSWIDTH_16;

/*
* Check for Spansion/AMD ID + repeating 5th, 6th byte since
* some Spansion chips have erasesize that conflicts with size
* listed in nand_ids table.
* Data sheet (5 byte ID): Spansion S30ML-P ORNAND (p.39)
*/
if (maf_id == NAND_MFR_AMD && id_data[4] != 0x00 && id_data[5] == 0x00
&& id_data[6] == 0x00 && id_data[7] == 0x00
&& mtd->writesize == 512) {
mtd->erasesize = 128 * 1024;
mtd->erasesize <<= ((id_data[3] & 0x03) << 1);
}
}

/*
* Set the bad block marker/indicator (BBM/BBI) patterns according to some
* heuristic patterns using various detected parameters (e.g., manufacturer,
@@ -3084,26 +3114,7 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
/* 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.
*/
mtd->erasesize = type->erasesize;
mtd->writesize = type->pagesize;
mtd->oobsize = mtd->writesize / 32;
busw = type->options & NAND_BUSWIDTH_16;

/*
* Check for Spansion/AMD ID + repeating 5th, 6th byte since
* some Spansion chips have erasesize that conflicts with size
* listed in nand_ids table.
* Data sheet (5 byte ID): Spansion S30ML-P ORNAND (p.39)
*/
if (*maf_id == NAND_MFR_AMD && id_data[4] != 0x00 &&
id_data[5] == 0x00 && id_data[6] == 0x00 &&
id_data[7] == 0x00 && mtd->writesize == 512) {
mtd->erasesize = 128 * 1024;
mtd->erasesize <<= ((id_data[3] & 0x03) << 1);
}
nand_decode_id(mtd, chip, type, id_data, &busw);
}
/* Get chip options */
chip->options |= type->options;

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