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From: Kevin Cernekee on 5 May 2010 00:20
Some of the newer MLC devices have a 6-byte ID sequence in which
several field definitions differ from older chips in a manner that is
not backward compatible. For instance:

Samsung K9GAG08U0M (5-byte sequence): ec d5 14 b6 74
4th byte, bits 1:0 encode the page size: 0=1KiB, 1=2KiB, 2=4KiB, 3=8KiB
4th byte, bits 5:4 encode the block size: 0=64KiB, 1=128KiB, ...
4th byte, bit 6 encodes the OOB size: 0=8B/512B, 1=16B/512B

Samsung K9GAG08U0D (6-byte sequence): ec d5 94 29 34 41
4th byte, bits 1:0 encode the page size: 0=2KiB, 1=4KiB, 3=8KiB, 4=rsvd
4th byte, bits 7;5:4 encode the block size: 0=128KiB, 1=256KiB, ...
4th byte, bits 6;3:2 encode the OOB size: 1=128B/page, 2=218B/page

This patch uses the new 6-byte scheme if the following conditions are
all true:

1) The ID code wraps around after exactly 6 bytes

2) Manufacturer is Samsung

3) 6th byte is zero

The patch also extends the maximum OOB size from 128B to 256B.

Signed-off-by: Kevin Cernekee <cernekee(a)gmail.com>
---
drivers/mtd/nand/nand_base.c | 64 ++++++++++++++++++++++++++++-------------
include/linux/mtd/nand.h | 2 +-
2 files changed, 45 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b9dc65c..85891dc 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2774,8 +2774,8 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
int busw, int *maf_id,
struct nand_flash_dev *type)
{
- int dev_id, maf_idx;
- int tmp_id, tmp_manf;
+ int i, dev_id, maf_idx;
+ u8 id_data[8];

/* Select the device */
chip->select_chip(mtd, 0);
@@ -2801,15 +2801,15 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,

chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

- /* Read manufacturer and device IDs */
+ /* Read entire ID string */

- tmp_manf = chip->read_byte(mtd);
- tmp_id = chip->read_byte(mtd);
+ for (i = 0; i < 8; i++)
+ id_data[i] = chip->read_byte(mtd);

- if (tmp_manf != *maf_id || tmp_id != dev_id) {
+ if (id_data[0] != *maf_id || id_data[1] != dev_id) {
printk(KERN_INFO "%s: second ID read did not match "
"%02x,%02x against %02x,%02x\n", __func__,
- *maf_id, dev_id, tmp_manf, tmp_id);
+ *maf_id, dev_id, id_data[0], id_data[1]);
return ERR_PTR(-ENODEV);
}

@@ -2832,21 +2832,45 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
if (!type->pagesize) {
int extid;
/* The 3rd id byte holds MLC / multichip data */
- chip->cellinfo = chip->read_byte(mtd);
+ chip->cellinfo = id_data[2];
/* The 4th id byte is the important one */
- extid = chip->read_byte(mtd);
- /* Calc pagesize */
- mtd->writesize = 1024 << (extid & 0x3);
- 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;
+ 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 K9GAG08U0D (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 &&
+ id_data[5] != 0x00) {
+ /* Calc pagesize */
+ mtd->writesize = 2048 << (extid & 0x03);
+ extid >>= 2;
+ /* Calc oobsize */
+ mtd->oobsize = (extid & 0x03) == 0x01 ? 128 : 218;
+ 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;
+ }
} else {
/*
* Old devices have chip data hardcoded in the device id table
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 8bdacb8..50f3aa0 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -53,7 +53,7 @@ extern int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
* is supported now. If you add a chip with bigger oobsize/page
* adjust this accordingly.
*/
-#define NAND_MAX_OOBSIZE 128
+#define NAND_MAX_OOBSIZE 256
#define NAND_MAX_PAGESIZE 4096

/*
--
1.6.5

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