mtd: nand: extend NAND flash detection to new MLC chips

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@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 44 insertions, 20 deletions

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b9dc65c7253c..85891dcc27ad 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