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r: 332780
b: refs/heads/master
c: e3b88bd
h: refs/heads/master
v: v3
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Brian Norris authored and David Woodhouse committed Sep 29, 2012
1 parent c5763e8 commit 6b5093f
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2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: f23a481c4e0ccb006470b1c890cc7236ba634e67
refs/heads/master: e3b88bd604283ef83ae6e8f53622d5b1ffe9d43a
72 changes: 65 additions & 7 deletions trunk/drivers/mtd/nand/nand_base.c
Original file line number Diff line number Diff line change
Expand Up @@ -2905,6 +2905,65 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
return 1;
}

/*
* nand_id_has_period - Check if an ID string has a given wraparound period
* @id_data: the ID string
* @arrlen: the length of the @id_data array
* @period: the period of repitition
*
* Check if an ID string is repeated within a given sequence of bytes at
* specific repetition interval period (e.g., {0x20,0x01,0x7F,0x20} has a
* period of 2). This is a helper function for nand_id_len(). Returns non-zero
* if the repetition has a period of @period; otherwise, returns zero.
*/
static int nand_id_has_period(u8 *id_data, int arrlen, int period)
{
int i, j;
for (i = 0; i < period; i++)
for (j = i + period; j < arrlen; j += period)
if (id_data[i] != id_data[j])
return 0;
return 1;
}

/*
* nand_id_len - Get the length of an ID string returned by CMD_READID
* @id_data: the ID string
* @arrlen: the length of the @id_data array
* Returns the length of the ID string, according to known wraparound/trailing
* zero patterns. If no pattern exists, returns the length of the array.
*/
static int nand_id_len(u8 *id_data, int arrlen)
{
int last_nonzero, period;

/* Find last non-zero byte */
for (last_nonzero = arrlen - 1; last_nonzero >= 0; last_nonzero--)
if (id_data[last_nonzero])
break;

/* All zeros */
if (last_nonzero < 0)
return 0;

/* Calculate wraparound period */
for (period = 1; period < arrlen; period++)
if (nand_id_has_period(id_data, arrlen, period))
break;

/* There's a repeated pattern */
if (period < arrlen)
return period;

/* There are trailing zeros */
if (last_nonzero < arrlen - 1)
return last_nonzero + 1;

/* No pattern detected */
return arrlen;
}

/*
* 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
Expand All @@ -2913,24 +2972,23 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
u8 id_data[8], int *busw)
{
int extid;
int extid, id_len;
/* 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];

id_len = nand_id_len(id_data, 8);

/*
* 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.
* Check for ID length + Samsung ID 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) {
if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG &&
(chip->cellinfo & NAND_CI_CELLTYPE_MSK)) {
/* Calc pagesize */
mtd->writesize = 2048 << (extid & 0x03);
extid >>= 2;
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