diff mbox

[U-Boot,5/5,v2] mtd/nand: workaround for Freescale FCM to support 4k pagesize Nand chip

Message ID 1323683398-11001-5-git-send-email-Shengzhou.Liu@freescale.com
State Superseded
Headers show

Commit Message

Shengzhou Liu Dec. 12, 2011, 9:49 a.m. UTC
Freescale FCM controller has a 2K size limitation of buffer RAM. In order
to support the Nand flash chip with pagesize larger than 2K bytes,
we read/write 2k data repeatedly by issuing FIR_OP_RB/FIR_OP_WB and save
them to a large buffer.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Signed-off-by: Liu Shuo <b35362@freescale.com>
---
 drivers/mtd/nand/fsl_elbc_nand.c |  283 +++++++++++++++++++++++++++++++++----
 1 files changed, 252 insertions(+), 31 deletions(-)

Comments

Scott Wood Dec. 12, 2011, 8:14 p.m. UTC | #1
On 12/12/2011 03:49 AM, Shengzhou Liu wrote:
> Freescale FCM controller has a 2K size limitation of buffer RAM. In order
> to support the Nand flash chip with pagesize larger than 2K bytes,
> we read/write 2k data repeatedly by issuing FIR_OP_RB/FIR_OP_WB and save
> them to a large buffer.
> 
> Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
> Signed-off-by: Liu Shuo <b35362@freescale.com>
> ---
>  drivers/mtd/nand/fsl_elbc_nand.c |  283 +++++++++++++++++++++++++++++++++----
>  1 files changed, 252 insertions(+), 31 deletions(-)

I've asked you several times what you're planning on doing for bad block
marker migration.  I am not going to let you ignore this.  NACK until
you have a migration tool, and a scheme for marking the flash as having
been migrated.

Also please mention below the --- what has changed since v1.

> @@ -393,9 +468,28 @@ static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
>  		     page_addr, column);
>  
>  		ctrl->column = column;
> -		ctrl->oob = 0;
> +		if (column >= mtd->writesize) {
> +			/* OOB area */
> +			column -= mtd->writesize;
> +			ctrl->oob = 1;
> +		} else {
> +			ctrl->oob = 0;
> +		}
[snip]
> @@ -432,12 +524,19 @@ static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
>  		}
>  
>  		out_be32(&lbc->fcr, fcr);
> -		set_addr(mtd, column, page_addr, ctrl->oob);
> +		if (column >= mtd->writesize && mtd->writesize > 2048) {

How can column >= mtd->writesize be true at this point?  You've already
subtracted it out.

>  		if (ctrl->oob || ctrl->column != 0 ||
> -		    ctrl->index != mtd->writesize + mtd->oobsize)
> -			out_be32(&lbc->fbcr, ctrl->index);
> -		else
> +				ctrl->index != mtd->writesize + mtd->oobsize) {
> +			if (ctrl->oob && mtd->writesize > 2048) {
> +				out_be32(&lbc->fbcr, 64);
> +			} else {
> +				out_be32(&lbc->fbcr, ctrl->index -
> +					ctrl->column);
> +			}
> +		} else {
>  			out_be32(&lbc->fbcr, 0);
> +		}

Again, if we're going to make an API assumption that we get either a
full page access or a full OOB access, then make the assumption fully.
Don't half-implement partial accessses.

> +int board_nand_init_tail(struct mtd_info *mtd)
> +{
> +	struct nand_chip *nand = mtd->priv;
> +	struct fsl_elbc_mtd *priv = nand->priv;
> +	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
> +
> +	/* adjust Option Register and ECC to match Flash page size */
> +	if (mtd->writesize == 512) {
> +		clrbits_be32(&ctrl->regs->bank[priv->bank].or, OR_FCM_PGS);
> +	} else if (mtd->writesize >= 2048 && mtd->writesize <= 8192) {
> +		setbits_be32(&ctrl->regs->bank[priv->bank].or, OR_FCM_PGS);
> +		/* adjust ecc setup if needed */
> +		if ((in_be32(&ctrl->regs->bank[priv->bank].br) & BR_DECC) ==
> +			BR_DECC_CHK_GEN) {
> +			nand->ecc.size = 512;

Please find some way to indent the continuation line so it doesn't line
up with the if-body.

> +			nand->ecc.layout = (priv->fmr & FMR_ECCM) ?
> +			   &fsl_elbc_oob_lp_eccm1 : &fsl_elbc_oob_lp_eccm0;
> +			nand->badblock_pattern = &largepage_memorybased;

Those oob layouts won't be quite right for larger page sizes.

-Scott
Scott Wood Dec. 14, 2011, 5:54 p.m. UTC | #2
On 12/14/2011 01:30 AM, Liu Shengzhou-B36685 wrote:
> 
> 
>> -----Original Message-----
>> From: Wood Scott-B07421
>> Sent: Tuesday, December 13, 2011 4:14 AM
>> To: Liu Shengzhou-B36685
>> Cc: u-boot@lists.denx.de; Gala Kumar-B11780; Liu Shuo-B35362
>> Subject: Re: [PATCH 5/5 v2] mtd/nand: workaround for Freescale FCM to
>> support 4k pagesize Nand chip
>>
>> I've asked you several times what you're planning on doing for bad block
>> marker migration.  I am not going to let you ignore this.  NACK until you
>> have a migration tool, and a scheme for marking the flash as having been
>> migrated.
>>
> 
> [Shengzhou] 
> This is the first time that you asked me about bad block marker migration.
> You asked LiuShuo several times in Linux mail list, as I am not in that thread
> And not known about it until Liushuo told me. 
> As LiuShuo will do it, so I am not planning on it.

Ah, sorry about that.

Still, I'd like to see it done, whoever does it, before this gets
merged.  I don't want people to be able to accidentally start using it
without doing migration.

>>> +			nand->ecc.layout = (priv->fmr & FMR_ECCM) ?
>>> +			   &fsl_elbc_oob_lp_eccm1 : &fsl_elbc_oob_lp_eccm0;
>>> +			nand->badblock_pattern = &largepage_memorybased;
>>
>> Those oob layouts won't be quite right for larger page sizes.
>>
>> -Scott
> [Shengzhou] It's the same with what Linux does. What's the right?

I think we need to explicitly define 4096 and 8192 variants, with the
extra eccpos/oobfree.  Or generate them programatically.

-Scott
Scott Wood Dec. 15, 2011, 5:36 p.m. UTC | #3
On 12/15/2011 04:53 AM, Liu Shengzhou-B36685 wrote:
>>>> -----Original Message-----
>>>> From: Wood Scott-B07421
>>>> Sent: Tuesday, December 13, 2011 4:14 AM
>>>> To: Liu Shengzhou-B36685
>>>> Cc: u-boot@lists.denx.de; Gala Kumar-B11780; Liu Shuo-B35362
>>>> Subject: Re: [PATCH 5/5 v2] mtd/nand: workaround for Freescale FCM to
>>>> support 4k pagesize Nand chip
>>
>>>>> +			nand->ecc.layout = (priv->fmr & FMR_ECCM) ?
>>>>> +			   &fsl_elbc_oob_lp_eccm1 : &fsl_elbc_oob_lp_eccm0;
>>>>> +			nand->badblock_pattern = &largepage_memorybased;
>>>>
>>>> Those oob layouts won't be quite right for larger page sizes.
>>>>
>>>> -Scott
>>> [Shengzhou] It's the same with what Linux does. What's the right?
>>
>> I think we need to explicitly define 4096 and 8192 variants, with the
>> extra eccpos/oobfree.  Or generate them programatically.
>>
>> -Scott
> 
> [Shengzhou]
> You mean we should define something like below?
> static struct nand_ecclayout fsl_elbc_oob_lp_4k_eccm0 = {
>         .eccbytes = 24,
>         .eccpos = {6, 7, 8, 22, 23, 24, 38, 39, 40, 54, 55, 56,
>         	       70, 71, 72, 86, 87, 88, 102, 103, 104, 118, 119, 120},
>         .oobfree = { {1, 5}, {9, 13}, {25, 13}, {41, 13}, {57, 7},...... },
> };
> static struct nand_ecclayout fsl_elbc_oob_lp_8k_eccm0 = {........};

Yes.

> eLBC RM says:
> ECC is checked/calculated over 512-Byte blocks. A 24-bit ECC is assigned to spare region bytes at offsets
> (N × 16) + 6 through (N × 16) + 8 for spare region N, N = 0–3.   (for ECCM=0 case)
> 
> Here RM just says N is 0–3, but it should be 0-7 for 4096 case, 

Well, yes, this is a hack to do things that the hardware doesn't
officially support.

> hardware ECC doesn't generate ECC in position of N=4,5,6,7. 

It will.  It just thinks that N=0,1,2,3.

> fsl_elbc_oob_lp_eccm0 and fsl_elbc_oob_lp_eccm1 are controller-associated, not device-associated,

Then why do we have separate small and large page versions?

> I think we don't need define 4096 and 8192 variants, it's emulating 4096/8192 case by 
> the existing 2K layout of fsl_elbc_oob_lp_eccm0 and fsl_elbc_oob_lp_eccm1.
> Please correct me if any wrong understanding.

It's supporting 4096/8192 by repeating the 2048 layout multiple times.
This repetition is not captured by the existing nand_ecclayout.

-Scott
diff mbox

Patch

diff --git a/drivers/mtd/nand/fsl_elbc_nand.c b/drivers/mtd/nand/fsl_elbc_nand.c
index 99d1061..a2d8067 100644
--- a/drivers/mtd/nand/fsl_elbc_nand.c
+++ b/drivers/mtd/nand/fsl_elbc_nand.c
@@ -64,7 +64,6 @@  struct fsl_elbc_mtd {
 	struct device *dev;
 	int bank;               /* Chip select bank number           */
 	u8 __iomem *vbase;      /* Chip select base virtual address  */
-	int page_size;          /* NAND page size (0=512, 1=2048)    */
 	unsigned int fmr;       /* FCM Flash Mode Register value     */
 };
 
@@ -85,6 +84,8 @@  struct fsl_elbc_ctrl {
 	unsigned int mdr;        /* UPM/FCM Data Register value           */
 	unsigned int use_mdr;    /* Non zero if the MDR is to be set      */
 	unsigned int oob;        /* Non zero if operating on OOB data     */
+	char *buffer;            /* Just used when pagesize is greater    */
+				 /* than FCM RAM 2K limitation		  */
 };
 
 /* These map to the positions used by the FCM hardware ECC generator */
@@ -159,6 +160,35 @@  static struct nand_bbt_descr bbt_mirror_descr = {
 	.pattern = mirror_pattern,
 };
 
+static void io_to_buffer(struct mtd_info *mtd, int subpage, int oob)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct fsl_elbc_mtd *priv = chip->priv;
+	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
+	void *src, *dst;
+	int len = oob ? 64 : 2048;
+
+	/* for emulating 4096+ bytes NAND using 2048-byte FCM RAM */
+	dst = ctrl->buffer + (oob ? mtd->writesize : 0) + subpage * len;
+	src = ctrl->addr + (oob ? 2048 : 0);
+	memcpy_fromio(dst, src, len);
+}
+
+static void buffer_to_io(struct mtd_info *mtd, int subpage, int oob)
+{
+	struct nand_chip *chip = mtd->priv;
+	struct fsl_elbc_mtd *priv = chip->priv;
+	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
+	void *src, *dst;
+	int len = oob ? 64 : 2048;
+
+	src = ctrl->buffer + (oob ? mtd->writesize : 0) + subpage * len;
+	dst = ctrl->addr + (oob ? 2048 : 0);
+	memcpy_toio(dst, src, len);
+	/* See the in_8() in fsl_elbc_write_buf() */
+	in_8(ctrl->addr);
+}
+
 /*=================================*/
 
 /*
@@ -175,7 +205,7 @@  static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob)
 
 	ctrl->page = page_addr;
 
-	if (priv->page_size) {
+	if (mtd->writesize >= 2048) {
 		out_be32(&lbc->fbar, page_addr >> 6);
 		out_be32(&lbc->fpar,
 			 ((page_addr << FPAR_LP_PI_SHIFT) & FPAR_LP_PI) |
@@ -194,7 +224,7 @@  static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob)
 
 	/* for OOB data point to the second half of the buffer */
 	if (oob)
-		ctrl->index += priv->page_size ? 2048 : 512;
+		ctrl->index += mtd->writesize;
 
 	vdbg("set_addr: bank=%d, ctrl->addr=0x%p (0x%p), "
 	     "index %x, pes %d ps %d\n",
@@ -256,13 +286,14 @@  static int fsl_elbc_run_command(struct mtd_info *mtd)
 	return ctrl->status == LTESR_CC ? 0 : -EIO;
 }
 
-static void fsl_elbc_do_read(struct nand_chip *chip, int oob)
+static void fsl_elbc_do_read(struct mtd_info *mtd, int oob)
 {
+	struct nand_chip *chip = mtd->priv;
 	struct fsl_elbc_mtd *priv = chip->priv;
 	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
 	fsl_lbc_t *lbc = ctrl->regs;
 
-	if (priv->page_size) {
+	if (mtd->writesize >= 2048) {
 		out_be32(&lbc->fir,
 			 (FIR_OP_CW0 << FIR_OP0_SHIFT) |
 			 (FIR_OP_CA  << FIR_OP1_SHIFT) |
@@ -295,6 +326,7 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 	struct fsl_elbc_mtd *priv = chip->priv;
 	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
 	fsl_lbc_t *lbc = ctrl->regs;
+	int i, nps = mtd->writesize / 2048;
 
 	ctrl->use_mdr = 0;
 
@@ -319,8 +351,28 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		ctrl->read_bytes = mtd->writesize + mtd->oobsize;
 		ctrl->index += column;
 
-		fsl_elbc_do_read(chip, 0);
+		fsl_elbc_do_read(mtd, 0);
 		fsl_elbc_run_command(mtd);
+
+		if (mtd->writesize <= 2048)
+			return;
+
+		/* Continue to read the rest bytes if writesize > 2048 */
+		io_to_buffer(mtd, 0, 0);
+		io_to_buffer(mtd, 0, 1);
+		/*
+		 * Maybe there are some reasons of FCM hardware timing,
+		 * we must insert a FIR_OP_NOP(0x00) before FIR_OP_RB.
+		 */
+		out_be32(&lbc->fir, FIR_OP_NOP << FIR_OP0_SHIFT |
+				    FIR_OP_RB << FIR_OP1_SHIFT);
+
+		for (i = 1; i < nps; i++) {
+			fsl_elbc_run_command(mtd);
+			io_to_buffer(mtd, i, 0);
+			io_to_buffer(mtd, i, 1);
+		}
+
 		return;
 
 	/* READOOB reads only the OOB because no ECC is performed. */
@@ -328,14 +380,35 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		vdbg("fsl_elbc_cmdfunc: NAND_CMD_READOOB, page_addr:"
 		     " 0x%x, column: 0x%x.\n", page_addr, column);
 
-		out_be32(&lbc->fbcr, mtd->oobsize - column);
-		set_addr(mtd, column, page_addr, 1);
+		if (mtd->writesize <= 2048) {
+			out_be32(&lbc->fbcr, mtd->oobsize - column);
+			set_addr(mtd, column, page_addr, 1);
+		} else {
+			out_be32(&lbc->fbcr, 64);
+			set_addr(mtd, 0, page_addr, 1);
+			ctrl->index += column;
+		}
 
 		ctrl->read_bytes = mtd->writesize + mtd->oobsize;
-
-		fsl_elbc_do_read(chip, 1);
+		fsl_elbc_do_read(mtd, 1);
 		fsl_elbc_run_command(mtd);
 
+		if (mtd->writesize <= 2048)
+			return;
+
+		if (column < 64)
+			io_to_buffer(mtd, 0, 1);
+
+		out_be32(&lbc->fpar, in_be32(&lbc->fpar) & ~FPAR_LP_MS);
+		out_be32(&lbc->fir, FIR_OP_RB << FIR_OP1_SHIFT);
+		out_be32(&lbc->fbcr, 2112);
+
+		for (i = 1; i < nps; i++) {
+			fsl_elbc_run_command(mtd);
+			if (column < (64 * (i + 1)))
+				io_to_buffer(mtd, i, 1);
+		}
+
 		return;
 
 	/* READID must read all 5 possible bytes while CEB is active */
@@ -357,6 +430,8 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		ctrl->mdr = column;
 		set_addr(mtd, 0, 0, 0);
 		fsl_elbc_run_command(mtd);
+		if (mtd->writesize > 2048)
+			memcpy_fromio(ctrl->buffer, ctrl->addr, 256);
 		return;
 
 	/* ERASE1 stores the block and page address */
@@ -393,9 +468,28 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		     page_addr, column);
 
 		ctrl->column = column;
-		ctrl->oob = 0;
+		if (column >= mtd->writesize) {
+			/* OOB area */
+			column -= mtd->writesize;
+			ctrl->oob = 1;
+		} else {
+			ctrl->oob = 0;
+		}
+
+		if (mtd->writesize > 2048) {
+			/* writesize > 2048 */
+			fcr = (NAND_CMD_STATUS << FCR_CMD1_SHIFT) |
+				(NAND_CMD_SEQIN << FCR_CMD2_SHIFT) |
+				(NAND_CMD_PAGEPROG << FCR_CMD3_SHIFT);
+			if (ctrl->oob)
+				fcr |= NAND_CMD_RNDIN << FCR_CMD0_SHIFT;
 
-		if (priv->page_size) {
+			out_be32(&lbc->fir,
+				(FIR_OP_CM2 << FIR_OP0_SHIFT) |
+				(FIR_OP_CA  << FIR_OP1_SHIFT) |
+				(FIR_OP_PA  << FIR_OP2_SHIFT) |
+				(FIR_OP_WB  << FIR_OP3_SHIFT));
+		} else if (mtd->writesize == 2048) {
 			fcr = (NAND_CMD_SEQIN << FCR_CMD0_SHIFT) |
 			      (NAND_CMD_PAGEPROG << FCR_CMD1_SHIFT);
 
@@ -417,11 +511,9 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 				 (FIR_OP_WB  << FIR_OP4_SHIFT) |
 				 (FIR_OP_CW1 << FIR_OP5_SHIFT));
 
-			if (column >= mtd->writesize) {
+			if (ctrl->oob) {
 				/* OOB area --> READOOB */
-				column -= mtd->writesize;
 				fcr |= NAND_CMD_READOOB << FCR_CMD0_SHIFT;
-				ctrl->oob = 1;
 			} else if (column < 256) {
 				/* First 256 bytes --> READ0 */
 				fcr |= NAND_CMD_READ0 << FCR_CMD0_SHIFT;
@@ -432,12 +524,19 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		}
 
 		out_be32(&lbc->fcr, fcr);
-		set_addr(mtd, column, page_addr, ctrl->oob);
+		if (column >= mtd->writesize && mtd->writesize > 2048) {
+			/* for write oob && writesize > 2048 */
+			set_addr(mtd, 0, page_addr, 0);
+			ctrl->index = column;
+		} else {
+			set_addr(mtd, column, page_addr, ctrl->oob);
+		}
 		return;
 	}
 
 	/* PAGEPROG reuses all of the setup from SEQIN and adds the length */
 	case NAND_CMD_PAGEPROG: {
+		int pos;
 		vdbg("fsl_elbc_cmdfunc: NAND_CMD_PAGEPROG "
 		     "writing %d bytes.\n", ctrl->index);
 
@@ -445,14 +544,71 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		 * then set the exact length, otherwise use a full page
 		 * write so the HW generates the ECC.
 		 */
+
 		if (ctrl->oob || ctrl->column != 0 ||
-		    ctrl->index != mtd->writesize + mtd->oobsize)
-			out_be32(&lbc->fbcr, ctrl->index);
-		else
+				ctrl->index != mtd->writesize + mtd->oobsize) {
+			if (ctrl->oob && mtd->writesize > 2048) {
+				out_be32(&lbc->fbcr, 64);
+			} else {
+				out_be32(&lbc->fbcr, ctrl->index -
+					ctrl->column);
+			}
+		} else {
 			out_be32(&lbc->fbcr, 0);
+		}
+
+		if (mtd->writesize > 2048) {
+			if (!ctrl->oob)
+				buffer_to_io(mtd, 0, 0);
+			buffer_to_io(mtd, 0, 1);
+		}
 
 		fsl_elbc_run_command(mtd);
 
+		if (mtd->writesize <= 2048)
+			return;
+
+		if (ctrl->oob) {
+			pos = 2048;
+			out_be32(&lbc->fir,
+				(FIR_OP_CM0 << FIR_OP0_SHIFT) |
+				(FIR_OP_UA  << FIR_OP1_SHIFT) |
+				(FIR_OP_UA  << FIR_OP2_SHIFT) |
+				(FIR_OP_WB  << FIR_OP3_SHIFT));
+
+			for (i = 1; i < nps; i++) {
+				pos += 2112;
+				ctrl->mdr = pos;
+				ctrl->use_mdr = 1;
+				if (i == nps - 1) {
+					out_be32(&lbc->fir,
+						(FIR_OP_CM0 << FIR_OP1_SHIFT) |
+						(FIR_OP_UA  << FIR_OP2_SHIFT) |
+						(FIR_OP_UA  << FIR_OP3_SHIFT) |
+						(FIR_OP_WB  << FIR_OP4_SHIFT) |
+						(FIR_OP_CM3 << FIR_OP5_SHIFT) |
+						(FIR_OP_CW1 << FIR_OP6_SHIFT) |
+						(FIR_OP_RS  << FIR_OP7_SHIFT));
+				}
+				buffer_to_io(mtd, i, 1);
+				fsl_elbc_run_command(mtd);
+			}
+		} else {
+			out_be32(&lbc->fir, FIR_OP_WB << FIR_OP1_SHIFT);
+			for (i = 1; i < nps; i++) {
+				if (i == nps - 1) {
+					ctrl->use_mdr = 1;
+					out_be32(&lbc->fir,
+						(FIR_OP_WB  << FIR_OP1_SHIFT) |
+						(FIR_OP_CM3 << FIR_OP2_SHIFT) |
+						(FIR_OP_CW1 << FIR_OP3_SHIFT) |
+						(FIR_OP_RS  << FIR_OP4_SHIFT));
+				}
+				buffer_to_io(mtd, i, 0);
+				buffer_to_io(mtd, i, 1);
+				fsl_elbc_run_command(mtd);
+			}
+		}
 		return;
 	}
 
@@ -473,6 +629,8 @@  static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
 		 * write-protected, even when it is not.
 		 */
 		out_8(ctrl->addr, in_8(ctrl->addr) | NAND_STATUS_WP);
+		if (mtd->writesize > 2048)
+			ctrl->buffer[0] = in_8(ctrl->addr);
 		return;
 
 	/* RESET without waiting for the ready line */
@@ -519,7 +677,11 @@  static void fsl_elbc_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
 		len = bufsize - ctrl->index;
 	}
 
-	memcpy_toio(&ctrl->addr[ctrl->index], buf, len);
+	if (mtd->writesize > 2048)
+		memcpy(&ctrl->buffer[ctrl->index], buf, len);
+	else
+		memcpy_toio(&ctrl->addr[ctrl->index], buf, len);
+
 	/*
 	 * This is workaround for the weird elbc hangs during nand write,
 	 * Scott Wood says: "...perhaps difference in how long it takes a
@@ -543,8 +705,13 @@  static u8 fsl_elbc_read_byte(struct mtd_info *mtd)
 	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
 
 	/* If there are still bytes in the FCM, then use the next byte. */
-	if (ctrl->index < ctrl->read_bytes)
-		return in_8(&ctrl->addr[ctrl->index++]);
+	if (ctrl->index < ctrl->read_bytes) {
+		int index = ctrl->index++;
+		if (mtd->writesize > 2048)
+			return ctrl->buffer[index];
+		else
+			return in_8(&ctrl->addr[index]);
+	}
 
 	printf("read_byte beyond end of buffer\n");
 	return ERR_BYTE;
@@ -564,7 +731,10 @@  static void fsl_elbc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
 		return;
 
 	avail = min((unsigned int)len, ctrl->read_bytes - ctrl->index);
-	memcpy_fromio(buf, &ctrl->addr[ctrl->index], avail);
+	if (mtd->writesize > 2048)
+		memcpy(buf, &ctrl->buffer[ctrl->index], avail);
+	else
+		memcpy_fromio(buf, &ctrl->addr[ctrl->index], avail);
 	ctrl->index += avail;
 
 	if (len > avail)
@@ -598,9 +768,17 @@  static int fsl_elbc_verify_buf(struct mtd_info *mtd,
 		return -EINVAL;
 	}
 
-	for (i = 0; i < len; i++)
-		if (in_8(&ctrl->addr[ctrl->index + i]) != buf[i])
-			break;
+	if (mtd->writesize > 2048) {
+		for (i = 0; i < len; i++) {
+			if (ctrl->buffer[ctrl->index + i] != buf[i])
+				break;
+		}
+	} else {
+		for (i = 0; i < len; i++) {
+			if (in_8(&ctrl->addr[ctrl->index + i]) != buf[i])
+				break;
+		}
+	}
 
 	ctrl->index += len;
 	return i == len && ctrl->status == LTESR_CC ? 0 : -EIO;
@@ -637,6 +815,8 @@  static int fsl_elbc_wait(struct mtd_info *mtd, struct nand_chip *chip)
 	 * write-protected, even when it is not.
 	 */
 	out_8(ctrl->addr, in_8(ctrl->addr) | NAND_STATUS_WP);
+	if (mtd->writesize > 2048)
+		ctrl->buffer[0] = in_8(ctrl->addr);
 	return fsl_elbc_read_byte(mtd);
 }
 
@@ -666,11 +846,11 @@  static void fsl_elbc_write_page(struct mtd_info *mtd,
 
 static struct fsl_elbc_ctrl *elbc_ctrl;
 
-static void fsl_elbc_ctrl_init(void)
+static int fsl_elbc_ctrl_init(void)
 {
 	elbc_ctrl = kzalloc(sizeof(*elbc_ctrl), GFP_KERNEL);
 	if (!elbc_ctrl)
-		return;
+		return -ENOMEM;
 
 	elbc_ctrl->regs = LBC_BASE_ADDR;
 
@@ -684,6 +864,21 @@  static void fsl_elbc_ctrl_init(void)
 	elbc_ctrl->read_bytes = 0;
 	elbc_ctrl->index = 0;
 	elbc_ctrl->addr = NULL;
+
+	/*
+	 * Freescale FCM controller has a 2KB size limitation of buffer RAM,
+	 * so elbc_ctrl->buffer have to be used if pagesize of NAND devices
+	 * chip greater than 2048. We malloc a large enough buffer(just max
+	 * 8K pagesize for now) at this point, because we don't know pagesize
+	 * before calling nand_scan_ident().
+	 */
+	elbc_ctrl->buffer = kmalloc(1024 * 8 + 1024, GFP_KERNEL);
+	if (!elbc_ctrl->buffer) {
+		printf("failed to allocate memory for elbc_ctrl->buffer\n");
+		return -ENOMEM;
+	}
+
+	return 0;
 }
 
 int board_nand_init(struct nand_chip *nand)
@@ -692,8 +887,7 @@  int board_nand_init(struct nand_chip *nand)
 	uint32_t br = 0, or = 0;
 
 	if (!elbc_ctrl) {
-		fsl_elbc_ctrl_init();
-		if (!elbc_ctrl)
+		if (fsl_elbc_ctrl_init())
 			return -1;
 	}
 
@@ -782,7 +976,6 @@  int board_nand_init(struct nand_chip *nand)
 
 	/* Large-page-specific setup */
 	if (or & OR_FCM_PGS) {
-		priv->page_size = 1;
 		nand->badblock_pattern = &largepage_memorybased;
 
 		/* adjust ecc setup if needed */
@@ -796,3 +989,31 @@  int board_nand_init(struct nand_chip *nand)
 
 	return 0;
 }
+
+int board_nand_init_tail(struct mtd_info *mtd)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct fsl_elbc_mtd *priv = nand->priv;
+	struct fsl_elbc_ctrl *ctrl = priv->ctrl;
+
+	/* adjust Option Register and ECC to match Flash page size */
+	if (mtd->writesize == 512) {
+		clrbits_be32(&ctrl->regs->bank[priv->bank].or, OR_FCM_PGS);
+	} else if (mtd->writesize >= 2048 && mtd->writesize <= 8192) {
+		setbits_be32(&ctrl->regs->bank[priv->bank].or, OR_FCM_PGS);
+		/* adjust ecc setup if needed */
+		if ((in_be32(&ctrl->regs->bank[priv->bank].br) & BR_DECC) ==
+			BR_DECC_CHK_GEN) {
+			nand->ecc.size = 512;
+			nand->ecc.layout = (priv->fmr & FMR_ECCM) ?
+			   &fsl_elbc_oob_lp_eccm1 : &fsl_elbc_oob_lp_eccm0;
+			nand->badblock_pattern = &largepage_memorybased;
+		}
+	} else {
+		printf("%s: page size %d is not supported\n", __func__,
+			mtd->writesize);
+		return -1;
+	}
+
+	return 0;
+}