Re: [PATCH 3/3] mtd/nand : workaround for Freescale FCM to support large-page Nand chip

=E4=BA=8E 2011=E5=B9=B412=E6=9C=8807=E6=97=A5 08:09, Scott Wood =E5=86=99=
=E9=81=93:

On 12/03/2011 10:31 PM, shuo.liu@freescale.com wrote:

quoted

From: Liu Shuo<redacted>

Freescale FCM controller has a 2K size limitation of buffer RAM. In or=

der

quoted

to support the Nand flash chip whose page size is larger than 2K bytes=

,

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we read/write 2k data repeatedly by issuing FIR_OP_RB/FIR_OP_WB and sa=

ve

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them to a large buffer.

Signed-off-by: Liu Shuo<redacted>
---
v3:
     -remove page_size of struct fsl_elbc_mtd.
     -do a oob write by NAND_CMD_RNDIN.

  drivers/mtd/nand/fsl_elbc_nand.c |  243 ++++++++++++++++++++++++++++=

++++++----

quoted

  1 files changed, 218 insertions(+), 25 deletions(-)

What is the plan for bad block marker migration?

This patch has been ported to uboot now, I think we can make a special=20
uboot image for bad
block marker migration when first use the chip.

quoted

@@ -473,13 +568,72 @@ static void fsl_elbc_cmdfunc(struct mtd_info *mt=

d, unsigned int command,

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  		 * write so the HW generates the ECC.
  		 */
  		if (elbc_fcm_ctrl->oob || elbc_fcm_ctrl->column !=3D 0 ||
-		    elbc_fcm_ctrl->index !=3D mtd->writesize + mtd->oobsize)
-			out_be32(&lbc->fbcr,
-				elbc_fcm_ctrl->index - elbc_fcm_ctrl->column);
-		else
+		    elbc_fcm_ctrl->index !=3D mtd->writesize + mtd->oobsize) {
+			if (elbc_fcm_ctrl->oob&&  mtd->writesize>  2048) {
+				out_be32(&lbc->fbcr, 64);
+			} else {
+				out_be32(&lbc->fbcr, elbc_fcm_ctrl->index
+						- elbc_fcm_ctrl->column);
+			}

We need to limit ourselves to the regions that have actually been
written to in the buffer.  fbcr needs to be set separately for first an=

d

last subpages, with intermediate subpages having 0, 64, or 2112 as
appropriate.  Subpages that are entirely before column or entirely afte=

r

column + index should be skipped.

I have considered this case, but I don't think it is useful.
     1.There isn't a 'length' parameter in driver interface, although we=20
can get it from 'index - column'.
     2.To see nand_do_write_oob() in nand_base.c, it fill '0xff' to=20
entire oob area first and write the user data by nand_fill_oob(), then=20
call ecc.write_oob (default is nand_write_oob_std()). 'column' is=20
mtd->writesize and 'length' of write_buf() is mtd->oobsize. So I don't=20
think we need to deal with it there.

quoted

+		} else {
+			out_be32(&lbc->fir, FIR_OP_WB<<  FIR_OP1_SHIFT);
+			for (i =3D 1; i<  n; i++) {
+				if (i =3D=3D n - 1) {
+					elbc_fcm_ctrl->use_mdr =3D 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));

Please explicitly show the (FIR_OP_NOP<<  FIR_OP0_SHIFT) compenent.

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+	} else if (mtd->writesize>=3D 2048&&  mtd->writesize<=3D 16 * 1024) =

{

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+
  		setbits32(&lbc->bank[priv->bank].or, OR_FCM_PGS);

Don't insert a blank line here.

Ok.

-LiuShuo

-Scott