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

[LiuShuo]

于 2011年12月09日 00:37, Marek Vasut 写道:

Freescale FCM controller has a 2K size limitation of buffer RAM. In order
to support the Nand flash chip whose page size is 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....@freescale.com>
Signed-off-by: Liu Shuo<b35...@freescale.com>
---
  drivers/mtd/nand/fsl_elbc_nand.c |  279
+++++++++++++++++++++++++++++++++---- 1 files changed, 248 insertions(+),
31 deletions(-)

diff --git a/drivers/mtd/nand/fsl_elbc_nand.c
b/drivers/mtd/nand/fsl_elbc_nand.c index 52362b1..3983c8c 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    */

Start sentence with capital letter

+                                /* than FCM RAM 2K limitation            */
  };

  /* These map to the positions used by the FCM hardware ECC generator */
@@ -159,6 +160,44 @@ 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);

No parenthesis ...

+
+       /* for emulating 4096+ bytes NAND using 2048-byte FCM RAM */
+       if (oob)
+               dst = ctrl->buffer + mtd->writesize + subpage * 64;
+       else
+               dst = ctrl->buffer + subpage * 2048;

subpage * len ?

dst = ctrl->buffer + (oob ? mtd->writesize : 0) + subpage * len ?
Is this important ? I think it is ok.

-LiuShuo

+
+       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);
+
+       if (oob)
+               src = ctrl->buffer + mtd->writesize + subpage * 64;
+       else
+               src = ctrl->buffer + subpage * 2048;

DTTO

M

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