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

[Marek Vasut <marek.vasut@gmail.com>]

> 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.Liu@freescale.com>
> Signed-off-by: Liu Shuo <b35362@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 ?

> +
> +	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