[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.Liu at freescale.com>
>> Signed-off-by: Liu Shuo<b35362 at 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
>