[U-Boot] [PATCH v3 5/5] mtd: nand: mxs_nand: add minimal ECC support

Stefan Agner stefan at agner.ch
Thu Jun 21 11:46:10 UTC 2018


Tom, Stefano,

Scott Wood seems not to be very active this days in the U-Boot
community.

This patchsets seem all to be blocked due to that:
https://patchwork.ozlabs.org/cover/897263/
https://patchwork.ozlabs.org/cover/901995/
https://patchwork.ozlabs.org/patch/922907/

Those patches have been around quite a while and I tested them well. Any
change to get that still in?

Best regards,
Stefan


On 30.05.2018 16:51, Stefan Agner wrote:
> Hi Stefano,
> 
> On 30.04.2018 10:08, Stefan Agner wrote:
>> On 27.04.2018 09:31, Stefano Babic wrote:
>>> Hi Stefan,
>>>
>>> On 11/04/2018 18:04, Stefan Agner wrote:
>>>> From: Stefan Agner <stefan.agner at toradex.com>
>>>>
>>>> Add support for minimum ECC strength supported by the NAND chip.
>>>> This aligns with the behavior when using the fsl,use-minimum-ecc
>>>> device tree property in Linux.
>>>>
>>>> Signed-off-by: Stefan Agner <stefan.agner at toradex.com>
>>>> ---
>>>>
>>>> Changes in v3: None
>>>> Changes in v2: None
>>>>
>>>>  drivers/mtd/nand/Kconfig    |  8 +++++
>>>>  drivers/mtd/nand/mxs_nand.c | 71 +++++++++++++++++++++++++++++--------
>>>>  2 files changed, 65 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
>>>> index 4db259fcb2..c039b9cc60 100644
>>>> --- a/drivers/mtd/nand/Kconfig
>>>> +++ b/drivers/mtd/nand/Kconfig
>>>> @@ -152,6 +152,14 @@ config NAND_MXS
>>>>  	  This enables NAND driver for the NAND flash controller on the
>>>>  	  MXS processors.
>>>>
>>>> +if NAND_MXS
>>>> +
>>>> +config NAND_MXS_USE_MINIMUM_ECC
>>>> +	bool "Use minimum ECC strength supported by the controller"
>>>> +	default false
>>>> +
>>>> +endif
>>>> +
>>>>  config NAND_ZYNQ
>>>>  	bool "Support for Zynq Nand controller"
>>>>  	select SYS_NAND_SELF_INIT
>>>> diff --git a/drivers/mtd/nand/mxs_nand.c b/drivers/mtd/nand/mxs_nand.c
>>>> index 2696b543ef..8305bf2302 100644
>>>> --- a/drivers/mtd/nand/mxs_nand.c
>>>> +++ b/drivers/mtd/nand/mxs_nand.c
>>>> @@ -211,11 +211,52 @@ static inline int mxs_nand_calc_mark_offset(struct bch_geometry *geo,
>>>>  	return 0;
>>>>  }
>>>>
>>>> +static inline unsigned int mxs_nand_max_ecc_strength_supported(void)
>>>> +{
>>>> +	/* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */
>>>> +	if (is_mx6sx() || is_mx7())
>>>> +		return 62;
>>>> +	else
>>>> +		return 40;
>>>> +}
>>>> +
>>>> +static inline int mxs_nand_calc_ecc_layout_by_info(struct bch_geometry *geo,
>>>> +						   struct mtd_info *mtd)
>>>> +{
>>>> +	struct nand_chip *chip = mtd_to_nand(mtd);
>>>> +
>>>> +	if (!(chip->ecc_strength_ds > 0 && chip->ecc_step_ds > 0))
>>>> +		return -ENOTSUPP;
>>>> +
>>>> +	switch (chip->ecc_step_ds) {
>>>> +	case SZ_512:
>>>> +		geo->gf_len = 13;
>>>> +		break;
>>>> +	case SZ_1K:
>>>> +		geo->gf_len = 14;
>>>> +		break;
>>>> +	default:
>>>> +		return -EINVAL;
>>>> +	}
>>>> +
>>>> +	geo->ecc_chunk_size = chip->ecc_step_ds;
>>>> +	geo->ecc_strength = round_up(chip->ecc_strength_ds, 2);
>>>> +
>>>> +	/* Keep the C >= O */
>>>> +	if (geo->ecc_chunk_size < mtd->oobsize)
>>>> +		return -EINVAL;
>>>> +
>>>> +	if (geo->ecc_strength > mxs_nand_max_ecc_strength_supported())
>>>> +		return -EINVAL;
>>>> +
>>>> +	geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size;
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>>  static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo,
>>>>  					   struct mtd_info *mtd)
>>>>  {
>>>> -	unsigned int max_ecc_strength_supported;
>>>> -
>>>>  	/* The default for the length of Galois Field. */
>>>>  	geo->gf_len = 13;
>>>>
>>>> @@ -235,12 +276,6 @@ static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo,
>>>>
>>>>  	geo->ecc_chunk_count = mtd->writesize / geo->ecc_chunk_size;
>>>>
>>>> -	/* Refer to Chapter 17 for i.MX6DQ, Chapter 18 for i.MX6SX */
>>>> -	if (is_mx6sx() || is_mx7())
>>>> -		max_ecc_strength_supported = 62;
>>>> -	else
>>>> -		max_ecc_strength_supported = 40;
>>>> -
>>>>  	/*
>>>>  	 * Determine the ECC layout with the formula:
>>>>  	 *	ECC bits per chunk = (total page spare data bits) /
>>>> @@ -252,10 +287,8 @@ static inline int mxs_nand_calc_ecc_layout(struct bch_geometry *geo,
>>>>  	geo->ecc_strength = ((mtd->oobsize - MXS_NAND_METADATA_SIZE) * 8)
>>>>  			/ (geo->gf_len * geo->ecc_chunk_count);
>>>>
>>>> -	geo->ecc_strength = min(round_down(geo->ecc_strength, 2), max_ecc_strength_supported);
>>>> -
>>>> -	if (mxs_nand_calc_mark_offset(geo, mtd->writesize) < 0)
>>>> -		return -EINVAL;
>>>> +	geo->ecc_strength = min(round_down(geo->ecc_strength, 2),
>>>> +				mxs_nand_max_ecc_strength_supported());
>>>>
>>>>  	return 0;
>>>>  }
>>>> @@ -1006,9 +1039,19 @@ static int mxs_nand_setup_ecc(struct mtd_info *mtd)
>>>>  	struct bch_geometry *geo = &nand_info->bch_geometry;
>>>>  	struct mxs_bch_regs *bch_regs = (struct mxs_bch_regs *)MXS_BCH_BASE;
>>>>  	uint32_t tmp;
>>>> +	int ret = -ENOTSUPP;
>>>>
>>>> -	if (mxs_nand_calc_ecc_layout(geo, mtd))
>>>> -		return -EINVAL;
>>>> +#ifdef CONFIG_NAND_MXS_USE_MINIMUM_ECC
>>>> +	ret = mxs_nand_calc_ecc_layout_by_info(geo, mtd);
>>>> +#endif
>>>> +
>>>> +	if (ret == -ENOTSUPP)
>>>> +		ret = mxs_nand_calc_ecc_layout(geo, mtd);
>>>> +
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	mxs_nand_calc_mark_offset(geo, mtd->writesize);
>>>>
>>>>  	/* Configure BCH and set NFC geometry */
>>>>  	mxs_reset_block(&bch_regs->hw_bch_ctrl_reg);
>>>>
>>>
>>> This is not completely clear to me - is this series replaced by :
>>>
>>> 	http://patchwork.ozlabs.org/patch/902010/
>>
>> No, the other patch set is on-top of this work.
>>
>> With this patch set I already introduce minimum ECC, but by just using a
>> config symbol. The other patchset allows to enable the same using the
>> device tree property.
>>
>> I guess the config symbol is still useful for non-dt platforms or SPLs.
> 
> Is there anything stopping these two patchset from getting merged?
> 
> --
> Stefan
> 
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