[PATCH -next v3 0/2] mtd: nand: toshiba: Add Toshiba BENAND support

[PATCH -next v3 0/2] mtd: nand: toshiba: Add Toshiba BENAND support

[KOBAYASHI Yoshitake]

This patch series enables to support Toshiba BENAND. The first patch
retreive ECC requirement from extended ID for all Toshiba SLC NAND
devices. The ECC requirement information uses to show a warning
message in second patch.

KOBAYASHI Yoshitake (2):
  mtd: nand: toshiba: Retrieve ECC requirements from extended ID
  mtd: nand: toshiba: Add support for Toshiba Memory BENAND (Built-in
    ECC NAND)

 drivers/mtd/nand/nand_toshiba.c | 117 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)

-- 
2.7.4

[PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[KOBAYASHI Yoshitake]

This patch enables support to read the ECC strength and size from the
NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
based on the information of the 6th ID byte of the Toshiba Memory SLC
NAND.

Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
---
 drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
index 57df857..c2c141b 100644
--- a/drivers/mtd/nand/nand_toshiba.c
+++ b/drivers/mtd/nand/nand_toshiba.c
@@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
 	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
 	    !(chip->id.data[4] & 0x80) /* !BENAND */)
 		mtd->oobsize = 32 * mtd->writesize >> 9;
+
+	/*
+	 * Extract ECC requirements from 6th id byte.
+	 * For Toshiba SLC, ecc requrements are as follows:
+	 *  - 43nm: 1 bit ECC for each 512Byte is required.
+	 *  - 32nm: 4 bit ECC for each 512Byte is required.
+	 *  - 24nm: 8 bit ECC for each 512Byte is required.
+	 */
+	if (chip->id.len >= 6 && nand_is_slc(chip)) {
+		chip->ecc_step_ds = 512;
+		switch (chip->id.data[5] & 0x7) {
+		case 0x4:
+			chip->ecc_strength_ds = 1;
+			break;
+		case 0x5:
+			chip->ecc_strength_ds = 4;
+			break;
+		case 0x6:
+			chip->ecc_strength_ds = 8;
+			break;
+		default:
+			WARN(1, "Could not get ECC info");
+			chip->ecc_step_ds = 0;
+			break;
+		}
+	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
+		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");
+	}
 }
 
 static int toshiba_nand_init(struct nand_chip *chip)
-- 
2.7.4

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[Boris Brezillon]

On Wed,  6 Dec 2017 23:04:57 +0900
KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:

> This patch enables support to read the ECC strength and size from the
> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
> based on the information of the 6th ID byte of the Toshiba Memory SLC
> NAND.
> 
> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> ---
>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> index 57df857..c2c141b 100644
> --- a/drivers/mtd/nand/nand_toshiba.c
> +++ b/drivers/mtd/nand/nand_toshiba.c
> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
>  		mtd->oobsize = 32 * mtd->writesize >> 9;
> +
> +	/*
> +	 * Extract ECC requirements from 6th id byte.
> +	 * For Toshiba SLC, ecc requrements are as follows:
> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
> +	 */
> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
> +		chip->ecc_step_ds = 512;
> +		switch (chip->id.data[5] & 0x7) {
> +		case 0x4:
> +			chip->ecc_strength_ds = 1;
> +			break;
> +		case 0x5:
> +			chip->ecc_strength_ds = 4;
> +			break;
> +		case 0x6:
> +			chip->ecc_strength_ds = 8;
> +			break;
> +		default:
> +			WARN(1, "Could not get ECC info");
> +			chip->ecc_step_ds = 0;
> +			break;
> +		}
> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");

I'm pretty sure you have old NAND chips that do not have 6bytes ids
(see the table here [1]), and printing a huge backtrace in this case is
probably not what you want.

If you're okay with dropping this else block, I'll do the change when
applying, no need to send a new version.

> +	}
>  }
>  
>  static int toshiba_nand_init(struct nand_chip *chip)

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[KOBAYASHI Yoshitake]

On 2017/12/07 0:08, Boris Brezillon wrote:
> On Wed,  6 Dec 2017 23:04:57 +0900
> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> 
>> This patch enables support to read the ECC strength and size from the
>> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
>> based on the information of the 6th ID byte of the Toshiba Memory SLC
>> NAND.
>>
>> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
>> ---
>>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
>>  1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
>> index 57df857..c2c141b 100644
>> --- a/drivers/mtd/nand/nand_toshiba.c
>> +++ b/drivers/mtd/nand/nand_toshiba.c
>> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
>>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
>>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
>>  		mtd->oobsize = 32 * mtd->writesize >> 9;
>> +
>> +	/*
>> +	 * Extract ECC requirements from 6th id byte.
>> +	 * For Toshiba SLC, ecc requrements are as follows:
>> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
>> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
>> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
>> +	 */
>> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
>> +		chip->ecc_step_ds = 512;
>> +		switch (chip->id.data[5] & 0x7) {
>> +		case 0x4:
>> +			chip->ecc_strength_ds = 1;
>> +			break;
>> +		case 0x5:
>> +			chip->ecc_strength_ds = 4;
>> +			break;
>> +		case 0x6:
>> +			chip->ecc_strength_ds = 8;
>> +			break;
>> +		default:
>> +			WARN(1, "Could not get ECC info");
>> +			chip->ecc_step_ds = 0;
>> +			break;
>> +		}
>> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
>> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");
> 
> I'm pretty sure you have old NAND chips that do not have 6bytes ids
> (see the table here [1]), and printing a huge backtrace in this case is
> probably not what you want.
> 
> If you're okay with dropping this else block, I'll do the change when
> applying, no need to send a new version.

Some controllers may have limitation in reading ids beyond 5 bytes, 
considering such scenario we think it is better to keep this warning.
However if you feel huge backtrace is an issue, how about we using pr_warn() instead?

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[Boris Brezillon]

On Tue, 19 Dec 2017 20:42:36 +0900
KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:

> On 2017/12/07 0:08, Boris Brezillon wrote:
> > On Wed,  6 Dec 2017 23:04:57 +0900
> > KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> >   
> >> This patch enables support to read the ECC strength and size from the
> >> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
> >> based on the information of the 6th ID byte of the Toshiba Memory SLC
> >> NAND.
> >>
> >> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> >> ---
> >>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
> >>  1 file changed, 28 insertions(+)
> >>
> >> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> >> index 57df857..c2c141b 100644
> >> --- a/drivers/mtd/nand/nand_toshiba.c
> >> +++ b/drivers/mtd/nand/nand_toshiba.c
> >> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
> >>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
> >>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
> >>  		mtd->oobsize = 32 * mtd->writesize >> 9;
> >> +
> >> +	/*
> >> +	 * Extract ECC requirements from 6th id byte.
> >> +	 * For Toshiba SLC, ecc requrements are as follows:
> >> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
> >> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
> >> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
> >> +	 */
> >> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
> >> +		chip->ecc_step_ds = 512;
> >> +		switch (chip->id.data[5] & 0x7) {
> >> +		case 0x4:
> >> +			chip->ecc_strength_ds = 1;
> >> +			break;
> >> +		case 0x5:
> >> +			chip->ecc_strength_ds = 4;
> >> +			break;
> >> +		case 0x6:
> >> +			chip->ecc_strength_ds = 8;
> >> +			break;
> >> +		default:
> >> +			WARN(1, "Could not get ECC info");
> >> +			chip->ecc_step_ds = 0;
> >> +			break;
> >> +		}
> >> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
> >> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");  
> > 
> > I'm pretty sure you have old NAND chips that do not have 6bytes ids
> > (see the table here [1]), and printing a huge backtrace in this case is
> > probably not what you want.
> > 
> > If you're okay with dropping this else block, I'll do the change when
> > applying, no need to send a new version.  
> 
> Some controllers may have limitation in reading ids beyond 5 bytes, 
> considering such scenario we think it is better to keep this warning.
> However if you feel huge backtrace is an issue, how about we using pr_warn() instead?
> 

Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should
not complain at all. If the controller is broken and can't read the 8 id
bytes the core is asking for, then it should be detected at the core
level not in the NAND manufacturer driver.

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[Boris Brezillon]

On Tue, 19 Dec 2017 12:56:24 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> On Tue, 19 Dec 2017 20:42:36 +0900
> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> 
> > On 2017/12/07 0:08, Boris Brezillon wrote:  
> > > On Wed,  6 Dec 2017 23:04:57 +0900
> > > KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> > >     
> > >> This patch enables support to read the ECC strength and size from the
> > >> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
> > >> based on the information of the 6th ID byte of the Toshiba Memory SLC
> > >> NAND.
> > >>
> > >> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> > >> ---
> > >>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
> > >>  1 file changed, 28 insertions(+)
> > >>
> > >> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> > >> index 57df857..c2c141b 100644
> > >> --- a/drivers/mtd/nand/nand_toshiba.c
> > >> +++ b/drivers/mtd/nand/nand_toshiba.c
> > >> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
> > >>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
> > >>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
> > >>  		mtd->oobsize = 32 * mtd->writesize >> 9;
> > >> +
> > >> +	/*
> > >> +	 * Extract ECC requirements from 6th id byte.
> > >> +	 * For Toshiba SLC, ecc requrements are as follows:
> > >> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
> > >> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
> > >> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
> > >> +	 */
> > >> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
> > >> +		chip->ecc_step_ds = 512;
> > >> +		switch (chip->id.data[5] & 0x7) {
> > >> +		case 0x4:
> > >> +			chip->ecc_strength_ds = 1;
> > >> +			break;
> > >> +		case 0x5:
> > >> +			chip->ecc_strength_ds = 4;
> > >> +			break;
> > >> +		case 0x6:
> > >> +			chip->ecc_strength_ds = 8;
> > >> +			break;
> > >> +		default:
> > >> +			WARN(1, "Could not get ECC info");
> > >> +			chip->ecc_step_ds = 0;
> > >> +			break;
> > >> +		}
> > >> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
> > >> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");    
> > > 
> > > I'm pretty sure you have old NAND chips that do not have 6bytes ids
> > > (see the table here [1]), and printing a huge backtrace in this case is
> > > probably not what you want.
> > > 
> > > If you're okay with dropping this else block, I'll do the change when
> > > applying, no need to send a new version.    
> > 
> > Some controllers may have limitation in reading ids beyond 5 bytes, 
> > considering such scenario we think it is better to keep this warning.
> > However if you feel huge backtrace is an issue, how about we using pr_warn() instead?
> >   
> 
> Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should
> not complain at all. If the controller is broken and can't read the 8 id
> bytes the core is asking for, then it should be detected at the core
> level not in the NAND manufacturer driver.

It seems I forgot the link to the NAND table, so here it is [1], and as
you can see, some chips have only 2 id bytes (TC58DVG02A5 is one of
them).

[1]http://www.linux-mtd.infradead.org/nand-data/nanddata.html

> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[KOBAYASHI Yoshitake]

On 2017/12/19 20:56, Boris Brezillon wrote:
> On Tue, 19 Dec 2017 20:42:36 +0900
> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> 
>> On 2017/12/07 0:08, Boris Brezillon wrote:
>>> On Wed,  6 Dec 2017 23:04:57 +0900
>>> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
>>>   
>>>> This patch enables support to read the ECC strength and size from the
>>>> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
>>>> based on the information of the 6th ID byte of the Toshiba Memory SLC
>>>> NAND.
>>>>
>>>> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
>>>> ---
>>>>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
>>>>  1 file changed, 28 insertions(+)
>>>>
>>>> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
>>>> index 57df857..c2c141b 100644
>>>> --- a/drivers/mtd/nand/nand_toshiba.c
>>>> +++ b/drivers/mtd/nand/nand_toshiba.c
>>>> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
>>>>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
>>>>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
>>>>  		mtd->oobsize = 32 * mtd->writesize >> 9;
>>>> +
>>>> +	/*
>>>> +	 * Extract ECC requirements from 6th id byte.
>>>> +	 * For Toshiba SLC, ecc requrements are as follows:
>>>> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
>>>> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
>>>> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
>>>> +	 */
>>>> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
>>>> +		chip->ecc_step_ds = 512;
>>>> +		switch (chip->id.data[5] & 0x7) {
>>>> +		case 0x4:
>>>> +			chip->ecc_strength_ds = 1;
>>>> +			break;
>>>> +		case 0x5:
>>>> +			chip->ecc_strength_ds = 4;
>>>> +			break;
>>>> +		case 0x6:
>>>> +			chip->ecc_strength_ds = 8;
>>>> +			break;
>>>> +		default:
>>>> +			WARN(1, "Could not get ECC info");
>>>> +			chip->ecc_step_ds = 0;
>>>> +			break;
>>>> +		}
>>>> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
>>>> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");  
>>>
>>> I'm pretty sure you have old NAND chips that do not have 6bytes ids
>>> (see the table here [1]), and printing a huge backtrace in this case is
>>> probably not what you want.
>>>
>>> If you're okay with dropping this else block, I'll do the change when
>>> applying, no need to send a new version.  
>>
>> Some controllers may have limitation in reading ids beyond 5 bytes, 
>> considering such scenario we think it is better to keep this warning.
>> However if you feel huge backtrace is an issue, how about we using pr_warn() instead?
>>
> 
> Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should
> not complain at all. If the controller is broken and can't read the 8 id
> bytes the core is asking for, then it should be detected at the core
> level not in the NAND manufacturer driver.

I understood your opinion. Please apply this patch with dropping the else block.

-- YOSHI

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[KOBAYASHI Yoshitake]

On 2017/12/27 15:06, KOBAYASHI Yoshitake wrote:
> On 2017/12/19 20:56, Boris Brezillon wrote:
>> On Tue, 19 Dec 2017 20:42:36 +0900
>> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
>>
>>> On 2017/12/07 0:08, Boris Brezillon wrote:
>>>> On Wed,  6 Dec 2017 23:04:57 +0900
>>>> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
>>>>   
>>>>> This patch enables support to read the ECC strength and size from the
>>>>> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
>>>>> based on the information of the 6th ID byte of the Toshiba Memory SLC
>>>>> NAND.
>>>>>
>>>>> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
>>>>> ---
>>>>>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
>>>>>  1 file changed, 28 insertions(+)
>>>>>
>>>>> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
>>>>> index 57df857..c2c141b 100644
>>>>> --- a/drivers/mtd/nand/nand_toshiba.c
>>>>> +++ b/drivers/mtd/nand/nand_toshiba.c
>>>>> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
>>>>>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
>>>>>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
>>>>>  		mtd->oobsize = 32 * mtd->writesize >> 9;
>>>>> +
>>>>> +	/*
>>>>> +	 * Extract ECC requirements from 6th id byte.
>>>>> +	 * For Toshiba SLC, ecc requrements are as follows:
>>>>> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
>>>>> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
>>>>> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
>>>>> +	 */
>>>>> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
>>>>> +		chip->ecc_step_ds = 512;
>>>>> +		switch (chip->id.data[5] & 0x7) {
>>>>> +		case 0x4:
>>>>> +			chip->ecc_strength_ds = 1;
>>>>> +			break;
>>>>> +		case 0x5:
>>>>> +			chip->ecc_strength_ds = 4;
>>>>> +			break;
>>>>> +		case 0x6:
>>>>> +			chip->ecc_strength_ds = 8;
>>>>> +			break;
>>>>> +		default:
>>>>> +			WARN(1, "Could not get ECC info");
>>>>> +			chip->ecc_step_ds = 0;
>>>>> +			break;
>>>>> +		}
>>>>> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
>>>>> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");  
>>>>
>>>> I'm pretty sure you have old NAND chips that do not have 6bytes ids
>>>> (see the table here [1]), and printing a huge backtrace in this case is
>>>> probably not what you want.
>>>>
>>>> If you're okay with dropping this else block, I'll do the change when
>>>> applying, no need to send a new version.  
>>>
>>> Some controllers may have limitation in reading ids beyond 5 bytes, 
>>> considering such scenario we think it is better to keep this warning.
>>> However if you feel huge backtrace is an issue, how about we using pr_warn() instead?
>>>
>>
>> Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should
>> not complain at all. If the controller is broken and can't read the 8 id
>> bytes the core is asking for, then it should be detected at the core
>> level not in the NAND manufacturer driver.
> 
> I understood your opinion. Please apply this patch with dropping the else block.

Should I repost patch with else block dropped? Please let me know if that is necessary.

-- Yoshi

Re: [PATCH -next v3 1/2] mtd: nand: toshiba: Retrieve ECC requirements from extended ID

[Boris Brezillon]

On Tue, 30 Jan 2018 08:44:30 +0900
KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:

> On 2017/12/27 15:06, KOBAYASHI Yoshitake wrote:
> > On 2017/12/19 20:56, Boris Brezillon wrote:  
> >> On Tue, 19 Dec 2017 20:42:36 +0900
> >> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> >>  
> >>> On 2017/12/07 0:08, Boris Brezillon wrote:  
> >>>> On Wed,  6 Dec 2017 23:04:57 +0900
> >>>> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> >>>>     
> >>>>> This patch enables support to read the ECC strength and size from the
> >>>>> NAND flash using Toshiba Memory SLC NAND extended-ID. This patch is
> >>>>> based on the information of the 6th ID byte of the Toshiba Memory SLC
> >>>>> NAND.
> >>>>>
> >>>>> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> >>>>> ---
> >>>>>  drivers/mtd/nand/nand_toshiba.c | 28 ++++++++++++++++++++++++++++
> >>>>>  1 file changed, 28 insertions(+)
> >>>>>
> >>>>> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> >>>>> index 57df857..c2c141b 100644
> >>>>> --- a/drivers/mtd/nand/nand_toshiba.c
> >>>>> +++ b/drivers/mtd/nand/nand_toshiba.c
> >>>>> @@ -35,6 +35,34 @@ static void toshiba_nand_decode_id(struct nand_chip *chip)
> >>>>>  	    (chip->id.data[5] & 0x7) == 0x6 /* 24nm */ &&
> >>>>>  	    !(chip->id.data[4] & 0x80) /* !BENAND */)
> >>>>>  		mtd->oobsize = 32 * mtd->writesize >> 9;
> >>>>> +
> >>>>> +	/*
> >>>>> +	 * Extract ECC requirements from 6th id byte.
> >>>>> +	 * For Toshiba SLC, ecc requrements are as follows:
> >>>>> +	 *  - 43nm: 1 bit ECC for each 512Byte is required.
> >>>>> +	 *  - 32nm: 4 bit ECC for each 512Byte is required.
> >>>>> +	 *  - 24nm: 8 bit ECC for each 512Byte is required.
> >>>>> +	 */
> >>>>> +	if (chip->id.len >= 6 && nand_is_slc(chip)) {
> >>>>> +		chip->ecc_step_ds = 512;
> >>>>> +		switch (chip->id.data[5] & 0x7) {
> >>>>> +		case 0x4:
> >>>>> +			chip->ecc_strength_ds = 1;
> >>>>> +			break;
> >>>>> +		case 0x5:
> >>>>> +			chip->ecc_strength_ds = 4;
> >>>>> +			break;
> >>>>> +		case 0x6:
> >>>>> +			chip->ecc_strength_ds = 8;
> >>>>> +			break;
> >>>>> +		default:
> >>>>> +			WARN(1, "Could not get ECC info");
> >>>>> +			chip->ecc_step_ds = 0;
> >>>>> +			break;
> >>>>> +		}
> >>>>> +	} else if (chip->id.len < 6 && nand_is_slc(chip)) {
> >>>>> +		WARN(1, "Could not get ECC info, 6th nand id byte does not exist.");    
> >>>>
> >>>> I'm pretty sure you have old NAND chips that do not have 6bytes ids
> >>>> (see the table here [1]), and printing a huge backtrace in this case is
> >>>> probably not what you want.
> >>>>
> >>>> If you're okay with dropping this else block, I'll do the change when
> >>>> applying, no need to send a new version.    
> >>>
> >>> Some controllers may have limitation in reading ids beyond 5 bytes, 
> >>> considering such scenario we think it is better to keep this warning.
> >>> However if you feel huge backtrace is an issue, how about we using pr_warn() instead?
> >>>  
> >>
> >> Toshiba NANDs with an id smaller than 6 bytes exist, so no, we should
> >> not complain at all. If the controller is broken and can't read the 8 id
> >> bytes the core is asking for, then it should be detected at the core
> >> level not in the NAND manufacturer driver.  
> > 
> > I understood your opinion. Please apply this patch with dropping the else block.  
> 
> Should I repost patch with else block dropped? Please let me know if that is necessary.

I forgot to apply it :-/. Please, send a new version so I can track
it in patchwork.

Thanks,

Boris

[PATCH -next v3 2/2] mtd: nand: toshiba: Add support for Toshiba Memory BENAND (Built-in ECC NAND)

[KOBAYASHI Yoshitake]

This patch enables support for Toshiba Memory BENAND. This checks
internal ECC status in read operation when using BENAND and selecting
ECC mode as on-die.

Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
---
 drivers/mtd/nand/nand_toshiba.c | 89 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)

diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
index c2c141b..35c0ddf 100644
--- a/drivers/mtd/nand/nand_toshiba.c
+++ b/drivers/mtd/nand/nand_toshiba.c
@@ -17,6 +17,91 @@
 
 #include <linux/mtd/rawnand.h>
 
+/* ECC Status Read Command for BENAND */
+#define TOSHIBA_NAND_CMD_ECC_STATUS	0x7A
+
+/* Recommended to rewrite for BENAND */
+#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED	BIT(3)
+
+static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
+					  struct nand_chip *chip)
+{
+	unsigned int max_bitflips = 0;
+	u8 status;
+
+	/* Check Read Status */
+	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
+	status = chip->read_byte(mtd);
+
+	/*
+	 * TOSHIBA_NAND_CMD_ECC_STATUS is vendor specific command.
+	 * Currently we have no way to send arbitrary sequences of
+	 * CMD+ADDR+DATA cycles and thus cannot support this custom
+	 * TOSHIBA_NAND_CMD_ECC_STATUS operation.
+	 * For now, we set max_bitflips mtd->bitflip_threshold.
+	 */
+	if (status & NAND_STATUS_FAIL) {
+		/* uncorrectable */
+		mtd->ecc_stats.failed++;
+	} else if (status & TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED) {
+		/* correctable */
+		max_bitflips = mtd->bitflip_threshold;
+		mtd->ecc_stats.corrected += max_bitflips;
+	}
+
+	return max_bitflips;
+}
+
+static int
+toshiba_nand_read_page_benand(struct mtd_info *mtd,
+			      struct nand_chip *chip, uint8_t *buf,
+			      int oob_required, int page)
+{
+	nand_read_page_raw(mtd, chip, buf, oob_required, page);
+
+	return toshiba_nand_benand_status_chk(mtd, chip);
+}
+
+static int
+toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
+				 struct nand_chip *chip, uint32_t data_offs,
+				 uint32_t readlen, uint8_t *bufpoi, int page)
+{
+	uint8_t *p;
+
+	if (data_offs != 0)
+		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
+
+	p = bufpoi + data_offs;
+	chip->read_buf(mtd, p, readlen);
+
+	return toshiba_nand_benand_status_chk(mtd, chip);
+}
+
+static void toshiba_nand_benand_init(struct nand_chip *chip)
+{
+	struct mtd_info *mtd = nand_to_mtd(chip);
+
+	/*
+	 * On BENAND, the entire OOB region can be used by the MTD user.
+	 * The calculated ECC bytes are stored into other isolated
+	 * area which is not accessible to users.
+	 * This is why chip->ecc.bytes = 0.
+	 */
+	chip->ecc.bytes = 0;
+	chip->ecc.size = 512;
+	chip->ecc.strength = 8;
+	chip->ecc.read_page = toshiba_nand_read_page_benand;
+	chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
+	chip->ecc.write_page = nand_write_page_raw;
+	chip->ecc.read_page_raw = nand_read_page_raw;
+	chip->ecc.write_page_raw = nand_write_page_raw;
+
+	chip->options |= NAND_SUBPAGE_READ;
+
+	mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
+}
+
 static void toshiba_nand_decode_id(struct nand_chip *chip)
 {
 	struct mtd_info *mtd = nand_to_mtd(chip);
@@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
 	if (nand_is_slc(chip))
 		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
 
+	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
+	    (chip->ecc.mode == NAND_ECC_ON_DIE))
+		toshiba_nand_benand_init(chip);
+
 	return 0;
 }
 
-- 
2.7.4

Re: [PATCH -next v3 2/2] mtd: nand: toshiba: Add support for Toshiba Memory BENAND (Built-in ECC NAND)

[Boris Brezillon]

On Wed,  6 Dec 2017 23:04:58 +0900
KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:

> This patch enables support for Toshiba Memory BENAND. This checks
> internal ECC status in read operation when using BENAND and selecting
> ECC mode as on-die.
> 
> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> ---
>  drivers/mtd/nand/nand_toshiba.c | 89 +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 89 insertions(+)
> 
> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> index c2c141b..35c0ddf 100644
> --- a/drivers/mtd/nand/nand_toshiba.c
> +++ b/drivers/mtd/nand/nand_toshiba.c
> @@ -17,6 +17,91 @@
>  
>  #include <linux/mtd/rawnand.h>
>  
> +/* ECC Status Read Command for BENAND */
> +#define TOSHIBA_NAND_CMD_ECC_STATUS	0x7A
> +
> +/* Recommended to rewrite for BENAND */
> +#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED	BIT(3)
> +
> +static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
> +					  struct nand_chip *chip)
> +{
> +	unsigned int max_bitflips = 0;
> +	u8 status;
> +
> +	/* Check Read Status */
> +	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
> +	status = chip->read_byte(mtd);

Please use the recently introduced nand_status_op() helper.

> +
> +	/*
> +	 * TOSHIBA_NAND_CMD_ECC_STATUS is vendor specific command.
> +	 * Currently we have no way to send arbitrary sequences of
> +	 * CMD+ADDR+DATA cycles and thus cannot support this custom
> +	 * TOSHIBA_NAND_CMD_ECC_STATUS operation.

That's about to change :-), if everything goes well, nand_exec_op()
should be available in 4.16.

> +	 * For now, we set max_bitflips mtd->bitflip_threshold.
> +	 */
> +	if (status & NAND_STATUS_FAIL) {
> +		/* uncorrectable */
> +		mtd->ecc_stats.failed++;
> +	} else if (status & TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED) {
> +		/* correctable */
> +		max_bitflips = mtd->bitflip_threshold;
> +		mtd->ecc_stats.corrected += max_bitflips;
> +	}
> +
> +	return max_bitflips;
> +}
> +
> +static int
> +toshiba_nand_read_page_benand(struct mtd_info *mtd,
> +			      struct nand_chip *chip, uint8_t *buf,
> +			      int oob_required, int page)
> +{
> +	nand_read_page_raw(mtd, chip, buf, oob_required, page);

Please check the return code of nand_read_page_raw().

> +
> +	return toshiba_nand_benand_status_chk(mtd, chip);
> +}
> +
> +static int
> +toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
> +				 struct nand_chip *chip, uint32_t data_offs,
> +				 uint32_t readlen, uint8_t *bufpoi, int page)
> +{
> +	uint8_t *p;
> +
> +	if (data_offs != 0)
> +		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
> +
> +	p = bufpoi + data_offs;
> +	chip->read_buf(mtd, p, readlen);

The core is no longer sending the initial READ0 command, so this should
be turned into:

	ret = nand_read_page_op(chip, data_offs, bufpoi + data_offs,
				readlen);
	if (ret)
		return ret;
		

> +
> +	return toshiba_nand_benand_status_chk(mtd, chip);
> +}
> +
> +static void toshiba_nand_benand_init(struct nand_chip *chip)
> +{
> +	struct mtd_info *mtd = nand_to_mtd(chip);
> +
> +	/*
> +	 * On BENAND, the entire OOB region can be used by the MTD user.
> +	 * The calculated ECC bytes are stored into other isolated
> +	 * area which is not accessible to users.
> +	 * This is why chip->ecc.bytes = 0.
> +	 */
> +	chip->ecc.bytes = 0;
> +	chip->ecc.size = 512;
> +	chip->ecc.strength = 8;
> +	chip->ecc.read_page = toshiba_nand_read_page_benand;
> +	chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
> +	chip->ecc.write_page = nand_write_page_raw;
> +	chip->ecc.read_page_raw = nand_read_page_raw;
> +	chip->ecc.write_page_raw = nand_write_page_raw;
> +
> +	chip->options |= NAND_SUBPAGE_READ;
> +
> +	mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
> +}
> +
>  static void toshiba_nand_decode_id(struct nand_chip *chip)
>  {
>  	struct mtd_info *mtd = nand_to_mtd(chip);
> @@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
>  	if (nand_is_slc(chip))
>  		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
>  
> +	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
> +	    (chip->ecc.mode == NAND_ECC_ON_DIE))
> +		toshiba_nand_benand_init(chip);
> +

Please move this block to toshiba_nand_init().

>  	return 0;
>  }
>  

Re: [PATCH -next v3 2/2] mtd: nand: toshiba: Add support for Toshiba Memory BENAND (Built-in ECC NAND)

[KOBAYASHI Yoshitake]

Thanks for reviewing the patches and taht is a good news for me about nand_exec_op().
I'll change this patch as you suggested.
I would like to make sure the following one.

>> @@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
>>  	if (nand_is_slc(chip))
>>  		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
>>  
>> +	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
>> +	    (chip->ecc.mode == NAND_ECC_ON_DIE))
>> +		toshiba_nand_benand_init(chip);
>> +
> 
> Please move this block to toshiba_nand_init().

I think it's already in toshiba_nand_init().

-- YOSHI


On 2017/12/07 0:24, Boris Brezillon wrote:
> On Wed,  6 Dec 2017 23:04:58 +0900
> KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> 
>> This patch enables support for Toshiba Memory BENAND. This checks
>> internal ECC status in read operation when using BENAND and selecting
>> ECC mode as on-die.
>>
>> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
>> ---
>>  drivers/mtd/nand/nand_toshiba.c | 89 +++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 89 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
>> index c2c141b..35c0ddf 100644
>> --- a/drivers/mtd/nand/nand_toshiba.c
>> +++ b/drivers/mtd/nand/nand_toshiba.c
>> @@ -17,6 +17,91 @@
>>  
>>  #include <linux/mtd/rawnand.h>
>>  
>> +/* ECC Status Read Command for BENAND */
>> +#define TOSHIBA_NAND_CMD_ECC_STATUS	0x7A
>> +
>> +/* Recommended to rewrite for BENAND */
>> +#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED	BIT(3)
>> +
>> +static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
>> +					  struct nand_chip *chip)
>> +{
>> +	unsigned int max_bitflips = 0;
>> +	u8 status;
>> +
>> +	/* Check Read Status */
>> +	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
>> +	status = chip->read_byte(mtd);
> 
> Please use the recently introduced nand_status_op() helper.
> 
>> +
>> +	/*
>> +	 * TOSHIBA_NAND_CMD_ECC_STATUS is vendor specific command.
>> +	 * Currently we have no way to send arbitrary sequences of
>> +	 * CMD+ADDR+DATA cycles and thus cannot support this custom
>> +	 * TOSHIBA_NAND_CMD_ECC_STATUS operation.
> 
> That's about to change :-), if everything goes well, nand_exec_op()
> should be available in 4.16.
> 
>> +	 * For now, we set max_bitflips mtd->bitflip_threshold.
>> +	 */
>> +	if (status & NAND_STATUS_FAIL) {
>> +		/* uncorrectable */
>> +		mtd->ecc_stats.failed++;
>> +	} else if (status & TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED) {
>> +		/* correctable */
>> +		max_bitflips = mtd->bitflip_threshold;
>> +		mtd->ecc_stats.corrected += max_bitflips;
>> +	}
>> +
>> +	return max_bitflips;
>> +}
>> +
>> +static int
>> +toshiba_nand_read_page_benand(struct mtd_info *mtd,
>> +			      struct nand_chip *chip, uint8_t *buf,
>> +			      int oob_required, int page)
>> +{
>> +	nand_read_page_raw(mtd, chip, buf, oob_required, page);
> 
> Please check the return code of nand_read_page_raw().
> 
>> +
>> +	return toshiba_nand_benand_status_chk(mtd, chip);
>> +}
>> +
>> +static int
>> +toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
>> +				 struct nand_chip *chip, uint32_t data_offs,
>> +				 uint32_t readlen, uint8_t *bufpoi, int page)
>> +{
>> +	uint8_t *p;
>> +
>> +	if (data_offs != 0)
>> +		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
>> +
>> +	p = bufpoi + data_offs;
>> +	chip->read_buf(mtd, p, readlen);
> 
> The core is no longer sending the initial READ0 command, so this should
> be turned into:
> 
> 	ret = nand_read_page_op(chip, data_offs, bufpoi + data_offs,
> 				readlen);
> 	if (ret)
> 		return ret;
> 		
> 
>> +
>> +	return toshiba_nand_benand_status_chk(mtd, chip);
>> +}
>> +
>> +static void toshiba_nand_benand_init(struct nand_chip *chip)
>> +{
>> +	struct mtd_info *mtd = nand_to_mtd(chip);
>> +
>> +	/*
>> +	 * On BENAND, the entire OOB region can be used by the MTD user.
>> +	 * The calculated ECC bytes are stored into other isolated
>> +	 * area which is not accessible to users.
>> +	 * This is why chip->ecc.bytes = 0.
>> +	 */
>> +	chip->ecc.bytes = 0;
>> +	chip->ecc.size = 512;
>> +	chip->ecc.strength = 8;
>> +	chip->ecc.read_page = toshiba_nand_read_page_benand;
>> +	chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
>> +	chip->ecc.write_page = nand_write_page_raw;
>> +	chip->ecc.read_page_raw = nand_read_page_raw;
>> +	chip->ecc.write_page_raw = nand_write_page_raw;
>> +
>> +	chip->options |= NAND_SUBPAGE_READ;
>> +
>> +	mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
>> +}
>> +
>>  static void toshiba_nand_decode_id(struct nand_chip *chip)
>>  {
>>  	struct mtd_info *mtd = nand_to_mtd(chip);
>> @@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
>>  	if (nand_is_slc(chip))
>>  		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
>>  
>> +	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
>> +	    (chip->ecc.mode == NAND_ECC_ON_DIE))
>> +		toshiba_nand_benand_init(chip);
>> +
> 
> Please move this block to toshiba_nand_init().
> 
>>  	return 0;
>>  }
>>  
> 
> 
> 

Re: [PATCH -next v3 2/2] mtd: nand: toshiba: Add support for Toshiba Memory BENAND (Built-in ECC NAND)

[Boris Brezillon]

On Tue, 19 Dec 2017 21:01:47 +0900
KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:

> Thanks for reviewing the patches and taht is a good news for me about nand_exec_op().
> I'll change this patch as you suggested.
> I would like to make sure the following one.
> 
> >> @@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
> >>  	if (nand_is_slc(chip))
> >>  		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
> >>  
> >> +	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
> >> +	    (chip->ecc.mode == NAND_ECC_ON_DIE))
> >> +		toshiba_nand_benand_init(chip);
> >> +  
> > 
> > Please move this block to toshiba_nand_init().  
> 
> I think it's already in toshiba_nand_init().

My bad, I thought it was in the decode_id() function.

> 
> -- YOSHI
> 
> 
> On 2017/12/07 0:24, Boris Brezillon wrote:
> > On Wed,  6 Dec 2017 23:04:58 +0900
> > KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp> wrote:
> >   
> >> This patch enables support for Toshiba Memory BENAND. This checks
> >> internal ECC status in read operation when using BENAND and selecting
> >> ECC mode as on-die.
> >>
> >> Signed-off-by: KOBAYASHI Yoshitake <yoshitake.kobayashi@toshiba.co.jp>
> >> ---
> >>  drivers/mtd/nand/nand_toshiba.c | 89 +++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 89 insertions(+)
> >>
> >> diff --git a/drivers/mtd/nand/nand_toshiba.c b/drivers/mtd/nand/nand_toshiba.c
> >> index c2c141b..35c0ddf 100644
> >> --- a/drivers/mtd/nand/nand_toshiba.c
> >> +++ b/drivers/mtd/nand/nand_toshiba.c
> >> @@ -17,6 +17,91 @@
> >>  
> >>  #include <linux/mtd/rawnand.h>
> >>  
> >> +/* ECC Status Read Command for BENAND */
> >> +#define TOSHIBA_NAND_CMD_ECC_STATUS	0x7A
> >> +
> >> +/* Recommended to rewrite for BENAND */
> >> +#define TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED	BIT(3)
> >> +
> >> +static int toshiba_nand_benand_status_chk(struct mtd_info *mtd,
> >> +					  struct nand_chip *chip)
> >> +{
> >> +	unsigned int max_bitflips = 0;
> >> +	u8 status;
> >> +
> >> +	/* Check Read Status */
> >> +	chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
> >> +	status = chip->read_byte(mtd);  
> > 
> > Please use the recently introduced nand_status_op() helper.
> >   
> >> +
> >> +	/*
> >> +	 * TOSHIBA_NAND_CMD_ECC_STATUS is vendor specific command.
> >> +	 * Currently we have no way to send arbitrary sequences of
> >> +	 * CMD+ADDR+DATA cycles and thus cannot support this custom
> >> +	 * TOSHIBA_NAND_CMD_ECC_STATUS operation.  
> > 
> > That's about to change :-), if everything goes well, nand_exec_op()
> > should be available in 4.16.
> >   
> >> +	 * For now, we set max_bitflips mtd->bitflip_threshold.
> >> +	 */
> >> +	if (status & NAND_STATUS_FAIL) {
> >> +		/* uncorrectable */
> >> +		mtd->ecc_stats.failed++;
> >> +	} else if (status & TOSHIBA_NAND_STATUS_REWRITE_RECOMMENDED) {
> >> +		/* correctable */
> >> +		max_bitflips = mtd->bitflip_threshold;
> >> +		mtd->ecc_stats.corrected += max_bitflips;
> >> +	}
> >> +
> >> +	return max_bitflips;
> >> +}
> >> +
> >> +static int
> >> +toshiba_nand_read_page_benand(struct mtd_info *mtd,
> >> +			      struct nand_chip *chip, uint8_t *buf,
> >> +			      int oob_required, int page)
> >> +{
> >> +	nand_read_page_raw(mtd, chip, buf, oob_required, page);  
> > 
> > Please check the return code of nand_read_page_raw().
> >   
> >> +
> >> +	return toshiba_nand_benand_status_chk(mtd, chip);
> >> +}
> >> +
> >> +static int
> >> +toshiba_nand_read_subpage_benand(struct mtd_info *mtd,
> >> +				 struct nand_chip *chip, uint32_t data_offs,
> >> +				 uint32_t readlen, uint8_t *bufpoi, int page)
> >> +{
> >> +	uint8_t *p;
> >> +
> >> +	if (data_offs != 0)
> >> +		chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
> >> +
> >> +	p = bufpoi + data_offs;
> >> +	chip->read_buf(mtd, p, readlen);  
> > 
> > The core is no longer sending the initial READ0 command, so this should
> > be turned into:
> > 
> > 	ret = nand_read_page_op(chip, data_offs, bufpoi + data_offs,
> > 				readlen);
> > 	if (ret)
> > 		return ret;
> > 		
> >   
> >> +
> >> +	return toshiba_nand_benand_status_chk(mtd, chip);
> >> +}
> >> +
> >> +static void toshiba_nand_benand_init(struct nand_chip *chip)
> >> +{
> >> +	struct mtd_info *mtd = nand_to_mtd(chip);
> >> +
> >> +	/*
> >> +	 * On BENAND, the entire OOB region can be used by the MTD user.
> >> +	 * The calculated ECC bytes are stored into other isolated
> >> +	 * area which is not accessible to users.
> >> +	 * This is why chip->ecc.bytes = 0.
> >> +	 */
> >> +	chip->ecc.bytes = 0;
> >> +	chip->ecc.size = 512;
> >> +	chip->ecc.strength = 8;
> >> +	chip->ecc.read_page = toshiba_nand_read_page_benand;
> >> +	chip->ecc.read_subpage = toshiba_nand_read_subpage_benand;
> >> +	chip->ecc.write_page = nand_write_page_raw;
> >> +	chip->ecc.read_page_raw = nand_read_page_raw;
> >> +	chip->ecc.write_page_raw = nand_write_page_raw;
> >> +
> >> +	chip->options |= NAND_SUBPAGE_READ;
> >> +
> >> +	mtd_set_ooblayout(mtd, &nand_ooblayout_lp_ops);
> >> +}
> >> +
> >>  static void toshiba_nand_decode_id(struct nand_chip *chip)
> >>  {
> >>  	struct mtd_info *mtd = nand_to_mtd(chip);
> >> @@ -70,6 +155,10 @@ static int toshiba_nand_init(struct nand_chip *chip)
> >>  	if (nand_is_slc(chip))
> >>  		chip->bbt_options |= NAND_BBT_SCAN2NDPAGE;
> >>  
> >> +	if (nand_is_slc(chip) && (chip->id.data[4] & 0x80) /* BENAND */ &&
> >> +	    (chip->ecc.mode == NAND_ECC_ON_DIE))
> >> +		toshiba_nand_benand_init(chip);
> >> +  
> > 
> > Please move this block to toshiba_nand_init().
> >   
> >>  	return 0;
> >>  }
> >>    
> > 
> > 
> >   
>