[1/4] mtd: nand: Drop busw variable and use chip->options field

Message ID 20220713071637.275456-1-michael@amarulasolutions.com
State New
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Series
  • [1/4] mtd: nand: Drop busw variable and use chip->options field
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Commit Message

Michael Nazzareno Trimarchi July 13, 2022, 7:16 a.m. UTC
No functional change. Reduce the function parameters in preparation
of support specific nand manufacture

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
---
 drivers/mtd/nand/raw/nand_base.c | 58 ++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 26 deletions(-)

Comments

Dario Binacchi July 13, 2022, 10:18 a.m. UTC | #1
Hi Michael,

On Wed, Jul 13, 2022 at 9:16 AM Michael Trimarchi
<michael@amarulasolutions.com> wrote:
>
> No functional change. Reduce the function parameters in preparation
> of support specific nand manufacture
>
> Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
> ---
>  drivers/mtd/nand/raw/nand_base.c | 58 ++++++++++++++++++--------------
>  1 file changed, 32 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> index 6f81257cf1..cb22e0ec13 100644
> --- a/drivers/mtd/nand/raw/nand_base.c
> +++ b/drivers/mtd/nand/raw/nand_base.c
> @@ -3890,8 +3890,7 @@ static void nand_onfi_detect_micron(struct nand_chip *chip,
>  /*
>   * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
>   */
> -static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> -                                       int *busw)
> +static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
>  {
>         struct nand_onfi_params *p = &chip->onfi_params;
>         char id[4];
> @@ -3963,9 +3962,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
>         chip->bits_per_cell = p->bits_per_cell;
>
>         if (onfi_feature(chip) & ONFI_FEATURE_16_BIT_BUS)
> -               *busw = NAND_BUSWIDTH_16;
> -       else
> -               *busw = 0;
> +               chip->options |= NAND_BUSWIDTH_16;
>
>         if (p->ecc_bits != 0xff) {
>                 chip->ecc_strength_ds = p->ecc_bits;
> @@ -3995,8 +3992,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
>         return 1;
>  }
>  #else
> -static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> -                                       int *busw)
> +static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
>  {
>         return 0;
>  }
> @@ -4005,8 +4001,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
>  /*
>   * Check if the NAND chip is JEDEC compliant, returns 1 if it is, 0 otherwise.
>   */
> -static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
> -                                       int *busw)
> +static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip)
>  {
>         struct nand_jedec_params *p = &chip->jedec_params;
>         struct jedec_ecc_info *ecc;
> @@ -4068,9 +4063,7 @@ static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
>         chip->bits_per_cell = p->bits_per_cell;
>
>         if (jedec_feature(chip) & JEDEC_FEATURE_16_BIT_BUS)
> -               *busw = NAND_BUSWIDTH_16;
> -       else
> -               *busw = 0;
> +               chip->options |= NAND_BUSWIDTH_16;
>
>         /* ECC info */
>         ecc = &p->ecc_info[0];
> @@ -4160,7 +4153,7 @@ static int nand_get_bits_per_cell(u8 cellinfo)
>   * manufacturer-specific "extended ID" decoding patterns.
>   */
>  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> -                               u8 id_data[8], int *busw)
> +                               u8 id_data[8])
>  {
>         int extid, id_len;
>         /* The 3rd id byte holds MLC / multichip data */
> @@ -4213,7 +4206,6 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>                 /* Calc blocksize */
>                 mtd->erasesize = (128 * 1024) <<
>                         (((extid >> 1) & 0x04) | (extid & 0x03));
> -               *busw = 0;
>         } else if (id_len == 6 && id_data[0] == NAND_MFR_HYNIX &&
>                         !nand_is_slc(chip)) {
>                 unsigned int tmp;
> @@ -4254,7 +4246,6 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>                         mtd->erasesize = 768 * 1024;
>                 else
>                         mtd->erasesize = (64 * 1024) << tmp;
> -               *busw = 0;
>         } else {
>                 /* Calc pagesize */
>                 mtd->writesize = 1024 << (extid & 0x03);
> @@ -4267,7 +4258,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>                 mtd->erasesize = (64 * 1024) << (extid & 0x03);
>                 extid >>= 2;
>                 /* Get buswidth information */
> -               *busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
> +               chip->options |= (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
>
>                 /*
>                  * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
> @@ -4293,15 +4284,14 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
>   * the chip.
>   */
>  static void nand_decode_id(struct mtd_info *mtd, struct nand_chip *chip,
> -                               struct nand_flash_dev *type, u8 id_data[8],
> -                               int *busw)
> +                               struct nand_flash_dev *type, u8 id_data[8])
>  {
>         int maf_id = id_data[0];
>
>         mtd->erasesize = type->erasesize;
>         mtd->writesize = type->pagesize;
>         mtd->oobsize = mtd->writesize / 32;
> -       *busw = type->options & NAND_BUSWIDTH_16;
> +       chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
>
>         /* All legacy ID NAND are small-page, SLC */
>         chip->bits_per_cell = 1;
> @@ -4363,7 +4353,7 @@ static inline bool is_full_id_nand(struct nand_flash_dev *type)
>  }
>
>  static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
> -                  struct nand_flash_dev *type, u8 *id_data, int *busw)
> +                  struct nand_flash_dev *type, u8 *id_data)
>  {
>         if (!strncmp((char *)type->id, (char *)id_data, type->id_len)) {
>                 mtd->writesize = type->pagesize;
> @@ -4378,7 +4368,7 @@ static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
>                 chip->onfi_timing_mode_default =
>                                         type->onfi_timing_mode_default;
>
> -               *busw = type->options & NAND_BUSWIDTH_16;
> +               chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
>
>                 if (!mtd->name)
>                         mtd->name = type->name;
> @@ -4441,9 +4431,24 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
>         if (!type)
>                 type = nand_flash_ids;
>
> +       /*
> +        * Save the NAND_BUSWIDTH_16 flag before letting auto-detection logic
> +        * override it.
> +        * This is required to make sure initial NAND bus width set by the
> +        * NAND controller driver is coherent with the real NAND bus width
> +        * (extracted by auto-detection code).
> +        */
> +       busw = chip->options & NAND_BUSWIDTH_16;
> +
> +       /*
> +        * The flag is only set (never cleared), reset it to its default value
> +        * before starting auto-detection.
> +        */
> +       chip->options &= ~NAND_BUSWIDTH_16;

Isn't it better and safer that functions can also reset the bit?
As was the case before.

Dario

> +
>         for (; type->name != NULL; type++) {
>                 if (is_full_id_nand(type)) {
> -                       if (find_full_id_nand(mtd, chip, type, id_data, &busw))
> +                       if (find_full_id_nand(mtd, chip, type, id_data))
>                                 goto ident_done;
>                 } else if (*dev_id == type->dev_id) {
>                         break;
> @@ -4453,11 +4458,11 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
>         chip->onfi_version = 0;
>         if (!type->name || !type->pagesize) {
>                 /* Check if the chip is ONFI compliant */
> -               if (nand_flash_detect_onfi(mtd, chip, &busw))
> +               if (nand_flash_detect_onfi(mtd, chip))
>                         goto ident_done;
>
>                 /* Check if the chip is JEDEC compliant */
> -               if (nand_flash_detect_jedec(mtd, chip, &busw))
> +               if (nand_flash_detect_jedec(mtd, chip))
>                         goto ident_done;
>         }
>
> @@ -4471,10 +4476,11 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
>
>         if (!type->pagesize) {
>                 /* Decode parameters from extended ID */
> -               nand_decode_ext_id(mtd, chip, id_data, &busw);
> +               nand_decode_ext_id(mtd, chip, id_data);
>         } else {
> -               nand_decode_id(mtd, chip, type, id_data, &busw);
> +               nand_decode_id(mtd, chip, type, id_data);
>         }
> +
>         /* Get chip options */
>         chip->options |= type->options;
>
> --
> 2.34.1
>
Michael Nazzareno Trimarchi July 13, 2022, 10:37 a.m. UTC | #2
Hi

On Wed, Jul 13, 2022 at 12:18 PM Dario Binacchi
<dario.binacchi@amarulasolutions.com> wrote:
>
> Hi Michael,
>
> On Wed, Jul 13, 2022 at 9:16 AM Michael Trimarchi
> <michael@amarulasolutions.com> wrote:
> >
> > No functional change. Reduce the function parameters in preparation
> > of support specific nand manufacture
> >
> > Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
> > ---
> >  drivers/mtd/nand/raw/nand_base.c | 58 ++++++++++++++++++--------------
> >  1 file changed, 32 insertions(+), 26 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
> > index 6f81257cf1..cb22e0ec13 100644
> > --- a/drivers/mtd/nand/raw/nand_base.c
> > +++ b/drivers/mtd/nand/raw/nand_base.c
> > @@ -3890,8 +3890,7 @@ static void nand_onfi_detect_micron(struct nand_chip *chip,
> >  /*
> >   * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
> >   */
> > -static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> > -                                       int *busw)
> > +static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
> >  {
> >         struct nand_onfi_params *p = &chip->onfi_params;
> >         char id[4];
> > @@ -3963,9 +3962,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> >         chip->bits_per_cell = p->bits_per_cell;
> >
> >         if (onfi_feature(chip) & ONFI_FEATURE_16_BIT_BUS)
> > -               *busw = NAND_BUSWIDTH_16;
> > -       else
> > -               *busw = 0;
> > +               chip->options |= NAND_BUSWIDTH_16;
> >
> >         if (p->ecc_bits != 0xff) {
> >                 chip->ecc_strength_ds = p->ecc_bits;
> > @@ -3995,8 +3992,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> >         return 1;
> >  }
> >  #else
> > -static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> > -                                       int *busw)
> > +static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
> >  {
> >         return 0;
> >  }
> > @@ -4005,8 +4001,7 @@ static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
> >  /*
> >   * Check if the NAND chip is JEDEC compliant, returns 1 if it is, 0 otherwise.
> >   */
> > -static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
> > -                                       int *busw)
> > +static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip)
> >  {
> >         struct nand_jedec_params *p = &chip->jedec_params;
> >         struct jedec_ecc_info *ecc;
> > @@ -4068,9 +4063,7 @@ static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
> >         chip->bits_per_cell = p->bits_per_cell;
> >
> >         if (jedec_feature(chip) & JEDEC_FEATURE_16_BIT_BUS)
> > -               *busw = NAND_BUSWIDTH_16;
> > -       else
> > -               *busw = 0;
> > +               chip->options |= NAND_BUSWIDTH_16;
> >
> >         /* ECC info */
> >         ecc = &p->ecc_info[0];
> > @@ -4160,7 +4153,7 @@ static int nand_get_bits_per_cell(u8 cellinfo)
> >   * manufacturer-specific "extended ID" decoding patterns.
> >   */
> >  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> > -                               u8 id_data[8], int *busw)
> > +                               u8 id_data[8])
> >  {
> >         int extid, id_len;
> >         /* The 3rd id byte holds MLC / multichip data */
> > @@ -4213,7 +4206,6 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> >                 /* Calc blocksize */
> >                 mtd->erasesize = (128 * 1024) <<
> >                         (((extid >> 1) & 0x04) | (extid & 0x03));
> > -               *busw = 0;
> >         } else if (id_len == 6 && id_data[0] == NAND_MFR_HYNIX &&
> >                         !nand_is_slc(chip)) {
> >                 unsigned int tmp;
> > @@ -4254,7 +4246,6 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> >                         mtd->erasesize = 768 * 1024;
> >                 else
> >                         mtd->erasesize = (64 * 1024) << tmp;
> > -               *busw = 0;
> >         } else {
> >                 /* Calc pagesize */
> >                 mtd->writesize = 1024 << (extid & 0x03);
> > @@ -4267,7 +4258,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> >                 mtd->erasesize = (64 * 1024) << (extid & 0x03);
> >                 extid >>= 2;
> >                 /* Get buswidth information */
> > -               *busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
> > +               chip->options |= (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
> >
> >                 /*
> >                  * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
> > @@ -4293,15 +4284,14 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
> >   * the chip.
> >   */
> >  static void nand_decode_id(struct mtd_info *mtd, struct nand_chip *chip,
> > -                               struct nand_flash_dev *type, u8 id_data[8],
> > -                               int *busw)
> > +                               struct nand_flash_dev *type, u8 id_data[8])
> >  {
> >         int maf_id = id_data[0];
> >
> >         mtd->erasesize = type->erasesize;
> >         mtd->writesize = type->pagesize;
> >         mtd->oobsize = mtd->writesize / 32;
> > -       *busw = type->options & NAND_BUSWIDTH_16;
> > +       chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
> >
> >         /* All legacy ID NAND are small-page, SLC */
> >         chip->bits_per_cell = 1;
> > @@ -4363,7 +4353,7 @@ static inline bool is_full_id_nand(struct nand_flash_dev *type)
> >  }
> >
> >  static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
> > -                  struct nand_flash_dev *type, u8 *id_data, int *busw)
> > +                  struct nand_flash_dev *type, u8 *id_data)
> >  {
> >         if (!strncmp((char *)type->id, (char *)id_data, type->id_len)) {
> >                 mtd->writesize = type->pagesize;
> > @@ -4378,7 +4368,7 @@ static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
> >                 chip->onfi_timing_mode_default =
> >                                         type->onfi_timing_mode_default;
> >
> > -               *busw = type->options & NAND_BUSWIDTH_16;
> > +               chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
> >
> >                 if (!mtd->name)
> >                         mtd->name = type->name;
> > @@ -4441,9 +4431,24 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
> >         if (!type)
> >                 type = nand_flash_ids;
> >
> > +       /*
> > +        * Save the NAND_BUSWIDTH_16 flag before letting auto-detection logic
> > +        * override it.
> > +        * This is required to make sure initial NAND bus width set by the
> > +        * NAND controller driver is coherent with the real NAND bus width
> > +        * (extracted by auto-detection code).
> > +        */
> > +       busw = chip->options & NAND_BUSWIDTH_16;
> > +
> > +       /*
> > +        * The flag is only set (never cleared), reset it to its default value
> > +        * before starting auto-detection.
> > +        */
> > +       chip->options &= ~NAND_BUSWIDTH_16;
>
> Isn't it better and safer that functions can also reset the bit?
> As was the case before.
>

Yes, you are right

Michael

> Dario
>
> > +
> >         for (; type->name != NULL; type++) {
> >                 if (is_full_id_nand(type)) {
> > -                       if (find_full_id_nand(mtd, chip, type, id_data, &busw))
> > +                       if (find_full_id_nand(mtd, chip, type, id_data))
> >                                 goto ident_done;
> >                 } else if (*dev_id == type->dev_id) {
> >                         break;
> > @@ -4453,11 +4458,11 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
> >         chip->onfi_version = 0;
> >         if (!type->name || !type->pagesize) {
> >                 /* Check if the chip is ONFI compliant */
> > -               if (nand_flash_detect_onfi(mtd, chip, &busw))
> > +               if (nand_flash_detect_onfi(mtd, chip))
> >                         goto ident_done;
> >
> >                 /* Check if the chip is JEDEC compliant */
> > -               if (nand_flash_detect_jedec(mtd, chip, &busw))
> > +               if (nand_flash_detect_jedec(mtd, chip))
> >                         goto ident_done;
> >         }
> >
> > @@ -4471,10 +4476,11 @@ struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
> >
> >         if (!type->pagesize) {
> >                 /* Decode parameters from extended ID */
> > -               nand_decode_ext_id(mtd, chip, id_data, &busw);
> > +               nand_decode_ext_id(mtd, chip, id_data);
> >         } else {
> > -               nand_decode_id(mtd, chip, type, id_data, &busw);
> > +               nand_decode_id(mtd, chip, type, id_data);
> >         }
> > +
> >         /* Get chip options */
> >         chip->options |= type->options;
> >
> > --
> > 2.34.1
> >
>
>
> --
>
> Dario Binacchi
>
> Embedded Linux Developer
>
> dario.binacchi@amarulasolutions.com
>
> __________________________________
>
>
> Amarula Solutions SRL
>
> Via Le Canevare 30, 31100 Treviso, Veneto, IT
>
> T. +39 042 243 5310
> info@amarulasolutions.com
>
> www.amarulasolutions.com

Patch

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 6f81257cf1..cb22e0ec13 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -3890,8 +3890,7 @@  static void nand_onfi_detect_micron(struct nand_chip *chip,
 /*
  * Check if the NAND chip is ONFI compliant, returns 1 if it is, 0 otherwise.
  */
-static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
-					int *busw)
+static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
 {
 	struct nand_onfi_params *p = &chip->onfi_params;
 	char id[4];
@@ -3963,9 +3962,7 @@  static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 	chip->bits_per_cell = p->bits_per_cell;
 
 	if (onfi_feature(chip) & ONFI_FEATURE_16_BIT_BUS)
-		*busw = NAND_BUSWIDTH_16;
-	else
-		*busw = 0;
+		chip->options |= NAND_BUSWIDTH_16;
 
 	if (p->ecc_bits != 0xff) {
 		chip->ecc_strength_ds = p->ecc_bits;
@@ -3995,8 +3992,7 @@  static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 	return 1;
 }
 #else
-static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
-					int *busw)
+static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip)
 {
 	return 0;
 }
@@ -4005,8 +4001,7 @@  static int nand_flash_detect_onfi(struct mtd_info *mtd, struct nand_chip *chip,
 /*
  * Check if the NAND chip is JEDEC compliant, returns 1 if it is, 0 otherwise.
  */
-static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
-					int *busw)
+static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip)
 {
 	struct nand_jedec_params *p = &chip->jedec_params;
 	struct jedec_ecc_info *ecc;
@@ -4068,9 +4063,7 @@  static int nand_flash_detect_jedec(struct mtd_info *mtd, struct nand_chip *chip,
 	chip->bits_per_cell = p->bits_per_cell;
 
 	if (jedec_feature(chip) & JEDEC_FEATURE_16_BIT_BUS)
-		*busw = NAND_BUSWIDTH_16;
-	else
-		*busw = 0;
+		chip->options |= NAND_BUSWIDTH_16;
 
 	/* ECC info */
 	ecc = &p->ecc_info[0];
@@ -4160,7 +4153,7 @@  static int nand_get_bits_per_cell(u8 cellinfo)
  * manufacturer-specific "extended ID" decoding patterns.
  */
 static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
-				u8 id_data[8], int *busw)
+				u8 id_data[8])
 {
 	int extid, id_len;
 	/* The 3rd id byte holds MLC / multichip data */
@@ -4213,7 +4206,6 @@  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 		/* Calc blocksize */
 		mtd->erasesize = (128 * 1024) <<
 			(((extid >> 1) & 0x04) | (extid & 0x03));
-		*busw = 0;
 	} else if (id_len == 6 && id_data[0] == NAND_MFR_HYNIX &&
 			!nand_is_slc(chip)) {
 		unsigned int tmp;
@@ -4254,7 +4246,6 @@  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 			mtd->erasesize = 768 * 1024;
 		else
 			mtd->erasesize = (64 * 1024) << tmp;
-		*busw = 0;
 	} else {
 		/* Calc pagesize */
 		mtd->writesize = 1024 << (extid & 0x03);
@@ -4267,7 +4258,7 @@  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
 		mtd->erasesize = (64 * 1024) << (extid & 0x03);
 		extid >>= 2;
 		/* Get buswidth information */
-		*busw = (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
+		chip->options |= (extid & 0x01) ? NAND_BUSWIDTH_16 : 0;
 
 		/*
 		 * Toshiba 24nm raw SLC (i.e., not BENAND) have 32B OOB per
@@ -4293,15 +4284,14 @@  static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip,
  * the chip.
  */
 static void nand_decode_id(struct mtd_info *mtd, struct nand_chip *chip,
-				struct nand_flash_dev *type, u8 id_data[8],
-				int *busw)
+				struct nand_flash_dev *type, u8 id_data[8])
 {
 	int maf_id = id_data[0];
 
 	mtd->erasesize = type->erasesize;
 	mtd->writesize = type->pagesize;
 	mtd->oobsize = mtd->writesize / 32;
-	*busw = type->options & NAND_BUSWIDTH_16;
+	chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
 
 	/* All legacy ID NAND are small-page, SLC */
 	chip->bits_per_cell = 1;
@@ -4363,7 +4353,7 @@  static inline bool is_full_id_nand(struct nand_flash_dev *type)
 }
 
 static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
-		   struct nand_flash_dev *type, u8 *id_data, int *busw)
+		   struct nand_flash_dev *type, u8 *id_data)
 {
 	if (!strncmp((char *)type->id, (char *)id_data, type->id_len)) {
 		mtd->writesize = type->pagesize;
@@ -4378,7 +4368,7 @@  static bool find_full_id_nand(struct mtd_info *mtd, struct nand_chip *chip,
 		chip->onfi_timing_mode_default =
 					type->onfi_timing_mode_default;
 
-		*busw = type->options & NAND_BUSWIDTH_16;
+		chip->options |= (type->options & NAND_BUSWIDTH_16) ? NAND_BUSWIDTH_16 : 0;
 
 		if (!mtd->name)
 			mtd->name = type->name;
@@ -4441,9 +4431,24 @@  struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 	if (!type)
 		type = nand_flash_ids;
 
+	/*
+	 * Save the NAND_BUSWIDTH_16 flag before letting auto-detection logic
+	 * override it.
+	 * This is required to make sure initial NAND bus width set by the
+	 * NAND controller driver is coherent with the real NAND bus width
+	 * (extracted by auto-detection code).
+	 */
+	busw = chip->options & NAND_BUSWIDTH_16;
+
+	/*
+	 * The flag is only set (never cleared), reset it to its default value
+	 * before starting auto-detection.
+	 */
+	chip->options &= ~NAND_BUSWIDTH_16;
+
 	for (; type->name != NULL; type++) {
 		if (is_full_id_nand(type)) {
-			if (find_full_id_nand(mtd, chip, type, id_data, &busw))
+			if (find_full_id_nand(mtd, chip, type, id_data))
 				goto ident_done;
 		} else if (*dev_id == type->dev_id) {
 			break;
@@ -4453,11 +4458,11 @@  struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 	chip->onfi_version = 0;
 	if (!type->name || !type->pagesize) {
 		/* Check if the chip is ONFI compliant */
-		if (nand_flash_detect_onfi(mtd, chip, &busw))
+		if (nand_flash_detect_onfi(mtd, chip))
 			goto ident_done;
 
 		/* Check if the chip is JEDEC compliant */
-		if (nand_flash_detect_jedec(mtd, chip, &busw))
+		if (nand_flash_detect_jedec(mtd, chip))
 			goto ident_done;
 	}
 
@@ -4471,10 +4476,11 @@  struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
 
 	if (!type->pagesize) {
 		/* Decode parameters from extended ID */
-		nand_decode_ext_id(mtd, chip, id_data, &busw);
+		nand_decode_ext_id(mtd, chip, id_data);
 	} else {
-		nand_decode_id(mtd, chip, type, id_data, &busw);
+		nand_decode_id(mtd, chip, type, id_data);
 	}
+
 	/* Get chip options */
 	chip->options |= type->options;