[1/3,v2] mtd/nand: add ooblayout for old hamming layout

Message ID 20170502081323.3138-2-lynxis@fe80.eu
State New
Headers show
Series
  • fixing 1bit hamming
Related show

Commit Message

Alexander Couzens May 2, 2017, 8:13 a.m.
The old 1bit hamming layout requires the ecc data to be exact at
predefined offsets. This can not changed because old installations
would break.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>

---
 drivers/mtd/nand/nand_base.c | 71 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/mtd/nand.h     |  1 +
 2 files changed, 72 insertions(+)

-- 
2.12.2


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Comments

Boris Brezillon May 2, 2017, 8:41 a.m. | #1
On Tue,  2 May 2017 10:13:21 +0200
Alexander Couzens <lynxis@fe80.eu> wrote:

> The old 1bit hamming layout requires the ecc data to be exact at

> predefined offsets.


"
The old 1-bit hamming layout requires ECC data to be placed at a
fixed offset, and not necessarily at the end of the OOB area.
"

> This can not changed because old installations

> would break.


"
Add this old layout back in order to fix legacy setup.
"

> 

> Signed-off-by: Alexander Couzens <lynxis@fe80.eu>


You should probably add Fixes and Cc:stable tags.

> ---

>  drivers/mtd/nand/nand_base.c | 71 ++++++++++++++++++++++++++++++++++++++++++++

>  include/linux/mtd/nand.h     |  1 +

>  2 files changed, 72 insertions(+)

> 

> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c

> index b0524f8accb6..daf3df157885 100644

> --- a/drivers/mtd/nand/nand_base.c

> +++ b/drivers/mtd/nand/nand_base.c

> @@ -139,6 +139,77 @@ const struct mtd_ooblayout_ops nand_ooblayout_lp_ops = {

>  };

>  EXPORT_SYMBOL_GPL(nand_ooblayout_lp_ops);

>  

> +/* support the old large page layout for Hamming 1 bit where the ECC start at

> + * a defined offset.


Please use regular comment style:

/*
 * <content>
 */

s/support/Support/

BTW, I'm not sure I understand this sentence. How about

"
Support the old "large page" layout used for 1-bit Hamming ECC where ECC
are placed at a fixed offset.
"

> Should only used by old devices to compatible with old

> + * layout. Use nand_ooblayout_lp_ops if possible.

> + */

> +static int nand_ooblayout_ecc_lp_hamming(struct mtd_info *mtd, int section,

> +				 struct mtd_oob_region *oobregion)

> +{

> +	struct nand_chip *chip = mtd_to_nand(mtd);

> +	struct nand_ecc_ctrl *ecc = &chip->ecc;

> +

> +	if (section)

> +		return -ERANGE;

> +

> +	switch (mtd->oobsize) {

> +	case 64:

> +		oobregion->offset = 40;

> +		break;

> +	case 128:

> +		oobregion->offset = 80;

> +		break;

> +	default:

> +		return -ERANGE;


Hm, can you return -EINVAL instead?

> +	}

> +

> +	oobregion->length = ecc->total;

> +	if (oobregion->offset + oobregion->length > mtd->oobsize)

> +		return -ERANGE;

> +

> +	return 0;

> +}

> +

> +static int nand_ooblayout_free_lp_hamming(struct mtd_info *mtd, int section,

> +				  struct mtd_oob_region *oobregion)

> +{

> +	struct nand_chip *chip = mtd_to_nand(mtd);

> +	struct nand_ecc_ctrl *ecc = &chip->ecc;

> +	int ecc_offset = 0;

> +

> +	if (section < 0 || section > 1)

> +		return -ERANGE;

> +

> +	switch (mtd->oobsize) {

> +	case 64:

> +		ecc_offset = 40;

> +		break;

> +	case 128:

> +		ecc_offset = 80;

> +		break;

> +	default:

> +		return -ERANGE;


Ditto.

> +	}

> +

> +	if (section == 0) {

> +		/* return the space before the ecc */


Not sure this comment is needed, it's pretty obvious that this section
is placed before the ECC bytes (and after the BBM).

> +		oobregion->offset = 2;

> +		oobregion->length = ecc_offset - 2;

> +	} else { /* section == 1 */


Drop this comment.

> +		/* return free space after ecc */


Ditto.

> +		oobregion->offset = ecc_offset + ecc->total;

> +		oobregion->length = mtd->oobsize - oobregion->offset;

> +	}

> +

> +	return 0;

> +}

> +

> +const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = {

> +	.ecc = nand_ooblayout_ecc_lp_hamming,

> +	.free = nand_ooblayout_free_lp_hamming,

> +};

> +EXPORT_SYMBOL_GPL(nand_ooblayout_lp_hamming_ops);

> +

>  static int check_offs_len(struct mtd_info *mtd,

>  					loff_t ofs, uint64_t len)

>  {

> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h

> index 9591e0fbe5bd..da33933950a5 100644

> --- a/include/linux/mtd/nand.h

> +++ b/include/linux/mtd/nand.h

> @@ -914,6 +914,7 @@ struct nand_chip {

>  

>  extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;

>  extern const struct mtd_ooblayout_ops nand_ooblayout_lp_ops;

> +extern const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops;

>  

>  static inline void nand_set_flash_node(struct nand_chip *chip,

>  				       struct device_node *np)



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Boris Brezillon May 2, 2017, 8:57 a.m. | #2
Just a nit, I prefer "mtd: nand: " instead of "mtd/nand: ", and since
you have to send a v3 anyway, I thought it wouldn't be a problem to
mention that ;-).

On Tue,  2 May 2017 10:13:21 +0200
Alexander Couzens <lynxis@fe80.eu> wrote:

> The old 1bit hamming layout requires the ecc data to be exact at

> predefined offsets. This can not changed because old installations

> would break.

> 

> Signed-off-by: Alexander Couzens <lynxis@fe80.eu>

> ---

>  drivers/mtd/nand/nand_base.c | 71 ++++++++++++++++++++++++++++++++++++++++++++

>  include/linux/mtd/nand.h     |  1 +

>  2 files changed, 72 insertions(+)

> 

> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c

> index b0524f8accb6..daf3df157885 100644

> --- a/drivers/mtd/nand/nand_base.c

> +++ b/drivers/mtd/nand/nand_base.c

> @@ -139,6 +139,77 @@ const struct mtd_ooblayout_ops nand_ooblayout_lp_ops = {

>  };

>  EXPORT_SYMBOL_GPL(nand_ooblayout_lp_ops);

>  

> +/* support the old large page layout for Hamming 1 bit where the ECC start at

> + * a defined offset. Should only used by old devices to compatible with old

> + * layout. Use nand_ooblayout_lp_ops if possible.

> + */

> +static int nand_ooblayout_ecc_lp_hamming(struct mtd_info *mtd, int section,

> +				 struct mtd_oob_region *oobregion)


Another nit: try to align arguments to the open parenthesis when
possible.

> +{

> +	struct nand_chip *chip = mtd_to_nand(mtd);

> +	struct nand_ecc_ctrl *ecc = &chip->ecc;

> +

> +	if (section)

> +		return -ERANGE;

> +

> +	switch (mtd->oobsize) {

> +	case 64:

> +		oobregion->offset = 40;

> +		break;

> +	case 128:

> +		oobregion->offset = 80;

> +		break;

> +	default:

> +		return -ERANGE;

> +	}

> +

> +	oobregion->length = ecc->total;

> +	if (oobregion->offset + oobregion->length > mtd->oobsize)

> +		return -ERANGE;

> +

> +	return 0;

> +}

> +

> +static int nand_ooblayout_free_lp_hamming(struct mtd_info *mtd, int section,

> +				  struct mtd_oob_region *oobregion)


Ditto.

> +{

> +	struct nand_chip *chip = mtd_to_nand(mtd);

> +	struct nand_ecc_ctrl *ecc = &chip->ecc;

> +	int ecc_offset = 0;

> +

> +	if (section < 0 || section > 1)

> +		return -ERANGE;

> +

> +	switch (mtd->oobsize) {

> +	case 64:

> +		ecc_offset = 40;

> +		break;

> +	case 128:

> +		ecc_offset = 80;

> +		break;

> +	default:

> +		return -ERANGE;

> +	}

> +

> +	if (section == 0) {

> +		/* return the space before the ecc */

> +		oobregion->offset = 2;

> +		oobregion->length = ecc_offset - 2;

> +	} else { /* section == 1 */

> +		/* return free space after ecc */

> +		oobregion->offset = ecc_offset + ecc->total;

> +		oobregion->length = mtd->oobsize - oobregion->offset;

> +	}

> +

> +	return 0;

> +}

> +

> +const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = {

> +	.ecc = nand_ooblayout_ecc_lp_hamming,

> +	.free = nand_ooblayout_free_lp_hamming,

> +};

> +EXPORT_SYMBOL_GPL(nand_ooblayout_lp_hamming_ops);


Please do not export symbols if it's not really needed.

> +

>  static int check_offs_len(struct mtd_info *mtd,

>  					loff_t ofs, uint64_t len)

>  {

> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h

> index 9591e0fbe5bd..da33933950a5 100644

> --- a/include/linux/mtd/nand.h

> +++ b/include/linux/mtd/nand.h

> @@ -914,6 +914,7 @@ struct nand_chip {

>  

>  extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;

>  extern const struct mtd_ooblayout_ops nand_ooblayout_lp_ops;

> +extern const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops;


Drop that line too.

>  

>  static inline void nand_set_flash_node(struct nand_chip *chip,

>  				       struct device_node *np)



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diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index b0524f8accb6..daf3df157885 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -139,6 +139,77 @@  const struct mtd_ooblayout_ops nand_ooblayout_lp_ops = {
 };
 EXPORT_SYMBOL_GPL(nand_ooblayout_lp_ops);
 
+/* support the old large page layout for Hamming 1 bit where the ECC start at
+ * a defined offset. Should only used by old devices to compatible with old
+ * layout. Use nand_ooblayout_lp_ops if possible.
+ */
+static int nand_ooblayout_ecc_lp_hamming(struct mtd_info *mtd, int section,
+				 struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+
+	if (section)
+		return -ERANGE;
+
+	switch (mtd->oobsize) {
+	case 64:
+		oobregion->offset = 40;
+		break;
+	case 128:
+		oobregion->offset = 80;
+		break;
+	default:
+		return -ERANGE;
+	}
+
+	oobregion->length = ecc->total;
+	if (oobregion->offset + oobregion->length > mtd->oobsize)
+		return -ERANGE;
+
+	return 0;
+}
+
+static int nand_ooblayout_free_lp_hamming(struct mtd_info *mtd, int section,
+				  struct mtd_oob_region *oobregion)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct nand_ecc_ctrl *ecc = &chip->ecc;
+	int ecc_offset = 0;
+
+	if (section < 0 || section > 1)
+		return -ERANGE;
+
+	switch (mtd->oobsize) {
+	case 64:
+		ecc_offset = 40;
+		break;
+	case 128:
+		ecc_offset = 80;
+		break;
+	default:
+		return -ERANGE;
+	}
+
+	if (section == 0) {
+		/* return the space before the ecc */
+		oobregion->offset = 2;
+		oobregion->length = ecc_offset - 2;
+	} else { /* section == 1 */
+		/* return free space after ecc */
+		oobregion->offset = ecc_offset + ecc->total;
+		oobregion->length = mtd->oobsize - oobregion->offset;
+	}
+
+	return 0;
+}
+
+const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops = {
+	.ecc = nand_ooblayout_ecc_lp_hamming,
+	.free = nand_ooblayout_free_lp_hamming,
+};
+EXPORT_SYMBOL_GPL(nand_ooblayout_lp_hamming_ops);
+
 static int check_offs_len(struct mtd_info *mtd,
 					loff_t ofs, uint64_t len)
 {
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 9591e0fbe5bd..da33933950a5 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -914,6 +914,7 @@  struct nand_chip {
 
 extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;
 extern const struct mtd_ooblayout_ops nand_ooblayout_lp_ops;
+extern const struct mtd_ooblayout_ops nand_ooblayout_lp_hamming_ops;
 
 static inline void nand_set_flash_node(struct nand_chip *chip,
 				       struct device_node *np)