[PATCH v2] spi: spi-qpic-snand: fix calculating of ECC OOB regions' properties

[PATCH v2] spi: spi-qpic-snand: fix calculating of ECC OOB regions' properties

[Gabor Juhos]

The OOB layout used by the driver has two distinct regions which contains
hardware specific ECC data, yet the qcom_spi_ooblayout_ecc() function sets
the same offset and length values for both regions which is clearly wrong.

Change the code to calculate the correct values for both regions.

For reference, the following table shows the computed offset and length
values for various OOB size/ECC strength configurations:

                              +-----------------+-----------------+
                              |before the change| after the change|
  +-------+----------+--------+--------+--------+--------+--------+
  |  OOB  |   ECC    | region | region | region | region | region |
  |  size | strength | index  | offset | length | offset | length |
  +-------+----------+--------+--------+--------+--------+--------+
  |  128  |     8    |    0   |   113  |   15   |    0   |   49   |
  |       |          |    1   |   113  |   15   |   65   |   63   |
  +-------+----------+--------+--------+--------+--------+--------+
  |  128  |     4    |    0   |   117  |   11   |    0   |   37   |
  |       |          |    1   |   117  |   11   |   53   |   75   |
  +-------+----------+--------+--------+--------+--------+--------+
  |   64  |     4    |    0   |    53  |   11   |    0   |   37   |
  |       |          |    1   |    53  |   11   |   53   |   11   |
  +-------+----------+--------+--------+--------+--------+--------+

Fixes: 7304d1909080 ("spi: spi-qpic: add driver for QCOM SPI NAND flash Interface")
Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
---
Changes in v2:
  - use switch statement to handle section numbers
  - reject negative section numbers as out-of-range
  - Link to v1: https://lore.kernel.org/r/20250731-qpic-snand-oob-ecc-fix-v1-1-29ba1c6f94e5@gmail.com
---
 drivers/spi/spi-qpic-snand.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-qpic-snand.c b/drivers/spi/spi-qpic-snand.c
index 0cfa0d960fd3c245c2bbf4f5e02d0fc0b13e7696..53205d5037dc4fd58a69063532b20ab10c652694 100644
--- a/drivers/spi/spi-qpic-snand.c
+++ b/drivers/spi/spi-qpic-snand.c
@@ -210,13 +210,21 @@ static int qcom_spi_ooblayout_ecc(struct mtd_info *mtd, int section,
 	struct qcom_nand_controller *snandc = nand_to_qcom_snand(nand);
 	struct qpic_ecc *qecc = snandc->qspi->ecc;
 
-	if (section > 1)
-		return -ERANGE;
-
-	oobregion->length = qecc->ecc_bytes_hw + qecc->spare_bytes;
-	oobregion->offset = mtd->oobsize - oobregion->length;
+	switch (section) {
+	case 0:
+		oobregion->offset = 0;
+		oobregion->length = qecc->bytes * (qecc->steps - 1) +
+				    qecc->bbm_size;
+		return 0;
+	case 1:
+		oobregion->offset = qecc->bytes * (qecc->steps - 1) +
+				    qecc->bbm_size +
+				    qecc->steps * 4;
+		oobregion->length = mtd->oobsize - oobregion->offset;
+		return 0;
+	}
 
-	return 0;
+	return -ERANGE;
 }
 
 static int qcom_spi_ooblayout_free(struct mtd_info *mtd, int section,

---
base-commit: 926406a85ad895fbe6ee4577cdbc4f55245a0742
change-id: 20250731-qpic-snand-oob-ecc-fix-8d3d80cc8680

Best regards,
-- 
Gabor Juhos <j4g8y7@gmail.com>


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Re: [PATCH v2] spi: spi-qpic-snand: fix calculating of ECC OOB regions' properties

[Konrad Dybcio]

On 8/5/25 6:05 PM, Gabor Juhos wrote:
> The OOB layout used by the driver has two distinct regions which contains
> hardware specific ECC data, yet the qcom_spi_ooblayout_ecc() function sets
> the same offset and length values for both regions which is clearly wrong.
> 
> Change the code to calculate the correct values for both regions.
> 
> For reference, the following table shows the computed offset and length
> values for various OOB size/ECC strength configurations:
> 
>                               +-----------------+-----------------+
>                               |before the change| after the change|
>   +-------+----------+--------+--------+--------+--------+--------+
>   |  OOB  |   ECC    | region | region | region | region | region |
>   |  size | strength | index  | offset | length | offset | length |
>   +-------+----------+--------+--------+--------+--------+--------+
>   |  128  |     8    |    0   |   113  |   15   |    0   |   49   |
>   |       |          |    1   |   113  |   15   |   65   |   63   |
>   +-------+----------+--------+--------+--------+--------+--------+
>   |  128  |     4    |    0   |   117  |   11   |    0   |   37   |
>   |       |          |    1   |   117  |   11   |   53   |   75   |
>   +-------+----------+--------+--------+--------+--------+--------+
>   |   64  |     4    |    0   |    53  |   11   |    0   |   37   |
>   |       |          |    1   |    53  |   11   |   53   |   11   |
>   +-------+----------+--------+--------+--------+--------+--------+
> 
> Fixes: 7304d1909080 ("spi: spi-qpic: add driver for QCOM SPI NAND flash Interface")
> Signed-off-by: Gabor Juhos <j4g8y7@gmail.com>
> ---

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>

Konrad

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Re: [PATCH v2] spi: spi-qpic-snand: fix calculating of ECC OOB regions' properties

[Mark Brown]

On Tue, 05 Aug 2025 18:05:42 +0200, Gabor Juhos wrote:
> The OOB layout used by the driver has two distinct regions which contains
> hardware specific ECC data, yet the qcom_spi_ooblayout_ecc() function sets
> the same offset and length values for both regions which is clearly wrong.
> 
> Change the code to calculate the correct values for both regions.
> 
> For reference, the following table shows the computed offset and length
> values for various OOB size/ECC strength configurations:
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/1] spi: spi-qpic-snand: fix calculating of ECC OOB regions' properties
      commit: 13d0fe84a214658254a7412b2b46ec1507dc51f0

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark


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