Hi Boris,

On 19-07-29 09:57, Boris Brezillon wrote:

On Mon, 29 Jul 2019 09:06:52 +0200 Marco Felsch m.felsch@pengutronix.de wrote:

...

Some devices are supposed to do not support on-die ECC but experience

^ are not supposed to support

Fixed both, thanks. I will keep you rb-tag okay?

Regards, Marco

...

shows that internal ECC machinery can actually be enabled through the "SET FEATURE (EFh)" command, even if a read of the "READ ID Parameter Tables" returns that it is not.

Currently, the driver checks the "READ ID Parameter" field directly after having enabled the feature. If the check fails it returns immediately but leaves the ECC on. When using buggy chips like MT29F2G08ABAGA and MT29F2G08ABBGA, all future read/program cycles will go through the on-die ECC, confusing the host controller which is supposed to be the one handling correction.

To address this in a common way we need to turn off the on-die ECC directly after reading the "READ ID Parameter" and before checking the "ECC status".

Cc: stable@vger.kernel.org Fixes: dbc44edbf833 ("mtd: rawnand: micron: Fix on-die ECC detection logic") Signed-off-by: Marco Felsch m.felsch@pengutronix.de Reviewed-by: Boris Brezillon boris.brezillon@collabora.com

---

v2:

• adapt commit message according Miquel comments
• add fixes, stable tags
• add Boris rb-tag

drivers/mtd/nand/raw/nand_micron.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_micron.c b/drivers/mtd/nand/raw/nand_micron.c index 1622d3145587..fb199ad2f1a6 100644 --- a/drivers/mtd/nand/raw/nand_micron.c +++ b/drivers/mtd/nand/raw/nand_micron.c @@ -390,6 +390,14 @@ static int micron_supports_on_die_ecc(struct nand_chip *chip) (chip->id.data[4] & MICRON_ID_INTERNAL_ECC_MASK) != 0x2) return MICRON_ON_DIE_UNSUPPORTED;

• /*

• * It seems that there are devices which do not support ECC official.
  

						    ^officially.

...

• * At least the MT29F2G08ABAGA / MT29F2G08ABBGA devices supports
  

• * enabling the ECC feature but don't reflect that to the READ_ID table.
  

• * So we have to guarantee that we disable the ECC feature directly
  

• * after we did the READ_ID table command. Later we can evaluate the
  

• * ECC_ENABLE support.
  

• */
  

  ret = micron_nand_on_die_ecc_setup(chip, true); if (ret) return MICRON_ON_DIE_UNSUPPORTED;

@@ -398,13 +406,13 @@ static int micron_supports_on_die_ecc(struct nand_chip *chip) if (ret) return MICRON_ON_DIE_UNSUPPORTED;

• if (!(id[4] & MICRON_ID_ECC_ENABLED))

• return MICRON_ON_DIE_UNSUPPORTED;
  

• ret = micron_nand_on_die_ecc_setup(chip, false); if (ret) return MICRON_ON_DIE_UNSUPPORTED;

• if (!(id[4] & MICRON_ID_ECC_ENABLED))

• return MICRON_ON_DIE_UNSUPPORTED;
  

• ret = nand_readid_op(chip, 0, id, sizeof(id)); if (ret) return MICRON_ON_DIE_UNSUPPORTED;