Re: [PATCH] - change calculating of position page containing BBM

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Hello

The 09/19/2019 13:33, Schrempf Frieder wrote:
EXTERNAL MAIL


On 19.09.19 15:18, Miquel Raynal wrote:
Hello,

Schrempf Frieder <frieder.schrempf@xxxxxxxxxx> wrote on Thu, 19 Sep
2019 13:15:08 +0000:

On 19.09.19 14:58, Miquel Raynal wrote:
Hi Piotr,

Piotr Sroka <piotrs@xxxxxxxxxxx> wrote on Thu, 19 Sep 2019 13:41:35
+0100:

Change calculating of position page containing BBM

If none of BBM flags is set then function nand_bbm_get_next_page
reports EINVAL. It causes that BBM is not read at all during scanning
factory bad blocks. The result is that the BBT table is build without
checking factory BBM at all. For Micron flash memories none of this
flag is set if page size is different than 2048 bytes.

I wonder if it wouldn't be better to fix the Micron driver instead:

--- a/drivers/mtd/nand/raw/nand_micron.c
+++ b/drivers/mtd/nand/raw/nand_micron.c
@@ -448,6 +448,8 @@ static int micron_nand_init(struct nand_chip *chip)

          if (mtd->writesize == 2048)
                  chip->options |= NAND_BBM_FIRSTPAGE |
                                   NAND_BBM_SECONDPAGE;
+       else
+               chip->options |= NAND_BBM_FIRSTPAGE;

That's what I forgot in my last answer to this thread, I think I only
told Piotr privately: I would like both. I think it is important to fix
the bbm_get_next_page function but for clarity, setting the FIRSTPAGE
flag in Micron's driver seems also pertinent.

Indeed, that sounds reasonable. Piotr, can you send another patch with
the diff above? And by the way: thanks for fixing my code ;)

Reviewed-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>

Thanks Frieder and Miquel for the very quick reply. I will send next
version containing Micron driver fix.



          ondie = micron_supports_on_die_ecc(chip);



"none of these flags are set"


This patch changes the nand_bbm_get_next_page function.

"Address this regression by changing the
nand_bbm_get_next_page_function."

It will return 0 if none of BBM flag is set and page parameter is 0.

                        no BBM flag is set

After that modification way of discovering factory bad blocks will work
similar as in kernel version 5.1.


Fixes + stable tags would be great!
Ok I will add fixes tag and "Cc: <stable@xxxxxxxxxxxxxxx>".

Signed-off-by: Piotr Sroka <piotrs@xxxxxxxxxxx>
---
   drivers/mtd/nand/raw/nand_base.c | 8 ++++++--
   1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c
index 5c2c30a7dffa..f64e3b6605c6 100644
--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -292,12 +292,16 @@ int nand_bbm_get_next_page(struct nand_chip *chip, int page)
   	struct mtd_info *mtd = nand_to_mtd(chip);
   	int last_page = ((mtd->erasesize - mtd->writesize) >>
   			 chip->page_shift) & chip->pagemask;
+	unsigned int bbm_flags = NAND_BBM_FIRSTPAGE | NAND_BBM_SECONDPAGE
+		| NAND_BBM_LASTPAGE;

+	if (page == 0 && !(chip->options & bbm_flags))
+		return 0;
   	if (page == 0 && chip->options & NAND_BBM_FIRSTPAGE)
   		return 0;
-	else if (page <= 1 && chip->options & NAND_BBM_SECONDPAGE)
+	if (page <= 1 && chip->options & NAND_BBM_SECONDPAGE)
   		return 1;
-	else if (page <= last_page && chip->options & NAND_BBM_LASTPAGE)
+	if (page <= last_page && chip->options & NAND_BBM_LASTPAGE)
   		return last_page;

   	return -EINVAL;

Lookgs good otherwise.

Thanks,
Miquèl


Thanks,
Miquèl


Thanks,
Piotr

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