Re: [PATCH 04/20] mtd: nand: ecc-bch: Stop exporting the private structure

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Adam,

Adam Ford <aford173@gmail.com> wrote on Sat, 9 Jan 2021 08:46:44 -0600:

> On Tue, Sep 29, 2020 at 6:09 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >
> > The NAND BCH control structure has nothing to do outside of this
> > driver, all users of the nand_bch_init/free() functions just save it
> > to chip->ecc.priv so do it in this driver directly and return a
> > regular error code instead.
> >
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---  
> 
> Starting with this commit:  3c0fe36abebe, the kernel either doesn't
> build or returns errors on some omap2plus devices with the following
> error:
> 
>     nand: device found, Manufacturer ID: 0x2c, Chip ID: 0xbc
>     nand: Micron MT29F4G16ABBDA3W
>     nand: 512 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
>     nand: using OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
>     Invalid ECC layout
>     omap2-nand 30000000.nand: unable to use BCH library
>     omap2-nand: probe of 30000000.nand failed with error -22
>     8<--- cut here ---
> 
> There are few commits using git bisect that have build errors, so it
> wasn't possible for me to determine the exact commit that broke the
> ECC.  If the build failed, I marked it as 'bad' to git bisect.

I am sorry to hear that, I regularly rebase with a make run between each
pick and push my branches to a 0-day repository to have robots check
for such errors, but sometimes I fail.

> Newer commits have remedied the build issue, but the Invalid ECC
> layout error still exists as of 5.11-RC2.

Ok so let's focus on these.

> Do you have any suggestions on what I can do to remedy this?  I am
> willing to try and test.

Glad to hear that.

Can you share the NAND controller DT node you are using?

Also, can you please add a few printk's like below and give me the
output?

---8<---

diff --git a/drivers/mtd/nand/ecc-sw-bch.c b/drivers/mtd/nand/ecc-sw-bch.c
index 0a0ac11d5725..0d3e948d02e9 100644
--- a/drivers/mtd/nand/ecc-sw-bch.c
+++ b/drivers/mtd/nand/ecc-sw-bch.c
@@ -205,6 +205,7 @@ int nand_ecc_sw_bch_init_ctx(struct nand_device *nand)
        }
 
        nsteps = mtd->writesize / conf->step_size;
+       printk("writesize %d, step_size %d, nsteps %d\n", mtd->writesize, conf->step_size, nsteps);
 
        /* Maximize */
        if (nand->ecc.user_conf.flags & NAND_ECC_MAXIMIZE_STRENGTH) {
@@ -213,11 +214,14 @@ int nand_ecc_sw_bch_init_ctx(struct nand_device *nand)
                /* Reserve 2 bytes for the BBM */
                code_size = (mtd->oobsize - 2) / nsteps;
                conf->strength = code_size * 8 / fls(8 * conf->step_size);
+               printk("Maximize => nsteps %d, code_size %d\n", nsteps, code_size);
        }
 
-       if (!code_size)
+       if (!code_size) {
                code_size = DIV_ROUND_UP(conf->strength *
                                         fls(8 * conf->step_size), 8);
+               printk("strength %d, step size %d, code_size %d\n", conf->strength, conf->step_size, code_size);
+       }
 
        if (!conf->strength)
                conf->strength = (code_size * 8) / fls(8 * conf->step_size);
@@ -252,6 +256,7 @@ int nand_ecc_sw_bch_init_ctx(struct nand_device *nand)
                goto free_bufs;
 
        /* Verify the layout validity */
+       printk("count eccbytes %d\n", mtd_ooblayout_count_eccbytes(mtd));
        if (mtd_ooblayout_count_eccbytes(mtd) !=
            engine_conf->nsteps * engine_conf->code_size) {
                pr_err("Invalid ECC layout\n");

--->8---

Thanks,
Miquèl