Hello Boris, On Fri, 18 Aug 2017 00:15:42 +0200 Boris Brezillon <[email protected]> wrote:
> +Yoshi > > Hi Miquel, > > Subject prefix should be "mtd: nand: " in lowercase. I was not aware of that kind of rule, next time I'll be careful. > > Le Wed, 16 Aug 2017 09:39:06 +0200, > Miquel Raynal <[email protected]> a écrit : > > > Add layout functions for small and large pages with mainly free > > bytes plus reserved space for Bad Block Markers. This may be useful > > for specific chip that use on-die ECC feature, ie. the TOSHIBA > > BENAND (Built-in ECC NAND). The ECC bytes are stored in an isolated > > area inaccessible by the driver and thus the OOB layout must only > > reserve space for Bad Block Markers. > > Yes, that's true, but as said below, I expect the toshiba driver to > explicitly set this layout. I will change: -for specific chips that use on-die ECC feature, ie. the [...]. +for configurations that does set ECC_NONE. Specific chips that use on-die ECC feature, ie. the [...], might also take advantage of it. > > > > > Bad Block Markers position was extracted from the existing OOB > > layouts by assigning as free all the bytes marked as ECC. > > > > The layout functions added by this patch were supposed to be used > > with ECC_NONE mode but it would break existing drivers that do not > > rely on an implementation of this layout by the core, so set it as > > a fallthrough when no other layout matches. > > Well, it's still supposed to be used when ECC_NONE is set, except we > can only use it for cases that were not already falling in the > supported large/small page with ECC cases. I'll edit the commit message, what about: The layout functions added by this patch intend to be used when ECC_NONE is set, except it is only usable for cases that were not already falling in the supported large/small page with ECC cases. Not breaking existing drivers needs these functions to be set as a fallthrough when no other layout matches and ECC_NONE is actually set. > > > > > Signed-off-by: Miquel Raynal <[email protected]> > > --- > > drivers/mtd/nand/nand_base.c | 65 > > ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 60 > > insertions(+), 5 deletions(-) > > > > diff --git a/drivers/mtd/nand/nand_base.c > > b/drivers/mtd/nand/nand_base.c index c5221795a1e8..7c0ae674e50a > > 100644 --- a/drivers/mtd/nand/nand_base.c > > +++ b/drivers/mtd/nand/nand_base.c > > @@ -53,7 +53,38 @@ static int nand_get_device(struct mtd_info *mtd, > > int new_state); static int nand_do_write_oob(struct mtd_info *mtd, > > loff_t to, struct mtd_oob_ops *ops); > > > > -/* Define default oob placement schemes for large and small page > > devices */ +/* > > + * Define default OOB placement schemes for: > > + * - no ECC or software ECC > > + * - small or large page devices > > + */ > > +static int nand_ooblayout_free_sp_no_ecc(struct mtd_info *mtd, int > > section, > > + struct mtd_oob_region > > *oobregion) +{ > > + if (section > 1) > > + return -ERANGE; > > + > > + if (!section) { > > + if (mtd->oobsize == 16) { > > + oobregion->offset = 0; > > + oobregion->length = 4; > > + } else { > > + oobregion->offset = 0; > > + oobregion->length = 5; > > + } > > + } else { > > + oobregion->offset = 6; > > + oobregion->length = mtd->oobsize - > > oobregion->offset; > > + } > > + > > + return 0; > > +} > > + > > +const struct mtd_ooblayout_ops nand_ooblayout_sp_no_ecc_ops = { > > + .free = nand_ooblayout_free_sp_no_ecc, > > +}; > > +EXPORT_SYMBOL_GPL(nand_ooblayout_sp_no_ecc_ops); > > + > > static int nand_ooblayout_ecc_sp(struct mtd_info *mtd, int section, > > struct mtd_oob_region *oobregion) > > { > > @@ -109,6 +140,23 @@ const struct mtd_ooblayout_ops > > nand_ooblayout_sp_ops = { }; > > EXPORT_SYMBOL_GPL(nand_ooblayout_sp_ops); > > > > +static int nand_ooblayout_free_lp_no_ecc(struct mtd_info *mtd, int > > section, > > + struct mtd_oob_region > > *oobregion) +{ > > + if (section) > > + return -ERANGE; > > + > > + oobregion->offset = 2; > > + oobregion->length = mtd->oobsize - oobregion->offset; > > + > > + return 0; > > +} > > + > > +const struct mtd_ooblayout_ops nand_ooblayout_lp_no_ecc_ops = { > > + .free = nand_ooblayout_free_lp_no_ecc, > > +}; > > +EXPORT_SYMBOL_GPL(nand_ooblayout_lp_no_ecc_ops); > > No need to export those symbols until someone really needs them. > BTW, they are exported but not declared in nand.h, so right now > nobody can use them. I though the EXPORT_* was expected as it was below every layout function. I'll remove both of the exports, but as you said, while nobody use them, I won't add the prototypes in nand.h neither, right ? > > > + > > static int nand_ooblayout_ecc_lp(struct mtd_info *mtd, int section, > > struct mtd_oob_region *oobregion) > > { > > @@ -4649,10 +4697,17 @@ int nand_scan_tail(struct mtd_info *mtd) > > mtd_set_ooblayout(mtd, > > &nand_ooblayout_lp_hamming_ops); break; > > default: > > - WARN(1, "No oob scheme defined for oobsize > > %d\n", > > - mtd->oobsize); > > - ret = -EINVAL; > > - goto err_free; > > + /* > > + * In the case of on-die ECC (when ECC are > > stored in an > > + * isolated area inaccessible by the > > driver), the OOB > > + * layout must only reserve space for Bad > > Block Markers. > > + */ > > This kind of on-die ECC is not yet supported and I'd expect NAND > manufacturer drivers to set the appropriate layout before reaching > this point, so that's not really relevant here. To be removed then. > > > + if (mtd->writesize <= 512) > > + mtd_set_ooblayout(mtd, > > + > > &nand_ooblayout_sp_no_ecc_ops); > > + else > > + mtd_set_ooblayout(mtd, > > + > > &nand_ooblayout_lp_no_ecc_ops); > > That's not exactly what I was suggesting. What I had in mind was: > > if (ecc->mode == NAND_ECC_NONE) { > /* > * Expose the whole OOB area to users > if ECC_NONE > * is passed. We could do that for > all kind of > * ->oobsize, but we must keep the old > * large/small page with ECC layout > for > * compatibility reasons. > */ > if (mtd->writesize <= 512) > mtd_set_ooblayout(mtd, > > &nand_ooblayout_sp_no_ecc_ops); > else > mtd_set_ooblayout(mtd, > > &nand_ooblayout_lp_no_ecc_ops); > > break; > } > > WARN(1, "No oob scheme defined for oobsize > %d\n", mtd->oobsize); > ret = -EINVAL; > goto err_free; Ok, I clearly misunderstood your previous explanation, sorry about that. I'll use your version as is. > > } > > } > > > > > ______________________________________________________ > Linux MTD discussion mailing list > http://lists.infradead.org/mailman/listinfo/linux-mtd/ Thank you, Miquèl
