From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Richard Weinberger <richard@nod.at>
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
Tudor Ambarus <Tudor.Ambarus@microchip.com>,
Boris Brezillon <boris.brezillon@bootlin.com>,
Boris Brezillon <boris.brezillon@collabora.com>,
linux-mtd <linux-mtd@lists.infradead.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH 4/8] mtd: Add support for emulated SLC mode on MLC NANDs
Date: Thu, 9 Jan 2020 19:16:12 +0100 [thread overview]
Message-ID: <20200109191612.77d987d3@xps13> (raw)
In-Reply-To: <1518112485.16967.1578527342428.JavaMail.zimbra@nod.at>
Hi Richard,
Richard Weinberger <richard@nod.at> wrote on Thu, 9 Jan 2020 00:49:02
+0100 (CET):
> ----- Ursprüngliche Mail -----
> > Von: "Miquel Raynal" <miquel.raynal@bootlin.com>
> > An: "richard" <richard@nod.at>, "Vignesh Raghavendra" <vigneshr@ti.com>, "Tudor Ambarus" <Tudor.Ambarus@microchip.com>,
> > "linux-mtd" <linux-mtd@lists.infradead.org>
> > CC: "Boris Brezillon" <boris.brezillon@collabora.com>, "Thomas Petazzoni" <thomas.petazzoni@bootlin.com>, "Boris
> > Brezillon" <boris.brezillon@bootlin.com>, "Miquel Raynal" <miquel.raynal@bootlin.com>
> > Gesendet: Montag, 30. Dezember 2019 17:51:25
> > Betreff: [PATCH 4/8] mtd: Add support for emulated SLC mode on MLC NANDs
>
> > From: Boris Brezillon <boris.brezillon@bootlin.com>
> >
> > MLC NANDs can be made a bit more reliable if we only program the lower
> > page of each pair. At least, this solves the paired-pages corruption
> > issue.
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
> > ---
> > drivers/mtd/mtdcore.c | 189 ++++++++++++++++++++++++++++++---
> > drivers/mtd/mtdpart.c | 54 ++++++----
> > include/linux/mtd/mtd.h | 7 +-
> > include/linux/mtd/partitions.h | 2 +
> > include/uapi/mtd/mtd-abi.h | 1 +
> > 5 files changed, 213 insertions(+), 40 deletions(-)
> >
> > diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> > index 2916674208b3..de0a692ecb29 100644
> > --- a/drivers/mtd/mtdcore.c
> > +++ b/drivers/mtd/mtdcore.c
> > @@ -617,6 +617,19 @@ int add_mtd_device(struct mtd_info *mtd)
> > !(mtd->flags & MTD_NO_ERASE)))
> > return -EINVAL;
> >
> > + /*
> > + * MTD_MLC_IN_SLC_MODE can only be set on partitions, when the master
>
> I suggest giving a name which indicates that we are actually emulating
> an SLC. Maybe MTD_SLC_EMULATION?
> Some MLC NANDs support SLC mode in hardware, MTD_MLC_IN_SLC_MODE reads like
> this feature.
You're right. What about MTD_SLC_ON_MLC_EMULATION?
I like to see that we are manipulating MLC NANDs.
>
> > + * is an MLC NAND and has a proper pairing scheme defined.
> > + * We also reject masters that implement ->_writev() for now, because
> > + * NAND controller drivers don't implement this hook, and adding the
> > + * SLC -> MLC address/length conversion to this path is useless if we
> > + * don't have a user.
> > + */
> > + if (mtd->flags & MTD_MLC_IN_SLC_MODE &&
> > + (!mtd_is_partition(mtd) || master->type != MTD_MLCNANDFLASH ||
> > + !master->pairing || master->_writev))
> > + return -EINVAL;
> > +
> > mutex_lock(&mtd_table_mutex);
> >
> > i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
> > @@ -632,6 +645,14 @@ int add_mtd_device(struct mtd_info *mtd)
> > if (mtd->bitflip_threshold == 0)
> > mtd->bitflip_threshold = mtd->ecc_strength;
> >
> > + if (mtd->flags & MTD_MLC_IN_SLC_MODE) {
> > + int ngroups = mtd_pairing_groups(master);
> > +
> > + mtd->erasesize /= ngroups;
> > + mtd->size = (u64)mtd_div_by_eb(mtd->size, master) *
> > + mtd->erasesize;
>
> Can we please have a helper for this? You use this formula many times.
Absolutely!
>
> > + }
> > +
> > if (is_power_of_2(mtd->erasesize))
> > mtd->erasesize_shift = ffs(mtd->erasesize) - 1;
> > else
> > @@ -1074,9 +1095,11 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info
> > *instr)
> > {
> > struct mtd_info *master = mtd_get_master(mtd);
> > u64 mst_ofs = mtd_get_master_ofs(mtd, 0);
> > + struct erase_info adjinstr;
> > int ret;
> >
> > instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
> > + adjinstr = *instr;
> >
> > if (!mtd->erasesize || !master->_erase)
> > return -ENOTSUPP;
> > @@ -1091,12 +1114,27 @@ int mtd_erase(struct mtd_info *mtd, struct erase_info
> > *instr)
> >
> > ledtrig_mtd_activity();
> >
> > - instr->addr += mst_ofs;
> > - ret = master->_erase(master, instr);
> > - if (instr->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
> > - instr->fail_addr -= mst_ofs;
> > + if (mtd->flags & MTD_MLC_IN_SLC_MODE) {
> > + adjinstr.addr = (loff_t)mtd_div_by_eb(instr->addr, mtd) *
> > + master->erasesize;
> > + adjinstr.len = ((u64)mtd_div_by_eb(instr->addr + instr->len, mtd) *
> > + master->erasesize) -
> > + adjinstr.addr;
> > + }
> > +
> > + adjinstr.addr += mst_ofs;
> > +
> > + ret = master->_erase(master, &adjinstr);
> > +
> > + if (adjinstr.fail_addr != MTD_FAIL_ADDR_UNKNOWN) {
> > + instr->fail_addr = adjinstr.fail_addr - mst_ofs;
> > + if (mtd->flags & MTD_MLC_IN_SLC_MODE) {
> > + instr->fail_addr = mtd_div_by_eb(instr->fail_addr,
> > + master);
> > + instr->fail_addr *= mtd->erasesize;
> > + }
> > + }
> >
> > - instr->addr -= mst_ofs;
> > return ret;
> > }
> > EXPORT_SYMBOL_GPL(mtd_erase);
> > @@ -1276,6 +1314,101 @@ static int mtd_check_oob_ops(struct mtd_info *mtd,
> > loff_t offs,
> > return 0;
> > }
> >
> > +static int mtd_read_oob_std(struct mtd_info *mtd, loff_t from,
> > + struct mtd_oob_ops *ops)
> > +{
> > + struct mtd_info *master = mtd_get_master(mtd);
> > + int ret;
> > +
> > + from = mtd_get_master_ofs(mtd, from);
> > + if (master->_read_oob)
> > + ret = master->_read_oob(master, from, ops);
> > + else
> > + ret = master->_read(master, from, ops->len, &ops->retlen,
> > + ops->datbuf);
> > +
> > + return ret;
> > +}
> > +
> > +static int mtd_write_oob_std(struct mtd_info *mtd, loff_t to,
> > + struct mtd_oob_ops *ops)
> > +{
> > + struct mtd_info *master = mtd_get_master(mtd);
> > + int ret;
> > +
> > + to = mtd_get_master_ofs(mtd, to);
> > + if (master->_write_oob)
> > + ret = master->_write_oob(master, to, ops);
> > + else
> > + ret = master->_write(master, to, ops->len, &ops->retlen,
> > + ops->datbuf);
> > +
> > + return ret;
> > +}
> > +
> > +static int mtd_oob_io_slc(struct mtd_info *mtd, loff_t start, bool read,
> > + struct mtd_oob_ops *ops)
>
> The name is misleading. We don't do OOB IO on a SLC NAND,
> we emulate SLC.
What would you recommend? mtd_oob_io_emul_slc?
>
> Thanks,
> //richard
Thanks,
Miquèl
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next prev parent reply other threads:[~2020-01-09 18:16 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-30 16:51 [PATCH 0/8] MLC in SLC mode Miquel Raynal
2019-12-30 16:51 ` [PATCH 1/8] mtd: rawnand: toshiba: Add a specific init for TC58TEG5DCLTA00 Miquel Raynal
2019-12-30 16:51 ` [PATCH 2/8] mtd: rawnand: Define the "distance 3" MLC pairing scheme Miquel Raynal
2019-12-30 16:51 ` [PATCH 3/8] mtd: rawnand: toshiba: Set the pairing scheme for TC58TEG5DCLTA00 Miquel Raynal
2019-12-30 16:51 ` [PATCH 4/8] mtd: Add support for emulated SLC mode on MLC NANDs Miquel Raynal
2020-01-08 23:49 ` Richard Weinberger
2020-01-09 18:16 ` Miquel Raynal [this message]
2020-01-09 18:39 ` Richard Weinberger
2020-01-09 19:19 ` Boris Brezillon
2020-01-09 19:22 ` Miquel Raynal
2020-01-14 10:04 ` Miquel Raynal
2019-12-30 16:51 ` [PATCH 5/8] dt-bindings: mtd: partition: Document the slc-mode property Miquel Raynal
2019-12-31 3:53 ` Florian Fainelli
2020-01-14 9:33 ` Miquel Raynal
2019-12-30 16:51 ` [PATCH 6/8] mtd: partitions: ofpart: Parse " Miquel Raynal
2019-12-30 16:51 ` [PATCH 7/8] mtd: cmdlinepart: Add an slc option to use SLC mode on a part Miquel Raynal
2019-12-30 16:51 ` [PATCH 8/8] ubi: Relax the 'no MLC' rule and allow MLCs operating in SLC mode Miquel Raynal
2020-01-08 23:50 ` Richard Weinberger
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