Re: [PATCH] mtd: nand: spi: Add initial support for Toshiba TC58CVG2S0H

From: ClÃment PÃron
Date: Tue Nov 27 2018 - 10:18:29 EST

Hi Frieder,

On Tue, 27 Nov 2018 at 16:08, Schrempf Frieder
<frieder.schrempf@xxxxxxxxxx> wrote:
>
> +ClÃment PÃron
>
> Hi ClÃment,
>
> FYI, this has already been merged to nand/next.
Just want to point the difference that I made when I try to introduce my driver.
The datasheet I used is this one :
https://media.digikey.com/pdf/Data%20Sheets/Toshiba%20PDFs/TC58CVG2S0HxAIx_Rev1.1_2016-11-08.pdf

>
> Regards,
> Frieder
>
> On 08.11.18 09:29, Frieder Schrempf wrote:
> > Add minimal support for the Toshiba TC58CVG2S0H SPI NAND chip.
> >
> > Signed-off-by: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> > ---
> > drivers/mtd/nand/spi/Makefile | 2 +-
> > drivers/mtd/nand/spi/core.c | 1 +
> > drivers/mtd/nand/spi/toshiba.c | 136 ++++++++++++++++++++++++++++++++++++
> > include/linux/mtd/spinand.h | 1 +
> > 4 files changed, 139 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
> > index b74e074..be5f735 100644
> > --- a/drivers/mtd/nand/spi/Makefile
> > +++ b/drivers/mtd/nand/spi/Makefile
> > @@ -1,3 +1,3 @@
> > # SPDX-License-Identifier: GPL-2.0
> > -spinand-objs := core.o macronix.o micron.o winbond.o
> > +spinand-objs := core.o macronix.o micron.o toshiba.o winbond.o
> > obj-$(CONFIG_MTD_SPI_NAND) += spinand.o
> > diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> > index 30f8364..87bdf2a 100644
> > --- a/drivers/mtd/nand/spi/core.c
> > +++ b/drivers/mtd/nand/spi/core.c
> > @@ -766,6 +766,7 @@ static const struct nand_ops spinand_ops = {
> > static const struct spinand_manufacturer *spinand_manufacturers[] = {
> > &macronix_spinand_manufacturer,
> > &micron_spinand_manufacturer,
> > + &toshiba_spinand_manufacturer,
> > &winbond_spinand_manufacturer,
> > };
> >
> > diff --git a/drivers/mtd/nand/spi/toshiba.c b/drivers/mtd/nand/spi/toshiba.c
> > new file mode 100644
> > index 0000000..294bcf6
> > --- /dev/null
> > +++ b/drivers/mtd/nand/spi/toshiba.c
> > @@ -0,0 +1,136 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (c) 2018 exceet electronics GmbH
> > + * Copyright (c) 2018 Kontron Electronics GmbH
> > + *
> > + * Author: Frieder Schrempf <frieder.schrempf@xxxxxxxxxx>
> > + */
> > +
> > +#include <linux/device.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mtd/spinand.h>
> > +
> > +#define SPINAND_MFR_TOSHIBA 0x98
> > +
> > +static SPINAND_OP_VARIANTS(read_cache_variants,
> > + SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
> > + SPINAND_PAGE_READ_FROM_CACHE_X2_OP(0, 1, NULL, 0),
> > + SPINAND_PAGE_READ_FROM_CACHE_OP(true, 0, 1, NULL, 0),
> > + SPINAND_PAGE_READ_FROM_CACHE_OP(false, 0, 1, NULL, 0));
> > +
> > +static SPINAND_OP_VARIANTS(write_cache_variants,
> > + SPINAND_PROG_LOAD(true, 0, NULL, 0));
> > +
> > +static SPINAND_OP_VARIANTS(update_cache_variants,
> > + SPINAND_PROG_LOAD(false, 0, NULL, 0));
> > +
> > +static int tc58cvg2s0h_ooblayout_ecc(struct mtd_info *mtd, int section,
> > + struct mtd_oob_region *region)
> > +{
> > + if (section > 7)
> > + return -ERANGE;
> > +
> > + region->offset = 128 + 16 * section;
> > + region->length = 16;

Here you expose the ECC bits has 8 sections of 16 bytes.
But regarding the datasheet this should not be accessed page 32.
"The ECC parity code generated by internal ECC is stored in column
addresses 4224-4351 and the users cannot access to these specific
addresses when internal ECC is enabled."

> > +
> > +
> > + return 0;
> > +}
> > +
> > +static int tc58cvg2s0h_ooblayout_free(struct mtd_info *mtd, int section,
> > + struct mtd_oob_region *region)
> > +{
> > + if (section > 7)
> > + return -ERANGE;
> > +
> > + region->offset = 2 + 16 * section;
> > + region->length = 14;

This reserved 2 bytes for BBM for each section.
But maybe we could declare this as 1 section of 128bytes:

if (section)
return -ERANGE;

region->offset = 2;
region->length = 126;


> > +
> > +
> > + return 0;
> > +}
> > +
> > +static const struct mtd_ooblayout_ops tc58cvg2s0h_ooblayout = {
> > + .ecc = tc58cvg2s0h_ooblayout_ecc,
> > + .free = tc58cvg2s0h_ooblayout_free,
> > +};
> > +
> > +static int tc58cvg2s0h_ecc_get_status(struct spinand_device *spinand,
> > + u8 status)
> > +{
> > + struct nand_device *nand = spinand_to_nand(spinand);
> > + u8 mbf = 0;
> > + struct spi_mem_op op = SPINAND_GET_FEATURE_OP(0x30, &mbf);
> > +
> > + switch (status & STATUS_ECC_MASK) {
> > + case STATUS_ECC_NO_BITFLIPS:
> > + return 0;
> > +
> > + case STATUS_ECC_UNCOR_ERROR:
> > + return -EBADMSG;
> > +
> > + case STATUS_ECC_HAS_BITFLIPS:
> > + /*
> > + * Let's try to retrieve the real maximum number of bitflips
> > + * in order to avoid forcing the wear-leveling layer to move
> > + * data around if it's not necessary.
> > + */
> > + if (spi_mem_exec_op(spinand->spimem, &op))
> > + return nand->eccreq.strength;
> > +
> > + mbf >>= 4;
> > +
> > + if (WARN_ON(mbf > nand->eccreq.strength || !mbf))
> > + return nand->eccreq.strength;
> > +
> > + return mbf;
> > +

These take take care of 0, 0x1 and 0x2 but not 0x3 which is valid
page 26 of the datasheet :

ECC status bits indicate the status of internal ECC operation
00b: No bit flips were detected in previous page read.
01b: Bit flips were detected and corrected. Bit flip count did not
exceed the bit flip detection threshold. The threshold is set by bits
[7:4] in address 10h in the feature table.
10b: Multiple bit flips were detected and not corrected.
11b: Bit flips were detected and corrected. Bit flip count exceeded
the bit flip detection threshold. The threshold is set by bits [7:4]
in address 10h in the feature table

Regards,
Clement

> > + default:
> > + break;
> > + }
> > +
> > + return -EINVAL;
> > +}
> > +
> > +static const struct spinand_info toshiba_spinand_table[] = {
> > + SPINAND_INFO("TC58CVG2S0H", 0xCD,
> > + NAND_MEMORG(1, 4096, 256, 64, 2048, 1, 1, 1),
> > + NAND_ECCREQ(8, 512),
> > + SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
> > + &write_cache_variants,
> > + &update_cache_variants),
> > + SPINAND_HAS_QE_BIT,
> > + SPINAND_ECCINFO(&tc58cvg2s0h_ooblayout,
> > + tc58cvg2s0h_ecc_get_status)),
> > +};
> > +
> > +static int toshiba_spinand_detect(struct spinand_device *spinand)
> > +{
> > + u8 *id = spinand->id.data;
> > + int ret;
> > +
> > + /*
> > + * Toshiba SPI NAND read ID needs a dummy byte,
> > + * so the first byte in id is garbage.
> > + */
> > + if (id[1] != SPINAND_MFR_TOSHIBA)
> > + return 0;
> > +
> > + ret = spinand_match_and_init(spinand, toshiba_spinand_table,
> > + ARRAY_SIZE(toshiba_spinand_table),
> > + id[2]);
> > + if (ret)
> > + return ret;
> > +
> > + return 1;
> > +}
> > +
> > +static const struct spinand_manufacturer_ops toshiba_spinand_manuf_ops = {
> > + .detect = toshiba_spinand_detect,
> > +};
> > +
> > +const struct spinand_manufacturer toshiba_spinand_manufacturer = {
> > + .id = SPINAND_MFR_TOSHIBA,
> > + .name = "Toshiba",
> > + .ops = &toshiba_spinand_manuf_ops,
> > +};
> > diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
> > index 088ff96..816c4b0 100644
> > --- a/include/linux/mtd/spinand.h
> > +++ b/include/linux/mtd/spinand.h
> > @@ -196,6 +196,7 @@ struct spinand_manufacturer {
> > /* SPI NAND manufacturers */
> > extern const struct spinand_manufacturer macronix_spinand_manufacturer;
> > extern const struct spinand_manufacturer micron_spinand_manufacturer;
> > +extern const struct spinand_manufacturer toshiba_spinand_manufacturer;
> > extern const struct spinand_manufacturer winbond_spinand_manufacturer;
> >
> > /**
> >