Re: [PATCH v2] mtd: spinand: Add support for Etron EM73D044VCx

[Frieder Schrempf]

Hi Bert,

On 08.09.21 22:16, Bert Vermeulen wrote:
> This adds a new vendor Etron, and support for a 2Gb chip.
> 
> The datasheet is available at
> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.etron.com%2Fcn%2Fproducts%2FEM73%255B8%255DC%255BD_E_F%255DVC%2520SPI%2520NAND%2520Flash_Promotion_Rev%25201_00A.pdf&data=04%7C01%7Cfrieder.schrempf%40kontron.de%7C871fa2a364d8484bbc0d08d97305f2f4%7C8c9d3c973fd941c8a2b1646f3942daf1%7C0%7C0%7C637667293724201439%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=SeopP6Mvu1CHj6eB22XlO78NGnMc3hCFzM%2F5jKmJZxU%3D&reserved=0
> 
> Signed-off-by: Bert Vermeulen <bert@xxxxxxxx>
> ---
> v2:
> - Made ooblayout_free/_ecc depend on chip-specific parameters, instead of
>   hardcoded to this 2Gb chip only
> - Fixed manufacturer ordering
> - Fixed minor formatting issues as reported
> - Removed debug comment
> 
>  drivers/mtd/nand/spi/Makefile |   2 +-
>  drivers/mtd/nand/spi/core.c   |   1 +
>  drivers/mtd/nand/spi/etron.c  | 104 ++++++++++++++++++++++++++++++++++
>  include/linux/mtd/spinand.h   |   1 +
>  4 files changed, 107 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/mtd/nand/spi/etron.c
> 
> diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
> index 9662b9c1d5a9..cc3c4e046ea9 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 gigadevice.o macronix.o micron.o paragon.o toshiba.o winbond.o
> +spinand-objs := core.o etron.o gigadevice.o macronix.o micron.o paragon.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 446ba8d43fbc..2cbf25b8caa2 100644
> --- a/drivers/mtd/nand/spi/core.c
> +++ b/drivers/mtd/nand/spi/core.c
> @@ -894,6 +894,7 @@ static const struct nand_ops spinand_ops = {
>  };
>  
>  static const struct spinand_manufacturer *spinand_manufacturers[] = {
> +	&etron_spinand_manufacturer,
>  	&gigadevice_spinand_manufacturer,
>  	&macronix_spinand_manufacturer,
>  	&micron_spinand_manufacturer,
> diff --git a/drivers/mtd/nand/spi/etron.c b/drivers/mtd/nand/spi/etron.c
> new file mode 100644
> index 000000000000..1a92b9cf3043
> --- /dev/null
> +++ b/drivers/mtd/nand/spi/etron.c
> @@ -0,0 +1,104 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/mtd/spinand.h>
> +
> +#define SPINAND_MFR_ETRON			0xd5
> +
> +static SPINAND_OP_VARIANTS(read_cache_variants,
> +		SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 1, NULL, 0),
> +		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
> +		SPINAND_PAGE_READ_FROM_CACHE_DUALIO_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_X4(true, 0, NULL, 0),
> +		SPINAND_PROG_LOAD(true, 0, NULL, 0));
> +
> +static SPINAND_OP_VARIANTS(update_cache_variants,
> +		SPINAND_PROG_LOAD_X4(false, 0, NULL, 0),
> +		SPINAND_PROG_LOAD(false, 0, NULL, 0));
> +
> +static int etron_oob_spare(struct mtd_info *mtd)
> +{
> +	if (mtd->size < 0x10000000)
> +		return mtd->oobsize / 2;
> +	else
> +		return mtd->oobsize / 2 + mtd->oobsize / 16;
> +}
> +
> +static int etron_ooblayout_ecc(struct mtd_info *mtd, int section,
> +					struct mtd_oob_region *oobregion)
> +{
> +	if (section)
> +		return -ERANGE;
> +
> +	oobregion->offset = etron_oob_spare(mtd);
> +	oobregion->length = mtd->oobsize - oobregion->offset;
> +
> +	return 0;
> +}
> +
> +static int etron_ooblayout_free(struct mtd_info *mtd, int section,
> +			   struct mtd_oob_region *oobregion)
> +{
> +	if (section)
> +		return -ERANGE;
> +
> +	oobregion->offset = 2;
> +	oobregion->length = etron_oob_spare(mtd) - 2;
> +
> +	return 0;
> +}
> +
> +static const struct mtd_ooblayout_ops etron_ooblayout = {
> +	.ecc = etron_ooblayout_ecc,
> +	.free = etron_ooblayout_free,
> +};
> +
> +static int etron_ecc_get_status(struct spinand_device *spinand, u8 status)
> +{
> +	switch (status & STATUS_ECC_MASK) {
> +	case STATUS_ECC_NO_BITFLIPS:
> +		return 0;
> +
> +	case STATUS_ECC_HAS_BITFLIPS:
> +		/* Between 1-7 bitflips were corrected */
> +		return 7;
> +
> +	case STATUS_ECC_MASK:

I'm not sure if using STATUS_ECC_MASK here to check for the 0b11 pattern
is really a good idea. I'd rather introduce a vendor-specific define for
this as other drivers do (see toshiba.c, paragon.c or gigadevice.c). As
this seems to be a common pattern among vendors we could also think
about introducing a new common flag like STATUS_ECC_HAS_MAX_BITFLIPS or
something like that and use this instead.

> +		/* Maximum bitflips were corrected */
> +		return 8;
> +
> +	case STATUS_ECC_UNCOR_ERROR:
> +		return -EBADMSG;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct spinand_info etron_spinand_table[] = {
> +	SPINAND_INFO("EM73D044VCx",
> +		     SPINAND_ID(SPINAND_READID_METHOD_OPCODE_ADDR, 0x1f),

According to the datasheet, the device id of the EM73D044VCL is 0x2e and
not 0x1f. Am I missing something?

Best regards
Frieder

> +		     NAND_MEMORG(1, 2048, 128, 64, 2048, 40, 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(&etron_ooblayout, etron_ecc_get_status)),
> +};
> +
> +static const struct spinand_manufacturer_ops etron_spinand_manuf_ops = {
> +};
> +
> +const struct spinand_manufacturer etron_spinand_manufacturer = {
> +	.id = SPINAND_MFR_ETRON,
> +	.name = "Etron",
> +	.chips = etron_spinand_table,
> +	.nchips = ARRAY_SIZE(etron_spinand_table),
> +	.ops = &etron_spinand_manuf_ops,
> +};
> diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
> index 6988956b8492..d7c0a0439652 100644
> --- a/include/linux/mtd/spinand.h
> +++ b/include/linux/mtd/spinand.h
> @@ -260,6 +260,7 @@ struct spinand_manufacturer {
>  };
>  
>  /* SPI NAND manufacturers */
> +extern const struct spinand_manufacturer etron_spinand_manufacturer;
>  extern const struct spinand_manufacturer gigadevice_spinand_manufacturer;
>  extern const struct spinand_manufacturer macronix_spinand_manufacturer;
>  extern const struct spinand_manufacturer micron_spinand_manufacturer;
>