[PATCH v1 2/5] mtd: spinand: add OTP support
Miquel Raynal
miquel.raynal at bootlin.com
Wed Jul 17 01:36:23 PDT 2024
Hi Martin,
mmkurbanov at salutedevices.com wrote on Mon, 17 Jun 2024 16:34:54 +0300:
> The MTD subsystem already supports accessing two OTP areas: user and
> factory. User areas can be written by the user. This patch only adds
> support for the user areas.
>
> In this patch the OTP_INFO macro is provided to add parameters to
> spinand_info.
> To implement OTP operations, the client (flash driver) is provided with
> 5 callbacks: .read(), .write(), .info(), .lock(), .erase().
Good job! Please find minor comments below.
>
> Signed-off-by: Martin Kurbanov <mmkurbanov at salutedevices.com>
> ---
> drivers/mtd/nand/spi/Makefile | 3 +-
> drivers/mtd/nand/spi/core.c | 3 +
> drivers/mtd/nand/spi/otp.c | 219 ++++++++++++++++++++++++++++++++++
> include/linux/mtd/spinand.h | 56 +++++++++
> 4 files changed, 280 insertions(+), 1 deletion(-)
> create mode 100644 drivers/mtd/nand/spi/otp.c
>
> diff --git a/drivers/mtd/nand/spi/Makefile b/drivers/mtd/nand/spi/Makefile
> index 19cc77288ebbc..60d2e830ffc6b 100644
> --- a/drivers/mtd/nand/spi/Makefile
> +++ b/drivers/mtd/nand/spi/Makefile
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
> -spinand-objs := core.o alliancememory.o ato.o esmt.o foresee.o gigadevice.o macronix.o
> +spinand-objs := core.o otp.o
> +spinand-objs += alliancememory.o ato.o esmt.o foresee.o gigadevice.o macronix.o
> spinand-objs += micron.o paragon.o toshiba.o winbond.o xtx.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 807c24b0c7c4f..2cb825edd49d0 100644
> --- a/drivers/mtd/nand/spi/core.c
> +++ b/drivers/mtd/nand/spi/core.c
> @@ -1111,6 +1111,7 @@ int spinand_match_and_init(struct spinand_device *spinand,
> spinand->flags = table[i].flags;
> spinand->id.len = 1 + table[i].devid.len;
> spinand->select_target = table[i].select_target;
> + spinand->otp = &table[i].otp;
>
> op = spinand_select_op_variant(spinand,
> info->op_variants.read_cache);
> @@ -1292,6 +1293,8 @@ static int spinand_init(struct spinand_device *spinand)
> mtd->_max_bad_blocks = nanddev_mtd_max_bad_blocks;
> mtd->_resume = spinand_mtd_resume;
>
> + spinand_set_mtd_otp_ops(spinand);
> +
> if (nand->ecc.engine) {
> ret = mtd_ooblayout_count_freebytes(mtd);
> if (ret < 0)
> diff --git a/drivers/mtd/nand/spi/otp.c b/drivers/mtd/nand/spi/otp.c
> new file mode 100644
> index 0000000000000..e1f96b1898dcb
> --- /dev/null
> +++ b/drivers/mtd/nand/spi/otp.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2024, SaluteDevices. All Rights Reserved.
> + *
> + * Author: Martin Kurbanov <mmkurbanov at salutedevices.com>
> + */
> +
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/spinand.h>
> +
> +static size_t spinand_otp_size(struct spinand_device *spinand)
> +{
> + struct nand_device *nand = spinand_to_nand(spinand);
> + size_t otp_pagesize = nanddev_page_size(nand) +
> + nanddev_per_page_oobsize(nand);
> +
> + return spinand->otp->layout.npages * otp_pagesize;
> +}
> +
> +static unsigned int spinand_otp_npages(const struct spinand_device *spinand)
> +{
> + return spinand->otp->layout.npages;
Maybe you can move this helper up and use it in spinand_otp_size().
> +}
> +
...
> +static int spinand_mtd_otp_rw(struct mtd_info *mtd, loff_t ofs, size_t len,
> + size_t *retlen, u8 *buf, bool is_write)
> +{
> + struct spinand_device *spinand = mtd_to_spinand(mtd);
> + const struct spinand_otp_ops *ops = spinand->otp->ops;
> + size_t total_len = len;
> + int ret;
> +
> + if (ofs < 0 || ofs + len > spinand_otp_size(spinand))
> + return -EINVAL;
> +
Please just check if (!len) here
> + total_len = min_t(size_t, total_len, spinand_otp_size(spinand) - ofs);
len ^^^
Here you can just compute the minimum and don't check the output. It
will be simpler to understand.
> + if (!total_len)
> + return 0;
> +
> + mutex_lock(&spinand->lock);
> +
> + ret = spinand_upd_cfg(spinand, CFG_OTP_ENABLE, CFG_OTP_ENABLE);
> + if (ret)
> + goto out_unlock;
> +
> + if (is_write)
> + ret = ops->write(spinand, ofs, len, buf, retlen);
> + else
> + ret = ops->read(spinand, ofs, len, buf, retlen);
> +
> + if (spinand_upd_cfg(spinand, CFG_OTP_ENABLE, 0)) {
> + WARN(1, "Can not disable OTP mode\n");
Please avoid WARN() statements like that. A normal pr_warn is enough.
> + ret = -EIO;
> + }
> +
> +out_unlock:
> + mutex_unlock(&spinand->lock);
> + return ret;
> +}
> +
> +static int spinand_mtd_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
Can you keep the naming consistent? ofs vs. from ^
> + size_t *retlen, u8 *buf)
> +{
> + return spinand_mtd_otp_rw(mtd, from, len, retlen, buf, false);
> +}
> +
> +static int spinand_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
> + size_t *retlen, const u8 *buf)
> +{
> + return spinand_mtd_otp_rw(mtd, to, len, retlen, (u8 *)buf, true);
> +}
> +
> +static int spinand_mtd_otp_erase(struct mtd_info *mtd, loff_t from, size_t len)
> +{
> + struct spinand_device *spinand = mtd_to_spinand(mtd);
> + const struct spinand_otp_ops *ops = spinand->otp->ops;
> + int ret;
> +
> + if (!ops->erase)
> + return -EOPNOTSUPP;
> +
> + if (!len)
> + return 0;
This check seems sensible but is absent in the other helpers. Any
reason? Please add it to _lock() and _rw()
> +
> + if (from < 0 || (from + len) > spinand_otp_size(spinand))
> + return -EINVAL;
And this is also repeated three times, it is probably worth factorizing
out.
> +
> + mutex_lock(&spinand->lock);
> + ret = ops->erase(spinand, from, len);
> + mutex_unlock(&spinand->lock);
> +
> + return ret;
> +}
> +
> +static int spinand_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
> +{
> + struct spinand_device *spinand = mtd_to_spinand(mtd);
> + const struct spinand_otp_ops *ops = spinand->otp->ops;
> + int ret;
> +
> + if (!ops->lock)
> + return -EOPNOTSUPP;
> +
> + if (from < 0 || (from + len) > spinand_otp_size(spinand))
> + return -EINVAL;
> +
> + mutex_lock(&spinand->lock);
> + ret = ops->lock(spinand, from, len);
> + mutex_unlock(&spinand->lock);
> +
> + return ret;
> +}
> +
> +/**
> + * spinand_set_mtd_otp_ops() - Set up OTP methods
> + * @spinand: the spinand device
> + *
> + * Set up OTP methods.
> + */
> +void spinand_set_mtd_otp_ops(struct spinand_device *spinand)
> +{
> + struct mtd_info *mtd = spinand_to_mtd(spinand);
> +
> + if (!spinand->otp->ops)
> + return;
> +
> + mtd->_get_user_prot_info = spinand_mtd_otp_info;
> + mtd->_read_user_prot_reg = spinand_mtd_otp_read;
> + mtd->_write_user_prot_reg = spinand_mtd_otp_write;
> + mtd->_lock_user_prot_reg = spinand_mtd_otp_lock;
> + mtd->_erase_user_prot_reg = spinand_mtd_otp_erase;
> +}
> diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
> index 555846517faf6..a0d42a9be333f 100644
> --- a/include/linux/mtd/spinand.h
> +++ b/include/linux/mtd/spinand.h
> @@ -322,6 +322,43 @@ struct spinand_ondie_ecc_conf {
> u8 status;
> };
>
> +/**
> + * struct spinand_otp_layout - structure to describe the SPI NAND OTP area
> + * @npages: number of pages in the OTP
> + */
> +struct spinand_otp_layout {
> + unsigned int npages;
> +};
> +
> +/**
> + * struct spinand_otp_ops - SPI NAND OTP methods
> + * @info: Get the OTP area information
> + * @lock: lock an OTP region
> + * @erase: erase an OTP region
> + * @read: read from the SPI NAND OTP area
> + * @write: write to the SPI NAND OTP area
> + */
> +struct spinand_otp_ops {
> + int (*info)(struct spinand_device *spinand, size_t len,
> + struct otp_info *buf, size_t *retlen);
> + int (*lock)(struct spinand_device *spinand, loff_t from, size_t len);
> + int (*erase)(struct spinand_device *spinand, loff_t from, size_t len);
> + int (*read)(struct spinand_device *spinand, loff_t from, size_t len,
> + u8 *buf, size_t *retlen);
> + int (*write)(struct spinand_device *spinand, loff_t from, size_t len,
> + const u8 *buf, size_t *retlen);
> +};
> +
> +/**
> + * struct spinand_otp - SPI NAND OTP grouping structure
> + * @layout: OTP region layout
> + * @ops: OTP access ops
> + */
> +struct spinand_otp {
> + const struct spinand_otp_layout layout;
> + const struct spinand_otp_ops *ops;
> +};
> +
> /**
> * struct spinand_info - Structure used to describe SPI NAND chips
> * @model: model name
> @@ -354,6 +391,7 @@ struct spinand_info {
> } op_variants;
> int (*select_target)(struct spinand_device *spinand,
> unsigned int target);
> + struct spinand_otp otp;
> };
>
> #define SPINAND_ID(__method, ...) \
> @@ -379,6 +417,14 @@ struct spinand_info {
> #define SPINAND_SELECT_TARGET(__func) \
> .select_target = __func,
>
> +#define SPINAND_OTP_INFO(__npages, __ops) \
> + .otp = { \
> + .layout = { \
> + .npages = __npages, \
> + }, \
> + .ops = __ops, \
> + }
> +
> #define SPINAND_INFO(__model, __id, __memorg, __eccreq, __op_variants, \
> __flags, ...) \
> { \
> @@ -422,6 +468,7 @@ struct spinand_dirmap {
> * passed in spi_mem_op be DMA-able, so we can't based the bufs on
> * the stack
> * @manufacturer: SPI NAND manufacturer information
> + * @otp: SPI NAND OTP info.
> * @priv: manufacturer private data
> */
> struct spinand_device {
> @@ -450,6 +497,7 @@ struct spinand_device {
> u8 *oobbuf;
> u8 *scratchbuf;
> const struct spinand_manufacturer *manufacturer;
> + const struct spinand_otp *otp;
> void *priv;
> };
>
> @@ -525,4 +573,12 @@ int spinand_read_page(struct spinand_device *spinand,
> int spinand_write_page(struct spinand_device *spinand,
> const struct nand_page_io_req *req);
>
> +void spinand_set_mtd_otp_ops(struct spinand_device *spinand);
> +
> +int spinand_otp_read(struct spinand_device *spinand, loff_t from, size_t len,
> + u8 *buf, size_t *retlen);
> +
> +int spinand_otp_write(struct spinand_device *spinand, loff_t from, size_t len,
> + const u8 *buf, size_t *retlen);
> +
Why exposing spinand_otp_read and spinand_otp_write ?
> #endif /* __LINUX_MTD_SPINAND_H */
Thanks,
Miquèl
More information about the linux-mtd
mailing list