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Message-ID: <05a0b543-9069-b8d6-c337-bd33409155f5@microchip.com>
Date: Thu, 3 Jun 2021 05:30:37 +0000
From: <Tudor.Ambarus@...rochip.com>
To: <michael@...le.cc>, <linux-mtd@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>
CC: <p.yadav@...com>, <miquel.raynal@...tlin.com>, <richard@....at>,
<vigneshr@...com>
Subject: Re: [PATCH v4 4/4] mtd: spi-nor: otp: implement erase for Winbond and
similar flashes
On 5/21/21 10:40 PM, Michael Walle wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> Winbond flashes with OTP support provide a command to erase the OTP
> data. This might come in handy during development.
>
> This was tested with a Winbond W25Q32JW on a LS1028A SoC with the
> NXP FSPI controller.
>
> Signed-off-by: Michael Walle <michael@...le.cc>
> ---
> drivers/mtd/spi-nor/core.c | 2 +-
> drivers/mtd/spi-nor/core.h | 4 ++
> drivers/mtd/spi-nor/otp.c | 83 +++++++++++++++++++++++++++++++++++
> drivers/mtd/spi-nor/winbond.c | 1 +
> 4 files changed, 89 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index bd2c7717eb10..9551effb6a44 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -1318,7 +1318,7 @@ static u32 spi_nor_convert_addr(struct spi_nor *nor, loff_t addr)
> /*
> * Initiate the erasure of a single sector
> */
> -static int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
> +int spi_nor_erase_sector(struct spi_nor *nor, u32 addr)
> {
> int i;
>
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index 28a2e0be97a3..9398a8738857 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -207,6 +207,7 @@ struct spi_nor_otp_organization {
> * @read: read from the SPI NOR OTP area.
> * @write: write to the SPI NOR OTP area.
> * @lock: lock an OTP region.
> + * @erase: erase an OTP region.
> * @is_locked: check if an OTP region of the SPI NOR is locked.
> */
> struct spi_nor_otp_ops {
> @@ -214,6 +215,7 @@ struct spi_nor_otp_ops {
> int (*write)(struct spi_nor *nor, loff_t addr, size_t len,
> const u8 *buf);
> int (*lock)(struct spi_nor *nor, unsigned int region);
> + int (*erase)(struct spi_nor *nor, loff_t addr);
> int (*is_locked)(struct spi_nor *nor, unsigned int region);
> };
>
> @@ -503,10 +505,12 @@ ssize_t spi_nor_read_data(struct spi_nor *nor, loff_t from, size_t len,
> u8 *buf);
> ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
> const u8 *buf);
> +int spi_nor_erase_sector(struct spi_nor *nor, u32 addr);
>
> int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
> int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
> const u8 *buf);
> +int spi_nor_otp_erase_secr(struct spi_nor *nor, loff_t addr);
> int spi_nor_otp_lock_sr2(struct spi_nor *nor, unsigned int region);
> int spi_nor_otp_is_locked_sr2(struct spi_nor *nor, unsigned int region);
>
> diff --git a/drivers/mtd/spi-nor/otp.c b/drivers/mtd/spi-nor/otp.c
> index b87f96593c13..afa348a3af70 100644
> --- a/drivers/mtd/spi-nor/otp.c
> +++ b/drivers/mtd/spi-nor/otp.c
> @@ -120,6 +120,38 @@ int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
> return ret ?: written;
> }
>
> +/**
> + * spi_nor_otp_erase_secr() - erase a security register
> + * @nor: pointer to 'struct spi_nor'
> + * @addr: offset of the security register to be erased
> + *
> + * Erase a security register by using the SPINOR_OP_ESECR command.
> + *
> + * For more information on the term "security register", see the documentation
> + * of spi_nor_otp_read_secr().
> + *
> + * This method is used on GigaDevice and Winbond flashes.
> + *
> + * Return: 0 on success, -errno otherwise
> + */
> +int spi_nor_otp_erase_secr(struct spi_nor *nor, loff_t addr)
> +{
> + u8 erase_opcode = nor->erase_opcode;
> + int ret;
> +
> + ret = spi_nor_write_enable(nor);
> + if (ret)
> + return ret;
> +
> + nor->erase_opcode = SPINOR_OP_ESECR;
> + ret = spi_nor_erase_sector(nor, addr);
> + nor->erase_opcode = erase_opcode;
> + if (ret)
> + return ret;
> +
> + return spi_nor_wait_till_ready(nor);
> +}
> +
> static int spi_nor_otp_lock_bit_cr(unsigned int region)
> {
> static const int lock_bits[] = { SR2_LB1, SR2_LB2, SR2_LB3 };
> @@ -360,6 +392,56 @@ static int spi_nor_mtd_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
> return spi_nor_mtd_otp_read_write(mtd, to, len, retlen, buf, true);
> }
>
> +static int spi_nor_mtd_otp_erase(struct mtd_info *mtd, loff_t from, size_t len)
> +{
> + struct spi_nor *nor = mtd_to_spi_nor(mtd);
> + const struct spi_nor_otp_ops *ops = nor->params->otp.ops;
> + const size_t rlen = spi_nor_otp_region_len(nor);
> + unsigned int region;
> + loff_t rstart;
> + int ret;
> +
> + /* OTP erase is optional */
> + if (!ops->erase)
> + return -EOPNOTSUPP;
if (!len)
return 0;
> +
> + if (from < 0 || (from + len) > spi_nor_otp_size(nor))
> + return -EINVAL;
> +
> + /* the user has to explicitly ask for whole regions */
> + if (!IS_ALIGNED(len, rlen) || !IS_ALIGNED(from, rlen))
> + return -EINVAL;
> +
> + ret = spi_nor_lock_and_prep(nor);
> + if (ret)
> + return ret;
> +
> + ret = spi_nor_mtd_otp_range_is_locked(nor, from, len);
> + if (ret < 0) {
> + goto out;
> + } else if (ret) {
> + ret = -EROFS;
> + goto out;
> + }
> +
> + while (len) {
> + region = spi_nor_otp_offset_to_region(nor, from);
> + rstart = spi_nor_otp_region_start(nor, region);
> +
> + ret = ops->erase(nor, rstart);
> + if (ret)
> + goto out;
> +
> + len -= rlen;
> + from += rlen;
> + }
> +
> +out:
> + spi_nor_unlock_and_unprep(nor);
> +
> + return ret;
> +}
> +
> static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
> {
> struct spi_nor *nor = mtd_to_spi_nor(mtd);
> @@ -418,4 +500,5 @@ void spi_nor_otp_init(struct spi_nor *nor)
> mtd->_read_user_prot_reg = spi_nor_mtd_otp_read;
> mtd->_write_user_prot_reg = spi_nor_mtd_otp_write;
> mtd->_lock_user_prot_reg = spi_nor_mtd_otp_lock;
> + mtd->_erase_user_prot_reg = spi_nor_mtd_otp_erase;
> }
> diff --git a/drivers/mtd/spi-nor/winbond.c b/drivers/mtd/spi-nor/winbond.c
> index 9a81c67a60c6..96573f61caf5 100644
> --- a/drivers/mtd/spi-nor/winbond.c
> +++ b/drivers/mtd/spi-nor/winbond.c
> @@ -139,6 +139,7 @@ static int winbond_set_4byte_addr_mode(struct spi_nor *nor, bool enable)
> static const struct spi_nor_otp_ops winbond_otp_ops = {
> .read = spi_nor_otp_read_secr,
> .write = spi_nor_otp_write_secr,
> + .erase = spi_nor_otp_erase_secr,
> .lock = spi_nor_otp_lock_sr2,
> .is_locked = spi_nor_otp_is_locked_sr2,
> };
> --
> 2.20.1
>
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