Re: [PATCH v4 4/4] mtd: spi-nor: implement OTP erase for Winbond and similar flashes

From: Tudor.Ambarus
Date: Mon Mar 15 2021 - 04:43:16 EST

On 3/6/21 2:05 AM, 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@xxxxxxxx>

I skimmed through this, seems ok. Send 4/4 with the new ioctl addition
in a dedicated patch set, ideally both will go through the spi-nor/next
branch. For the new ioctl we'll need ACKs from all the mtd maintainers
and at least a Tested-by tag. Please send the mtd-utils changes too.

Cheers,
ta
> ---
> drivers/mtd/spi-nor/core.c | 4 +-
> drivers/mtd/spi-nor/core.h | 4 ++
> drivers/mtd/spi-nor/otp.c | 74 ++++++++++++++++++++++++++++++++++-
> drivers/mtd/spi-nor/winbond.c | 1 +
> 4 files changed, 79 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index ef7df26896f1..21a737804576 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -166,8 +166,8 @@ static int spi_nor_controller_ops_read_reg(struct spi_nor *nor, u8 opcode,
> return nor->controller_ops->read_reg(nor, opcode, buf, len);
> }
>
> -static int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
> - const u8 *buf, size_t len)
> +int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
> + const u8 *buf, size_t len)
> {
> if (spi_nor_protocol_is_dtr(nor->reg_proto))
> return -EOPNOTSUPP;
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index dfbf6ba42b57..ef62ec4625a1 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -213,6 +213,7 @@ struct spi_nor_otp_ops {
> int (*read)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
> int (*write)(struct spi_nor *nor, loff_t addr, size_t len, 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);
> };
>
> @@ -481,6 +482,8 @@ extern const struct spi_nor_manufacturer spi_nor_xmc;
> void spi_nor_spimem_setup_op(const struct spi_nor *nor,
> struct spi_mem_op *op,
> const enum spi_nor_protocol proto);
> +int spi_nor_controller_ops_write_reg(struct spi_nor *nor, u8 opcode,
> + const u8 *buf, size_t len);
> int spi_nor_write_enable(struct spi_nor *nor);
> int spi_nor_write_disable(struct spi_nor *nor);
> int spi_nor_set_4byte_addr_mode(struct spi_nor *nor, bool enable);
> @@ -506,6 +509,7 @@ ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
>
> 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, 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 4e8da9108c77..78ec79368c29 100644
> --- a/drivers/mtd/spi-nor/otp.c
> +++ b/drivers/mtd/spi-nor/otp.c
> @@ -8,6 +8,7 @@
> #include <linux/log2.h>
> #include <linux/mtd/mtd.h>
> #include <linux/mtd/spi-nor.h>
> +#include <linux/spi/spi-mem.h>
>
> #include "core.h"
>
> @@ -111,6 +112,50 @@ int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf
> return ret ?: written;
> }
>
> +/**
> + * spi_nor_otp_erase_secr() - erase one OTP region
> + * @nor: pointer to 'struct spi_nor'
> + * @to: offset to write to
> + * @len: number of bytes to write
> + * @buf: pointer to src buffer
> + *
> + * Erase one OTP region by using the SPINOR_OP_ESECR commands. 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)
> +{
> + int ret;
> +
> + ret = spi_nor_write_enable(nor);
> + if (ret)
> + return ret;
> +
> + if (nor->spimem) {
> + struct spi_mem_op op =
> + SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_ESECR, 0),
> + SPI_MEM_OP_ADDR(3, addr, 0),
> + SPI_MEM_OP_NO_DUMMY,
> + SPI_MEM_OP_NO_DATA);
> +
> + spi_nor_spimem_setup_op(nor, &op, nor->write_proto);
> +
> + ret = spi_mem_exec_op(nor->spimem, &op);
> + } else {
> + nor->bouncebuf[2] = addr & 0xff;
> + nor->bouncebuf[1] = (addr >> 8) & 0xff;
> + nor->bouncebuf[0] = (addr >> 16) & 0xff;
> +
> + ret = spi_nor_controller_ops_write_reg(nor, SPINOR_OP_ESECR,
> + nor->bouncebuf, 3);
> + }
> + 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 };
> @@ -319,11 +364,13 @@ 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_lock(struct mtd_info *mtd, loff_t from, size_t len)
> +static int spi_nor_mtd_otp_lock_erase(struct mtd_info *mtd, loff_t from,
> + size_t len, bool is_erase)
> {
> struct spi_nor *nor = mtd_to_spi_nor(mtd);
> const struct spi_nor_otp_ops *ops = spi_nor_otp_ops(nor);
> unsigned int region;
> + loff_t start;
> int ret;
>
> if (from < 0 || (from + len) > spi_nor_otp_size(nor))
> @@ -342,7 +389,12 @@ static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
>
> while (len) {
> region = spi_nor_otp_offset_to_region(nor, from);
> - ret = ops->lock(nor, region);
> + start = spi_nor_otp_region_start(nor, region);
> +
> + if (is_erase)
> + ret = ops->erase(nor, start);
> + else
> + ret = ops->lock(nor, region);
> if (ret)
> goto out;
>
> @@ -356,6 +408,23 @@ static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
> return ret;
> }
>
> +static int spi_nor_mtd_otp_lock(struct mtd_info *mtd, loff_t from, size_t len)
> +{
> + return spi_nor_mtd_otp_lock_erase(mtd, from, len, false);
> +}
> +
> +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 = spi_nor_otp_ops(nor);
> +
> + /* OTP erase is optional */
> + if (!ops->erase)
> + return -EOPNOTSUPP;
> +
> + return spi_nor_mtd_otp_lock_erase(mtd, from, len, true);
> +}
> +
> void spi_nor_otp_init(struct spi_nor *nor)
> {
> struct mtd_info *mtd = &nor->mtd;
> @@ -379,4 +448,5 @@ 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 9a3f8ff007fd..e04219ac11fd 100644
> --- a/drivers/mtd/spi-nor/winbond.c
> +++ b/drivers/mtd/spi-nor/winbond.c
> @@ -138,6 +138,7 @@ 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
>