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

[<Tudor.Ambarus@microchip.com>]

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@walle.cc>

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
>