Re: [PATCH v11 1/3] mtd: spi-nor: spansion: Add support for volatile QE bit

[<Tudor.Ambarus@microchip.com>]

On 4/18/22 08:41, tkuw584924@gmail.com wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> From: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
> 
> Some of Infineon chips support volatile version of configuration registers
> and it is recommended to update volatile registers in the field application
> due to a risk of the non-volatile registers corruption by power interrupt.
> 
> Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
> ---
> Changes in v11:
>   - Rebase on top of Tudor's series
>     https://patchwork.ozlabs.org/project/linux-mtd/list/?series=294490
> 
> Changes in v10:
>   - Remove dependencies on other series
> 
> Changes in v9:
>   - Rename function per mwalle's series
> 
> Changes in v8:
>   - Use spi_nor_read/write_reg() functions
>   - Use nor->bouncebuf instead of a variable on stack
> 
> Changes in v7:
>   - Add missing macro definitions in v6
> 
> Changes in v6:
>   - Remove multi die package support
> 
> Changes in v5:
>   - No change
> 
> Changes in v4:
>   - No change
> 
> Changes in v3:
>   - Add multi-die package parts support
> 
>  drivers/mtd/spi-nor/spansion.c | 60 ++++++++++++++++++++++++++++++++++
>  1 file changed, 60 insertions(+)
> 
> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
> index 952db7af6932..6bcd25180af4 100644
> --- a/drivers/mtd/spi-nor/spansion.c
> +++ b/drivers/mtd/spi-nor/spansion.c
> @@ -14,6 +14,8 @@
>  #define SPINOR_OP_CLSR         0x30    /* Clear status register 1 */
>  #define SPINOR_OP_RD_ANY_REG                   0x65    /* Read any register */
>  #define SPINOR_OP_WR_ANY_REG                   0x71    /* Write any register */
> +#define SPINOR_REG_CYPRESS_CFR1V               0x00800002
> +#define SPINOR_REG_CYPRESS_CFR1V_QUAD_EN       BIT(1)  /* Quad Enable */
>  #define SPINOR_REG_CYPRESS_CFR2V               0x00800003
>  #define SPINOR_REG_CYPRESS_CFR2V_MEMLAT_11_24  0xb
>  #define SPINOR_REG_CYPRESS_CFR3V               0x00800004
> @@ -117,6 +119,64 @@ static int cypress_nor_octal_dtr_dis(struct spi_nor *nor)
>         return 0;
>  }
> 
> +/**
> + * cypress_nor_quad_enable_volatile() - enable Quad I/O mode in volatile
> + *                                      register.
> + * @nor:       pointer to a 'struct spi_nor'
> + *
> + * It is recommended to update volatile registers in the field application due
> + * to a risk of the non-volatile registers corruption by power interrupt. This
> + * function sets Quad Enable bit in CFR1 volatile. If users set the Quad Enable
> + * bit in the CFR1 non-volatile in advance (typically by a Flash programmer
> + * before mounting Flash on PCB), the Quad Enable bit in the CFR1 volatile is
> + * also set during Flash power-up.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int cypress_nor_quad_enable_volatile(struct spi_nor *nor)
> +{
> +       struct spi_mem_op op;
> +       u32 reg_addr = SPINOR_REG_CYPRESS_CFR1V;
> +       u8 cfr1v_written;
> +       int ret;
> +
> +       op = (struct spi_mem_op)
> +               CYPRESS_NOR_RD_ANY_REG_OP(nor->addr_width, reg_addr,
> +                                         nor->bouncebuf);
> +       ret = spi_nor_read_reg(nor, &op, SNOR_PROTO_1_1_1);
> +       if (ret)
> +               return ret;
> +
> +       if (nor->bouncebuf[0] & SPINOR_REG_CYPRESS_CFR1V_QUAD_EN)
> +               return 0;
> +
> +       /* Update the Quad Enable bit. */
> +       nor->bouncebuf[0] |= SPINOR_REG_CYPRESS_CFR1V_QUAD_EN;
> +       op = (struct spi_mem_op)
> +               CYPRESS_NOR_WR_ANY_REG_OP(nor->addr_width, reg_addr, 1,
> +                                         nor->bouncebuf);
> +       ret = spi_nor_write_reg(nor, &op, SNOR_PROTO_1_1_1);
> +       if (ret)
> +               return ret;

should you call spi_nor_wait_until_ready() here?

> +
> +       cfr1v_written = nor->bouncebuf[0];
> +
> +       /* Read back and check it. */
> +       op = (struct spi_mem_op)
> +               CYPRESS_NOR_RD_ANY_REG_OP(nor->addr_width, reg_addr,
> +                                         nor->bouncebuf);
> +       ret = spi_nor_read_reg(nor, &op, SNOR_PROTO_1_1_1);
> +       if (ret)
> +               return ret;
> +
> +       if (nor->bouncebuf[0] != cfr1v_written) {
> +               dev_err(nor->dev, "CFR1: Read back test failed\n");
> +               return -EIO;
> +       }
> +
> +       return 0;
> +}
> +
>  /**
>   * cypress_nor_octal_dtr_enable() - Enable octal DTR on Cypress flashes.
>   * @nor:               pointer to a 'struct spi_nor'
> --
> 2.25.1
> 

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