Re: [PATCH v13 2/4] mtd: spi-nor: spansion: Add support for volatile QE bit

[<Tudor.Ambarus@microchip.com>]

On 4/21/22 12:40, 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>
> Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> ---
> Changes in v13:
>   - Use 3-byte address width
> 
> Changes in v12:
>   - Rebase on top of Tudor's series
>     https://patchwork.ozlabs.org/project/linux-mtd/list/?series=295933
>   - Use macro directly instead of local variable
>   - Use nor->reg_proto instead of SNOR_PROTO_1_1_1
> 
> 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 | 59 ++++++++++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
> 
> diff --git a/drivers/mtd/spi-nor/spansion.c b/drivers/mtd/spi-nor/spansion.c
> index 43cd6cd92537..65ae3ade0b95 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
> @@ -113,6 +115,63 @@ 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;
> +       u8 cfr1v_written;
> +       int ret;
> +
> +       op = (struct spi_mem_op)
> +               CYPRESS_NOR_RD_ANY_REG_OP(3, SPINOR_REG_CYPRESS_CFR1V,
nor->addr_width is 3, isn't it? can we use nor->addr_width instead of 3, please?

> +                                         nor->bouncebuf);
> +       ret = spi_nor_read_any_reg(nor, &op, nor->reg_proto);
> +       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(3, SPINOR_REG_CYPRESS_CFR1V, 1,
same

> +                                         nor->bouncebuf);
> +       ret = spi_nor_write_any_volatile_reg(nor, &op, nor->reg_proto);
> +       if (ret)
> +               return ret;
> +
> +       cfr1v_written = nor->bouncebuf[0];
> +
> +       /* Read back and check it. */
> +       op = (struct spi_mem_op)
> +               CYPRESS_NOR_RD_ANY_REG_OP(3, SPINOR_REG_CYPRESS_CFR1V,
same

Thanks!
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