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SubjectRe: [PATCH v14 10/15] mtd: spi-nor: Parse SFDP SCCR Map
Date
On 9/30/20 9:57 PM, Pratyush Yadav wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> From: Tudor Ambarus <tudor.ambarus@microchip.com>
>
> Parse just the 22nd dword and look for the 'DTR Octal Mode Enable
> Volatile bit'.
>
> SPI_NOR_IO_MODE_EN_VOLATILE should be set just for the flashes
> that don't define the optional SFDP SCCR Map. For the others,
> let the SFDP do its job and fill the SNOR_F_IO_MODE_EN_VOLATILE
> flag. We avoid this way polluting the flash flags when declaring
> one.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> ---
> drivers/mtd/spi-nor/sfdp.c | 52 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 52 insertions(+)
>
> diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
> index ebc1188f7533..0b5b9ea44cfc 100644
> --- a/drivers/mtd/spi-nor/sfdp.c
> +++ b/drivers/mtd/spi-nor/sfdp.c
> @@ -21,6 +21,10 @@
> #define SFDP_SECTOR_MAP_ID 0xff81 /* Sector Map Table */
> #define SFDP_4BAIT_ID 0xff84 /* 4-byte Address Instruction Table */
> #define SFDP_PROFILE1_ID 0xff05 /* xSPI Profile 1.0 table. */
> +#define SFDP_SCCR_MAP_ID 0xff87 /*
> + * Status, Control and Configuration
> + * Register Map.
> + */
>
> #define SFDP_SIGNATURE 0x50444653U
>
> @@ -1195,6 +1199,50 @@ static int spi_nor_parse_profile1(struct spi_nor *nor,
> return ret;
> }
>
> +#define SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE BIT(31)
> +
> +/**
> + * spi_nor_parse_sccr() - Parse the Status, Control and Configuration Register
> + * Map.
> + * @nor: pointer to a 'struct spi_nor'
> + * @sccr_header: pointer to the 'struct sfdp_parameter_header' describing
> + * the SCCR Map table length and version.
> + * @params: pointer to the 'struct spi_nor_flash_parameter' to be.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_parse_sccr(struct spi_nor *nor,
> + const struct sfdp_parameter_header *sccr_header,
> + struct spi_nor_flash_parameter *params)
> +{
> + u32 *dwords, addr;
> + size_t len;
> + int ret;
> + u8 io_mode_en_volatile;

would a bool work here?

> +
> + len = sccr_header->length * sizeof(*dwords);
> + dwords = kmalloc(len, GFP_KERNEL);
> + if (!dwords)
> + return -ENOMEM;
> +
> + addr = SFDP_PARAM_HEADER_PTP(sccr_header);
> + ret = spi_nor_read_sfdp(nor, addr, len, dwords);
> + if (ret)
> + goto out;
> +
> + le32_to_cpu_array(dwords, sccr_header->length);
> +
> + io_mode_en_volatile = FIELD_GET(SCCR_DWORD22_OCTAL_DTR_EN_VOLATILE,
> + dwords[22]);
> +
> + if (io_mode_en_volatile)
> + nor->flags |= SNOR_F_IO_MODE_EN_VOLATILE;
> +
> +out:
> + kfree(dwords);
> + return ret;
> +}
> +
> /**
> * spi_nor_parse_sfdp() - parse the Serial Flash Discoverable Parameters.
> * @nor: pointer to a 'struct spi_nor'
> @@ -1300,6 +1348,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor,
> err = spi_nor_parse_profile1(nor, param_header, params);
> break;
>
> + case SFDP_SCCR_MAP_ID:
> + err = spi_nor_parse_sccr(nor, param_header, params);
> + break;
> +
> default:
> break;
> }
> --
> 2.28.0
>

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