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SubjectRe: [PATCH v14 08/15] mtd: spi-nor: core: enable octal DTR mode when possible
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
>
> Allow flashes to specify a hook to enable octal DTR mode. Use this hook
> whenever possible to get optimal transfer speeds.
>
> Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> ---
> drivers/mtd/spi-nor/core.c | 35 +++++++++++++++++++++++++++++++++++
> drivers/mtd/spi-nor/core.h | 2 ++
> 2 files changed, 37 insertions(+)
>
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 73a26e7e32c2..6b54a923002a 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3068,6 +3068,35 @@ static int spi_nor_init_params(struct spi_nor *nor)
> return 0;
> }
>
> +/** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
> + * @nor: pointer to a 'struct spi_nor'
> + * @enable: whether to enable or disable Octal DTR
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_octal_dtr_enable(struct spi_nor *nor, bool enable)
> +{
> + int ret;
> +
> + if (!nor->params->octal_dtr_enable)
> + return 0;
> +
> + if (!(nor->read_proto == SNOR_PROTO_8_8_8_DTR &&
> + nor->write_proto == SNOR_PROTO_8_8_8_DTR))
> + return 0;
> +
> + ret = nor->params->octal_dtr_enable(nor, enable);

Ideally patch 9/15 and 10/15 should have been before 8/15. We should deny
the access to octal dtr enable for NV flashes since moment 0.

> + if (ret)
> + return ret;
> +
> + if (enable)
> + nor->reg_proto = SNOR_PROTO_8_8_8_DTR;
> + else
> + nor->reg_proto = SNOR_PROTO_1_1_1;
> +
> + return 0;
> +}
> +
> /**
> * spi_nor_quad_enable() - enable Quad I/O if needed.
> * @nor: pointer to a 'struct spi_nor'
> @@ -3107,6 +3136,12 @@ static int spi_nor_init(struct spi_nor *nor)
> {
> int err;
>
> + err = spi_nor_octal_dtr_enable(nor, true);
> + if (err) {
> + dev_dbg(nor->dev, "octal mode not supported\n");
> + return err;
> + }
> +
> err = spi_nor_quad_enable(nor);
> if (err) {
> dev_dbg(nor->dev, "quad mode not supported\n");
> diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
> index 9a33c8d07335..5cfe2db9ee13 100644
> --- a/drivers/mtd/spi-nor/core.h
> +++ b/drivers/mtd/spi-nor/core.h
> @@ -203,6 +203,7 @@ struct spi_nor_locking_ops {
> * higher index in the array, the higher priority.
> * @erase_map: the erase map parsed from the SFDP Sector Map Parameter
> * Table.
> + * @octal_dtr_enable: enables SPI NOR octal DTR mode.
> * @quad_enable: enables SPI NOR quad mode.
> * @set_4byte_addr_mode: puts the SPI NOR in 4 byte addressing mode.
> * @convert_addr: converts an absolute address into something the flash
> @@ -226,6 +227,7 @@ struct spi_nor_flash_parameter {
>
> struct spi_nor_erase_map erase_map;
>
> + int (*octal_dtr_enable)(struct spi_nor *nor, bool enable);
> int (*quad_enable)(struct spi_nor *nor);
> int (*set_4byte_addr_mode)(struct spi_nor *nor, bool enable);
> u32 (*convert_addr)(struct spi_nor *nor, u32 addr);
> --
> 2.28.0
>

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