Re: [PATCH v14 08/15] mtd: spi-nor: core: enable octal DTR mode when possible

From: Pratyush Yadav
Date: Thu Oct 01 2020 - 04:42:24 EST


On 01/10/20 08:09AM, Tudor.Ambarus@xxxxxxxxxxxxx wrote:
> 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@xxxxxx>
> > ---
> > 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.

Ok. I'll re-order them.

> > + 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
> >
>

--
Regards,
Pratyush Yadav
Texas Instruments India