Re: [PATCH v14 10/15] mtd: spi-nor: Parse SFDP SCCR Map

From: Pratyush Yadav
Date: Thu Oct 01 2020 - 07:56:30 EST


On 01/10/20 08:20AM, 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
> >
> > From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxx>
> > Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
> > ---
> > 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
> > 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?

It should. I'll change it.

> > +
> > + 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;
> > +}
> > +
> > /**
>

--
Regards,
Pratyush Yadav
Texas Instruments India