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

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Message-ID: <20201001115612.7i4d2wmeinv2kyz5@ti.com>
Date:   Thu, 1 Oct 2020 17:26:14 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     <Tudor.Ambarus@...rochip.com>
CC:     <miquel.raynal@...tlin.com>, <richard@....at>, <vigneshr@...com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <nsekhar@...com>, <boris.brezillon@...labora.com>
Subject: Re: [PATCH v14 10/15] mtd: spi-nor: Parse SFDP SCCR Map

On 01/10/20 08:20AM, Tudor.Ambarus@...rochip.com 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@...rochip.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@...rochip.com>
> > Signed-off-by: Pratyush Yadav <p.yadav@...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
> >         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