Re: [PATCH 06/10] drm/i915/spi: spi register with mtd

Miquel Raynal
2023-10-17T13:56:05Z

Hi Alexander,

alexander.usyskin@intel.com wrote on Tue, 17 Oct 2023 11:54:41 +0000:

> Hi Miquel,
>
> > > +static int i915_spi_init_mtd(struct i915_spi *spi, struct device *device,
> > > + unsigned int nparts)
> > > +{
> > > + unsigned int i;
> > > + unsigned int n;
> > > + struct mtd_partition *parts = NULL;
> > > + int ret;
> > > +
> > > + dev_dbg(device, "registering with mtd\n");
> > > +
> > > + spi->mtd.owner = THIS_MODULE;
> > > + spi->mtd.dev.parent = device;
> > > + spi->mtd.flags = MTD_CAP_NORFLASH | MTD_WRITEABLE;
> > > + spi->mtd.type = MTD_DATAFLASH;
> > > + spi->mtd.priv = spi;
> > > + spi->mtd._write = i915_spi_write;
> > > + spi->mtd._read = i915_spi_read;
> > > + spi->mtd._erase = i915_spi_erase;
> > > + spi->mtd._get_device = i915_spi_get_device;
> > > + spi->mtd._put_device = i915_spi_put_device;
> > > + spi->mtd.writesize = SZ_1; /* 1 byte granularity */
> >
> > You say writesize should be aligned with 4 in your next patch?
>
> We support unaligned write by reading aligned 4bytes,
> replacing changed bytes there and writing whole 4bytes back.
> Is there any problem with this approach?

Is there a reason to do that manually rather than letting the core
handle the complexity?

>
> >
> > > + spi->mtd.erasesize = SZ_4K; /* 4K bytes granularity */
> > > + spi->mtd.size = spi->size;
> > > +
>

Thanks,
Miquèl