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

[Miquel Raynal <miquel.raynal@bootlin.com>]

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

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