Re: Kernel Summit request for Discussion of future of ATA (libata)and IDE

[Robert Hancock]

Tejun Heo wrote:
> Robert Hancock wrote:
> > Here's my first cut at it. Compile tested only. This sets most controllers
> > to use 32-bit PIO except for those which could potentially be on a real ISA
> > or other 16-bit bus. It's a bit non-obvious what to do with some of the
> > drivers, so input is welcome.
> >
> > This implementation doesn't check the ata_id_has_dword_io at all, since it
> > would only make a difference on controllers where we don't really want to
> > use it anyway.
> >
> > It seems like regardless of whether we do 32-bit by default or not the 32-bit
> > data_xfer function should be added to libata core as we have several drivers
> > which duplicate the same code currently..
>
> Great, just some minor nitpicks as I don't have much idea about 16 bit ones.
>
> > +unsigned int ata_sff_data_xfer(struct ata_device *dev, unsigned char *buf,
> > +			       unsigned int buflen, int rw)
> > +{
> > +	struct ata_port *ap = dev->link->ap;
> > +	void __iomem *data_addr = ap->ioaddr.data_addr;
> > +	unsigned int words = buflen >> 2;
>
> dwords maybe?
>
> > +	unsigned int slop = buflen & 3;
> > +
> > +	/* Transfer multiple of 4 bytes */
> > +	if (rw == READ)
> > +		ioread32_rep(data_addr, buf, words);
> > +	else
> > +		iowrite32_rep(data_addr, buf, words);
> > +
> > +	/* Transfer trailing 1 byte, if any. */
>
> 1byte?

Yeah, those are both leftovers from the 16-bit code. I'll fix them up in 
the next version, if the approach looks good..

> Thanks.
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