Re: [PATCH 7/8] ide: add struct ide_port_info instances to legacy host drivers

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Sat, Feb 02, 2008 at 12:35:30AM +0100, Bartlomiej Zolnierkiewicz wrote:
> > > Index: b/drivers/ide/arm/icside.c
> > > ===================================================================
> > > --- a/drivers/ide/arm/icside.c
> > > +++ b/drivers/ide/arm/icside.c
> > > @@ -459,11 +456,19 @@ icside_register_v5(struct icside_state *
> > >  
> > >  	idx[0] = hwif->index;
> > >  
> > > -	ide_device_add(idx);
> > > +	ide_device_add(idx, NULL);
> > >  
> > >  	return 0;
> > >  }
> > >  
> > > +static const struct ide_port_info icside_v6_port_info __initdata = {
> > > +	.host_flags		= IDE_HFLAG_SERIALIZE |
> > > +				  IDE_HFLAG_NO_DMA | /* no SFF-style DMA */
> > > +				  IDE_HFLAG_NO_AUTOTUNE,
> > > +	.mwdma_mask		= ATA_MWDMA2,
> > > +	.swdma_mask		= ATA_SWDMA2,
> > > +};
> > > +
> > 
> >     Interesting... this driver's support for SWDMA0 is broken since the cycle 
> > should be 960 ns long, not 480, and SWDMA2 is underclocked using the same 
> > cycle as SWDMA1, 480 ns...
> 
> Added Russell to Cc:.

Underclocking the DMA is not a problem - if you look at the timing
diagrams and associated tables in the ATA specifications, you'll
find that they specify the *minimum* cycle timings.

However, you're correct that SWDMA0 is not able to be supported.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of: