Re: [RESEND PATCH] arm: assabet_defconfig: disable IDE subsystem

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

On Thursday, March 09, 2017 03:42:49 PM Bartlomiej Zolnierkiewicz wrote:

> > Yes, it's very obscure - but what it comes down to is the silly way the
> > "ISA" IO is handled on the platform (which depends whether it's an 8-bit
> > or 16-bit ISA-style peripheral.)  The old IDE CS driver _could_ be bent
> > to work via a patch like this:
> > 
> > ARM: EBSA110: Enable 16-bit IO type for ide-iops
> > 
> > diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> > index 047a20780fc1..2eb501d6b5fe 100644
> > --- a/arch/arm/Makefile
> > +++ b/arch/arm/Makefile
> > @@ -217,7 +217,8 @@ ifeq ($(CONFIG_ARCH_EBSA110),y)
> >  # This is what happens if you forget the IOCS16 line.
> >  # PCMCIA cards stop working.
> >  CFLAGS_3c589_cs.o :=-DISA_SIXTEEN_BIT_PERIPHERAL
> > -export CFLAGS_3c589_cs.o
> > +CFLAGS_ide-io-std.o :=-DISA_SIXTEEN_BIT_PERIPHERAL
> > +export CFLAGS_3c589_cs.o CFLAGS_ide-io-std.o
> >  endif
> 
> As I've already explained in the past, the proper fix for the problem
> (for both old IDE and libata) is to define custom transport ops in
> ide-cs.c/ata_pcmcia.c and use them on affected platforms.
> 
> >  # The byte offset of the kernel image in RAM from the start of RAM.
> > 
> > but the PATA driver is much harder.
> 
> There are a lot examples of using your own transport operations in
> existing code (i.e. pata_octeon_cf.c or drivers/ata/sata_rcar.c).

Basically it should come down to copypasting all transport ops
from libata-sff.c and replacing all ioread8()/iowrite8() with
__inb16()__outb16(). Then you need to add detection of EBSA1100
which should also be as simple as using machine_is_ebsa110() in
the proper place.

If you ever get to running current upstream on your EBSA110
I can provide you with the draft patch doing this.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics