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Subject: Re: [PATCH v3 02/38] ata: add HAS_IOPORT dependencies
From:   Niklas Schnelle <schnelle@linux.ibm.com>
To:     Arnd Bergmann <arnd@arndb.de>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Alan Stern <stern@rowland.harvard.edu>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-kernel@vger.kernel.org,
        Linux-Arch <linux-arch@vger.kernel.org>,
        linux-pci@vger.kernel.org, Arnd Bergmann <arnd@kernel.org>,
        linux-ide@vger.kernel.org
Date:   Fri, 28 Apr 2023 15:32:07 +0200
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On Thu, 2023-03-16 at 16:21 +0100, Arnd Bergmann wrote:
> On Thu, Mar 16, 2023, at 00:57, Damien Le Moal wrote:
> > On 2023/03/15 20:36, Geert Uytterhoeven wrote:
>=20
> > Ah. OK. I see now. So indeed, applying the dependency on the entire ATA=
_SFF
> > group of drivers is very coarse.
>=20
>=20
> > Can you change this to apply the dependency per driver ?
>=20
> I think that will fail to build because of this function
> on architectures that drop their non-functional
> inb/outb helpers:
>=20
> int ata_pci_bmdma_clear_simplex(struct pci_dev *pdev)
> {
>         unsigned long bmdma =3D pci_resource_start(pdev, 4);
>         u8 simplex;
> =20
>         if (bmdma =3D=3D 0)
>                 return -ENOENT;
> =20
>         simplex =3D inb(bmdma + 0x02);=20
>         outb(simplex & 0x60, bmdma + 0x02);
>         simplex =3D inb(bmdma + 0x02);
>         if (simplex & 0x80)
>                 return -EOPNOTSUPP;
>         return 0;
> }
>=20
> This is only called from five pata drivers (ali, amd,
> cmd64x, netcell, serverworks), so an easy workaround
> would be to make sure those depend on HAS_IOPORT
> and enclose the function definition in an #ifdef.
>=20
>         Arnd

There were a few additional inb()/outb() uses so a few more drivers had
to have the dependency added but for v4 it will no longer be on the
ATA_SFF option and I used your suggestion above for this function.
There was another call to it in ata_generic_init_one() that is only
done for PCI_VENDOR_ID_AL so I added an #ifdef CONFIG_PATA_ALI around
that.

Thanks,
Niklas