[PATCH] ata: ahci_platform: Add ACPI support for APM X-Gene AHCI controller v3 hardware.

[Graeme Gregory]

On Tue, Jun 21, 2016 at 04:31:38PM -0700, Suman Tripathi wrote:
> Hi Arnd,
> 
> On Tue, Jun 21, 2016 at 11:08 AM, Suman Tripathi <stripathi at apm.com> wrote:
> > On Wed, Jun 15, 2016 at 11:54 PM, Arnd Bergmann <arnd at arndb.de> wrote:
> >>
> >> On Wednesday, June 15, 2016 5:44:00 PM CEST suman-tripathi wrote:
> >> > This patch adds ACPI support for APM X-Gene AHCI controller in
> >> > ahci_platform driver for v3 hardware. APM X-Gene AHCI controller
> >> > v3 hardware is fully compliant with ahci_platform driver and requires
> >> > no workaround quirk.
> >> >
> >> > Signed-off-by: Suman Tripathi <stripathi at apm.com>
> >> > ---
> >> >  drivers/ata/ahci_platform.c |    1 +
> >> >  1 files changed, 1 insertions(+), 0 deletions(-)
> >> >
> >> > diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
> >> > index 62a04c8..3395baf 100644
> >> > --- a/drivers/ata/ahci_platform.c
> >> > +++ b/drivers/ata/ahci_platform.c
> >> > @@ -86,6 +86,7 @@ MODULE_DEVICE_TABLE(of, ahci_of_match);
> >> >
> >> >  static const struct acpi_device_id ahci_acpi_match[] = {
> >> >         { ACPI_DEVICE_CLASS(PCI_CLASS_STORAGE_SATA_AHCI, 0xffffff) },
> >> > +       { "APMC0D33", 0},
> >> >         {},
> >> >  };
> >> >  MODULE_DEVICE_TABLE(acpi, ahci_acpi_match);
> >> >
> >>
> >> Doesn't the ACPI_DEVICE_CLASS entry take care of this? I thought it had been
> >
> >
> > yeah it also works. Just thought that we need something different as
> > our's is a non-PCI SATA.
> 
> Are you suggesting to introduce a new class ACPI_DEVICE_CLASS for
> non-pci ahci ? or to reuse the existing PCI_CLASS_STORAGE_SATA_AHCI ?

This was discussed when AMD Seattle SoC had the same issue and it was
decided in standards body and on LKML that using PCI device classes for
non PCI devices was fine.

Example from Overdrive DSDT

Device (AHC0)
{
  Name (_HID, "AMDI0600")  // _HID: Hardware ID
  Name (_UID, 0x00)  // _UID: Unique ID
  Name (_CCA, 0x01) // _CCA: Cache Coherency Attribute
  Name (_CLS,
    Package (0x03) // _CLS: Class Code
    {
      0x01,
      0x06,
      0x01
    })
  ...

Graeme