CXL 2.0 specification adds 2 new dwords to the existing _OSC definition
from PCIe. The new dwords are accessed with a new uuid. This
implementation supports what is in the specification.

iasl -d decodes the result of this patch as:

Name (SUPP, Zero)
Name (CTRL, Zero)
Name (SUPC, Zero)
Name (CTRC, Zero)
Method (_OSC, 4, NotSerialized)  // _OSC: Operating System Capabilities
{
    CreateDWordField (Arg3, Zero, CDW1)
    If (((Arg0 == ToUUID ("33db4d5b-1ff7-401c-9657-7441c03dd766") /* PCI Host Bridge Device */) || (Arg0 == ToUUID ("68f2d50b-c469-4d8a-bd3d-941a103fd3fc") /* Unknown UUID */)))
    {
        CreateDWordField (Arg3, 0x04, CDW2)
        CreateDWordField (Arg3, 0x08, CDW3)
        Local0 = CDW3 /* \_SB_.PC0C._OSC.CDW3 */
        Local0 &= 0x1F
        If ((Arg1 != One))
        {
            CDW1 |= 0x08
        }

        If ((CDW3 != Local0))
        {
            CDW1 |= 0x10
        }

        SUPP = CDW2 /* \_SB_.PC0C._OSC.CDW2 */
        CTRL = CDW3 /* \_SB_.PC0C._OSC.CDW3 */
        CDW3 = Local0
        If ((Arg0 == ToUUID ("68f2d50b-c469-4d8a-bd3d-941a103fd3fc") /* Unknown UUID */))
        {
            CreateDWordField (Arg3, 0x0C, CDW4)
            CreateDWordField (Arg3, 0x10, CDW5)
            SUPC = CDW4 /* \_SB_.PC0C._OSC.CDW4 */
            CTRC = CDW5 /* \_SB_.PC0C._OSC.CDW5 */
            CDW5 |= One
        }

        Return (Arg3)
    }
    Else
    {
        CDW1 |= 0x04
        Return (Arg3)
    }

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-Id: <20220429144110.25167-25-Jonathan.Cameron@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>