Re: [Qemu-devel] [PATCH v5 19/20] hw/arm/virt-acpi-build: Add PCIe controller in ACPI DSDT table

[Igor Mammedov <imammedo@redhat.com>]

On Wed, 29 Apr 2015 11:12:04 +0800
Shannon Zhao <zhaoshenglong@huawei.com> wrote:

> On 2015/4/28 23:54, Michael S. Tsirkin wrote:
> > On Tue, Apr 28, 2015 at 05:13:10PM +0200, Igor Mammedov wrote:
> >>> Here I need to set the value of buffer to 1 or 0, we could
> >>> createbitfield, but if we want to set the value to non one or zero and
> >>> the BufferSize is large, how could we do? CreateByteField? It's a little
> >>> complex for user.
> >> that's what one would have to do writing it in ASL if bits
> >> are flipped on/off dynamically.
> >>
> >> In ASL you also can declare buffer with static initializer
> >>
> >>    Buffer (0x01) { 0x03 }
> >>
> >> and compiler is smart enough to set appropriate bits but it doesn't
> >> allow you to do so with large values. For example:
> >>
> >>    Buffer (0x01) { 0xAABBCCDD }
> >>
> >> gives error:
> >> Error 6139 - Constant out of range ^  (0xAABBCCDD, allowable: 0x0-0xFF)
> >>
> >> If one wants to manipulate specific fields in Buffer, ASL has
> >> a bunch of CreateFOOField operators, so lets follow spec and use
> >> API consistently to avoid confusion.
> >>
> >> BTW:
> >> packaging value as int (even without prefix) is wrong since
> >> its LE encoding will shuffle bytes and you won't get bits in
> >> positions that you expect if value is more than 1 byte.
> > 
> > I don't care about ASL, we are writing in C
> > But AML is same:
> > DefBuffer := BufferOp PkgLength BufferSize ByteList
> > BufferOp := 0x11
> > BufferSize := TermArg => Integer
> > 
> > So really just a bytelist.
> > We don't have any users for aml_buffer, maybe just add
> > const uint8_t *bytes, unsigned len as parameters.
> > 
> 
> Agree. It's consistent with the spec. If want to modify the value, could
> use CreateFOOField.
> 
> So use following fuction to initialize Buffer?
> 
> /* ACPI 1.0b: 16.2.5.4 Type 2 Opcodes Encoding: DefBuffer */
> Aml *aml_buffer(int buffer_size, uint8_t *byte_list)
> {
>     int i;
>     Aml *var = aml_bundle(0x11 /* BufferOp */, AML_BUFFER);
>     for (i = 0; i < buffer_size; i++) {
>         build_append_byte(var->buf, *(byte_list + i));
>     }
>     return var;
> }
maybe

Aml *aml_buffer_initialized(int buffer_size, uint8_t *byte_list);
Aml *aml_buffer(int buffer_size);

the second one is needed for implementing code like:
Name(BUFF, Buffer(4){}) // Create SerialBus data buffer as BUFF
CreateByteField(BUFF, 0x00, STAT) // STAT = Status (Byte)
CreateWordField(BUFF, 0x02, DATA) // DATA = Data (Byte)

and could reuse aml_buffer_initialized() to reserve space.

> 
> > Would that be enough?
> > 
> > 
> >>>
> >>>> ifctx1 = aml_if(aml_equal(aml_arg(2), aml_int(0)));
> >>>> aml_append(ifctx1, aml_store(aml_name("FNEN", aml_int(1)));
> >>>> ...
> >>>> /* create bit field for every supported function if supported */
> >>>> ...
> >>>> aml_append(method, aml_return(aml_name("RET")));
> >>>>
> >>>>
> >>>>>
> >>>>>>>
> >>>>>>>> +    aml_append(ifctx1, aml_return(buf));
> >>>>>>>> +    aml_append(ifctx, ifctx1);
> >>>>>>>> +    aml_append(method, ifctx);
> >>>>>>>> +
> >>>>>>>> +    buf = aml_buffer();
> >>>>>>>> +    build_append_int_noprefix(buf->buf, 0x00, 1);
> >>>>>>>> +    aml_append(method, aml_return(buf));
> >>>>>>>> +    aml_append(dev, method);
> >>>>>>>> +
> >>>>>>>> +    Aml *dev_rp0 = aml_device("%s", "RP0");
> >>>>>>>> +    aml_append(dev_rp0, aml_name_decl("_ADR", aml_int(0)));
> >>>>>>>> +    aml_append(dev, dev_rp0);
> >>>>>>>> +    aml_append(scope, dev);
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>>  /* RSDP */
> >>>>>>>>  static GArray *
> >>>>>>>>  build_rsdp(GArray *rsdp_table, GArray *linker, unsigned rsdt)
> >>>>>>>> @@ -318,6 +468,8 @@ build_dsdt(GArray *table_data, GArray *linker, VirtGuestInfo *guest_info)
> >>>>>>>>      acpi_dsdt_add_flash(scope, info->flash_memmap);
> >>>>>>>>      acpi_dsdt_add_virtio(scope, info->virtio_mmio_memmap,
> >>>>>>>>               info->virtio_mmio_irq, info->virtio_mmio_num);
> >>>>>>>> +    acpi_dsdt_add_pci(scope, guest_info->pcie_info);
> >>>>>>>> +
> >>>>>>>>      aml_append(dsdt, scope);
> >>>>>>>>  
> >>>>>>>>      /* copy AML table into ACPI tables blob and patch header there */
> >>>>>>
> >>>>>> .
> >>>>>>
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>> .
> >>>>
> >>>
> >>>
> > 
> > .
> > 
> 
>