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

[Shannon Zhao <zhaoshenglong@huawei.com>]

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;
}

> 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 */
>>>>>>
>>>>>> .
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> .
>>>>
>>>
>>>
> 
> .
>