[U-Boot] x86: acpi: Disabling SoC functions defined in ASL on a per board basis

[Bin Meng]

Hi George,

On Tue, Jun 14, 2016 at 8:46 PM, George McCollister
<george.mccollister at gmail.com> wrote:
> On Mon, Jun 13, 2016 at 8:45 PM, Bin Meng <bmeng.cn at gmail.com> wrote:
>> Hi George,
>>
>> On Tue, Jun 14, 2016 at 12:12 AM, George McCollister
>> <george.mccollister at gmail.com> wrote:
>>> On Fri, Jun 10, 2016 at 7:25 PM, Bin Meng <bmeng.cn at gmail.com> wrote:
>>>> Hi George,
>>>>
>>>> +Simon, Stefan
>>>>
>>>> On Fri, Jun 10, 2016 at 1:17 AM, George McCollister
>>>> <george.mccollister at gmail.com> wrote:
>>>>> Does anyone have any ideas on how we might go about disabling
>>>>> functions defined in arch/x86/include/asm/arch-*/acpi on a per board
>>>>> basis? With DT it's trivial to define all of the functions available
>>>>> on an SoC and default them to disabled in the .dtsi, then simply mark
>>>>> them as enabled in the board .dts if the board uses them. I need to
>>>>> disable the internal UART definition for the baytrail board I'm adding
>>>>> since if it's included the off chip UART gets killed when Linux does
>>>>> it's acpi_bus_scan.
>>>>>
>>>>
>>>> Which board are you using? Looks you are using a board that is similar
>>>> to conga-qeval20-qa3-e3845.
>>> I'm using an Advantech SOM-DB5800 carrier board with an SOM-6867 Com
>>> Express board installed. I have a patch almost ready to add it to
>>> u-boot. I'll need to make some changes to reflect recent patches and
>>> was hoping to get this issue and azalia configuration resolved as
>>> well. I could upstream it sooner but the UART will be broken in linux
>>> (unless hacked out of dsdt prior to build) and HD audio wouldn't work.
>>>
>>
>> Great, that means we will have another baytrail board support :)
>>
>>>>
>>>> See the TODO comments in arch/x86/include/asm/arch-baytrail/acpi/lpc.asl.
>>>>
>>>> /* Internal UART */
>>>> Device (IURT)
>>>> {
>>>> Name(_HID, EISAID("PNP0501"))
>>>> Name(_UID, 1)
>>>>
>>>> Method(_STA, 0, Serialized)
>>>> {
>>>> /*
>>>> * TODO:
>>>> *
>>>> * Need to hide the internal UART depending on whether
>>>> * internal UART is enabled or not so that external
>>>> * SuperIO UART can be exposed to system.
>>>> */
>>>> Store(1, UI3E)
>>>> Store(1, UI4E)
>>>> Store(1, C1EN)
>>>> Return (STA_VISIBLE)
>>>> }
>>>>
>>>> To solve this, we need introduce a variable that is set at runtime by
>>>> U-Boot to tell the ASL codes to hide the internal UART. This is
>>>> documented in README.x86 below as optional features, but I also
>>>> mentioned we will need this sooner or later.
>>> Okay, I see how this is handled in coreboot. Looks like global_nvs_t
>>> for fsp_baytrail in coreboot has over 20 parameters I suppose I'd just
>>> start with one and it would be expanded as needed. I need to
>>> investigate more about gnvs then maybe I can implement it, time
>>> permitting.
>>>
>>
>> That's actually on my todo list. I will see if I can implement this
>> soon while leaving you to focus on HD audio.
>
> Sounds great!
>

Patches are available at u-boot-x86/gnvs-working branch now. Please test it.

Regards,
Bin