[U-Boot] [PATCH v3] arm: add acpi support for the arm

[Simon Glass <sjg@chromium.org>]

Hi,

On Mon, 25 Nov 2019 at 15:57, Heinrich Schuchardt <xypron.glpk@gmx.de> wrote:
>
> On 11/25/19 3:42 AM, Steven Hao wrote:> 获取 Outlook for iOS
> <https://aka.ms/o0ukef>
> > ------------------------------------------------------------------------
> > *发件人:* Bin Meng <bmeng.cn@gmail.com>
> > *发送时间:* Monday, November 25, 2019 10:13:40 AM
> > *收件人:* Steven Hao <steven_hao5189@outlook.com>
> > *抄送:* xypron.glpk at gmx.de <xypron.glpk@gmx.de>; liuhao at phytium.com.cn
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> > patrice.chotard at st.com <patrice.chotard@st.com>; afd at ti.com
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> > Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > *主题:* Re: [PATCH v3] arm: add acpi support for the arm
> > Hi Steven,
> >
> > On Mon, Nov 25, 2019 at 10:09 AM Steven Hao <steven_hao5189@outlook.com>
> > wrote:
> >>
> >> Dear Bin：
> >>
> >> Firstly：
> >> I know that acpi about x86 is existing. And it is usefull for x86
> platfporm. If it  is used to arm platform，some modification may have to
> do. For example，facs table is useless for arm.
> >>
> >> In adition，The acpi table is writed statically and then modified
> dynamically in my patch. It is a new method.
> >>
> >> I want to consult that whether my method is helpful or not.
> >>
> >> Secondly：
> >> If i want to reuse the x86-acpi. I will overwrite the
> write_acpi_tables function. But the definition about acpi strcuture is
> placed in arch/x86/include/asm directory. It can not be used to arm
> plateform. If the acpi library need to surport for all platform，i  think
> it should move to /include directory.
> >>
> >
> > Yes, we all are aware that modifications are needed to the existing
> > x86 ACPI support to support ARM. We don't want to create 2 ACP
> > implementation in U-Boot.
> >
> > Regards,
> > Bin> Dear Bin：
> >
> > I have a suggetion that the acpi specification definition such as all
> > acpi table structure definition  should be place in /include directory.
> > and write_acpi_tables function can be placed in platform directory.
> >   Creating acpi table mothod  can be diffrent between x86 and arm.
> >
> > Thank you
> > Steven Hao
> >
>
> Currently we are using CPU specific C files generating ACPI tables, e.g.
> arch/x86/cpu/tangier/acpi.c.
>
> I would prefer if we would generate the ACPI tables and definition
> blocks completely from text files instead of using C code. This would
> avoid any architecture specific code.

I am finding with Apollo Lake that this isn't possible - we need to
insert run-time information into the tables set up with .asl files.

>
> Such table generation is already in use in the Windows world. See:
> https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/generate-acpi-tables-by-using-acpigenfx

That looks like a programmatic way to create ACPI tables. If so, I'm
trying to bring something similar over from coreboot.

Regards,
Simon