[PATCH v1 07/43] dm: acpi: Add support for the NHLT table

[Simon Glass]

Hi Bin,

On Thu, 2 Jul 2020 at 22:33, Bin Meng <bmeng.cn at gmail.com> wrote:
>
> Hi Simon,
>
> On Fri, Jul 3, 2020 at 11:50 AM Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Bin,
> >
> > On Thu, 2 Jul 2020 at 18:54, Bin Meng <bmeng.cn at gmail.com> wrote:
> > >
> > > Hi Simon,
> > >
> > > On Fri, Jul 3, 2020 at 8:46 AM Simon Glass <sjg at chromium.org> wrote:
> > > >
> > > > Hi Bin,
> > > >
> > > > On Mon, 29 Jun 2020 at 20:49, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > >
> > > > > Hi Simon,
> > > > >
> > > > > On Mon, Jun 15, 2020 at 11:57 AM Simon Glass <sjg at chromium.org> wrote:
> > > > > >
> > > > > > The Intel Non-High-Definition-Audio Link Table (NHLT) table describes the
> > > > > > audio codecs and connections in a system. Various devices can contribute
> > > > > > information to produce the table.
> > > > > >
> > > > > > Add core support for this, based on a structure which is built up through
> > > > > > calls to the driver.
> > > > > >
> > > > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > > > ---
> > > > > >
> > > > > >  drivers/core/acpi.c | 15 +++++++++++++++
> > > > > >  include/dm/acpi.h   | 26 ++++++++++++++++++++++++++
> > > > > >  2 files changed, 41 insertions(+)
> > > > > >
> > > > > > diff --git a/drivers/core/acpi.c b/drivers/core/acpi.c
> > > > > > index ea304a3067..a5053fec6f 100644
> > > > > > --- a/drivers/core/acpi.c
> > > > > > +++ b/drivers/core/acpi.c
> > > > > > @@ -31,6 +31,7 @@ enum method_t {
> > > > > >         METHOD_WRITE_TABLES,
> > > > > >         METHOD_FILL_SSDT,
> > > > > >         METHOD_INJECT_DSDT,
> > > > > > +       METHOD_SETUP_NHLT,
> > > > >
> > > > > Do we really need to promote this to be an ACPI core method? Can we
> > > > > reuse the SSDT/DSDT one?
> > > >
> > > > I don't think so. Those two are for a particular purpose. In fact NHLT
> > > > is generated while doing SSDT I think. The idea is that drivers that
> > > > want to contribute to NHLT can do so. But we cannot use the SSDT
> > > > mechanism since each driver contributes only a part of the info, and
> > > > we need something else to bring it all together.
> > >
> > > Will there be only one device that sets up the NHLT info?
> >
> > WIth coral it is two devices. I'm not sure of the maximum, but I
> > suppose it depends on the audio codecs present.
>
> Could we make this method to be provided by the codec device, instead
> of a generic ACPI core method?

The codec device does implement this. See the drivers where they
actually implement the NHLT method.

This is definitely an ACPI-specific thing, so I think we need core
support for iterating through drivers that want to provide this info.

Regards,
Simon