On Tue, Mar 31, 2020 at 12:29 PM Kevin O'Connor <ke...@koconnor.net> wrote:
>
> On Tue, Mar 31, 2020 at 04:53:02PM +0200, Gerd Hoffmann wrote:
> > On Fri, Mar 27, 2020 at 09:15:19AM -0400, Kevin O'Connor wrote:
> > > On Fri, Mar 27, 2020 at 09:12:06AM +0100, Gerd Hoffmann wrote:
> > > > > Something like:
> > > > >
> > > > > struct hlist_head DSDTTree;
> > > > >
> > > > > struct dsdt_entry {
> > > > > struct hlist_node node;
> > > > > char *name; // eg, "_SB.PCI0.ISA.COM1._HID"
> > > > > int type; // eg: Device, Name, Integer, String, ResourceTemplate,
> > > > > other
> > > > > void *value; // points to integer, string, resource template, or
> > > > > NULL
> > > > > };
> > > > >
> > > > > Once the tree is parsed, it should be simple to walk the in-memory
> > > > > linked-list to find desired values later.
> > > >
> > > > I was thinking more about storing a list of devices with parsed data,
> > > > i.e. basically put into a linked list what the current code collects
> > > > in the parse_dev struct.
> > >
> > > FWIW, I suspect it will be painful to grow 'struct parse_dev' if there
> > > are future users. (For example, if there is more than one memory
> > > range needed, if it is necessary to check for the existence of some
> > > name other than _STA, etc. .) In contrast, I suspect a few helper
> > > functions that can walk the tree would be sufficient to extract the
> > > info currently in 'struct parse_dev' as needed.
> >
> > Went with a hybrid approach now. parse_dev is still there, but for the
> > most part part it stores pointers into the dsdt table and parsing
> > happens later as needed.
> >
> > sneak preview @ https://git.kraxel.org/cgit/seabios/log/?h=dsdt
>
> Thanks. FWIW, I think the code would be simpler if it first parsed
> the tree into an internal structure, and then searched for _STA, _HID,
> etc. Attempting to do both at the same time seems to complicate the
> code.
>
> > > > Then we can easily lookup the virtio-mmio devices later. Maybe also
> > > > check for isa devices (don't bother waiting for ps2 probe timeout if
> > > > acpi says there isn't a keyboard ...). I don't see any other use
> > > > cases.
> > >
> > > It would be helpful to extract the location of builtin sdcards from
> > > the dsdt (currently, the "etc/sdcard" cbfs file is used instead).
> >
> > That'll be used with coreboot, right? How do sdcard dsdt entries look
> > like?
>
> Yes, with coreboot. I don't recall the details right now - perhaps
> Matt or John recall?
currently, the etc/sdcard entries point to the PCI BAR0 for the
eMMC/SD controllers on Baytrail/Braswell devices which coreboot puts
into ACPI mode. Those values are somewhat build-specific (ie, they
differ between the stock Google firmware and upstream coreboot), and
are extracted from the cbmem log of a booted system. They aren't
directly contained in the DSDT anywhere either -- you'll just find
references to BAR0 inside the EMMC/SDCD objects, which is a GNVS
variable.
>
> -Kevin
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