Re: [Qemu-devel] [PATCH v3 0/5] add ACPI node for fw_cfg on pc and arm

[Michael S. Tsirkin]

On Thu, Sep 17, 2015 at 10:56:29AM -0400, Gabriel L. Somlo wrote:
> New since v2:
> 
>       - pc/i386 node in ssdt only on machine types *newer* than 2.4
>         (as suggested by Eduardo)
> 
> I appreciate any further comments and reviews. Hopefully we can make
> this palatable for upstream, modulo the lingering concerns about whether
> "QEMU0002" is ok to use as the value of _HID, which I'll hopefully get
> sorted out with the kernel crew...
> 
> Thanks much,
>   --Gabriel


What I'm still missing is the motivation for the change.

Went through old threads, still can't find it.

> >New since v1:
> >
> >     - expose control register size (suggested by Marc Marí)
> >
> >     - leaving out _UID and _STA fields (thanks Shannon & Igor)
> >
> >     - using "QEMU0002" as the value of _HID (thanks Michael)
> >
> >     - added documentation blurb to docs/specs/fw_cfg.txt
> >       (mainly to record usage of the "QEMU0002" string with fw_cfg).
> >
> >> This series adds a fw_cfg device node to the SSDT (on pc), or to the
> >> DSDT (on arm).
> >>
> >>    - Patch 1/3 moves (and renames) the BIOS_CFG_IOPORT (0x510)
> >>      define from pc.c to pc.h, so that it could be used from
> >>      acpi-build.c in patch 2/3.
> >> 
> >>    - Patch 2/3 adds a fw_cfg node to the pc SSDT.
> >> 
> >>    - Patch 3/3 adds a fw_cfg node to the arm DSDT.
> >>
> >> I made up some names - "FWCF" for the node name, and "FWCF0001"
> >> for _HID; no idea whether that's appropriate, or how else I should
> >> figure out what to use instead...
> >>
> >> Also, using scope "\\_SB", based on where fw_cfg shows up in the
> >> output of "info qtree". Again, if that's wrong, please point me in
> >> the right direction.
> >>
> >> Re. 3/3 (also mentioned after the commit blurb in the patch itself),
> >> I noticed none of the other DSDT entries contain a _STA field, wondering
> >> why it would (not) make sense to include that, same as on the PC.
> 
> Gabriel L. Somlo (5):
>   fw_cfg: expose control register size in fw_cfg.h
>   pc: fw_cfg: move ioport base constant to pc.h
>   acpi: pc: add fw_cfg device node to ssdt
>   acpi: arm: add fw_cfg device node to dsdt
>   fw_cfg: document ACPI device node information
> 
>  docs/specs/fw_cfg.txt     |  9 +++++++++
>  hw/arm/virt-acpi-build.c  | 13 +++++++++++++
>  hw/i386/acpi-build.c      | 21 +++++++++++++++++++++
>  hw/i386/pc.c              |  5 ++---
>  hw/i386/pc_piix.c         |  1 +
>  hw/i386/pc_q35.c          |  1 +
>  hw/nvram/fw_cfg.c         |  8 +++++---
>  include/hw/i386/pc.h      |  3 +++
>  include/hw/nvram/fw_cfg.h |  3 +++
>  9 files changed, 58 insertions(+), 6 deletions(-)
> 
> -- 
> 2.4.3