Re: [Qemu-devel] [PATCH 00/31] PPC: mpc8544ds: Create device tree dynamically

[Blue Swirl]

On Tue, Jun 5, 2012 at 11:52 PM, Alexander Graf <address@hidden> wrote:
> Today we have two separate places where we keep information which device
> is where:
>
>  - hw/ppce500_mpc8544ds.c to instantiate all devices
>  - pc-bios/mpc8544ds.dtb as device tree to tell the guest about devices
>
> Every time we split crucial information, things can go terribly wrong. If
> you update one file, but not the other, you can screw things up without
> realizing it quickly.
>
> The redundancy is also unnecessary, because QEMU already knows all the
> information at which addresses its devices live. So we can generate the
> device tree from the same variables - and even have the device tree adjust
> if something changes in there.
>
> The one functionality we lose with this approach is the ability to manually
> patch the device tree to contain additional devices. To still be able to do
> so easily, we introduce a new option -machine dumpdtb=<file> that creates a
> dtb output file which can be used with -machine dtb=<file> later. In between
> these 2 executions of QEMU, the dtb can be modified however much you like.
>
> A lot of bits in this patch set are still hardcoded. We also don't accomodate
> for dynamic creation of device tree nodes when -device is used. This requires
> a bit more QOM'ification for us to be able to loop through all devices, so we
> can dynamically create the device tree nodes for them. The basic concept 
> should
> still hold as is though.
>
>
> Alex

Please use snprintf() instead of sprintf().

>
> v1 -> v2:
>
>  - rename cell64 -> u64
>  - don't treat memory as single u64
>  - remove commit id from patch description
>  - NEW: PPC: e500: Use new MPIC dt format
>         PPC: e500: Use new SOC dt format
>         PPC: e500: Define addresses as always 64bit
>         PPC: e500: Extend address/size of / to 64bit
>         dt: Add global option to set phandle start offset
>         PPC: e500: Refactor serial dt generation
>
> Alexander Graf (31):
>  dt: allow add_subnode to create root subnodes
>  dt: add helpers for 2, 3 and 4 cell adds
>  dt: add helper for phandle references
>  dt: temporarily disable subtree creation failure check
>  dt: add helper for phandle enumeration
>  dt: add helper for empty dt creation
>  dt: add helper for phandle allocation
>  dt: add helper for 64bit cell adds
>  PPC: e500: require libfdt
>  PPC: e500: dt: create memory node dynamically
>  PPC: e500: dt: create /cpus node dynamically
>  PPC: e500: dt: create /hypervisor node dynamically
>  PPC: e500: dt: create / node dynamically
>  PPC: e500: dt: create /chosen node dynamically
>  PPC: e500: dt: create /soc8544 node dynamically
>  PPC: e500: dt: create serial nodes dynamically
>  PPC: e500: dt: create mpic node dynamically
>  PPC: e500: dt: create global-utils node dynamically
>  PPC: e500: dt: create pci node dynamically
>  PPC: e500: dt: start with empty device tree
>  dt: Add -machine dumpdtb option to dump the current dtb
>  PPC: e500: dt: use 64bit cell helper
>  PPC: e500: dt: use target_phys_addr_t for ramsize
>  PPC: e500: enable manual loading of dtb blob
>  Revert "dt: temporarily disable subtree creation failure check"
>  PPC: e500: Use new MPIC dt format
>  PPC: e500: Use new SOC dt format
>  PPC: e500: Define addresses as always 64bit
>  PPC: e500: Extend address/size of / to 64bit
>  dt: Add global option to set phandle start offset
>  PPC: e500: Refactor serial dt generation
>
>  Makefile               |    1 -
>  Makefile.target        |    2 +-
>  device_tree.c          |  134 +++++++++++++++++++++++++++-
>  device_tree.h          |   16 +++
>  hw/ppce500_mpc8544ds.c |  237 +++++++++++++++++++++++++++++++++++++++++------
>  pc-bios/mpc8544ds.dtb  |  Bin 2028 -> 0 bytes
>  pc-bios/mpc8544ds.dts  |  119 ------------------------
>  qemu-config.c          |    8 ++
>  roms/openbios          |    2 +-
>  9 files changed, 365 insertions(+), 154 deletions(-)
>  delete mode 100644 pc-bios/mpc8544ds.dtb
>  delete mode 100644 pc-bios/mpc8544ds.dts
>
>