qbus: register reset handler for qbus whose parent is NULL

Stefan Weil reported the regression caused by
ec990eb622ad46df5ddcb1e94c418c271894d416 as follows

> The second regression also occurs with MIPS malta.
> Networking no longer works with the default pcnet nic.
>
> This is caused because the reset function for pcnet is no
> longer called during system boot. The result in an invalid
> mac address (all zero) and a non-working nic.
>
> For this second regression I still have no simple solution.
> Of course mips_malta.c should be converted to qdev which
> would fix both problems (but only for malta system emulation).

The issue is, it is assumed that all qbuses, qdeves are under
main_system_bus. But there are qbuses whose parent is NULL. So it
is necessary to trigger reset for those qbuses.
(On the other hand, if NULL is passed to qdev_create(), its parent bus
is main_system_bus.)
Ideally those buses should be moved under bus controller
device which is qdev. But it's not done yet.
So register qbus reset handler for qbus whose parent is NULL.

Reported-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Tested-by: Stefan Weil <weil@mail.berlios.de>
---
 hw/qdev.c |    5 ++++-
 vl.c      |    2 ++
 2 files changed, 6 insertions(+), 1 deletions(-)

On Sun, Dec 19, 2010 at 10:22:50AM +0900, Isaku Yamahata wrote:
> Stefan Weil reported the regression caused by
> ec990eb622ad46df5ddcb1e94c418c271894d416 as follows
> 
> > The second regression also occurs with MIPS malta.
> > Networking no longer works with the default pcnet nic.
> >
> > This is caused because the reset function for pcnet is no
> > longer called during system boot. The result in an invalid
> > mac address (all zero) and a non-working nic.
> >
> > For this second regression I still have no simple solution.
> > Of course mips_malta.c should be converted to qdev which
> > would fix both problems (but only for malta system emulation).
> 
> The issue is, it is assumed that all qbuses, qdeves are under
> main_system_bus. But there are qbuses whose parent is NULL. So it
> is necessary to trigger reset for those qbuses.
> (On the other hand, if NULL is passed to qdev_create(), its parent bus
> is main_system_bus.)
> Ideally those buses should be moved under bus controller
> device which is qdev. But it's not done yet.
> So register qbus reset handler for qbus whose parent is NULL.
> 
> Reported-by: Stefan Weil <weil@mail.berlios.de>
> Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
> Tested-by: Stefan Weil <weil@mail.berlios.de>
> ---
>  hw/qdev.c |    5 ++++-
>  vl.c      |    2 ++
>  2 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/qdev.c b/hw/qdev.c
> index 10e28df..774c53b 100644
> --- a/hw/qdev.c
> +++ b/hw/qdev.c
> @@ -753,8 +753,11 @@ void qbus_create_inplace(BusState *bus, BusInfo *info,
>      if (parent) {
>          QLIST_INSERT_HEAD(&parent->child_bus, bus, sibling);
>          parent->num_child_bus++;
> +    } else if (bus != main_system_bus) {
> +        /* TODO: once all device is qdevified,
> +           reset handler for main_system_bus should also be registered here */


Something like: 'TODO: remove the below once all bus devices are qdevified'?

> +        qemu_register_reset((void *)qbus_reset_all, bus);
>      }
> -
>  }
>  

Don't we need to unregister the reset on free?

>  BusState *qbus_create(BusInfo *info, DeviceState *parent, const char *name)
> diff --git a/vl.c b/vl.c
> index c4d3fc0..2ec3989 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3088,6 +3088,8 @@ int main(int argc, char **argv, char **envp)
>          exit(1);
>      }
>  
> +    /* TODO: once all device is qdevified, this should be done by
> +       qbus_create_inplace() */

all device is -> all system bus devices are

>      qemu_register_reset((void *)qbus_reset_all, sysbus_get_default());
>      qemu_run_machine_init_done_notifiers();


Actually the casts both here and above are pretty scary.
I think we need a wrapper that gets the proper arguments
and does the container_of properly.

>  
> -- 
> 1.7.1.1