Re: [Qemu-devel] [PATCH RFC 5/9] ich9: Document why cannot_instantiate_with_device_add_yet

[Paolo Bonzini <pbonzini@redhat.com>]

Il 10/10/2013 18:01, Paolo Bonzini ha scritto:
> Il 10/10/2013 16:42, armbru@redhat.com ha scritto:
>> From: Markus Armbruster <armbru@redhat.com>
>>
>> An ICH9 southbridge contains several PCI devices, some of them with
>> multiple functions.  We model each function as a separate qdev.  Two
>> of them need some special wiring set up in pc_q35_init() to work: the
>> LPC controller at 00:1f.0, and the SMBus controller at 00:1f.3.
>>
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>> ---
>>  hw/i2c/smbus_ich9.c | 6 +++++-
>>  hw/isa/lpc_ich9.c   | 7 +++++--
>>  2 files changed, 10 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/i2c/smbus_ich9.c b/hw/i2c/smbus_ich9.c
>> index c1ffa34..8d47eaf 100644
>> --- a/hw/i2c/smbus_ich9.c
>> +++ b/hw/i2c/smbus_ich9.c
>> @@ -97,11 +97,15 @@ static void ich9_smb_class_init(ObjectClass *klass, void *data)
>>      k->device_id = PCI_DEVICE_ID_INTEL_ICH9_6;
>>      k->revision = ICH9_A2_SMB_REVISION;
>>      k->class_id = PCI_CLASS_SERIAL_SMBUS;
>> -    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
>>      dc->vmsd = &vmstate_ich9_smbus;
>>      dc->desc = "ICH9 SMBUS Bridge";
>>      k->init = ich9_smbus_initfn;
>>      k->config_write = ich9_smbus_write_config;
>> +    /*
>> +     * Reason: part of ICH9 southbridge, needs to be wired up by
>> +     * pc_q35_init()
>> +     */
>> +    dc->cannot_instantiate_with_device_add_yet = true;
>>  }
>>  
>>  i2c_bus *ich9_smb_init(PCIBus *bus, int devfn, uint32_t smb_io_base)
>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
>> index ad841b5..d00d698 100644
>> --- a/hw/isa/lpc_ich9.c
>> +++ b/hw/isa/lpc_ich9.c
>> @@ -604,14 +604,17 @@ static void ich9_lpc_class_init(ObjectClass *klass, void *data)
>>      dc->reset = ich9_lpc_reset;
>>      k->init = ich9_lpc_initfn;
>>      dc->vmsd = &vmstate_ich9_lpc;
>> -    dc->cannot_instantiate_with_device_add_yet = true; /* FIXME explain why */
>>      k->config_write = ich9_lpc_config_write;
>>      dc->desc = "ICH9 LPC bridge";
>>      k->vendor_id = PCI_VENDOR_ID_INTEL;
>>      k->device_id = PCI_DEVICE_ID_INTEL_ICH9_8;
>>      k->revision = ICH9_A2_LPC_REVISION;
>>      k->class_id = PCI_CLASS_BRIDGE_ISA;
>> -
>> +    /*
>> +     * Reason: part of ICH9 southbridge, needs to be wired up by
>> +     * pc_q35_init()
>> +     */
>> +    dc->cannot_instantiate_with_device_add_yet = true;
>>  }
>>  
>>  static const TypeInfo ich9_lpc_info = {
>>
> 
> I think SMBus is fine.  Even though the standard configuration of the
> Q35 SMBus cannot be reproduced with -device, that's a problem of
> hw/i2c/smbus_eeprom.c, not of the smbus bridge itself.  I think
> hw/i2c/smbus_eeprom.c should rather be marked as
> cannot_instantiate_with_device_add_yet (which makes sense, because it
> has a PROP_PTR).
> 
> Alternatively, you can resuscitate the first two patches of
> http://lists.gnu.org/archive/html/qemu-devel/2012-02/msg00449.html

Ah, got it---the SMBus and LPC need to be connected to each other.
Still, the SMBus EEPROM is a candidate for
cannot_instantiate_with_device_add_yet.

Paolo