Re: [PATCH] hw/char/mchp_pfsoc_mmuart: QOM'ify PolarFire MMUART

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On 9/23/21 12:41, Peter Maydell wrote:
> On Thu, 23 Sept 2021 at 11:29, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>> On 9/23/21 07:16, Bin Meng wrote:> On Sun, Sep 19, 2021 at 2:07 AM
>> Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>>> +static void mchp_pfsoc_mmuart_realize(DeviceState *dev, Error **errp)
>>>> +{
>>>> +    MchpPfSoCMMUartState *s = MCHP_PFSOC_UART(dev);
>>>> +
>>>> +    qdev_prop_set_uint8(DEVICE(&s->serial_mm), "regshift", 2);
>>>> +    qdev_prop_set_uint32(DEVICE(&s->serial_mm), "baudbase", 399193);
>>>> +    qdev_prop_set_uint8(DEVICE(&s->serial_mm), "endianness",
>>>> +                        DEVICE_LITTLE_ENDIAN);
>>>
>>> It looks like serial_mm_init() does one more thing:
>>>
>>>       qdev_set_legacy_instance_id(DEVICE(smm), base, 2);
>>>
>>> I am not sure what that is.
>>
>> I'll defer on Paolo / Marc-André for that part, I think this is for
>> migrating legacy (x86?) machines, which is not the case.
> 
> Yes, this is only needed for backwards-compatibility of incoming
> migration data with old versions of QEMU which implemented migration
> of devices with hand-rolled code. If a device didn't previously
> handle migration at all then it should not now be setting the
> legacy instance ID.

Thanks. I'll try to add that in the documentation somewhere.

> Speaking of migration, I notice that this QOM conversion does
> not add a vmstate, which usually we do as part of the QOM conversion.
> The device is also missing a reset method.

OK, I'll add that in a previous patch.

Thanks,

Phil.