Re: [Qemu-devel] [PATCH 1/5] i8259: qdev-ify creation

[Jan Kiszka]

On 2012-01-12 09:05, Alexander Graf wrote:
> 
> On 12.01.2012, at 09:00, Jan Kiszka wrote:
> 
>> On 2012-01-12 08:58, Alexander Graf wrote:
>>>
>>> On 12.01.2012, at 08:35, Jan Kiszka wrote:
>>>
>>>> On 2012-01-12 01:04, Andreas Färber wrote:
>>>>> Alex,
>>>>>
>>>>> I have this in my mailbox, but I'm still waiting for an SoB. Hervé?
>>>>>
>>>>> Regards,
>>>>> Andreas
>>>>>
>>>>> -------- Original-Nachricht --------
>>>>> Betreff: [PATCH 1/5] i8259: qdev-ify creation
>>>>> Datum: Sun, 26 Jun 2011 14:47:09 +0200
>>>>> Von: Hervé Poussineau <address@hidden>
>>>>> An: address@hidden
>>>>> Kopie (CC): Hervé Poussineau <address@hidden>
>>>>>
>>>>> ---
>>>>> hw/i8259.c |   53 +++++++++++++++++++++++++++++++++++++++++++++++++----
>>>>> 1 files changed, 49 insertions(+), 4 deletions(-)
>>>>>
>>>>> diff --git a/hw/i8259.c b/hw/i8259.c
>>>>> index 84d330d..59e8bd6 100644
>>>>> --- a/hw/i8259.c
>>>>> +++ b/hw/i8259.c
>>>>> @@ -26,6 +26,7 @@
>>>>> #include "isa.h"
>>>>> #include "monitor.h"
>>>>> #include "qemu-timer.h"
>>>>> +#include "sysbus.h"
>>>>>
>>>>> /* debug PIC */
>>>>> //#define DEBUG_PIC
>>>>> @@ -524,16 +525,60 @@ void irq_info(Monitor *mon)
>>>>>
>>>>> qemu_irq *i8259_init(qemu_irq parent_irq)
>>>>> {
>>>>> -    PicState2 *s;
>>>>> +    DeviceState *dev;
>>>>> +    dev = qdev_create(NULL, "i8259");
>>>>> +    qdev_init_nofail(dev);
>>>>> +    qdev_connect_gpio_out(dev, 0, parent_irq);
>>>>> +
>>>>> +    return dev->gpio_in;
>>>>> +}
>>>>> +
>>>>> +typedef struct SysBusPicState2 {
>>>>> +    SysBusDevice busdev;
>>>>> +    PicState2 state;
>>>>> +} SysBusPicState2;
>>>>> +
>>>>> +static void i8259_set_irq_sysbus(void *opaque, int line, int level)
>>>>> +{
>>>>> +    SysBusPicState2 *sysbus = opaque;
>>>>> +    PicState2 *s = &sysbus->state;
>>>>> +    i8259_set_irq(s, line, level);
>>>>> +}
>>>>> +
>>>>> +static int i8259_sysbus_init(SysBusDevice *dev)
>>>>> +{
>>>>> +    SysBusPicState2 *sysbus = FROM_SYSBUS(SysBusPicState2, dev);
>>>>> +    PicState2 *s = &sysbus->state;
>>>>> +
>>>>> +    if (isa_pic) {
>>>>> +        return 1;
>>>>> +    }
>>>>>
>>>>> -    s = qemu_mallocz(sizeof(PicState2));
>>>>>    pic_init1(0x20, 0x4d0, &s->pics[0]);
>>>>>    pic_init1(0xa0, 0x4d1, &s->pics[1]);
>>>>>    s->pics[0].elcr_mask = 0xf8;
>>>>>    s->pics[1].elcr_mask = 0xde;
>>>>> -    s->parent_irq = parent_irq;
>>>>>    s->pics[0].pics_state = s;
>>>>>    s->pics[1].pics_state = s;
>>>>>    isa_pic = s;
>>>>> -    return qemu_allocate_irqs(i8259_set_irq, s, 16);
>>>>> +
>>>>> +    qdev_init_gpio_in(&dev->qdev, i8259_set_irq_sysbus, 16);
>>>>> +    qdev_init_gpio_out(&dev->qdev, &s->parent_irq, 1);
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static SysBusDeviceInfo i8259_sysbus_info = {
>>>>> +    .qdev.name = "i8259",
>>>>> +    .qdev.size = sizeof(SysBusPicState2),
>>>>> +    .init = i8259_sysbus_init,
>>>>> +    .qdev.props = (Property[]) {
>>>>> +        DEFINE_PROP_END_OF_LIST()
>>>>> +    },
>>>>> +};
>>>>> +
>>>>> +static void i8259_register_devices(void)
>>>>> +{
>>>>> +   sysbus_register_withprop(&i8259_sysbus_info);
>>>>> }
>>>>> +
>>>>> +device_init(i8259_register_devices)
>>>>
>>>> This is obsolete. The i8259 has been significantly refactored (into two
>>>> ISA devices) and qdev'ified some moons ago.
>>>
>>> The reason we were discussing this was a circular dependency on PREP.
>>>
>>> The PIC is sitting on the ISA bus.
>>> The ISA bus is behind a PCI-ISA bridge
>>> the PCI-ISA bridge is behind a PCI host controller
>>> the PCI host controller needs interrupt lines in its initialization which 
>>> are attached to the PIC
>>>
>>> Any good ideas on how to resolve this? :)
>>
>> As we do this always: Split up initialization and IRQ line wiring.
> 
> Well, yes, the theory is obvious. How would this look like in practice? To 
> create a PIC device I need a bus:
> 
>     dev = isa_create(bus, "isa-i8259");
> 
> But to create the bus, I need an interrupt line, which I only get after I 
> created the PIC device.

ISA bus creation and IRQ assignment are split up IIRC.

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux