Re: [PATCH 3/3] hw/input/pckbd: Rename i8042_setup_a20_line() and its a20 irq argument

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

On 11/22/21 12:14, Peter Maydell wrote:
> On Fri, 5 Nov 2021 at 17:21, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>>
>> 'a20_out' is an input IRQ, rename it as 'a20_input'.
>> i8042_setup_a20_line() doesn't take a Device parameter
>> but an ISADevice one. Rename it as i8042_isa_*() to
>> make it explicit.
>>
>> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
>> ---
>>  include/hw/input/i8042.h | 2 +-
>>  hw/i386/pc.c             | 2 +-
>>  hw/input/pckbd.c         | 4 ++--
>>  3 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/include/hw/input/i8042.h b/include/hw/input/i8042.h
>> index 1d90432daef..3534fcc4b43 100644
>> --- a/include/hw/input/i8042.h
>> +++ b/include/hw/input/i8042.h
>> @@ -21,6 +21,6 @@ void i8042_mm_init(qemu_irq kbd_irq, qemu_irq mouse_irq,
>>                     MemoryRegion *region, ram_addr_t size,
>>                     hwaddr mask);
>>  void i8042_isa_mouse_fake_event(ISAKBDState *isa);
>> -void i8042_setup_a20_line(ISADevice *dev, qemu_irq a20_out);
>> +void i8042_isa_setup_a20_line(ISADevice *dev, qemu_irq a20_input);
>>
>>  #endif /* HW_INPUT_I8042_H */
>> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
>> index 2592a821486..06ef74ca22b 100644
>> --- a/hw/i386/pc.c
>> +++ b/hw/i386/pc.c
>> @@ -1043,7 +1043,7 @@ static void pc_superio_init(ISABus *isa_bus, bool create_fdctrl, bool no_vmport)
>>      port92 = isa_create_simple(isa_bus, TYPE_PORT92);
>>
>>      a20_line = qemu_allocate_irqs(handle_a20_line_change, first_cpu, 2);
>> -    i8042_setup_a20_line(i8042, a20_line[0]);
>> +    i8042_isa_setup_a20_line(i8042, a20_line[0]);
> 
> I think these days we can directly call
>     qdev_connect_gpio_out_named(DEVICE(i8042), I8042_A20_LINE, 0, a20_line[0]);
> and drop the i8042_setup_a20_line() wrapper entirely,
> since the named GPIO lines are a "public" interface to the device.
> We only have this i8042_setup_a20_line() because the original
> implementation (added in commit 956a3e6bb738) predates gpio lines
> and did an assignment into the KBDState struct which needed to
> be private to pckbd.c.
> 
>>      qdev_connect_gpio_out_named(DEVICE(port92),
>>                                  PORT92_A20_LINE, 0, a20_line[1]);
> 
> That would then make it consistent with how we're wiring up the
> other A20 input source here.

Very good point, thank you.

> (Some day we should perhaps make the A20 input to the CPU an actual
> GPIO input on the CPU device object, so we could wire the I8042_A20_LINE
> and PORT92_A20_LINE to it via an OR gate, and drop the intermidate
> qemu_irq array and handle_a20_line_change function. But needing
> the OR gate makes that a little clunky so I'm not sure it's
> really worth the effort.)

I once worked on an "info irqtree" HMP command; if I finish it
then would be nice to display.