On Monday, November 25, 2019, Marc-André Lureau <marcandre.lur...@redhat.com>
wrote:
> Hi
>
> On Mon, Nov 25, 2019 at 2:12 PM Aleksandar Markovic
> <aleksandar.m.m...@gmail.com> wrote:
> >
> >
> >
> > On Wednesday, November 20, 2019, Marc-André Lureau <
> marcandre.lur...@redhat.com> wrote:
> >>
> >> The function is specific to mipssim, let's inline it.
> >>
> >> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> >> ---
> >> hw/char/serial.c | 16 ----------------
> >> hw/mips/mips_mipssim.c | 15 ++++++++++++---
> >> include/hw/char/serial.h | 2 --
> >> 3 files changed, 12 insertions(+), 21 deletions(-)
> >>
> >> diff --git a/hw/char/serial.c b/hw/char/serial.c
> >> index 164146ede8..23f0b02516 100644
> >> --- a/hw/char/serial.c
> >> +++ b/hw/char/serial.c
> >> @@ -1023,22 +1023,6 @@ static const TypeInfo serial_io_info = {
> >> .class_init = serial_io_class_init,
> >> };
> >>
> >> -SerialIO *serial_init(int base, qemu_irq irq, int baudbase,
> >> - Chardev *chr, MemoryRegion *system_io)
> >> -{
> >> - SerialIO *sio = SERIAL_IO(qdev_create(NULL, TYPE_SERIAL_IO));
> >> -
> >> - qdev_prop_set_uint32(DEVICE(sio), "baudbase", baudbase);
> >> - qdev_prop_set_chr(DEVICE(sio), "chardev", chr);
> >> - qdev_set_legacy_instance_id(DEVICE(sio), base, 2);
> >> - qdev_init_nofail(DEVICE(sio));
> >> -
> >> - sysbus_connect_irq(SYS_BUS_DEVICE(sio), 0, irq);
> >> - memory_region_add_subregion(system_io, base, &sio->serial.io);
> >> -
> >> - return sio;
> >> -}
> >> -
> >> static Property serial_properties[] = {
> >> DEFINE_PROP_CHR("chardev", SerialState, chr),
> >> DEFINE_PROP_UINT32("baudbase", SerialState, baudbase, 115200),
> >> diff --git a/hw/mips/mips_mipssim.c b/hw/mips/mips_mipssim.c
> >> index 282bbecb24..bfafa4d7e9 100644
> >> --- a/hw/mips/mips_mipssim.c
> >> +++ b/hw/mips/mips_mipssim.c
> >> @@ -40,6 +40,7 @@
> >> #include "hw/loader.h"
> >> #include "elf.h"
> >> #include "hw/sysbus.h"
> >> +#include "hw/qdev-properties.h"
> >> #include "exec/address-spaces.h"
> >> #include "qemu/error-report.h"
> >> #include "sysemu/qtest.h"
> >> @@ -219,9 +220,17 @@ mips_mipssim_init(MachineState *machine)
> >> * A single 16450 sits at offset 0x3f8. It is attached to
> >> * MIPS CPU INT2, which is interrupt 4.
> >> */
> >> - if (serial_hd(0)) a
> >> - serial_init(0x3f8, env->irq[4], 115200, serial_hd(0),
> >> - get_system_io());
> >> + if (serial_hd(0)) {
> >> + DeviceState *dev = qdev_create(NULL, TYPE_SERIAL_IO);
> >> +
> >> + qdev_prop_set_uint32(DEVICE(dev), "baudbase", 115200);
> >> + qdev_prop_set_chr(dev, "chardev", serial_hd(0));
> >> + qdev_set_legacy_instance_id(dev, 0x3f8, 2);
> >> + qdev_init_nofail(dev);
> >> + sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, env->irq[4]);
> >> + memory_region_add_subregion(get_system_io(), 0x3f8,
> >> + &SERIAL_IO(dev)->serial.io);
> >> + }
> >
> >
> >
> > Please explain why the code in the deleted function and the new function
> are not identical. Why is the new code better?
>
> What differences do you spot?
>
> serial_init() looks very generic, but it is not, and this is
> confusing. QDev users should call qdev_create().
>
> If there is a single user, it is better to inline the code where it is
> being used, or move the function there.
>
>
Marc-Andre, you misunderstood me: I am not complaining about inlining at
all, I would do the same if I were you.
I just see you expressed the same thing from former function in a slightly
different way in the inlined version, and they look functionally equivalent
to me. But I suppose the new way is better, and I want to know why. Is it a
more standard way, or something even more? Please understand that I don't
come from device emulation background - I want to learn a little bit about
device-related QEMU customs and conventions, that is all. :)
For example,
in old version:
>> -SerialIO *serial_init(int base, qemu_irq irq, int baudbase,
>> - Chardev *chr, MemoryRegion *system_io)
>> -{
>> - SerialIO *sio = SERIAL_IO(qdev_create(NULL, TYPE_SERIAL_IO));
>> -
>> - qdev_prop_set_uint32(DEVICE(sio), "baudbase", baudbase);
>> - qdev_prop_set_chr(DEVICE(sio), "chardev", chr);
>> - qdev_set_legacy_instance_id(DEVICE(sio), base, 2);
>> - qdev_init_nofail(DEVICE(sio));
>> -
>> - sysbus_connect_irq(SYS_BUS_DEVICE(sio), 0, irq);
>> - memory_region_add_subregion(system_io, base, &sio->serial.io);
>> -
>> - return sio;
>> -}
in new version:
>> + if (serial_hd(0)) {
>> + DeviceState *dev = qdev_create(NULL, TYPE_SERIAL_IO);
>> +
>> + qdev_prop_set_uint32(DEVICE(dev), "baudbase", 115200);
>> + qdev_prop_set_chr(dev, "chardev", serial_hd(0)); <-- you
didn't use here DEVICE(), while it is used in the previous line, and also
in the old version, and similar questions
>> + qdev_set_legacy_instance_id(dev, 0x3f8, 2);
>> + qdev_init_nofail(dev);
>> + sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, env->irq[4]);
>> + memory_region_add_subregion(get_system_io(), 0x3f8,
>> + &SERIAL_IO(dev)->serial.io);
>> + }
For you all these details are probably perfectly natural and obvois, but
not for me.
Yours, Aleksandar
