Re: [PATCH v3 18/33] mips: inline serial_init

[Peter Maydell]

On Wed, 23 Oct 2019 at 18:34, Marc-André Lureau
<address@hidden> wrote:
>
> The function is specific to mipssim, let's inline it.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  hw/char/serial.c         | 16 ----------------
>  hw/mips/mips_mipssim.c   | 13 ++++++++++---
>  include/hw/char/serial.h |  2 --
>  3 files changed, 10 insertions(+), 21 deletions(-)
>
> diff --git a/hw/char/serial.c b/hw/char/serial.c
> index 84de2740a7..ca95e09ec9 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 *self = SERIAL_IO(qdev_create(NULL, TYPE_SERIAL_IO));
> -
> -    qdev_prop_set_uint32(DEVICE(self), "baudbase", baudbase);
> -    qdev_prop_set_chr(DEVICE(self), "chardev", chr);
> -    qdev_prop_set_int32(DEVICE(self), "instance-id", base);
> -    qdev_init_nofail(DEVICE(self));
> -
> -    sysbus_connect_irq(SYS_BUS_DEVICE(self), 0, irq);
> -    memory_region_add_subregion(system_io, base, &self->serial.io);
> -
> -    return self;
> -}
> -
>  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..26fb8fa4de 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 +220,15 @@ 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))
> -        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_chr(dev, "chardev", serial_hd(0));
> +        qdev_prop_set_int32(dev, "instance-id", 0x3f8);
> +        qdev_init_nofail(dev);
> +        sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, env->irq[4]);
> +        sysbus_add_io(SYS_BUS_DEVICE(dev), 0x3f8, 
> &SERIAL_IO(dev)->serial.io);
> +    }

The code being inlined here doesn't seem to be identical to the
code in the function above (it uses sysbus_add_io() rather than
memory_region_add_subregion()).

It's also a bit ugly that the code has to reach into the
internals of the device to get the MemoryRegion pointer.
Would it work to have the device use sysbus_init_mmio()
in its init or realize method to register the IO port MemoryRegion,
and then we could use sysbus_mmio_get_region() to get the
MemoryRegion pointer ?

(If that does work, we should someday refactor
sysbus_add_io() so that all the devices it's used with
register the MemoryRegions that way, and then sysbus_add_io()
can just take an 'int n' the way sysbus_mmio_map() does.
But not today.)

thanks
-- PMM