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Re: [PATCH-for-5.2 1/2] hw/mips/mipssim: Use MMIO serial device on fake
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH-for-5.2 1/2] hw/mips/mipssim: Use MMIO serial device on fake ISA I/O |
Date: |
Wed, 2 Sep 2020 12:35:28 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 |
On 9/1/20 7:20 PM, Marc-André Lureau wrote:
> Hi
>
> On Thu, Jul 30, 2020 at 9:04 PM Philippe Mathieu-Daudé
> <philmd@redhat.com <mailto:philmd@redhat.com>> wrote:
>
> The 'mipssim' is not a real hardware, it is a simulator.
>
> There is an ISA MMIO space mapped at 0x1fd00000, however
> this is not a real ISA bus (no ISA IRQ). So can not use
> the TYPE_ISA_SERIAL device...
> Instead we have been using a plain MMIO device, but named
> it IO.
>
> TYPE_SERIAL_IO is a superset of TYPE_SERIAL_MM, using
> regshift=0 and endianness=DEVICE_LITTLE_ENDIAN.
>
> Directly use the TYPE_SERIAL_MM device, enforcing the
> regshift/endianness values. 'regshift' default is already
> '0'. 'endianness' is meaningless for 8-bit accesses.
>
> Note, there is no migration problem, because TYPE_SERIAL_IO
> was not migrated.
>
>
> I am not so sure about that. It has:
> /* No dc->vmsd: class has no migratable state */
>
> but that doesn't mean it's not migratable I think.
Can you be more verbose... I don't understand what I should do.
Reword the patch description or modify the patch?
Thanks.
>
>
> Suggested-by: Peter Maydell <peter.maydell@linaro.org
> <mailto:peter.maydell@linaro.org>>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com
> <mailto:philmd@redhat.com>>
> ---
> hw/mips/mipssim.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/mips/mipssim.c b/hw/mips/mipssim.c
> index 1b3b762203..853bbaca58 100644
> --- a/hw/mips/mipssim.c
> +++ b/hw/mips/mipssim.c
> @@ -216,9 +216,11 @@ mips_mipssim_init(MachineState *machine)
> * MIPS CPU INT2, which is interrupt 4.
> */
> if (serial_hd(0)) {
> - DeviceState *dev = qdev_new(TYPE_SERIAL_IO);
> + DeviceState *dev = qdev_new(TYPE_SERIAL_MM);
>
> qdev_prop_set_chr(dev, "chardev", serial_hd(0));
> + qdev_prop_set_uint8(dev, "regshift", 0);
> + qdev_prop_set_uint8(dev, "endianness", DEVICE_LITTLE_ENDIAN);
> qdev_set_legacy_instance_id(dev, 0x3f8, 2);
> sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
> sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, env->irq[4]);
> --
> 2.21.3
>
>
>
>
> --
> Marc-André Lureau