Re: [PATCH 2/2] rtc/mc146818rtc: QOM'ify io_base offset

[Bernhard Beschow]

Am 22. Mai 2022 12:13:48 UTC schrieb Mark Cave-Ayland 
<mark.cave-ayland@ilande.co.uk>:
>On 22/05/2022 10:07, Bernhard Beschow wrote:
>
>> On Sat, May 21, 2022 at 11:24 AM Mark Cave-Ayland 
>> <mark.cave-ayland@ilande.co.uk <mailto:mark.cave-ayland@ilande.co.uk>> wrote:
>> 
>>     On 20/05/2022 18:45, Bernhard Beschow wrote:
>> 
>>      > Exposing the io_base offset as a QOM property not only allows it to be
>>      > configurable but also to be displayed in HMP:
>>      >
>>      > Before:
>>      >
>>      > (qemu) info qtree
>>      >         ...
>>      >            dev: mc146818rtc, id ""
>>      >              gpio-out "" 1
>>      >              base_year = 0 (0x0)
>>      >              irq = 8 (0x8)
>>      >              lost_tick_policy = "discard"
>>      >
>>      > After:
>>      >
>>      >            dev: mc146818rtc, id ""
>>      >              gpio-out "" 1
>>      >              base_year = 0 (0x0)
>>      >              iobase = 112 (0x70)
>>      >              irq = 8 (0x8)
>>      >              lost_tick_policy = "discard"
>>      >
>>      > Signed-off-by: Bernhard Beschow <shentey@gmail.com 
>> <mailto:shentey@gmail.com>>
>>      > ---
>>      >   hw/i386/microvm-dt.c         | 2 +-
>>      >   hw/rtc/mc146818rtc.c         | 7 ++++---
>>      >   include/hw/rtc/mc146818rtc.h | 2 +-
>>      >   3 files changed, 6 insertions(+), 5 deletions(-)
>>      >
>>      > diff --git a/hw/i386/microvm-dt.c b/hw/i386/microvm-dt.c
>>      > index a5db9e4e5a..39fe425b26 100644
>>      > --- a/hw/i386/microvm-dt.c
>>      > +++ b/hw/i386/microvm-dt.c
>>      > @@ -209,7 +209,7 @@ static void dt_add_isa_rtc(MicrovmMachineState 
>> *mms,
>>     ISADevice *dev)
>>      >   {
>>      >       const char compat[] = "motorola,mc146818";
>>      >       uint32_t irq = object_property_get_uint(OBJECT(dev), "irq", 
>> NULL);
>>      > -    hwaddr base = RTC_ISA_BASE;
>>      > +    hwaddr base = object_property_get_int(OBJECT(dev), "iobase", 
>> NULL);
>> 
>>     Same comment here re: &error_abort.
>> 
>> 
>> Ack.
>> 
>> 
>>      >       hwaddr size = 8;
>>      >       char *nodename;
>>      >
>>      > diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c
>>      > index f235c2ddbe..484f91b6f8 100644
>>      > --- a/hw/rtc/mc146818rtc.c
>>      > +++ b/hw/rtc/mc146818rtc.c
>>      > @@ -941,7 +941,7 @@ static void rtc_realizefn(DeviceState *dev, Error 
>> **errp)
>>      >       qemu_register_suspend_notifier(&s->suspend_notifier);
>>      >
>>      >       memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 
>> 2);
>>      > -    isa_register_ioport(isadev, &s->io, RTC_ISA_BASE);
>>      > +    isa_register_ioport(isadev, &s->io, s->io_base);
>>      >
>>      >       /* register rtc 0x70 port for coalesced_pio */
>>      >       memory_region_set_flush_coalesced(&s->io);
>>      > @@ -950,7 +950,7 @@ static void rtc_realizefn(DeviceState *dev, Error 
>> **errp)
>>      >       memory_region_add_subregion(&s->io, 0, &s->coalesced_io);
>>      >       memory_region_add_coalescing(&s->coalesced_io, 0, 1);
>>      >
>>      > -    qdev_set_legacy_instance_id(dev, RTC_ISA_BASE, 3);
>>      > +    qdev_set_legacy_instance_id(dev, s->io_base, 3);
>>      >
>>      >       object_property_add_tm(OBJECT(s), "date", rtc_get_date);
>>      >
>>      > @@ -983,6 +983,7 @@ ISADevice *mc146818_rtc_init(ISABus *bus, int 
>> base_year,
>>     qemu_irq intercept_irq)
>>      >
>>      >   static Property mc146818rtc_properties[] = {
>>      >       DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
>>      > +    DEFINE_PROP_UINT32("iobase", RTCState, io_base, 0x70),
>> 
>>     I think this should be RTC_ISA_BASE?
>> 
>>      >       DEFINE_PROP_UINT8("irq", RTCState, isairq, RTC_ISA_IRQ),
>>      >       DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
>>      >                                  lost_tick_policy, 
>> LOST_TICK_POLICY_DISCARD),
>>      > @@ -1028,7 +1029,7 @@ static void rtc_build_aml(ISADevice *isadev, 
>> Aml *scope)
>>      >        * does, even though qemu only responds to the first two ports.
>>      >        */
>>      >       crs = aml_resource_template();
>>      > -    aml_append(crs, aml_io(AML_DECODE16, RTC_ISA_BASE, RTC_ISA_BASE,
>>      > +    aml_append(crs, aml_io(AML_DECODE16, s->io_base, s->io_base,
>>      >                              0x01, 0x08));
>>      >       aml_append(crs, aml_irq_no_flags(s->isairq));
>>      >
>>      > diff --git a/include/hw/rtc/mc146818rtc.h 
>> b/include/hw/rtc/mc146818rtc.h
>>      > index 33d85753c0..1f7942a9f8 100644
>>      > --- a/include/hw/rtc/mc146818rtc.h
>>      > +++ b/include/hw/rtc/mc146818rtc.h
>>      > @@ -26,6 +26,7 @@ struct RTCState {
>>      >       uint8_t cmos_data[128];
>>      >       uint8_t cmos_index;
>>      >       uint8_t isairq;
>>      > +    uint32_t io_base;
>>      >       int32_t base_year;
>>      >       uint64_t base_rtc;
>>      >       uint64_t last_update;
>>      > @@ -49,7 +50,6 @@ struct RTCState {
>>      >   };
>>      >
>>      >   #define RTC_ISA_IRQ 8
>>      > -#define RTC_ISA_BASE 0x70
>> 
>>     ... and so you'll need to keep this.
>> 
>> 
>> My intention was indeed to remove it since it is now redundant. Keeping the 
>> constant public has the risk of using it instead of the user-configurable 
>> QOM property which could cause bugs.
>
>True, that's not a completely unreasonable argument. In that case how about 
>moving the RTC_ISA_BASE define to somewhere around the top of 
>hw/rtc/mc146818rtc.c so that the origin of the 0x70 address is preserved?

Okay, I'll move it there.
>
>>      >   ISADevice *mc146818_rtc_init(ISABus *bus, int base_year,
>>      >                                qemu_irq intercept_irq);
>> 
>>     Otherwise:
>> 
>>     Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk
>>     <mailto:mark.cave-ayland@ilande.co.uk>>
>> 
>> 
>>     ATB,
>> 
>>     Mark.
>
>
>ATB,
>
>Mark.