Re: [PATCH 4/8] mac_via: add GPIO for A/UX mode

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

On 15/10/2021 07:58, Laurent Vivier wrote:

> Le 13/10/2021 à 23:21, Mark Cave-Ayland a écrit :
>> Add a new auxmode GPIO that is updated when port B bit 6 is changed indicating
>> whether the hardware is configured for A/UX mode.
>>
>> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>> ---
>>   hw/misc/mac_via.c         | 18 ++++++++++++++++++
>>   hw/misc/trace-events      |  1 +
>>   include/hw/misc/mac_via.h |  1 +
>>   3 files changed, 20 insertions(+)
>>
>> diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
>> index 7a53a8b4c0..a08ffbcd88 100644
>> --- a/hw/misc/mac_via.c
>> +++ b/hw/misc/mac_via.c
>> @@ -880,6 +880,20 @@ static void via1_adb_update(MOS6522Q800VIA1State *v1s)
>>       }
>>   }
>>   
>> +static void via1_auxmode_update(MOS6522Q800VIA1State *v1s)
>> +{
>> +    MOS6522State *s = MOS6522(v1s);
>> +    int oldirq, irq;
>> +
> 
> Please, add a comment to explain what happens here as "vMystery" is not self-explicit.

Would something simple like:

/* Check to see if the A/UX mode bit has changed */

suffice here?

>> +    oldirq = (v1s->last_b & VIA1B_vMystery) ? 1 : 0;
>> +    irq = (s->b & VIA1B_vMystery) ? 1 : 0;
> 
> For me, it would be clearer with:
> 
>      oldirq = !!(v1s->last_b & VIA1B_vMystery);
>      irq = !!(s->b & VIA1B_vMystery);
> 
> but it's a matter of taste.

I had to think carefully about that one :)  If you're fine with the existing version 
I'd prefer to keep it as I find it easier to read.

>> +
>> +    if (irq != oldirq) {
>> +        trace_via1_auxmode(irq);
>> +        qemu_set_irq(v1s->auxmode_irq, irq);
>> +    }
>> +}
>> +
>>   static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size)
>>   {
>>       MOS6522Q800VIA1State *s = MOS6522_Q800_VIA1(opaque);
>> @@ -902,6 +916,7 @@ static void mos6522_q800_via1_write(void *opaque, hwaddr addr, uint64_t val,
>>       case VIA_REG_B:
>>           via1_rtc_update(v1s);
>>           via1_adb_update(v1s);
>> +        via1_auxmode_update(v1s);
>>   
>>           v1s->last_b = ms->b;
>>           break;
>> @@ -1046,6 +1061,9 @@ static void mos6522_q800_via1_init(Object *obj)
>>                 TYPE_ADB_BUS, DEVICE(v1s), "adb.0");
>>   
>>       qdev_init_gpio_in(DEVICE(obj), via1_irq_request, VIA1_IRQ_NB);
>> +
>> +    /* A/UX mode */
>> +    qdev_init_gpio_out(DEVICE(obj), &v1s->auxmode_irq, 1);
>>   }
>>   
>>   static const VMStateDescription vmstate_q800_via1 = {
>> diff --git a/hw/misc/trace-events b/hw/misc/trace-events
>> index ede413965b..2da96d167a 100644
>> --- a/hw/misc/trace-events
>> +++ b/hw/misc/trace-events
>> @@ -228,6 +228,7 @@ via1_rtc_cmd_pram_sect_write(int sector, int offset, int addr, int value) "secto
>>   via1_adb_send(const char *state, uint8_t data, const char *vadbint) "state %s data=0x%02x vADBInt=%s"
>>   via1_adb_receive(const char *state, uint8_t data, const char *vadbint, int status, int index, int size) "state %s data=0x%02x vADBInt=%s status=0x%x index=%d size=%d"
>>   via1_adb_poll(uint8_t data, const char *vadbint, int status, int index, int size) "data=0x%02x vADBInt=%s status=0x%x index=%d size=%d"
>> +via1_auxmode(int mode) "setting auxmode to %d"
>>   
>>   # grlib_ahb_apb_pnp.c
>>   grlib_ahb_pnp_read(uint64_t addr, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" data:0x%08x"
>> diff --git a/include/hw/misc/mac_via.h b/include/hw/misc/mac_via.h
>> index 4506abe5d0..b445565866 100644
>> --- a/include/hw/misc/mac_via.h
>> +++ b/include/hw/misc/mac_via.h
>> @@ -43,6 +43,7 @@ struct MOS6522Q800VIA1State {
>>       MemoryRegion via_mem;
>>   
>>       qemu_irq irqs[VIA1_IRQ_NB];
>> +    qemu_irq auxmode_irq;
>>       uint8_t last_b;
>>   
>>       /* RTC */
>>
> 
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>


ATB,

Mark.