Re: [Qemu-devel] [PATCH] armv7-m: exit on external reset request

[Michael Davidsaver]

On 10/09/2015 02:51 PM, Michael Davidsaver wrote:
> On 10/09/2015 02:18 PM, Peter Crosthwaite wrote:
>> On Fri, Oct 9, 2015 at 10:25 AM, Michael Davidsaver
>> <address@hidden> wrote:
>>>
>>>
>>> On 10/09/2015 12:59 PM, Peter Maydell wrote:
>>>> On 8 October 2015 at 16:40, Michael Davidsaver <address@hidden> wrote:
>>>>> ...
>>>>>      case 0xd0c: /* Application Interrupt/Reset Control.  */
>>>>>          if ((value >> 16) == 0x05fa) {
>>>>> +            if (value & 4) {
>>>>> +                qemu_system_reset_request();
>>>>> +            }
>>> ...
>>>>
>>>> Strictly speaking what this bit does is assert a signal out of
>>>> the CPU to some external power management or similar device
>>>> in the SoC, which then is responsible for doing the reset.
>>>> So just calling qemu_system_reset_request() here is a bit of
>>>> a shortcut. But maybe it's a pragmatic shortcut?
>>>
>>> I'm not sure what you mean by shortcut?  Most targets have some way to 
>>> trigger qemu to exit.  I actually compiled a list recently (see below).  I 
>>> couldn't find one for the lm3s6965evb machine, thus this patch.
>>>
>>
> ...
>> I think it would be better for SoC (or board) level to
>> install the GPIO handler to do the reset. As far as target-arm is
>> concerned this is then just a GPIO.
> 
> I don't think I'm well versed enough in qemu lingo to parse this sentence :)
> Are you concerned about adding this function to AIRCR (which would effect 
> every armv7-m board),
> or about directly calling qemu_system_reset_request() in armv7m_nvic.c?

I think I've answered my own question.  You mean to replace the call to 
qemu_system_reset_request() with something like qemu_irq_pulse()?

I think I see how to do this.  The simplest (adding another named GPIO to the 
NVIC devices) is complicated by the fact that the armv7m_init() doesn't return 
the nvic object, but rather an array of qemu_irq.  Is it reasonable to change 
armv7m_init() to return DeviceState*?