Re: [Qemu-devel] [Qemu-ppc] [RESEND][PATCH] booke timers

[Alexander Graf]

Fabien Chouteau wrote:
> On 12/09/2011 19:23, Scott Wood wrote:
>   
>> On 09/09/2011 09:58 AM, Alexander Graf wrote:
>>     
>>> On 09.09.2011, at 16:22, Fabien Chouteau wrote:
>>>       
>>>> if the interrupt is already set and you clear TCR.DIE, the interrupt has to
>>>> remain set. The only way to unset an interrupt is to clear the 
>>>> corresponding
>>>> bit in TSR (currently in store_booke_tsr).
>>>>         
>>> Are you sure? I see several things in the 2.06 spec:
>>>       
>> [snip]
>>     
>>> To me that sounds as if the decrementer interrupt gets injected only
>>> when TSR.DIS=1, TCR.DIE=1 and MSR.EE=1. Unsetting any of these bits
>>> stops the interrupt from being delivered.
>>>
>>> Scott, can you please check up with the hardware guys if this is correct?
>>>       
>> This is how I've always understood it to work (assuming the interrupt
>> hasn't already been delivered, of course).  Fabien, do you have real
>> hardware that you see behave the way you describe?
>>
>>     
>
> No I don't, it was just my understanding of Book-E documentation. I've tried
> your solution (below) with VxWorks, and it works like a charm.
>
> static void booke_update_irq(CPUState *env)
> {
>     ppc_set_irq(env, PPC_INTERRUPT_DECR,
>                 (env->spr[SPR_BOOKE_TSR] & TSR_DIS
>                  && env->spr[SPR_BOOKE_TCR] & TCR_DIE));
>
>     ppc_set_irq(env, PPC_INTERRUPT_WDT,
>                 (env->spr[SPR_BOOKE_TSR] & TSR_WIS
>                  && env->spr[SPR_BOOKE_TCR] & TCR_WIE));
>
>     ppc_set_irq(env, PPC_INTERRUPT_FIT,
>                 (env->spr[SPR_BOOKE_TSR] & TSR_FIS
>                  && env->spr[SPR_BOOKE_TCR] & TCR_FIE));
> }
>   

Awesome! Please also check on MSR.EE and send a new patch then :)


Alex