Re: [PATCH v8 06/11] irqchip: mips-cpu: Convert to simple domain

[Thomas Bogendoerfer]

On Wed, Mar 25, 2020 at 10:31:21PM +0800, Jiaxun Yang wrote:
> 
> 
> ä 2020å3æ25æ GMT+08:00 äå10:15:16, Marc Zyngier <maz@xxxxxxxxxx> åå:
> >On 2020-03-25 13:59, Jiaxun Yang wrote:
> >
> >[...]
> >
> >>>> So probably we can use legacy domain when  MIPS IRQ BASE is in the
> >>>> range of legacy IRQ
> >>>> and switch to simple domain when it's not in that range?
> >>> 
> >>> No, see below.
> >>> 
> >>>> Here in Loongson systems IRQ 0-15 is occupied by I8259 so I did
> >this
> >>>> hack.
> >>> 
> >>> Well, if you have to consider which Linux IRQ gets assigned,
> >>> then your platform is definitely not ready for non-legacy
> >>> irqdomains. Just stick to legacy for now until you have removed
> >>> all the code that knows the hwirq mapping.
> >> 
> >> Thanks.
> >> 
> >> So I have to allocate irq_desc here in driver manually?
> >
> >No, you are probably better off just dropping this patch, as MIPS
> >doesn't seem to be ready for a wholesale switch to virtual interrupts.
> 
> It can't work without this patch.
> 
> Legacy domain require IRQ number within 0-15 
> however it's already occupied by i8259 or "HTPIC" driver.

what's the problem here ? AFAIK there could be more than one
legacy domain, at least that's what at least IP22/SNI in MIPS world 
are doing.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]