于 2020年3月25日 GMT+08:00 下午11:46:00, Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> 写到: >On Wed, Mar 25, 2020 at 11:09:10PM +0800, Jiaxun Yang wrote: >> >> >> 于 2020年3月25日 GMT+08:00 下午11:04:37, Thomas Bogendoerfer ><tsbogend@xxxxxxxxxxxxxxxx> 写到: >> >On Wed, Mar 25, 2020 at 10:31:21PM +0800, Jiaxun Yang wrote: >> >> >> >> >> >> 于 2020年3月25日 GMT+08:00 下午10:15:16, Marc Zyngier <maz@xxxxxxxxxx> >写到: >> >> >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. >> >> MIPS_IRQ_BASE must be higher than 15, otherwise it will conflict with >i8259. > >I still don't get it. > >We have following in arch/mips/include/asm/mach-generic/irq.h: > >#ifndef MIPS_CPU_IRQ_BASE >#ifdef CONFIG_I8259 >#define MIPS_CPU_IRQ_BASE 16 >#else >#define MIPS_CPU_IRQ_BASE 0 >#endif /* CONFIG_I8259 */ >#endif > >So every legacy platform with i8259 has MIPS_CPU_IRQ_BASE = 16. > >> However we have only preallocated irq_desc for 0-15. >> And legacy domain require irq_desc being preallocated. > >maybe I'm too fast by judging the irq code, but without >CONFIG_SPARSE_IRQ >the whole irq_desc is pre-allocated. Sorry. You're right. I found the problem is CONFIG_SPARSE_IRQ is accidentally enabled in my config due to another out-of-tree patch during my initial test and I always consider it as a problem. So we can drop this patch safely for now. But just need to consider how to deal with it when we want to enable SPARSE_IRQ. Thanks. > >Thomas. -- Jiaxun Yang
