Re: [Qemu-arm] [PATCH] hw/arm/bcm2836: Wire up CPU timer interrupts correctly

[Peter Maydell]

On 17 March 2016 at 13:37, Thomas Hanson <address@hidden> wrote:
>
> On Mar 17, 2016 4:33 AM, "Peter Maydell" <address@hidden> wrote:
>>
>> Wire up the CPU timer interrupts in the right order, with the
>> nonsecure physical timer on cntpnsirq, the hyp timer on cnthpirq,
>> and the secure physical timer on cntpsirq. (We did get the
>> virt timer right, at least.)

> What drives the order?

This is modelling the hardware:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm2836/README.md

The interrupt controller has 4 lines named CNTPSIRQ, CNTPNSIRQ, etc,
and we need to hook the lines from the CPU up to the interrupt
controller appropriately. The names we ended up with in QEMU's
CPU model (GTIMER_PHYS, etc) don't match the signal names that
a hardware A7 uses, which is slightly irritating, but not a big deal.

The A7 TRM lists which timer is which signal:
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0464f/BABBABDJ.html
(though you can pretty much guess from the signal names).

thanks
-- PMM