Re: [Qemu-devel] IRQ number, interrupt number, interrupt line & GPIO[in/out]

[Zhi Yong Wu]

On Fri, Mar 2, 2012 at 11:12 PM, ���f任 <address@hidden> wrote:
>> Can anyone explain their relationship and difference among them?  It
>> is very appreciated if you can make some comments. thanks.
>
>  I think IRQ number, interrupt number are quite similar things. You can
> check PIC [1] first, especially 8259A [2]. When a device raise an interrupt,
> the interrupt is delivered to CPU through PIC. Each device attaches itself
> to one of PIC's pins. Thus, when we say the IRQ number of device X is Y,
> it means device X attaches itself to PIC's pin Y. PIC will deliver the highest
> priority interrupt to the CPU. The term "interrupt line" might appear in PCI
> context [3]. BIOS usually uses interrupt line to represent what PIC pin the
> device attatches to. Note that PIC (Programmable Interrupt Controller) and
> PCI (Peripheral Component Interconnect) are different things.
>
>  GPIO mostly is used on SoC. It depends on the vendor how to use GPIO. One
> of GPIO capabilities is similar to PIC, I guess. But I leave this to SoC
> experts. I strongly recommend the book [5] if you want to learn how things
> work.
thanks a lot for your help, they are very in theory.:). actually these
concepts all exist in QEMU. I would like to know how they work
together.
>
> HTH,
> chenwj
>
> [1] http://en.wikipedia.org/wiki/Programmable_Interrupt_Controller
> [2] http://en.wikipedia.org/wiki/Intel_8259
> [3] http://en.wikipedia.org/wiki/Conventional_PCI
> [4] http://en.wikipedia.org/wiki/General_Purpose_Input/Output
> [5] 系统虚拟化:原理与实现
>
> --
> Wei-Ren Chen (���f任)
> Computer Systems Lab, Institute of Information Science,
> Academia Sinica, Taiwan (R.O.C.)
> Tel:886-2-2788-3799 #1667
> Homepage: http://people.cs.nctu.edu.tw/~chenwj



-- 
Regards,

Zhi Yong Wu