Re: [Kernel-discuss] RFC - platform device, IRQs and SoC devices

From: Ian Molton
Date: Sat Nov 25 2006 - 07:51:21 EST


Russell King wrote:

It's quite possible to have:

IRQ chip
0 irqchip_0
1 irqchip_0
2 irqchip_1
3 irqchip_0
4 irqchip_0
5 irqchip_1
6 irqchip_2
7 irqchip_2
8 irqchip_2
9 irqchip_1

Where do you start '0' for each irqchip? How do you split the irq_desc
array between the irqchips?

I see no reason why this couldnt continue to work 'as is' with the new behaviour only applying to irqchips with their own non-NULL irq_desc array.

The other problem is integration with /proc, specifically the irq usage counter.

The irq numbers in /proc wouldnt have to be 'real' they can be synthesized from a base starting after the main system IRQs.

Im not sure how fixed the format of /proc/interrupts is, wether the IRQ numbers are required to be sequential or not (some arent even numbers like NMI on x86). if they dont have to be sequential then its simply a matter of keeping a counter starting from BOARD_IRQ_END+1 and for each IRQchip adding its individual irq numbers to it as they are displayed, then incrementing the counter by the size of the irqdesc array for that chip.
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