Re: INTC / IRQ Numbers

[Magnus D. <mag...@gm...>]

Hi Kristoffer,

On 8/24/07, Kristoffer Ericson <kri...@gm...> wrote:
> Greetings,
>
> Didn't get a reply on my last mail, so here goes again. Basicly how do I calculate the IRQ number using the INTC table in setup-sh770x.c.

Hehe, your email are still on my todo list.

I wanted to answer your question, but I hesitated a bit because i'm
still not really sure why the official tree is broken and what the
state is of your tree. I wish we could work together and fix up the
official 2.6.24 tree step by step.

> For instance I want to know where IRQ4 ends up, If I check how the RTC IRQ's are calculated and use the I end up at IRQ 30.
> Not sure If I understand it properly.

There is a private set of enum_ids for each set of tables passed to
the intc code using register_intc_controller(). The enum_id value zero
needs to be treated as unused and all other values are used to provide
mappings for the intc code between interrupts and bits or bit fields
in registers. For setup-sh770x.c the first useful enum_id is IRQ0.
These enum_ids are private data for the intc code and there is no
point in trying to use them somewhere else.

What you are looking for is hidden inside vectors[] - the information
provided by INTC_VECT(). The first argument to INTC_VECT() is the
private enum_id and the second one the vector number specified by the
processor data sheet. This vector number is hard coded in the
processor chip and the intc tables are used to describe the
relationship between these vectors and certain registers.

You should look at the evt2irq() macro in include/asm-sh/irq.h to
figure out the relationship between the processor vector number
(second argument to INTC_VECT()) and the IRQ number passed to
request_irq(). The PINT07 interrupt source for example is located on
vector 0x700 and using the evt2irq() macro this gives us IRQ 40.

Hope this helps. I'd be happy to help out hacking up the new pint
controller but I feel we need to get the upstream kernel in a better
shape first. Hint: send patches! =)

Happy hacking!

/ magnus