I have a MPC5200 based board which has an FPGA for external
I/O, etc. This FPGA also funnels interrupts from the various
external devices through to the CPU.
I've defined this structure in my DTS:
[EMAIL PROTECTED] {
device_type = "board-control";
#address-cells = <1>;
#size-cells = <1>;
// Note: includes sub-devices like CAN, A/D, etc
reg = <0xf8000000 0x100000>;
fpga_ic: [EMAIL PROTECTED] {
device_type = "fpga-int-ctlr";
interrupt-controller;
#address-cells = <0>;
#interrupt-cells = <2>;
interrupts = <2 26 3>; // IRQ2
interrupt-parent = <&mpc5200_pic>;
};
[EMAIL PROTECTED] {
compatible = "am,can";
device_type = "can";
interrupts = <0 0>;
interrupt_parent = <&fpga_ic>;
reg = <0xf8010000 0x200>;
};
};
Of course, there will be more devices and interrupts later on,
this is just the first of many.
Now the questions:
* How do I choose the VIRQ range supported by my FPGA?
I'm interested in this in particular for the MPC5200, but
also for other chips (I have many such board configurations).
* How do I pass this information along to my drivers? I would
think that the interrupts value for the can interface above
would use a [logical] IRQ (an offset from the base VIRQ),
so how does the driver get the actual number (VIRQ+offset)
when probing the tree?
* I know how to define the interrupt controller using irq_alloc_host()
(once I have the VIRQ range) but it's not clear to me where to stick
this initialization when bringing up my platform.
Thanks for any pointers/ideas
n.b. I've read all the arguments about not using "device_type"
and this will be resolved. At the moment, I'm basing my
code on a slightly older kernel codebase (2.6.26), so those
entries remain.
--
------------------------------------------------------------
Gary Thomas | Consulting for the
MLB Associates | Embedded world
------------------------------------------------------------
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