[PATCH 3/6] ARM: plat-versatile: add DT support to FPGA IRQ controller

On Thu, Aug 16, 2012 at 3:50 PM, Arnd Bergmann [off-list ref] wrote:

On Thursday 16 August 2012, Linus Walleij wrote:

quoted

+- irq-start: the u32 hardware IRQ number of the first interrupt handled by
+  this FPGA IRQ instance - since there may be many FPGA IRQ controller
+  instances, each will have its unique hardware offset number.

The irq-start value is a Linux specific invention, the hardware doesn't
know anything about these. As long as you depend on specific IRQ numbers
to get assigned, I would use something like auxdata to find the
start number.

Sorry that does not work. Auxdata is not used with IRQ controllers,
only with devices.

of_irq_init() will dereference the .data field of struct of_device_id
and use as a callback function to initialize the IRQ controller, no
chance to pass any other data that way.

When all devices get their IRQ numbers from the device
tree, you can move to linear IRQ domains instead of legacy, and let
the irq domain code pick the numbers.

It seems I have no other choice here than to move directly to
linear numbers or atleast dynamically allocated descriptors.

Yours,
Linus Walleij