DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP

Some socs have a large number of interrupts requests to service
the needs of its many peripherals and subsystems. All of the
interrupt lines from the subsystems are not needed at the same
time, so they have to be muxed to the irq-controller appropriately.
In such places a interrupt controllers are preceded by an CROSSBAR
that provides flexibility in muxing the device requests to the controller
inputs.

This driver takes care a allocating a free irq and then configuring the
crossbar IP as a part of the mpu's irqchip callbacks. crossbar_init should
be called right before the irqchip_init, so that it is setup to handle the
irqchip callbacks.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>
Acked-by: Kumar Gala <galak@codeaurora.org> (for DT binding portion)
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 27 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
new file mode 100644
index 0000000..fb88585
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
@@ -0,0 +1,27 @@
+Some socs have a large number of interrupts requests to service
+the needs of its many peripherals and subsystems. All of the
+interrupt lines from the subsystems are not needed at the same
+time, so they have to be muxed to the irq-controller appropriately.
+In such places a interrupt controllers are preceded by an CROSSBAR
+that provides flexibility in muxing the device requests to the controller
+inputs.
+
+Required properties:
+- compatible : Should be "ti,irq-crossbar"
+- reg: Base address and the size of the crossbar registers.
+- ti,max-irqs: Total number of irqs available at the interrupt controller.
+- ti,reg-size: Size of a individual register in bytes. Every individual
+	    register is assumed to be of same size. Valid sizes are 1, 2, 4.
+- ti,irqs-reserved: List of the reserved irq lines that are not muxed using
+		 crossbar. These interrupt lines are reserved in the soc,
+		 so crossbar bar driver should not consider them as free
+		 lines.
+
+Examples:
+		crossbar_mpu: @4a020000 {
+			compatible = "ti,irq-crossbar";
+			reg = <0x4a002a48 0x130>;
+			ti,max-irqs = <160>;
+			ti,reg-size = <2>;
+			ti,irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
+		};