[RFC PATCH 2/6] DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP

Hi Kumar,

On Thursday 24 October 2013 03:03 PM, Kumar Gala wrote:

On Sep 30, 2013, at 8:59 AM, Sricharan R wrote:

quoted

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 <redacted>
Cc: Linus Walleij <redacted>
Cc: Santosh Shilimkar <redacted>
Cc: Russell King <redacted>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Rajendra Nayak <redacted>
Cc: Marc Zyngier <redacted>
Cc: Grant Likely <redacted>
Cc: Rob Herring <redacted>
Signed-off-by: Sricharan R <redacted>
---
.../devicetree/bindings/arm/omap/crossbar.txt      |   27 +++
drivers/irqchip/Kconfig                            |    8 +
drivers/irqchip/Makefile                           |    1 +
drivers/irqchip/irq-crossbar.c                     |  195 ++++++++++++++++++++
include/linux/irqchip/irq-crossbar.h               |   11 ++
5 files changed, 242 insertions(+)
create mode 100644 Documentation/devicetree/bindings/arm/omap/crossbar.txt
create mode 100644 drivers/irqchip/irq-crossbar.c
create mode 100644 include/linux/irqchip/irq-crossbar.h

diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
new file mode 100644
index 0000000..cdec2cd
--- /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.
+- max-irqs: Total number of irqs available at the interrupt controller.

Should be 'ti,max-irqs

 Ok, will correct.

quoted

+- 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.

Is this something that really needs to be encoded in the dts?

If we keep it should be ti,reg-size

Currently, this is the only IP with a fixed register-size.
 So this can be in the driver also. I thought keeping it
DT will avoid any hard-coding in driver.

quoted

+- 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.
+

ti,irqs-reserved

Ok, will correct

quoted

+Examples:
+		crossbar_mpu: @4a020000 {

Did you mean for there to be a label and no node name?

 ya, name is missing. Will add.

quoted

+			compatible = "ti,irq-crossbar";
+			reg = <0x4a002a48 0x130>;
+			max-irqs = <160>;
+			reg-size = <2>;
+			irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
+		};

Regards,
 Sricharan