ARM: bcm2835: add interrupt controller driver

The BCM2835 contains a custom interrupt controller, which supports 72
interrupt sources using a 2-level register scheme. The interrupt
controller, or the HW block containing it, is referred to occasionally
as "armctrl" in the SoC documentation, hence the symbol naming in the
code.

This patch was extracted from git://github.com/lp0/linux.git branch
rpi-split as of 2012/09/08, and modified as follows:

* s/bcm2708/bcm2835/.
* Modified device tree vendor prefix.
* Moved implementation to drivers/irchip/.
* Added devicetree documentation, and hence removed list of IRQs from
  bcm2835.dtsi.
* Changed shift in MAKE_HWIRQ() and HWIRQ_BANK() from 8 to 5 to reduce
  the size of the hwirq space, and pass the total size of the hwirq space
  to irq_domain_add_linear(), rather than just the number of valid hwirqs;
  the two are different due to the hwirq space being sparse.
* Added the interrupt controller DT node to the top-level of the DT,
  rather than nesting it inside a /axi node. Hence, changed the reg value
  since /axi had a ranges property. This seems simpler to me, but I'm not
  sure if everyone will like this change or not.
* Don't set struct irq_domain_ops.map = irq_domain_simple_map, hence
  removing the need to patch include/linux/irqdomain.h or
  kernel/irq/irqdomain.c.
* Simplified armctrl_of_init() using of_iomap().
* Removed unused IS_VALID_BANK()/IS_VALID_IRQ() macros.
* Renamed armctrl_handle_irq() to prevent possible symbol clashes.
* Made armctrl_of_init() static.
* Removed comment "Each bank is registered as a separate interrupt
  controller" since this is no longer true.
* Removed FSF address from license header.
* Added my name to copyright header.

Signed-off-by: Chris Boot <[email protected]>
Signed-off-by: Simon Arlott <[email protected]>
Signed-off-by: Dom Cobley <[email protected]>
Signed-off-by: Dom Cobley <[email protected]>
Signed-off-by: Stephen Warren <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>

Documentation/devicetree/bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt

@@ -0,0 +1,110 @@
+BCM2835 Top-Level ("ARMCTRL") Interrupt Controller
+
+The BCM2835 contains a custom top-level interrupt controller, which supports
+72 interrupt sources using a 2-level register scheme. The interrupt
+controller, or the HW block containing it, is referred to occasionally
+as "armctrl" in the SoC documentation, hence naming of this binding.
+
+Required properties:
+
+- compatible : should be "brcm,bcm2835-armctrl-ic.txt"
+- reg : Specifies base physical address and size of the registers.
+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 2.
+
+  The 1st cell is the interrupt bank; 0 for interrupts in the "IRQ basic
+  pending" register, or 1/2 respectively for interrupts in the "IRQ pending
+  1/2" register.
+
+  The 2nd cell contains the interrupt number within the bank. Valid values
+  are 0..7 for bank 0, and 0..31 for bank 1.
+
+The interrupt sources are as follows:
+
+Bank 0:
+0: ARM_TIMER
+1: ARM_MAILBOX
+2: ARM_DOORBELL_0
+3: ARM_DOORBELL_1
+4: VPU0_HALTED
+5: VPU1_HALTED
+6: ILLEGAL_TYPE0
+7: ILLEGAL_TYPE1
+
+Bank 1:
+0: TIMER0
+1: TIMER1
+2: TIMER2
+3: TIMER3
+4: CODEC0
+5: CODEC1
+6: CODEC2
+7: VC_JPEG
+8: ISP
+9: VC_USB
+10: VC_3D
+11: TRANSPOSER
+12: MULTICORESYNC0
+13: MULTICORESYNC1
+14: MULTICORESYNC2
+15: MULTICORESYNC3
+16: DMA0
+17: DMA1
+18: VC_DMA2
+19: VC_DMA3
+20: DMA4
+21: DMA5
+22: DMA6
+23: DMA7
+24: DMA8
+25: DMA9
+26: DMA10
+27: DMA11
+28: DMA12
+29: AUX
+30: ARM
+31: VPUDMA
+
+Bank 2:
+0: HOSTPORT
+1: VIDEOSCALER
+2: CCP2TX
+3: SDC
+4: DSI0
+5: AVE
+6: CAM0
+7: CAM1
+8: HDMI0
+9: HDMI1
+10: PIXELVALVE1
+11: I2CSPISLV
+12: DSI1
+13: PWA0
+14: PWA1
+15: CPR
+16: SMI
+17: GPIO0
+18: GPIO1
+19: GPIO2
+20: GPIO3
+21: VC_I2C
+22: VC_SPI
+23: VC_I2SPCM
+24: VC_SDIO
+25: VC_UART
+26: SLIMBUS
+27: VEC
+28: CPG
+29: RNG
+30: VC_ARASANSDIO
+31: AVSPMON
+
+Example:
+
+intc: interrupt-controller {
+	compatible = "brcm,bcm2835-armctrl-ic";
+	reg = <0x7e00b200 0x200>;
+	interrupt-controller;
+	#interrupt-cells = <2>;
+};

arch/arm/boot/dts/bcm2835.dtsi

@@ -3,6 +3,7 @@
 / {
 	compatible = "brcm,bcm2835";
 	model = "BCM2835";
+	interrupt-parent = <&intc>;
 
 	chosen {
 		bootargs = "earlyprintk";
@@ -13,5 +14,12 @@
 		#address-cells = <1>;
 		#size-cells = <1>;
 		ranges = <0x7e000000 0x20000000 0x02000000>;
+
+		intc: interrupt-controller {
+			compatible = "brcm,bcm2835-armctrl-ic";
+			reg = <0x7e00b200 0x200>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
+		};
 	};
 };

arch/arm/mach-bcm2835/bcm2835.c

@@ -13,12 +13,12 @@
  */
 
 #include <linux/init.h>
+#include <linux/irqchip/bcm2835.h>
 #include <linux/of_platform.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 #include <asm/mach/time.h>
-#include <asm/exception.h>
 
 #include <mach/bcm2835_soc.h>
 
@@ -34,14 +34,6 @@ void __init bcm2835_map_io(void)
 	iotable_init(&io_map, 1);
 }
 
-void __init bcm2835_init_irq(void)
-{
-}
-
-asmlinkage void __exception_irq_entry bcm2835_handle_irq(struct pt_regs *regs)
-{
-}
-
 void __init bcm2835_init(void)
 {
 	int ret;

drivers/Kconfig

@@ -152,4 +152,6 @@ source "drivers/vme/Kconfig"
 
 source "drivers/pwm/Kconfig"
 
+source "drivers/irqchip/Kconfig"
+
 endmenu

drivers/Makefile

@@ -5,6 +5,8 @@
 # Rewritten to use lists instead of if-statements.
 #
 
+obj-y				+= irqchip/
+
 # GPIO must come after pinctrl as gpios may need to mux pins etc
 obj-y				+= pinctrl/
 obj-y				+= gpio/

drivers/irqchip/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o