[PATCH linux-next 1/2] irqchip: Add brcm,bcm6345-l1-intc device tree binding

[PATCH linux-next 1/2] irqchip: Add brcm,bcm6345-l1-intc device tree binding

[Simon Arlott]

Add device tree binding for the BCM6345 interrupt controller.

This controller is similar to the SMP-capable BCM7038 and
the BCM3380 but with packed interrupt registers.

Signed-off-by: Simon Arlott <simon-A6De1vDTPLDsq35pWSNszA@public.gmane.org>
---
Corrected example device name to be "interrupt-controller".

 .../interrupt-controller/brcm,bcm6345-l1-intc.txt  | 57 ++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt

diff --git a/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt
new file mode 100644
index 0000000..4040905
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt
@@ -0,0 +1,57 @@
+Broadcom BCM6345-style Level 1 interrupt controller
+
+This block is a first level interrupt controller that is typically connected
+directly to one of the HW INT lines on each CPU.
+
+Key elements of the hardware design include:
+
+- 32, 64 or 128 incoming level IRQ lines
+
+- Most onchip peripherals are wired directly to an L1 input
+
+- A separate instance of the register set for each CPU, allowing individual
+  peripheral IRQs to be routed to any CPU
+
+- Contains one or more enable/status word pairs per CPU
+
+- No atomic set/clear operations
+
+- No polarity/level/edge settings
+
+- No FIFO or priority encoder logic; software is expected to read all
+  2-4 status words to determine which IRQs are pending
+
+Required properties:
+
+- compatible: should be "brcm,bcm<soc>-l1-intc", "brcm,bcm6345-l1-intc"
+- reg: specifies the base physical address and size of the registers;
+  the number of supported IRQs is inferred from the size argument
+- interrupt-controller: identifies the node as an interrupt controller
+- #interrupt-cells: specifies the number of cells needed to encode an interrupt
+  source, should be 1.
+- interrupt-parent: specifies the phandle to the parent interrupt controller(s)
+  this one is cascaded from
+- interrupts: specifies the interrupt line(s) in the interrupt-parent controller
+  node; valid values depend on the type of parent interrupt controller
+
+If multiple reg ranges and interrupt-parent entries are present on an SMP
+system, the driver will allow IRQ SMP affinity to be set up through the
+/proc/irq/ interface.  In the simplest possible configuration, only one
+reg range and one interrupt-parent is needed.
+
+The driver operates in native CPU endian by default, there is no support for
+specifying an alternative endianness.
+
+Example:
+
+periph_intc: interrupt-controller@10000000 {
+        compatible = "brcm,bcm63168-l1-intc", "brcm,bcm6345-l1-intc";
+        reg = <0x10000020 0x20>,
+              <0x10000040 0x20>;
+
+        interrupt-controller;
+        #interrupt-cells = <1>;
+
+        interrupt-parent = <&cpu_intc>;
+        interrupts = <2>, <3>;
+};
-- 
2.1.4

-- 
Simon Arlott
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[PATCH linux-next 2/2] MIPS: bmips: Add bcm6345-l1 interrupt controller

[Simon Arlott]

Add the BCM6345 interrupt controller based on the SMP-capable BCM7038
and the BCM3380 but with packed interrupt registers.

Add the BCM6345 interrupt controller to a list with the existing BCM7038
so that interrupts on CPU1 are not ignored.

Update the maintainers file list for BMIPS to include this driver.

Signed-off-by: Simon Arlott <simon-A6De1vDTPLDsq35pWSNszA@public.gmane.org>
---
Rebased against linux-next-20151209, no other changes.

 MAINTAINERS                      |   1 +
 arch/mips/Kconfig                |   1 +
 arch/mips/bmips/irq.c            |  10 +-
 drivers/irqchip/Kconfig          |   5 +
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-bcm6345-l1.c | 364 +++++++++++++++++++++++++++++++++++++++
 6 files changed, 380 insertions(+), 2 deletions(-)
 create mode 100644 drivers/irqchip/irq-bcm6345-l1.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 82f296a..9c49d4e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2387,6 +2387,7 @@ F:	arch/mips/bmips/*
 F:	arch/mips/include/asm/mach-bmips/*
 F:	arch/mips/kernel/*bmips*
 F:	arch/mips/boot/dts/brcm/bcm*.dts*
+F:	drivers/irqchip/irq-bcm63*
 F:	drivers/irqchip/irq-bcm7*
 F:	drivers/irqchip/irq-brcmstb*
 
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index fbf3f66..9caf55a 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -151,6 +151,7 @@ config BMIPS_GENERIC
 	select CSRC_R4K
 	select SYNC_R4K
 	select COMMON_CLK
+	select BCM6345_L1_IRQ
 	select BCM7038_L1_IRQ
 	select BCM7120_L2_IRQ
 	select BRCMSTB_L2_IRQ
diff --git a/arch/mips/bmips/irq.c b/arch/mips/bmips/irq.c
index e7fc6f934..7efefcf 100644
--- a/arch/mips/bmips/irq.c
+++ b/arch/mips/bmips/irq.c
@@ -15,6 +15,12 @@
 #include <asm/irq_cpu.h>
 #include <asm/time.h>
 
+static const struct of_device_id smp_intc_dt_match[] = {
+	{ .compatible = "brcm,bcm7038-l1-intc" },
+	{ .compatible = "brcm,bcm6345-l1-intc" },
+	{}
+};
+
 unsigned int get_c0_compare_int(void)
 {
 	return CP0_LEGACY_COMPARE_IRQ;
@@ -24,8 +30,8 @@ void __init arch_init_irq(void)
 {
 	struct device_node *dn;
 
-	/* Only the STB (bcm7038) controller supports SMP IRQ affinity */
-	dn = of_find_compatible_node(NULL, NULL, "brcm,bcm7038-l1-intc");
+	/* Only these controllers support SMP IRQ affinity */
+	dn = of_find_matching_node(NULL, smp_intc_dt_match);
 	if (dn)
 		of_node_put(dn);
 	else
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 4d7294e..d307bb3 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -65,6 +65,11 @@ config I8259
 	bool
 	select IRQ_DOMAIN
 
+config BCM6345_L1_IRQ
+	bool
+	select GENERIC_IRQ_CHIP
+	select IRQ_DOMAIN
+
 config BCM7038_L1_IRQ
 	bool
 	select GENERIC_IRQ_CHIP
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 177f78f..ded59cf 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_XTENSA)			+= irq-xtensa-pic.o
 obj-$(CONFIG_XTENSA_MX)			+= irq-xtensa-mx.o
 obj-$(CONFIG_IRQ_CROSSBAR)		+= irq-crossbar.o
 obj-$(CONFIG_SOC_VF610)			+= irq-vf610-mscm-ir.o
+obj-$(CONFIG_BCM6345_L1_IRQ)		+= irq-bcm6345-l1.o
 obj-$(CONFIG_BCM7038_L1_IRQ)		+= irq-bcm7038-l1.o
 obj-$(CONFIG_BCM7120_L2_IRQ)		+= irq-bcm7120-l2.o
 obj-$(CONFIG_BRCMSTB_L2_IRQ)		+= irq-brcmstb-l2.o
diff --git a/drivers/irqchip/irq-bcm6345-l1.c b/drivers/irqchip/irq-bcm6345-l1.c
new file mode 100644
index 0000000..b844c89
--- /dev/null
+++ b/drivers/irqchip/irq-bcm6345-l1.c
@@ -0,0 +1,364 @@
+/*
+ * Broadcom BCM6345 style Level 1 interrupt controller driver
+ *
+ * Copyright (C) 2014 Broadcom Corporation
+ * Copyright 2015 Simon Arlott
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This is based on the BCM7038 (which supports SMP) but with a single
+ * enable register instead of separate mask/set/clear registers.
+ *
+ * The BCM3380 has a similar mask/status register layout, but each pair
+ * of words is at separate locations (and SMP is not supported).
+ *
+ * ENABLE/STATUS words are packed next to each other for each CPU:
+ *
+ * BCM6368:
+ *   0x1000_0020: CPU0_W0_ENABLE
+ *   0x1000_0024: CPU0_W1_ENABLE
+ *   0x1000_0028: CPU0_W0_STATUS		IRQs 31-63
+ *   0x1000_002c: CPU0_W1_STATUS		IRQs 0-31
+ *   0x1000_0030: CPU1_W0_ENABLE
+ *   0x1000_0034: CPU1_W1_ENABLE
+ *   0x1000_0038: CPU1_W0_STATUS		IRQs 31-63
+ *   0x1000_003c: CPU1_W1_STATUS		IRQs 0-31
+ *
+ * BCM63168:
+ *   0x1000_0020: CPU0_W0_ENABLE
+ *   0x1000_0024: CPU0_W1_ENABLE
+ *   0x1000_0028: CPU0_W2_ENABLE
+ *   0x1000_002c: CPU0_W3_ENABLE
+ *   0x1000_0030: CPU0_W0_STATUS	IRQs 96-127
+ *   0x1000_0034: CPU0_W1_STATUS	IRQs 64-95
+ *   0x1000_0038: CPU0_W2_STATUS	IRQs 32-63
+ *   0x1000_003c: CPU0_W3_STATUS	IRQs 0-31
+ *   0x1000_0040: CPU1_W0_ENABLE
+ *   0x1000_0044: CPU1_W1_ENABLE
+ *   0x1000_0048: CPU1_W2_ENABLE
+ *   0x1000_004c: CPU1_W3_ENABLE
+ *   0x1000_0050: CPU1_W0_STATUS	IRQs 96-127
+ *   0x1000_0054: CPU1_W1_STATUS	IRQs 64-95
+ *   0x1000_0058: CPU1_W2_STATUS	IRQs 32-63
+ *   0x1000_005c: CPU1_W3_STATUS	IRQs 0-31
+ *
+ * IRQs are numbered in CPU native endian order
+ * (which is big-endian in these examples)
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME	": " fmt
+
+#include <linux/bitops.h>
+#include <linux/cpumask.h>
+#include <linux/kconfig.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/smp.h>
+#include <linux/types.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+
+#define IRQS_PER_WORD		32
+#define REG_BYTES_PER_IRQ_WORD	(sizeof(u32) * 2)
+
+struct bcm6345_l1_cpu;
+
+struct bcm6345_l1_chip {
+	raw_spinlock_t		lock;
+	unsigned int		n_words;
+	struct irq_domain	*domain;
+	struct cpumask		cpumask;
+	struct bcm6345_l1_cpu	*cpus[NR_CPUS];
+};
+
+struct bcm6345_l1_cpu {
+	void __iomem		*map_base;
+	unsigned int		parent_irq;
+	u32			enable_cache[];
+};
+
+static inline unsigned int reg_enable(struct bcm6345_l1_chip *intc,
+					   unsigned int word)
+{
+#ifdef __BIG_ENDIAN
+	return (1 * intc->n_words - word - 1) * sizeof(u32);
+#else
+	return (0 * intc->n_words + word) * sizeof(u32);
+#endif
+}
+
+static inline unsigned int reg_status(struct bcm6345_l1_chip *intc,
+				      unsigned int word)
+{
+#ifdef __BIG_ENDIAN
+	return (2 * intc->n_words - word - 1) * sizeof(u32);
+#else
+	return (1 * intc->n_words + word) * sizeof(u32);
+#endif
+}
+
+static inline unsigned int cpu_for_irq(struct bcm6345_l1_chip *intc,
+					struct irq_data *d)
+{
+	return cpumask_first_and(&intc->cpumask, irq_data_get_affinity_mask(d));
+}
+
+static void bcm6345_l1_irq_handle(struct irq_desc *desc)
+{
+	struct bcm6345_l1_chip *intc = irq_desc_get_handler_data(desc);
+	struct bcm6345_l1_cpu *cpu;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned int idx;
+
+#ifdef CONFIG_SMP
+	cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
+#else
+	cpu = intc->cpus[0];
+#endif
+
+	chained_irq_enter(chip, desc);
+
+	for (idx = 0; idx < intc->n_words; idx++) {
+		int base = idx * IRQS_PER_WORD;
+		unsigned long pending;
+		irq_hw_number_t hwirq;
+		unsigned int irq;
+
+		pending = __raw_readl(cpu->map_base + reg_status(intc, idx));
+		pending &= __raw_readl(cpu->map_base + reg_enable(intc, idx));
+
+		for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
+			irq = irq_linear_revmap(intc->domain, base + hwirq);
+			if (irq)
+				do_IRQ(irq);
+			else
+				spurious_interrupt();
+		}
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static inline void __bcm6345_l1_unmask(struct irq_data *d)
+{
+	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	u32 word = d->hwirq / IRQS_PER_WORD;
+	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
+	unsigned int cpu_idx = cpu_for_irq(intc, d);
+
+	intc->cpus[cpu_idx]->enable_cache[word] |= mask;
+	__raw_writel(intc->cpus[cpu_idx]->enable_cache[word],
+		intc->cpus[cpu_idx]->map_base + reg_enable(intc, word));
+}
+
+static inline void __bcm6345_l1_mask(struct irq_data *d)
+{
+	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	u32 word = d->hwirq / IRQS_PER_WORD;
+	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
+	unsigned int cpu_idx = cpu_for_irq(intc, d);
+
+	intc->cpus[cpu_idx]->enable_cache[word] &= ~mask;
+	__raw_writel(intc->cpus[cpu_idx]->enable_cache[word],
+		intc->cpus[cpu_idx]->map_base + reg_enable(intc, word));
+}
+
+static void bcm6345_l1_unmask(struct irq_data *d)
+{
+	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&intc->lock, flags);
+	__bcm6345_l1_unmask(d);
+	raw_spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static void bcm6345_l1_mask(struct irq_data *d)
+{
+	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&intc->lock, flags);
+	__bcm6345_l1_mask(d);
+	raw_spin_unlock_irqrestore(&intc->lock, flags);
+}
+
+static int bcm6345_l1_set_affinity(struct irq_data *d,
+				   const struct cpumask *dest,
+				   bool force)
+{
+	struct bcm6345_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	u32 word = d->hwirq / IRQS_PER_WORD;
+	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
+	unsigned int old_cpu = cpu_for_irq(intc, d);
+	unsigned int new_cpu;
+	struct cpumask valid;
+	unsigned long flags;
+	bool enabled;
+
+	if (!cpumask_and(&valid, &intc->cpumask, dest))
+		return -EINVAL;
+
+	new_cpu = cpumask_any_and(&valid, cpu_online_mask);
+	if (new_cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	dest = cpumask_of(new_cpu);
+
+	raw_spin_lock_irqsave(&intc->lock, flags);
+	if (old_cpu != new_cpu) {
+		enabled = intc->cpus[old_cpu]->enable_cache[word] & mask;
+		if (enabled)
+			__bcm6345_l1_mask(d);
+		cpumask_copy(irq_data_get_affinity_mask(d), dest);
+		if (enabled)
+			__bcm6345_l1_unmask(d);
+	} else {
+		cpumask_copy(irq_data_get_affinity_mask(d), dest);
+	}
+	raw_spin_unlock_irqrestore(&intc->lock, flags);
+
+	return IRQ_SET_MASK_OK_NOCOPY;
+}
+
+static int __init bcm6345_l1_init_one(struct device_node *dn,
+				      unsigned int idx,
+				      struct bcm6345_l1_chip *intc)
+{
+	struct resource res;
+	resource_size_t sz;
+	struct bcm6345_l1_cpu *cpu;
+	unsigned int i, n_words;
+
+	if (of_address_to_resource(dn, idx, &res))
+		return -EINVAL;
+	sz = resource_size(&res);
+	n_words = sz / REG_BYTES_PER_IRQ_WORD;
+
+	if (!intc->n_words)
+		intc->n_words = n_words;
+	else if (intc->n_words != n_words)
+		return -EINVAL;
+
+	cpu = intc->cpus[idx] = kzalloc(sizeof(*cpu) + n_words * sizeof(u32),
+					GFP_KERNEL);
+	if (!cpu)
+		return -ENOMEM;
+
+	cpu->map_base = ioremap(res.start, sz);
+	if (!cpu->map_base)
+		return -ENOMEM;
+
+	for (i = 0; i < n_words; i++) {
+		cpu->enable_cache[i] = 0;
+		__raw_writel(0, cpu->map_base + reg_enable(intc, i));
+	}
+
+	cpu->parent_irq = irq_of_parse_and_map(dn, idx);
+	if (!cpu->parent_irq) {
+		pr_err("failed to map parent interrupt %d\n", cpu->parent_irq);
+		return -EINVAL;
+	}
+	irq_set_chained_handler_and_data(cpu->parent_irq,
+						bcm6345_l1_irq_handle, intc);
+
+	return 0;
+}
+
+static struct irq_chip bcm6345_l1_irq_chip = {
+	.name			= "bcm6345-l1",
+	.irq_mask		= bcm6345_l1_mask,
+	.irq_unmask		= bcm6345_l1_unmask,
+	.irq_set_affinity	= bcm6345_l1_set_affinity,
+};
+
+static int bcm6345_l1_map(struct irq_domain *d, unsigned int virq,
+			  irq_hw_number_t hw_irq)
+{
+	irq_set_chip_and_handler(virq,
+		&bcm6345_l1_irq_chip, handle_percpu_irq);
+	irq_set_chip_data(virq, d->host_data);
+	return 0;
+}
+
+static const struct irq_domain_ops bcm6345_l1_domain_ops = {
+	.xlate			= irq_domain_xlate_onecell,
+	.map			= bcm6345_l1_map,
+};
+
+static int __init bcm6345_l1_of_init(struct device_node *dn,
+			      struct device_node *parent)
+{
+	struct bcm6345_l1_chip *intc;
+	unsigned int idx;
+	int ret;
+
+	intc = kzalloc(sizeof(*intc), GFP_KERNEL);
+	if (!intc)
+		return -ENOMEM;
+
+	for_each_possible_cpu(idx) {
+		ret = bcm6345_l1_init_one(dn, idx, intc);
+		if (ret)
+			pr_err("failed to init intc L1 for cpu %d: %d\n",
+				idx, ret);
+		else
+			cpumask_set_cpu(idx, &intc->cpumask);
+	}
+
+	if (!cpumask_weight(&intc->cpumask)) {
+		ret = -ENODEV;
+		goto out_free;
+	}
+
+	raw_spin_lock_init(&intc->lock);
+
+	intc->domain = irq_domain_add_linear(dn, IRQS_PER_WORD * intc->n_words,
+					     &bcm6345_l1_domain_ops,
+					     intc);
+	if (!intc->domain) {
+		ret = -ENOMEM;
+		goto out_unmap;
+	}
+
+	pr_info("registered BCM6345 L1 intc (IRQs: %d)\n",
+			IRQS_PER_WORD * intc->n_words);
+	for_each_cpu(idx, &intc->cpumask) {
+		struct bcm6345_l1_cpu *cpu = intc->cpus[idx];
+
+		pr_info("  CPU%u at MMIO 0x%p (irq = %d)\n", idx,
+				cpu->map_base, cpu->parent_irq);
+	}
+
+	return 0;
+
+out_unmap:
+	for_each_possible_cpu(idx) {
+		struct bcm6345_l1_cpu *cpu = intc->cpus[idx];
+
+		if (cpu) {
+			if (cpu->map_base)
+				iounmap(cpu->map_base);
+			kfree(cpu);
+		}
+	}
+out_free:
+	kfree(intc);
+	return ret;
+}
+
+IRQCHIP_DECLARE(bcm6345_l1, "brcm,bcm6345-l1-intc", bcm6345_l1_of_init);
-- 
2.1.4

-- 
Simon Arlott
--
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Re: [PATCH linux-next 1/2] irqchip: Add brcm,bcm6345-l1-intc device tree binding

[Rob Herring]

On Wed, Dec 09, 2015 at 08:27:09PM +0000, Simon Arlott wrote:
> Add device tree binding for the BCM6345 interrupt controller.
> 
> This controller is similar to the SMP-capable BCM7038 and
> the BCM3380 but with packed interrupt registers.
> 
> Signed-off-by: Simon Arlott <simon-A6De1vDTPLDsq35pWSNszA@public.gmane.org>

Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

> ---
> Corrected example device name to be "interrupt-controller".
> 
>  .../interrupt-controller/brcm,bcm6345-l1-intc.txt  | 57 ++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt
> new file mode 100644
> index 0000000..4040905
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm6345-l1-intc.txt
> @@ -0,0 +1,57 @@
> +Broadcom BCM6345-style Level 1 interrupt controller
> +
> +This block is a first level interrupt controller that is typically connected
> +directly to one of the HW INT lines on each CPU.
> +
> +Key elements of the hardware design include:
> +
> +- 32, 64 or 128 incoming level IRQ lines
> +
> +- Most onchip peripherals are wired directly to an L1 input
> +
> +- A separate instance of the register set for each CPU, allowing individual
> +  peripheral IRQs to be routed to any CPU
> +
> +- Contains one or more enable/status word pairs per CPU
> +
> +- No atomic set/clear operations
> +
> +- No polarity/level/edge settings
> +
> +- No FIFO or priority encoder logic; software is expected to read all
> +  2-4 status words to determine which IRQs are pending
> +
> +Required properties:
> +
> +- compatible: should be "brcm,bcm<soc>-l1-intc", "brcm,bcm6345-l1-intc"
> +- reg: specifies the base physical address and size of the registers;
> +  the number of supported IRQs is inferred from the size argument
> +- interrupt-controller: identifies the node as an interrupt controller
> +- #interrupt-cells: specifies the number of cells needed to encode an interrupt
> +  source, should be 1.
> +- interrupt-parent: specifies the phandle to the parent interrupt controller(s)
> +  this one is cascaded from
> +- interrupts: specifies the interrupt line(s) in the interrupt-parent controller
> +  node; valid values depend on the type of parent interrupt controller
> +
> +If multiple reg ranges and interrupt-parent entries are present on an SMP
> +system, the driver will allow IRQ SMP affinity to be set up through the
> +/proc/irq/ interface.  In the simplest possible configuration, only one
> +reg range and one interrupt-parent is needed.
> +
> +The driver operates in native CPU endian by default, there is no support for
> +specifying an alternative endianness.
> +
> +Example:
> +
> +periph_intc: interrupt-controller@10000000 {
> +        compatible = "brcm,bcm63168-l1-intc", "brcm,bcm6345-l1-intc";
> +        reg = <0x10000020 0x20>,
> +              <0x10000040 0x20>;
> +
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +
> +        interrupt-parent = <&cpu_intc>;
> +        interrupts = <2>, <3>;
> +};
> -- 
> 2.1.4
> 
> -- 
> Simon Arlott
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