[RFC PATCH v3] irqchip: Add support for Tango interrupt controller

[marc_gonzalez@sigmadesigns.com (Marc Gonzalez)]

From: Mans Rullgard <mans@mansr.com>

Add support for the interrupt controller used in Sigma Designs
SMP86xx (Tango3) and SMP87xx (Tango4) chips.

Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
---
For the arch/arm/mach-tango port, I'm using this driver written
by Mans. Version 1 of the patch was submitted two months ago:
http://thread.gmane.org/gmane.linux.kernel/2089471

I've tried to address Marc Zyngier's remarks.

I kept Mans as the commit author, but I removed his Signed-off-by
(because I might have introduced errors that he didn't sign off on).
Is that the right thing to do?

I didn't rename tangox to tango inside irq-tango.c because I didn't
want to change the code too much, but I'm OK either way.

The matching DT description currently is

intc: interrupt-controller at 6e000 {
	compatible = "sigma,smp8642-intc";
	reg = <0x6e000 0x400>;
	ranges = <0 0x6e000 0x400>;
	interrupt-parent = <&gic>;
	interrupt-controller;
	#address-cells = <1>;
	#size-cells = <1>;

	irq0: irq0 at 000 {
		reg = <0x000 0x100>;
		interrupt-controller;
		#interrupt-cells = <2>;
		interrupts = <GIC_SPI 2 IRQ_TYPE_LEVEL_HIGH>;
	};

	irq1: irq1 at 100 {
		reg = <0x100 0x100>;
		interrupt-controller;
		#interrupt-cells = <2>;
		interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
	};

	irq2: irq2 at 300 {
		reg = <0x300 0x100>;
		interrupt-controller;
		#interrupt-cells = <2>;
		interrupts = <GIC_SPI 4 IRQ_TYPE_LEVEL_HIGH>;
	};
};

---
 drivers/irqchip/Kconfig     |   5 +
 drivers/irqchip/Makefile    |   1 +
 drivers/irqchip/irq-tango.c | 225 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 231 insertions(+)
 create mode 100644 drivers/irqchip/irq-tango.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 4d7294e5d982..399eda54b860 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -133,6 +133,11 @@ config ST_IRQCHIP
 	help
 	  Enables SysCfg Controlled IRQs on STi based platforms.
 
+config TANGO_IRQ
+	bool
+	select IRQ_DOMAIN
+	select GENERIC_IRQ_CHIP
+
 config TB10X_IRQC
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 177f78f6e6d6..74512452cc8b 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
 obj-$(CONFIG_ARCH_NSPIRE)		+= irq-zevio.o
 obj-$(CONFIG_ARCH_VT8500)		+= irq-vt8500.o
 obj-$(CONFIG_ST_IRQCHIP)		+= irq-st.o
+obj-$(CONFIG_TANGO_IRQ)			+= irq-tango.o
 obj-$(CONFIG_TB10X_IRQC)		+= irq-tb10x.o
 obj-$(CONFIG_XTENSA)			+= irq-xtensa-pic.o
 obj-$(CONFIG_XTENSA_MX)			+= irq-xtensa-mx.o
diff --git a/drivers/irqchip/irq-tango.c b/drivers/irqchip/irq-tango.c
new file mode 100644
index 000000000000..ace9bd50be6b
--- /dev/null
+++ b/drivers/irqchip/irq-tango.c
@@ -0,0 +1,225 @@
+/*
+ * Copyright (C) 2014 Mans Rullgard <mans@mansr.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+
+#define IRQ0_CTL_BASE		0x0000
+#define IRQ1_CTL_BASE		0x0100
+#define EDGE_CTL_BASE		0x0200
+#define IRQ2_CTL_BASE		0x0300
+
+#define IRQ_CTL_HI		0x18
+#define EDGE_CTL_HI		0x20
+
+#define IRQ_STATUS		0x00
+#define IRQ_RAWSTAT		0x04
+#define IRQ_EN_SET		0x08
+#define IRQ_EN_CLR		0x0c
+#define IRQ_SOFT_SET		0x10
+#define IRQ_SOFT_CLR		0x14
+
+#define EDGE_STATUS		0x00
+#define EDGE_RAWSTAT		0x04
+#define EDGE_CFG_RISE		0x08
+#define EDGE_CFG_FALL		0x0c
+#define EDGE_CFG_RISE_SET	0x10
+#define EDGE_CFG_RISE_CLR	0x14
+#define EDGE_CFG_FALL_SET	0x18
+#define EDGE_CFG_FALL_CLR	0x1c
+
+struct tangox_irq_chip {
+	void __iomem *base;
+	unsigned long ctl;
+};
+
+static inline u32 intc_readl(struct tangox_irq_chip *chip, int reg)
+{
+	return readl_relaxed(chip->base + reg);
+}
+
+static inline void intc_writel(struct tangox_irq_chip *chip, int reg, u32 val)
+{
+	writel_relaxed(val, chip->base + reg);
+}
+
+static void tangox_dispatch_irqs(struct irq_domain *dom, unsigned int status,
+				 int base)
+{
+	unsigned int hwirq;
+	unsigned int virq;
+
+	while (status) {
+		hwirq = __ffs(status);
+		virq = irq_find_mapping(dom, base + hwirq);
+		if (virq) generic_handle_irq(virq);
+		status &= ~BIT(hwirq);
+	}
+}
+
+static void tangox_irq_handler(struct irq_desc *desc)
+{
+	struct irq_domain *dom = irq_desc_get_handler_data(desc);
+	struct irq_chip *host_chip = irq_desc_get_chip(desc);
+	struct tangox_irq_chip *chip = dom->host_data;
+	unsigned int status_lo, status_hi;
+
+	chained_irq_enter(host_chip, desc);
+
+	status_lo = intc_readl(chip, chip->ctl + IRQ_STATUS);
+	status_hi = intc_readl(chip, chip->ctl + IRQ_CTL_HI + IRQ_STATUS);
+
+	tangox_dispatch_irqs(dom, status_lo, 0);
+	tangox_dispatch_irqs(dom, status_hi, 32);
+
+	chained_irq_exit(host_chip, desc);
+}
+
+static int tangox_irq_set_type(struct irq_data *d, unsigned int flow_type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct tangox_irq_chip *chip = gc->domain->host_data;
+	struct irq_chip_regs *regs = &gc->chip_types[0].regs;
+
+	switch (flow_type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_RISING:
+		intc_writel(chip, regs->type + EDGE_CFG_RISE_SET, d->mask);
+		intc_writel(chip, regs->type + EDGE_CFG_FALL_CLR, d->mask);
+		break;
+
+	case IRQ_TYPE_EDGE_FALLING:
+		intc_writel(chip, regs->type + EDGE_CFG_RISE_CLR, d->mask);
+		intc_writel(chip, regs->type + EDGE_CFG_FALL_SET, d->mask);
+		break;
+
+	case IRQ_TYPE_LEVEL_HIGH:
+		intc_writel(chip, regs->type + EDGE_CFG_RISE_CLR, d->mask);
+		intc_writel(chip, regs->type + EDGE_CFG_FALL_CLR, d->mask);
+		break;
+
+	case IRQ_TYPE_LEVEL_LOW:
+		intc_writel(chip, regs->type + EDGE_CFG_RISE_SET, d->mask);
+		intc_writel(chip, regs->type + EDGE_CFG_FALL_SET, d->mask);
+		break;
+
+	default:
+		pr_err("Invalid trigger mode %x for IRQ %d\n",
+		       flow_type, d->irq);
+		return -EINVAL;
+	}
+
+	return irq_setup_alt_chip(d, flow_type);
+}
+
+static void __init tangox_irq_init_chip(struct irq_chip_generic *gc,
+					unsigned long ctl_offs,
+					unsigned long edge_offs)
+{
+	struct tangox_irq_chip *chip = gc->domain->host_data;
+	struct irq_chip_type *ct = gc->chip_types;
+	unsigned long ctl_base = chip->ctl + ctl_offs;
+	unsigned long edge_base = EDGE_CTL_BASE + edge_offs;
+	int i;
+
+	gc->reg_base = chip->base;
+	gc->unused = 0;
+
+	for (i = 0; i < 2; i++) {
+		ct[i].chip.irq_ack = irq_gc_ack_set_bit;
+		ct[i].chip.irq_mask = irq_gc_mask_disable_reg;
+		ct[i].chip.irq_mask_ack = irq_gc_mask_disable_reg_and_ack;
+		ct[i].chip.irq_unmask = irq_gc_unmask_enable_reg;
+		ct[i].chip.irq_set_type = tangox_irq_set_type;
+		ct[i].chip.name = gc->domain->name;
+
+		ct[i].regs.enable = ctl_base + IRQ_EN_SET;
+		ct[i].regs.disable = ctl_base + IRQ_EN_CLR;
+		ct[i].regs.ack = edge_base + EDGE_RAWSTAT;
+		ct[i].regs.type = edge_base;
+	}
+
+	ct[0].type = IRQ_TYPE_LEVEL_MASK;
+	ct[0].handler = handle_level_irq;
+
+	ct[1].type = IRQ_TYPE_EDGE_BOTH;
+	ct[1].handler = handle_edge_irq;
+
+	intc_writel(chip, ct->regs.disable, 0xffffffff);
+	intc_writel(chip, ct->regs.ack, 0xffffffff);
+}
+
+static void __init tangox_irq_domain_init(struct irq_domain *dom)
+{
+	struct irq_chip_generic *gc;
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		gc = irq_get_domain_generic_chip(dom, i * 32);
+		tangox_irq_init_chip(gc, i * IRQ_CTL_HI, i * EDGE_CTL_HI);
+	}
+}
+
+static int __init tangox_irq_init(void __iomem *base, struct device_node *node)
+{
+	struct tangox_irq_chip *chip;
+	struct irq_domain *dom;
+	u32 ctl;
+	int irq;
+	int err;
+
+	irq = irq_of_parse_and_map(node, 0);
+	if (!irq)
+		panic("%s: failed to get IRQ", node->name);
+
+	if (of_property_read_u32(node, "reg", &ctl))
+		panic("%s: failed to get reg base", node->name);
+
+	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+	chip->ctl = ctl;
+	chip->base = base;
+
+	dom = irq_domain_add_linear(node, 64, &irq_generic_chip_ops, chip);
+	if (!dom)
+		panic("%s: failed to create irqdomain", node->name);
+
+	err = irq_alloc_domain_generic_chips(dom, 32, 2, node->name,
+			handle_level_irq, 0, 0, 0);
+	if (err)
+		panic("%s: failed to allocate irqchip", node->name);
+
+	tangox_irq_domain_init(dom);
+
+	irq_set_chained_handler(irq, tangox_irq_handler);
+	irq_set_handler_data(irq, dom);
+
+	return 0;
+}
+
+static int __init tangox_of_irq_init(struct device_node *node,
+				     struct device_node *parent)
+{
+	struct device_node *c;
+	void __iomem *base;
+
+	base = of_iomap(node, 0);
+
+	for_each_child_of_node(node, c)
+		tangox_irq_init(base, c);
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(tangox_intc, "sigma,smp8642-intc", tangox_of_irq_init);