irqchip/exiu: Add support for Socionext Synquacer EXIU controller

The Socionext Synquacer SoC has an external interrupt unit (EXIU)
that forwards a block of 32 configurable input lines to 32 adjacent
level-high type GICv3 SPIs.

The EXIU has per-interrupt level/edge and polarity controls, and
mask bits that keep the outgoing lines de-asserted, even though
the controller may still latch interrupt conditions that occur
while the line is masked.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

3 files changed, 231 insertions, 0 deletions

diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms
index 6b54ee8c1262..1d03ef54295a 100644
--- a/arch/arm64/Kconfig.platforms
+++ b/arch/arm64/Kconfig.platforms
@@ -161,6 +161,9 @@ config ARCH_SEATTLE
 config ARCH_SHMOBILE
 	bool
 
+config ARCH_SYNQUACER
+	bool "Socionext SynQuacer SoC Family"
+
 config ARCH_RENESAS
 	bool "Renesas SoC Platforms"
 	select ARCH_SHMOBILE
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 065adf4102c9..dee3390390d5 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -79,4 +79,5 @@ obj-$(CONFIG_ARCH_ASPEED)		+= irq-aspeed-vic.o irq-aspeed-i2c-ic.o
 obj-$(CONFIG_STM32_EXTI) 		+= irq-stm32-exti.o
 obj-$(CONFIG_QCOM_IRQ_COMBINER)		+= qcom-irq-combiner.o
 obj-$(CONFIG_IRQ_UNIPHIER_AIDET)	+= irq-uniphier-aidet.o
+obj-$(CONFIG_ARCH_SYNQUACER)		+= irq-sni-exiu.o
 obj-$(CONFIG_MESON_IRQ_GPIO)		+= irq-meson-gpio.o
diff --git a/drivers/irqchip/irq-sni-exiu.c b/drivers/irqchip/irq-sni-exiu.c
new file mode 100644
index 000000000000..1b6e2f7c59af
--- /dev/null
+++ b/drivers/irqchip/irq-sni-exiu.c
@@ -0,0 +1,227 @@
+/*
+ * Driver for Socionext External Interrupt Unit (EXIU)
+ *
+ * Copyright (c) 2017 Linaro, Ltd. <ard.biesheuvel@linaro.org>
+ *
+ * Based on irq-tegra.c:
+ *   Copyright (C) 2011 Google, Inc.
+ *   Copyright (C) 2010,2013, NVIDIA Corporation
+ *
+ * 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.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+#define NUM_IRQS	32
+
+#define EIMASK		0x00
+#define EISRCSEL	0x04
+#define EIREQSTA	0x08
+#define EIRAWREQSTA	0x0C
+#define EIREQCLR	0x10
+#define EILVL		0x14
+#define EIEDG		0x18
+#define EISIR		0x1C
+
+struct exiu_irq_data {
+	void __iomem	*base;
+	u32		spi_base;
+};
+
+static void exiu_irq_eoi(struct irq_data *d)
+{
+	struct exiu_irq_data *data = irq_data_get_irq_chip_data(d);
+
+	writel(BIT(d->hwirq), data->base + EIREQCLR);
+	irq_chip_eoi_parent(d);
+}
+
+static void exiu_irq_mask(struct irq_data *d)
+{
+	struct exiu_irq_data *data = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	val = readl_relaxed(data->base + EIMASK) | BIT(d->hwirq);
+	writel_relaxed(val, data->base + EIMASK);
+	irq_chip_mask_parent(d);
+}
+
+static void exiu_irq_unmask(struct irq_data *d)
+{
+	struct exiu_irq_data *data = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	val = readl_relaxed(data->base + EIMASK) & ~BIT(d->hwirq);
+	writel_relaxed(val, data->base + EIMASK);
+	irq_chip_unmask_parent(d);
+}
+
+static void exiu_irq_enable(struct irq_data *d)
+{
+	struct exiu_irq_data *data = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	/* clear interrupts that were latched while disabled */
+	writel_relaxed(BIT(d->hwirq), data->base + EIREQCLR);
+
+	val = readl_relaxed(data->base + EIMASK) & ~BIT(d->hwirq);
+	writel_relaxed(val, data->base + EIMASK);
+	irq_chip_enable_parent(d);
+}
+
+static int exiu_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct exiu_irq_data *data = irq_data_get_irq_chip_data(d);
+	u32 val;
+
+	val = readl_relaxed(data->base + EILVL);
+	if (type == IRQ_TYPE_EDGE_RISING || type == IRQ_TYPE_LEVEL_HIGH)
+		val |= BIT(d->hwirq);
+	else
+		val &= ~BIT(d->hwirq);
+	writel_relaxed(val, data->base + EILVL);
+
+	val = readl_relaxed(data->base + EIEDG);
+	if (type == IRQ_TYPE_LEVEL_LOW || type == IRQ_TYPE_LEVEL_HIGH)
+		val &= ~BIT(d->hwirq);
+	else
+		val |= BIT(d->hwirq);
+	writel_relaxed(val, data->base + EIEDG);
+
+	writel_relaxed(BIT(d->hwirq), data->base + EIREQCLR);
+
+	return irq_chip_set_type_parent(d, IRQ_TYPE_LEVEL_HIGH);
+}
+
+static struct irq_chip exiu_irq_chip = {
+	.name			= "EXIU",
+	.irq_eoi		= exiu_irq_eoi,
+	.irq_enable		= exiu_irq_enable,
+	.irq_mask		= exiu_irq_mask,
+	.irq_unmask		= exiu_irq_unmask,
+	.irq_set_type		= exiu_irq_set_type,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+	.flags			= IRQCHIP_SET_TYPE_MASKED |
+				  IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_EOI_THREADED |
+				  IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int exiu_domain_translate(struct irq_domain *domain,
+				 struct irq_fwspec *fwspec,
+				 unsigned long *hwirq,
+				 unsigned int *type)
+{
+	struct exiu_irq_data *info = domain->host_data;
+
+	if (is_of_node(fwspec->fwnode)) {
+		if (fwspec->param_count != 3)
+			return -EINVAL;
+
+		if (fwspec->param[0] != GIC_SPI)
+			return -EINVAL; /* No PPI should point to this domain */
+
+		*hwirq = fwspec->param[1] - info->spi_base;
+		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+static int exiu_domain_alloc(struct irq_domain *dom, unsigned int virq,
+			     unsigned int nr_irqs, void *data)
+{
+	struct irq_fwspec *fwspec = data;
+	struct irq_fwspec parent_fwspec;
+	struct exiu_irq_data *info = dom->host_data;
+	irq_hw_number_t hwirq;
+
+	if (fwspec->param_count != 3)
+		return -EINVAL;	/* Not GIC compliant */
+	if (fwspec->param[0] != GIC_SPI)
+		return -EINVAL;	/* No PPI should point to this domain */
+
+	WARN_ON(nr_irqs != 1);
+	hwirq = fwspec->param[1] - info->spi_base;
+	irq_domain_set_hwirq_and_chip(dom, virq, hwirq, &exiu_irq_chip, info);
+
+	parent_fwspec = *fwspec;
+	parent_fwspec.fwnode = dom->parent->fwnode;
+	return irq_domain_alloc_irqs_parent(dom, virq, nr_irqs, &parent_fwspec);
+}
+
+static const struct irq_domain_ops exiu_domain_ops = {
+	.translate	= exiu_domain_translate,
+	.alloc		= exiu_domain_alloc,
+	.free		= irq_domain_free_irqs_common,
+};
+
+static int __init exiu_init(struct device_node *node,
+			    struct device_node *parent)
+{
+	struct irq_domain *parent_domain, *domain;
+	struct exiu_irq_data *data;
+	int err;
+
+	if (!parent) {
+		pr_err("%pOF: no parent, giving up\n", node);
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent);
+	if (!parent_domain) {
+		pr_err("%pOF: unable to obtain parent domain\n", node);
+		return -ENXIO;
+	}
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	if (of_property_read_u32(node, "socionext,spi-base", &data->spi_base)) {
+		pr_err("%pOF: failed to parse 'spi-base' property\n", node);
+		err = -ENODEV;
+		goto out_free;
+	}
+
+	data->base = of_iomap(node, 0);
+	if (IS_ERR(data->base)) {
+		err = PTR_ERR(data->base);
+		goto out_free;
+	}
+
+	/* clear and mask all interrupts */
+	writel_relaxed(0xFFFFFFFF, data->base + EIREQCLR);
+	writel_relaxed(0xFFFFFFFF, data->base + EIMASK);
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0, NUM_IRQS, node,
+					  &exiu_domain_ops, data);
+	if (!domain) {
+		pr_err("%pOF: failed to allocate domain\n", node);
+		err = -ENOMEM;
+		goto out_unmap;
+	}
+
+	pr_info("%pOF: %d interrupts forwarded to %pOF\n", node, NUM_IRQS,
+		parent);
+
+	return 0;
+
+out_unmap:
+	iounmap(data->base);
+out_free:
+	kfree(data);
+	return err;
+}
+IRQCHIP_DECLARE(exiu, "socionext,synquacer-exiu", exiu_init);