irqchip: Add Mediatek mtk-cirq driver

In Mediatek SOCs, the CIRQ is a low power interrupt controller
designed to works outside MCUSYS which comprises with Cortex-Ax
cores,CCI and GIC.

The CIRQ controller is integrated in between MCUSYS( include
Cortex-Ax, CCI and GIC ) and interrupt sources as the second
level interrupt controller. The external interrupts which outside
MCUSYS will feed through CIRQ then bypass to GIC. CIRQ can monitors
all edge trigger interupts. When an edge interrupt is triggered,
CIRQ can record the status and generate a pulse signal to GIC when
flush command executed.

When system enters sleep mode, MCUSYS will be turned off to improve
power consumption, also GIC is power down. The edge trigger interrupts
will be lost in this scenario without CIRQ.

This commit provides the CIRQ irqchip implement.
Signed-off-by: Youlin Pei <youlin.pei@mediatek.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Makefile

@@ -61,7 +61,7 @@ obj-$(CONFIG_BCM7120_L2_IRQ)		+= irq-bcm7120-l2.o
 obj-$(CONFIG_BRCMSTB_L2_IRQ)		+= irq-brcmstb-l2.o
 obj-$(CONFIG_KEYSTONE_IRQ)		+= irq-keystone.o
 obj-$(CONFIG_MIPS_GIC)			+= irq-mips-gic.o
-obj-$(CONFIG_ARCH_MEDIATEK)		+= irq-mtk-sysirq.o
+obj-$(CONFIG_ARCH_MEDIATEK)		+= irq-mtk-sysirq.o irq-mtk-cirq.o
 obj-$(CONFIG_ARCH_DIGICOLOR)		+= irq-digicolor.o
 obj-$(CONFIG_RENESAS_H8300H_INTC)	+= irq-renesas-h8300h.o
 obj-$(CONFIG_RENESAS_H8S_INTC)		+= irq-renesas-h8s.o

drivers/irqchip/irq-mtk-cirq.c

+/*
+ * Copyright (c) 2016 MediaTek Inc.
+ * Author: Youlin.Pei <youlin.pei@mediatek.com>
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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_irq.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/syscore_ops.h>
+
+#define CIRQ_ACK	0x40
+#define CIRQ_MASK_SET	0xc0
+#define CIRQ_MASK_CLR	0x100
+#define CIRQ_SENS_SET	0x180
+#define CIRQ_SENS_CLR	0x1c0
+#define CIRQ_POL_SET	0x240
+#define CIRQ_POL_CLR	0x280
+#define CIRQ_CONTROL	0x300
+
+#define CIRQ_EN	0x1
+#define CIRQ_EDGE	0x2
+#define CIRQ_FLUSH	0x4
+
+struct mtk_cirq_chip_data {
+	void __iomem *base;
+	unsigned int ext_irq_start;
+	unsigned int ext_irq_end;
+	struct irq_domain *domain;
+};
+
+static struct mtk_cirq_chip_data *cirq_data;
+
+static void mtk_cirq_write_mask(struct irq_data *data, unsigned int offset)
+{
+	struct mtk_cirq_chip_data *chip_data = data->chip_data;
+	unsigned int cirq_num = data->hwirq;
+	u32 mask = 1 << (cirq_num % 32);
+
+	writel_relaxed(mask, chip_data->base + offset + (cirq_num / 32) * 4);
+}
+
+static void mtk_cirq_mask(struct irq_data *data)
+{
+	mtk_cirq_write_mask(data, CIRQ_MASK_SET);
+	irq_chip_mask_parent(data);
+}
+
+static void mtk_cirq_unmask(struct irq_data *data)
+{
+	mtk_cirq_write_mask(data, CIRQ_MASK_CLR);
+	irq_chip_unmask_parent(data);
+}
+
+static int mtk_cirq_set_type(struct irq_data *data, unsigned int type)
+{
+	int ret;
+
+	switch (type & IRQ_TYPE_SENSE_MASK) {
+	case IRQ_TYPE_EDGE_FALLING:
+		mtk_cirq_write_mask(data, CIRQ_POL_CLR);
+		mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		mtk_cirq_write_mask(data, CIRQ_POL_SET);
+		mtk_cirq_write_mask(data, CIRQ_SENS_CLR);
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		mtk_cirq_write_mask(data, CIRQ_POL_CLR);
+		mtk_cirq_write_mask(data, CIRQ_SENS_SET);
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		mtk_cirq_write_mask(data, CIRQ_POL_SET);
+		mtk_cirq_write_mask(data, CIRQ_SENS_SET);
+		break;
+	default:
+		break;
+	}
+
+	data = data->parent_data;
+	ret = data->chip->irq_set_type(data, type);
+	return ret;
+}
+
+static struct irq_chip mtk_cirq_chip = {
+	.name			= "MT_CIRQ",
+	.irq_mask		= mtk_cirq_mask,
+	.irq_unmask		= mtk_cirq_unmask,
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_set_type		= mtk_cirq_set_type,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+#ifdef CONFIG_SMP
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+#endif
+};
+
+static int mtk_cirq_domain_translate(struct irq_domain *d,
+				     struct irq_fwspec *fwspec,
+				     unsigned long *hwirq,
+				     unsigned int *type)
+{
+	if (is_of_node(fwspec->fwnode)) {
+		if (fwspec->param_count != 3)
+			return -EINVAL;
+
+		/* No PPI should point to this domain */
+		if (fwspec->param[0] != 0)
+			return -EINVAL;
+
+		/* cirq support irq number check */
+		if (fwspec->param[1] < cirq_data->ext_irq_start ||
+		    fwspec->param[1] > cirq_data->ext_irq_end)
+			return -EINVAL;
+
+		*hwirq = fwspec->param[1] - cirq_data->ext_irq_start;
+		*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int mtk_cirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				 unsigned int nr_irqs, void *arg)
+{
+	int ret;
+	irq_hw_number_t hwirq;
+	unsigned int type;
+	struct irq_fwspec *fwspec = arg;
+	struct irq_fwspec parent_fwspec = *fwspec;
+
+	ret = mtk_cirq_domain_translate(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	if (WARN_ON(nr_irqs != 1))
+		return -EINVAL;
+
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+				      &mtk_cirq_chip,
+				      domain->host_data);
+
+	parent_fwspec.fwnode = domain->parent->fwnode;
+	return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
+					    &parent_fwspec);
+}
+
+static const struct irq_domain_ops cirq_domain_ops = {
+	.translate	= mtk_cirq_domain_translate,
+	.alloc		= mtk_cirq_domain_alloc,
+	.free		= irq_domain_free_irqs_common,
+};
+
+#ifdef CONFIG_PM_SLEEP
+static int mtk_cirq_suspend(void)
+{
+	u32 value, mask;
+	unsigned int irq, hwirq_num;
+	bool pending, masked;
+	int i, pendret, maskret;
+
+	/*
+	 * When external interrupts happened, CIRQ will record the status
+	 * even CIRQ is not enabled. When execute flush command, CIRQ will
+	 * resend the signals according to the status. So if don't clear the
+	 * status, CIRQ will resend the wrong signals.
+	 *
+	 * arch_suspend_disable_irqs() will be called before CIRQ suspend
+	 * callback. If clear all the status simply, the external interrupts
+	 * which happened between arch_suspend_disable_irqs and CIRQ suspend
+	 * callback will be lost. Using following steps to avoid this issue;
+	 *
+	 * - Iterate over all the CIRQ supported interrupts;
+	 * - For each interrupt, inspect its pending and masked status at GIC
+	 *   level;
+	 * - If pending and unmasked, it happened between
+	 *   arch_suspend_disable_irqs and CIRQ suspend callback, don't ACK
+	 *   it. Otherwise, ACK it.
+	 */
+	hwirq_num = cirq_data->ext_irq_end - cirq_data->ext_irq_start + 1;
+	for (i = 0; i < hwirq_num; i++) {
+		irq = irq_find_mapping(cirq_data->domain, i);
+		if (irq) {
+			pendret = irq_get_irqchip_state(irq,
+							IRQCHIP_STATE_PENDING,
+							&pending);
+
+			maskret = irq_get_irqchip_state(irq,
+							IRQCHIP_STATE_MASKED,
+							&masked);
+
+			if (pendret == 0 && maskret == 0 &&
+			    (pending && !masked))
+				continue;
+		}
+
+		mask = 1 << (i % 32);
+		writel_relaxed(mask, cirq_data->base + CIRQ_ACK + (i / 32) * 4);
+	}
+
+	/* set edge_only mode, record edge-triggerd interrupts */
+	/* enable cirq */
+	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
+	value |= (CIRQ_EDGE | CIRQ_EN);
+	writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
+
+	return 0;
+}
+
+static void mtk_cirq_resume(void)
+{
+	u32 value;
+
+	/* flush recored interrupts, will send signals to parent controller */
+	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
+	writel_relaxed(value | CIRQ_FLUSH, cirq_data->base + CIRQ_CONTROL);
+
+	/* disable cirq */
+	value = readl_relaxed(cirq_data->base + CIRQ_CONTROL);
+	value &= ~(CIRQ_EDGE | CIRQ_EN);
+	writel_relaxed(value, cirq_data->base + CIRQ_CONTROL);
+}
+
+static struct syscore_ops mtk_cirq_syscore_ops = {
+	.suspend	= mtk_cirq_suspend,
+	.resume		= mtk_cirq_resume,
+};
+
+static void mtk_cirq_syscore_init(void)
+{
+	register_syscore_ops(&mtk_cirq_syscore_ops);
+}
+#else
+static inline void mtk_cirq_syscore_init(void) {}
+#endif
+
+static int __init mtk_cirq_of_init(struct device_node *node,
+				   struct device_node *parent)
+{
+	struct irq_domain *domain, *domain_parent;
+	unsigned int irq_num;
+	int ret;
+
+	domain_parent = irq_find_host(parent);
+	if (!domain_parent) {
+		pr_err("mtk_cirq: interrupt-parent not found\n");
+		return -EINVAL;
+	}
+
+	cirq_data = kzalloc(sizeof(*cirq_data), GFP_KERNEL);
+	if (!cirq_data)
+		return -ENOMEM;
+
+	cirq_data->base = of_iomap(node, 0);
+	if (!cirq_data->base) {
+		pr_err("mtk_cirq: unable to map cirq register\n");
+		ret = -ENXIO;
+		goto out_free;
+	}
+
+	ret = of_property_read_u32_index(node, "mediatek,ext-irq-range", 0,
+					 &cirq_data->ext_irq_start);
+	if (ret)
+		goto out_unmap;
+
+	ret = of_property_read_u32_index(node, "mediatek,ext-irq-range", 1,
+					 &cirq_data->ext_irq_end);
+	if (ret)
+		goto out_unmap;
+
+	irq_num = cirq_data->ext_irq_end - cirq_data->ext_irq_start + 1;
+	domain = irq_domain_add_hierarchy(domain_parent, 0,
+					  irq_num, node,
+					  &cirq_domain_ops, cirq_data);
+	if (!domain) {
+		ret = -ENOMEM;
+		goto out_unmap;
+	}
+	cirq_data->domain = domain;
+
+	mtk_cirq_syscore_init();
+
+	return 0;
+
+out_unmap:
+	iounmap(cirq_data->base);
+out_free:
+	kfree(cirq_data);
+	return ret;
+}
+
+IRQCHIP_DECLARE(mtk_cirq, "mediatek,mtk-cirq", mtk_cirq_of_init);