From cb376159800b9b44be76949c3aee89eb06d29faa Mon Sep 17 00:00:00 2001
From: John Crispin <john@phrozen.org>
Date: Tue, 6 Mar 2018 09:55:13 +0100
Subject: [PATCH 07/27] irqchip/irq-ath79-intc: add irq cascade driver for
 QCA9556 SoCs

Signed-off-by: John Crispin <john@phrozen.org>
---
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-ath79-intc.c | 104 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)
 create mode 100644 drivers/irqchip/irq-ath79-intc.c

--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_IRQCHIP)			+= irqchip.o
 
 obj-$(CONFIG_ALPINE_MSI)		+= irq-alpine-msi.o
 obj-$(CONFIG_ATH79)			+= irq-ath79-cpu.o
+obj-$(CONFIG_ATH79)			+= irq-ath79-intc.o
 obj-$(CONFIG_ATH79)			+= irq-ath79-misc.o
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2835.o
 obj-$(CONFIG_ARCH_BCM2835)		+= irq-bcm2836.o
--- /dev/null
+++ b/drivers/irqchip/irq-ath79-intc.c
@@ -0,0 +1,104 @@
+/*
+ *  Atheros AR71xx/AR724x/AR913x specific interrupt handling
+ *
+ *  Copyright (C) 2018 John Crispin <john@phrozen.org>
+ *
+ *  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/irqchip.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/mach-ath79/ath79.h>
+#include <asm/mach-ath79/ar71xx_regs.h>
+
+#define ATH79_MAX_INTC_CASCADE	3
+
+struct ath79_intc {
+	struct irq_chip chip;
+	u32 irq;
+	u32 pending_mask;
+	u32 irq_mask[ATH79_MAX_INTC_CASCADE];
+};
+
+static void ath79_intc_irq_handler(struct irq_desc *desc)
+{
+	struct irq_domain *domain = irq_desc_get_handler_data(desc);
+	struct ath79_intc *intc = domain->host_data;
+	u32 pending;
+
+	pending = ath79_reset_rr(QCA955X_RESET_REG_EXT_INT_STATUS);
+	pending &= intc->pending_mask;
+
+	if (pending) {
+		int i;
+
+		for (i = 0; i < domain->hwirq_max; i++)
+			if (pending & intc->irq_mask[i])
+				generic_handle_irq(irq_find_mapping(domain, i));
+	} else {
+		spurious_interrupt();
+	}
+}
+
+static void ath79_intc_irq_unmask(struct irq_data *d)
+{
+}
+
+static void ath79_intc_irq_mask(struct irq_data *d)
+{
+}
+
+static int ath79_intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+{
+	struct ath79_intc *intc = d->host_data;
+
+	irq_set_chip_and_handler(irq, &intc->chip, handle_level_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops ath79_irq_domain_ops = {
+	.xlate = irq_domain_xlate_onecell,
+	.map = ath79_intc_map,
+};
+
+static int __init qca9556_intc_of_init(
+	struct device_node *node, struct device_node *parent)
+{
+	struct irq_domain *domain;
+	struct ath79_intc *intc;
+	int cnt, i;
+
+	cnt = of_property_count_u32_elems(node, "qcom,pending-bits");
+	if (cnt > ATH79_MAX_INTC_CASCADE)
+		panic("Too many INTC pending bits\n");
+
+	intc = kzalloc(sizeof(*intc), GFP_KERNEL);
+	if (!intc)
+		panic("Failed to allocate INTC memory\n");
+	intc->chip.name = "INTC";
+	intc->chip.irq_unmask = ath79_intc_irq_unmask,
+	intc->chip.irq_mask = ath79_intc_irq_mask,
+
+	of_property_read_u32_array(node, "qcom,pending-bits", intc->irq_mask, cnt);
+	for (i = 0; i < cnt; i++)
+		intc->pending_mask |= intc->irq_mask[i];
+
+	intc->irq = irq_of_parse_and_map(node, 0);
+	if (!intc->irq)
+		panic("Failed to get INTC IRQ");
+
+	domain = irq_domain_add_linear(node, cnt, &ath79_irq_domain_ops, intc);
+	irq_set_chained_handler_and_data(intc->irq, ath79_intc_irq_handler, domain);
+
+	return 0;
+}
+IRQCHIP_DECLARE(qca9556_intc, "qcom,qca9556-intc",
+		qca9556_intc_of_init);