irqchip: Add StarFive external interrupt controller

Add StarFive external interrupt controller for JH8100 SoC.

Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20240226055025.1669223-3-changhuang.liang@starfivetech.com

MAINTAINERS

@@ -20956,6 +20956,12 @@ F:	Documentation/devicetree/bindings/phy/starfive,jh7110-usb-phy.yaml
 F:	drivers/phy/starfive/phy-jh7110-pcie.c
 F:	drivers/phy/starfive/phy-jh7110-usb.c
 
+STARFIVE JH8100 EXTERNAL INTERRUPT CONTROLLER DRIVER
+M:	Changhuang Liang <changhuang.liang@starfivetech.com>
+S:	Supported
+F:	Documentation/devicetree/bindings/interrupt-controller/starfive,jh8100-intc.yaml
+F:	drivers/irqchip/irq-starfive-jh8100-intc.c
+
 STATIC BRANCH/CALL
 M:	Peter Zijlstra <peterz@infradead.org>
 M:	Josh Poimboeuf <jpoimboe@kernel.org>

drivers/irqchip/Kconfig

@@ -546,6 +546,17 @@ config SIFIVE_PLIC
 	select IRQ_DOMAIN_HIERARCHY
 	select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
 
+config STARFIVE_JH8100_INTC
+	bool "StarFive JH8100 External Interrupt Controller"
+	depends on ARCH_STARFIVE || COMPILE_TEST
+	default ARCH_STARFIVE
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	  This enables support for the INTC chip found in StarFive JH8100
+	  SoC.
+
+	  If you don't know what to do here, say Y.
+
 config EXYNOS_IRQ_COMBINER
 	bool "Samsung Exynos IRQ combiner support" if COMPILE_TEST
 	depends on (ARCH_EXYNOS && ARM) || COMPILE_TEST

drivers/irqchip/Makefile

@@ -96,6 +96,7 @@ obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_CSKY_APB_INTC)		+= irq-csky-apb-intc.o
 obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
+obj-$(CONFIG_STARFIVE_JH8100_INTC)	+= irq-starfive-jh8100-intc.o
 obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
 obj-$(CONFIG_IMX_INTMUX)		+= irq-imx-intmux.o
 obj-$(CONFIG_IMX_MU_MSI)		+= irq-imx-mu-msi.o

drivers/irqchip/irq-starfive-jh8100-intc.c

@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * StarFive JH8100 External Interrupt Controller driver
+ *
+ * Copyright (C) 2023 StarFive Technology Co., Ltd.
+ *
+ * Author: Changhuang Liang <changhuang.liang@starfivetech.com>
+ */
+
+#define pr_fmt(fmt) "irq-starfive-jh8100: " fmt
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/reset.h>
+#include <linux/spinlock.h>
+
+#define STARFIVE_INTC_SRC0_CLEAR	0x10
+#define STARFIVE_INTC_SRC0_MASK		0x14
+#define STARFIVE_INTC_SRC0_INT		0x1c
+
+#define STARFIVE_INTC_SRC_IRQ_NUM	32
+
+struct starfive_irq_chip {
+	void __iomem		*base;
+	struct irq_domain	*domain;
+	raw_spinlock_t		lock;
+};
+
+static void starfive_intc_bit_set(struct starfive_irq_chip *irqc,
+				  u32 reg, u32 bit_mask)
+{
+	u32 value;
+
+	value = ioread32(irqc->base + reg);
+	value |= bit_mask;
+	iowrite32(value, irqc->base + reg);
+}
+
+static void starfive_intc_bit_clear(struct starfive_irq_chip *irqc,
+				    u32 reg, u32 bit_mask)
+{
+	u32 value;
+
+	value = ioread32(irqc->base + reg);
+	value &= ~bit_mask;
+	iowrite32(value, irqc->base + reg);
+}
+
+static void starfive_intc_unmask(struct irq_data *d)
+{
+	struct starfive_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+
+	raw_spin_lock(&irqc->lock);
+	starfive_intc_bit_clear(irqc, STARFIVE_INTC_SRC0_MASK, BIT(d->hwirq));
+	raw_spin_unlock(&irqc->lock);
+}
+
+static void starfive_intc_mask(struct irq_data *d)
+{
+	struct starfive_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+
+	raw_spin_lock(&irqc->lock);
+	starfive_intc_bit_set(irqc, STARFIVE_INTC_SRC0_MASK, BIT(d->hwirq));
+	raw_spin_unlock(&irqc->lock);
+}
+
+static struct irq_chip intc_dev = {
+	.name		= "StarFive JH8100 INTC",
+	.irq_unmask	= starfive_intc_unmask,
+	.irq_mask	= starfive_intc_mask,
+};
+
+static int starfive_intc_map(struct irq_domain *d, unsigned int irq,
+			     irq_hw_number_t hwirq)
+{
+	irq_domain_set_info(d, irq, hwirq, &intc_dev, d->host_data,
+			    handle_level_irq, NULL, NULL);
+
+	return 0;
+}
+
+static const struct irq_domain_ops starfive_intc_domain_ops = {
+	.xlate	= irq_domain_xlate_onecell,
+	.map	= starfive_intc_map,
+};
+
+static void starfive_intc_irq_handler(struct irq_desc *desc)
+{
+	struct starfive_irq_chip *irqc = irq_data_get_irq_handler_data(&desc->irq_data);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	unsigned long value;
+	int hwirq;
+
+	chained_irq_enter(chip, desc);
+
+	value = ioread32(irqc->base + STARFIVE_INTC_SRC0_INT);
+	while (value) {
+		hwirq = ffs(value) - 1;
+
+		generic_handle_domain_irq(irqc->domain, hwirq);
+
+		starfive_intc_bit_set(irqc, STARFIVE_INTC_SRC0_CLEAR, BIT(hwirq));
+		starfive_intc_bit_clear(irqc, STARFIVE_INTC_SRC0_CLEAR, BIT(hwirq));
+
+		__clear_bit(hwirq, &value);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static int __init starfive_intc_init(struct device_node *intc,
+				     struct device_node *parent)
+{
+	struct starfive_irq_chip *irqc;
+	struct reset_control *rst;
+	struct clk *clk;
+	int parent_irq;
+	int ret;
+
+	irqc = kzalloc(sizeof(*irqc), GFP_KERNEL);
+	if (!irqc)
+		return -ENOMEM;
+
+	irqc->base = of_iomap(intc, 0);
+	if (!irqc->base) {
+		pr_err("Unable to map registers\n");
+		ret = -ENXIO;
+		goto err_free;
+	}
+
+	rst = of_reset_control_get_exclusive(intc, NULL);
+	if (IS_ERR(rst)) {
+		pr_err("Unable to get reset control %pe\n", rst);
+		ret = PTR_ERR(rst);
+		goto err_unmap;
+	}
+
+	clk = of_clk_get(intc, 0);
+	if (IS_ERR(clk)) {
+		pr_err("Unable to get clock %pe\n", clk);
+		ret = PTR_ERR(clk);
+		goto err_reset_put;
+	}
+
+	ret = reset_control_deassert(rst);
+	if (ret)
+		goto err_clk_put;
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		goto err_reset_assert;
+
+	raw_spin_lock_init(&irqc->lock);
+
+	irqc->domain = irq_domain_add_linear(intc, STARFIVE_INTC_SRC_IRQ_NUM,
+					     &starfive_intc_domain_ops, irqc);
+	if (!irqc->domain) {
+		pr_err("Unable to create IRQ domain\n");
+		ret = -EINVAL;
+		goto err_clk_disable;
+	}
+
+	parent_irq = of_irq_get(intc, 0);
+	if (parent_irq < 0) {
+		pr_err("Failed to get main IRQ: %d\n", parent_irq);
+		ret = parent_irq;
+		goto err_remove_domain;
+	}
+
+	irq_set_chained_handler_and_data(parent_irq, starfive_intc_irq_handler,
+					 irqc);
+
+	pr_info("Interrupt controller register, nr_irqs %d\n",
+		STARFIVE_INTC_SRC_IRQ_NUM);
+
+	return 0;
+
+err_remove_domain:
+	irq_domain_remove(irqc->domain);
+err_clk_disable:
+	clk_disable_unprepare(clk);
+err_reset_assert:
+	reset_control_assert(rst);
+err_clk_put:
+	clk_put(clk);
+err_reset_put:
+	reset_control_put(rst);
+err_unmap:
+	iounmap(irqc->base);
+err_free:
+	kfree(irqc);
+	return ret;
+}
+
+IRQCHIP_PLATFORM_DRIVER_BEGIN(starfive_intc)
+IRQCHIP_MATCH("starfive,jh8100-intc", starfive_intc_init)
+IRQCHIP_PLATFORM_DRIVER_END(starfive_intc)
+
+MODULE_DESCRIPTION("StarFive JH8100 External Interrupt Controller");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Changhuang Liang <changhuang.liang@starfivetech.com>");