[v4,2/6] irqchip: Add interrupt controller support for Realtek DHC SoCs

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index f7149d0f3d45..267c3429b48d 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -218,6 +218,10 @@  config RDA_INTC
 	bool
 	select IRQ_DOMAIN
 
+config REALTEK_DHC_INTC
+	tristate
+	select IRQ_DOMAIN
+
 config RENESAS_INTC_IRQPIN
 	bool "Renesas INTC External IRQ Pin Support" if COMPILE_TEST
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index ffd945fe71aa..f6774af7fde2 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -47,6 +47,7 @@  obj-$(CONFIG_IRQ_MIPS_CPU)		+= irq-mips-cpu.o
 obj-$(CONFIG_IXP4XX_IRQ)		+= irq-ixp4xx.o
 obj-$(CONFIG_JCORE_AIC)			+= irq-jcore-aic.o
 obj-$(CONFIG_RDA_INTC)			+= irq-rda-intc.o
+obj-$(CONFIG_REALTEK_DHC_INTC)		+= irq-realtek-intc-common.o
 obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
 obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
 obj-$(CONFIG_RENESAS_RZA1_IRQC)		+= irq-renesas-rza1.o
diff --git a/drivers/irqchip/irq-realtek-intc-common.c b/drivers/irqchip/irq-realtek-intc-common.c
new file mode 100644
index 000000000000..caff61730ff8
--- /dev/null
+++ b/drivers/irqchip/irq-realtek-intc-common.c
@@ -0,0 +1,211 @@ 
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * Realtek DHC SoCs interrupt controller driver
+ *
+ * Copyright (c) 2023 Realtek Semiconductor Corporation
+ */
+
+#include <linux/irqchip.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include "irq-realtek-intc-common.h"
+
+static inline unsigned int realtek_intc_get_ints(struct realtek_intc_data *data)
+{
+	return readl(data->base + data->info->isr_offset);
+}
+
+static inline void realtek_intc_clear_ints_bit(struct realtek_intc_data *data, int bit)
+{
+	writel(BIT(bit) & CLEAN_INTC_STATUS, data->base + data->info->isr_offset);
+}
+
+static inline unsigned int realtek_intc_get_inte(struct realtek_intc_data *data)
+{
+	unsigned int val;
+
+	val = readl(data->base + data->info->scpu_int_en_offset);
+
+	return val;
+}
+
+static void realtek_intc_handler(struct irq_desc *desc)
+{
+	struct realtek_intc_subset_data *subset_data = irq_desc_get_handler_data(desc);
+	struct realtek_intc_data *data = subset_data->common;
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u32 ints, inte, mask;
+	int irq;
+
+	chained_irq_enter(chip, desc);
+
+	ints = realtek_intc_get_ints(data) & subset_data->subset_mask->ints_mask;
+	inte = realtek_intc_get_inte(data);
+
+	while (ints) {
+		irq = __ffs(ints);
+		ints &= ~BIT(irq);
+
+		mask = data->info->isr_to_scpu_int_en_mask[irq];
+		if (mask != IRQ_ALWAYS_ENABLED && !(inte & mask))
+			continue;
+
+		generic_handle_irq(irq_find_mapping(data->domain, irq));
+		realtek_intc_clear_ints_bit(data, irq);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void realtek_intc_mask_irq(struct irq_data *data)
+{
+	struct realtek_intc_data *intc_data = irq_data_get_irq_chip_data(data);
+	unsigned long lock_flags;
+	u32 scpu_int_en, mask;
+
+	mask = intc_data->info->isr_to_scpu_int_en_mask[data->hwirq];
+	if (!mask)
+		return;
+
+	raw_spin_lock_irqsave(&intc_data->lock, lock_flags);
+	scpu_int_en = readl(intc_data->base + intc_data->info->scpu_int_en_offset);
+	scpu_int_en &= ~mask;
+	writel(scpu_int_en, intc_data->base + intc_data->info->scpu_int_en_offset);
+	raw_spin_unlock_irqrestore(&intc_data->lock, lock_flags);
+}
+
+static void realtek_intc_unmask_irq(struct irq_data *data)
+{
+	struct realtek_intc_data *intc_data = irq_data_get_irq_chip_data(data);
+	unsigned long lock_flags;
+	u32 scpu_int_en, mask;
+
+	mask = intc_data->info->isr_to_scpu_int_en_mask[data->hwirq];
+	if (!mask)
+		return;
+
+	raw_spin_lock_irqsave(&intc_data->lock, lock_flags);
+	scpu_int_en = readl(intc_data->base + intc_data->info->scpu_int_en_offset);
+	scpu_int_en |= mask;
+	writel(scpu_int_en, intc_data->base + intc_data->info->scpu_int_en_offset);
+	raw_spin_unlock_irqrestore(&intc_data->lock, lock_flags);
+}
+
+static struct irq_chip realtek_intc_chip = {
+	.name	     = "realtek-intc",
+	.irq_mask    = realtek_intc_mask_irq,
+	.irq_unmask  = realtek_intc_unmask_irq,
+};
+
+static int realtek_intc_domain_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+{
+	struct realtek_intc_data *data = d->host_data;
+
+	irq_set_chip_and_handler(irq, &realtek_intc_chip, handle_level_irq);
+	irq_set_chip_data(irq, data);
+	irq_set_probe(irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops realtek_intc_domain_ops = {
+	.xlate = irq_domain_xlate_onecell,
+	.map   = realtek_intc_domain_map,
+};
+
+static int realtek_intc_subset(struct device_node *node, struct realtek_intc_data *data, int index)
+{
+	struct realtek_intc_subset_data *subset_data = &data->subset_data[index];
+	const struct realtek_intc_mask *mask = &data->info->subset_mask[index];
+	int irq;
+
+	irq = of_irq_get(node, index);
+	if (irq <= 0)
+		return -EINVAL;
+
+	subset_data->common = data;
+	subset_data->subset_mask = mask;
+	subset_data->parent_irq = irq;
+	irq_set_chained_handler_and_data(irq, realtek_intc_handler, subset_data);
+
+	return irq;
+}
+
+int realtek_intc_suspend(struct device *dev)
+{
+	struct realtek_intc_data *data = dev_get_drvdata(dev);
+	const struct realtek_intc_info *info = data->info;
+
+	data->saved_en = readl(data->base + info->scpu_int_en_offset);
+
+	writel(DISABLE_INTC, data->base + info->scpu_int_en_offset);
+	writel(CLEAN_INTC_STATUS, data->base + info->isr_offset);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(realtek_intc_suspend);
+
+int realtek_intc_resume(struct device *dev)
+{
+	struct realtek_intc_data *data = dev_get_drvdata(dev);
+	const struct realtek_intc_info *info = data->info;
+
+	writel(CLEAN_INTC_STATUS, data->base + info->isr_offset);
+	writel(data->saved_en, data->base + info->scpu_int_en_offset);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(realtek_intc_resume);
+
+int realtek_intc_probe(struct platform_device *pdev, const struct realtek_intc_info *info)
+{
+	struct realtek_intc_data *data;
+	struct device *dev = &pdev->dev;
+	struct device_node *node = dev->of_node;
+	int ret, i;
+
+	data = devm_kzalloc(dev, struct_size(data, subset_data, info->subset_num), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->base = of_iomap(node, 0);
+	if (!data->base)
+		goto iomap_cleanup;
+
+	data->info = info;
+
+	raw_spin_lock_init(&data->lock);
+
+	data->domain = irq_domain_add_linear(node, 32, &realtek_intc_domain_ops, data);
+	if (!data->domain)
+		goto iomap_cleanup;
+
+	data->subset_data_num = info->subset_num;
+	for (i = 0; i < info->subset_num; i++) {
+		ret = realtek_intc_subset(node, data, i);
+		if (ret <= 0) {
+			dev_err(dev, "failed to init subset %d: %d", i, ret);
+			goto irq_domain_cleanup;
+		}
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+
+irq_domain_cleanup:
+	if (data->domain)
+		irq_domain_remove(data->domain);
+
+iomap_cleanup:
+	if (data->base)
+		iounmap(data->base);
+
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(realtek_intc_probe);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Realtek DHC SoC Interrupt Controller Driver");
diff --git a/drivers/irqchip/irq-realtek-intc-common.h b/drivers/irqchip/irq-realtek-intc-common.h
new file mode 100644
index 000000000000..0af989c09693
--- /dev/null
+++ b/drivers/irqchip/irq-realtek-intc-common.h
@@ -0,0 +1,76 @@ 
+/* SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause) */
+/*
+ * Copyright (c) 2023 Realtek Semiconductor Corporation
+ */
+
+#ifndef _IRQ_REALTEK_COMMON_H
+#define _IRQ_REALTEK_COMMON_H
+
+#include <linux/bits.h>
+#include <linux/limits.h>
+#include <linux/hwspinlock.h>
+
+/**
+ * realtek_intc_mask - The mask of an interrupt subset.
+ * @ints_mask: The interrupt mask.
+ */
+struct realtek_intc_mask {
+	u32	ints_mask;
+};
+
+/**
+ * realtek_intc_info - Information about the interrupt controller.
+ * @subset_mask:	The masks of the interrupt subsets.
+ * @subset_num:		The number of interrupt subsets.
+ * @isr_offset:		The offset of the interrupt status register.
+ * @scpu_int_en_offset:	The offset of the interrupt enable register.
+ */
+struct realtek_intc_info {
+	const struct realtek_intc_mask	*subset_mask;
+	int				subset_num;
+	unsigned int			isr_offset;
+	unsigned int			scpu_int_en_offset;
+	const u32			*isr_to_scpu_int_en_mask;
+};
+
+/**
+ * realtek_intc_subset_data - The data of interrupt subset.
+ * @subset_mask:	The subset interrupt masks.
+ * @common:		The configuration data of interrupt controller.
+ * @parent_irq:		The subset interrupt source.
+ */
+struct realtek_intc_subset_data {
+	const struct realtek_intc_mask	*subset_mask;
+	struct realtek_intc_data	*common;
+	int				parent_irq;
+};
+
+/**
+ * realtek_intc_data - The configuration data for interrupt controller driver.
+ * @base:		The base address of interrupt register.
+ * @info:		The Information of the interrupt controller.
+ * @domain:		Interrupt domain of the interrupt controller.
+ * @lock:		The lock of the interrupt controller.
+ * @saved_en:		Stores the state of the interrupt enable.
+ * @subset_data_num:	The number of entries in the interrupt subset data.
+ * @subset_data:	The data for the interrupt subset.
+ */
+struct realtek_intc_data {
+	void __iomem			*base;
+	const struct realtek_intc_info	*info;
+	struct irq_domain		*domain;
+	struct raw_spinlock		lock;
+	unsigned int			saved_en;
+	int				subset_data_num;
+	struct realtek_intc_subset_data subset_data[];
+};
+
+#define IRQ_ALWAYS_ENABLED	U32_MAX
+#define DISABLE_INTC		(0)
+#define CLEAN_INTC_STATUS	GENMASK(31, 1)
+
+int realtek_intc_probe(struct platform_device *pdev, const struct realtek_intc_info *info);
+int realtek_intc_suspend(struct device *dev);
+int realtek_intc_resume(struct device *dev);
+
+#endif /* _IRQ_REALTEK_COMMON_H */