[PATCH v3 2/6] irqchip: Add interrupt controller support for Realtek DHC SoCs

[James Tai]

Realtek DHC (Digital Home Center) SoCs share a common interrupt controller
design. This universal interrupt controller driver provides support for
various variants within the Realtek DHC SoC family.

Each DHC SoC features two sets of extended interrupt controllers, each
capable of handling up to 32 interrupts. These expansion controllers are
connected to the GIC (Generic Interrupt Controller).

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <error27@xxxxxxxxx>
Closes: https://lore.kernel.org/r/202311201929.2FpvMRlg-lkp@xxxxxxxxx/
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Marc Zyngier <maz@xxxxxxxxxx>
CC: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: James Tai <james.tai@xxxxxxxxxxx>
---
v2 to v3 change:
- Resolved kernel test robot build warnings
  https://lore.kernel.org/r/202311201929.2FpvMRlg-lkp@xxxxxxxxx/

v1 to v2 change:
- Fixed code style issues
- Removed the realtek_intc_set_affinity funcation
- Replaced spin_lock_irqsave with raw_spin_lock

 drivers/irqchip/Kconfig                   |   4 +
 drivers/irqchip/Makefile                  |   1 +
 drivers/irqchip/irq-realtek-intc-common.c | 208 ++++++++++++++++++++++
 drivers/irqchip/irq-realtek-intc-common.h |  77 ++++++++
 4 files changed, 290 insertions(+)
 create mode 100644 drivers/irqchip/irq-realtek-intc-common.c
 create mode 100644 drivers/irqchip/irq-realtek-intc-common.h

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..64d656e5a015
--- /dev/null
+++ b/drivers/irqchip/irq-realtek-intc-common.c
@@ -0,0 +1,208 @@
+// 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/mfd/syscon.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include "irq-realtek-intc-common.h"
+
+struct realtek_intc_data;
+
+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) & ~1, data->base + data->info->isr_offset);
+}
+
+static inline unsigned int realtek_intc_get_inte(struct realtek_intc_data *data)
+{
+	unsigned int val;
+
+	raw_spin_lock(&data->lock);
+	val = readl(data->base + data->info->scpu_int_en_offset);
+	raw_spin_unlock(&data->lock);
+
+	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->cfg->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);
+
+	writel(BIT(data->hwirq), intc_data->base + intc_data->info->isr_offset);
+}
+
+static void realtek_intc_unmask_irq(struct irq_data *data)
+{
+	struct realtek_intc_data *intc_data = irq_data_get_irq_chip_data(data);
+
+	writel(BIT(data->hwirq), intc_data->base + intc_data->info->umsk_isr_offset);
+}
+
+static void realtek_intc_enable_irq(struct irq_data *data)
+{
+	struct realtek_intc_data *intc_data = irq_data_get_irq_chip_data(data);
+	u32 scpu_int_en, mask;
+
+	mask = intc_data->info->isr_to_scpu_int_en_mask[data->hwirq];
+	if (!mask)
+		return;
+
+	raw_spin_lock(&intc_data->lock);
+	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->umsk_isr_offset);
+	raw_spin_unlock(&intc_data->lock);
+}
+
+static void realtek_intc_disable_irq(struct irq_data *data)
+{
+	struct realtek_intc_data *intc_data = irq_data_get_irq_chip_data(data);
+	u32 scpu_int_en, mask;
+
+	mask = intc_data->info->isr_to_scpu_int_en_mask[data->hwirq];
+	if (!mask)
+		return;
+
+	raw_spin_lock(&intc_data->lock);
+	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->umsk_isr_offset);
+	raw_spin_unlock(&intc_data->lock);
+}
+
+static struct irq_chip realtek_intc_chip = {
+	.name		  = "realtek-intc",
+	.irq_mask	  = realtek_intc_mask_irq,
+	.irq_unmask	  = realtek_intc_unmask_irq,
+	.irq_enable	  = realtek_intc_enable_irq,
+	.irq_disable	  = realtek_intc_disable_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_subset_cfg *cfg = &data->info->cfg[index];
+	int irq;
+
+	irq = irq_of_parse_and_map(node, index);
+	if (irq <= 0)
+		return irq;
+
+	subset_data->common = data;
+	subset_data->cfg = cfg;
+	subset_data->parent_irq = irq;
+	irq_set_chained_handler_and_data(irq, realtek_intc_handler, subset_data);
+
+	return 0;
+}
+
+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->cfg_num), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->base = of_iomap(node, 0);
+	if (!data->base) {
+		ret = -ENOMEM;
+		goto out_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) {
+		ret = -ENOMEM;
+		goto out_cleanup;
+	}
+
+	data->subset_data_num = info->cfg_num;
+	for (i = 0; i < info->cfg_num; i++) {
+		ret = realtek_intc_subset(node, data, i);
+		if (ret) {
+			WARN(ret, "failed to init subset %d: %d", i, ret);
+			ret = -ENOMEM;
+			goto out_cleanup;
+		}
+	}
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+
+out_cleanup:
+
+	if (data->base)
+		iounmap(data->base);
+
+	devm_kfree(dev, data);
+
+	return ret;
+}
+EXPORT_SYMBOL(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..38be116dba60
--- /dev/null
+++ b/drivers/irqchip/irq-realtek-intc-common.h
@@ -0,0 +1,77 @@
+/* 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_subset_cfg - subset interrupt mask
+ * @ints_mask: inetrrupt mask
+ */
+struct realtek_intc_subset_cfg {
+	unsigned int	ints_mask;
+};
+
+/**
+ * realtek_intc_info - interrupt controller data.
+ * @isr_offset: interrupt status register offset.
+ * @umsk_isr_offset: unmask interrupt status register offset.
+ * @scpu_int_en_offset: interrupt enable register offset.
+ * @cfg: cfg of the subset.
+ * @cfg_num: number of cfg.
+ */
+struct realtek_intc_info {
+	const struct realtek_intc_subset_cfg *cfg;
+	unsigned int			     isr_offset;
+	unsigned int			     umsk_isr_offset;
+	unsigned int			     scpu_int_en_offset;
+	const u32			     *isr_to_scpu_int_en_mask;
+	int				     cfg_num;
+};
+
+/**
+ * realtek_intc_subset_data - handler of a interrupt source only handles ints
+ *                            bits in the mask.
+ * @cfg: cfg of the subset.
+ * @common: common data.
+ * @parent_irq: interrupt source.
+ */
+struct realtek_intc_subset_data {
+	const struct realtek_intc_subset_cfg *cfg;
+	struct realtek_intc_data	     *common;
+	int				     parent_irq;
+};
+
+/**
+ * realtek_intc_data - configuration data for realtek interrupt controller driver.
+ * @base: base of interrupt register
+ * @info: info of intc
+ * @domain: interrupt domain
+ * @lock: lock
+ * @saved_en: status of interrupt enable
+ * @subset_data_num: number of subset data
+ * @subset_data: subset data
+ */
+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);
+
+#endif /* _IRQ_REALTEK_COMMON_H */
-- 
2.25.1