diff --git a/MAINTAINERS b/MAINTAINERS
index 0508cf8ed02224c7b4d97a29a054bf0263bf500e..e12f7fc21b2b533495f7c39969c8590d3bb8fe35 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1691,6 +1691,8 @@ M: Krzysztof Halasa <khalasa@piap.pl>
L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
S: Maintained
F: arch/arm/mach-ixp4xx/
+F: drivers/irqchip/irq-ixp4xx.c
+F: include/linux/irqchip/irq-ixp4xx.h
ARM/INTEL RESEARCH IMOTE/STARGATE 2 MACHINE SUPPORT
M: Jonathan Cameron <jic23@cam.ac.uk>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 5438abb1babaf042eb9190e7de2b1aa1161285bc..cf7984991062987e30e9119cfe9164dc9fea4c5b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -160,6 +160,12 @@ config IMGPDC_IRQ
select GENERIC_IRQ_CHIP
select IRQ_DOMAIN
+config IXP4XX_IRQ
+ bool
+ select IRQ_DOMAIN
+ select GENERIC_IRQ_MULTI_HANDLER
+ select SPARSE_IRQ
+
config MADERA_IRQ
tristate
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 85972ae1bd7f978bab67cef8ebc0d9effa6edb63..f8c66e958a64deaad16fea727ab5d9f2ace020bc 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_ATMEL_AIC5_IRQ) += irq-atmel-aic-common.o irq-atmel-aic5.o
obj-$(CONFIG_I8259) += irq-i8259.o
obj-$(CONFIG_IMGPDC_IRQ) += irq-imgpdc.o
obj-$(CONFIG_IRQ_MIPS_CPU) += irq-mips-cpu.o
+obj-$(CONFIG_IXP4XX_IRQ) += irq-ixp4xx.o
obj-$(CONFIG_SIRF_IRQ) += irq-sirfsoc.o
obj-$(CONFIG_JCORE_AIC) += irq-jcore-aic.o
obj-$(CONFIG_RDA_INTC) += irq-rda-intc.o
diff --git a/drivers/irqchip/irq-ixp4xx.c b/drivers/irqchip/irq-ixp4xx.c
new file mode 100644
index 0000000000000000000000000000000000000000..89c80ce047a7b508829e71e5405e2913a9b90882
--- /dev/null
+++ b/drivers/irqchip/irq-ixp4xx.c
@@ -0,0 +1,362 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * irqchip for the IXP4xx interrupt controller
+ * Copyright (C) 2019 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Based on arch/arm/mach-ixp4xx/common.c
+ * Copyright 2002 (C) Intel Corporation
+ * Copyright 2003-2004 (C) MontaVista, Software, Inc.
+ * Copyright (C) Deepak Saxena <dsaxena@plexity.net>
+ */
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/irqchip/irq-ixp4xx.h>
+#include <linux/irqdomain.h>
+#include <linux/platform_device.h>
+#include <linux/cpu.h>
+
+#include <asm/exception.h>
+#include <asm/mach/irq.h>
+
+#define IXP4XX_ICPR 0x00 /* Interrupt Status */
+#define IXP4XX_ICMR 0x04 /* Interrupt Enable */
+#define IXP4XX_ICLR 0x08 /* Interrupt IRQ/FIQ Select */
+#define IXP4XX_ICIP 0x0C /* IRQ Status */
+#define IXP4XX_ICFP 0x10 /* FIQ Status */
+#define IXP4XX_ICHR 0x14 /* Interrupt Priority */
+#define IXP4XX_ICIH 0x18 /* IRQ Highest Pri Int */
+#define IXP4XX_ICFH 0x1C /* FIQ Highest Pri Int */
+
+/* IXP43x and IXP46x-only */
+#define IXP4XX_ICPR2 0x20 /* Interrupt Status 2 */
+#define IXP4XX_ICMR2 0x24 /* Interrupt Enable 2 */
+#define IXP4XX_ICLR2 0x28 /* Interrupt IRQ/FIQ Select 2 */
+#define IXP4XX_ICIP2 0x2C /* IRQ Status */
+#define IXP4XX_ICFP2 0x30 /* FIQ Status */
+#define IXP4XX_ICEEN 0x34 /* Error High Pri Enable */
+
+/**
+ * struct ixp4xx_irq - state container for the Faraday IRQ controller
+ * @irqbase: IRQ controller memory base in virtual memory
+ * @is_356: if this is an IXP43x, IXP45x or IX46x SoC (with 64 IRQs)
+ * @irqchip: irqchip for this instance
+ * @domain: IRQ domain for this instance
+ */
+struct ixp4xx_irq {
+ void __iomem *irqbase;
+ bool is_356;
+ struct irq_chip irqchip;
+ struct irq_domain *domain;
+};
+
+/* Local static state container */
+static struct ixp4xx_irq ixirq;
+
+/* GPIO Clocks */
+#define IXP4XX_GPIO_CLK_0 14
+#define IXP4XX_GPIO_CLK_1 15
+
+static int ixp4xx_set_irq_type(struct irq_data *d, unsigned int type)
+{
+ /* All are level active high (asserted) here */
+ if (type != IRQ_TYPE_LEVEL_HIGH)
+ return -EINVAL;
+ return 0;
+}
+
+static void ixp4xx_irq_mask(struct irq_data *d)
+{
+ struct ixp4xx_irq *ixi = irq_data_get_irq_chip_data(d);
+ u32 val;
+
+ if (ixi->is_356 && d->hwirq >= 32) {
+ val = __raw_readl(ixi->irqbase + IXP4XX_ICMR2);
+ val &= ~BIT(d->hwirq - 32);
+ __raw_writel(val, ixi->irqbase + IXP4XX_ICMR2);
+ } else {
+ val = __raw_readl(ixi->irqbase + IXP4XX_ICMR);
+ val &= ~BIT(d->hwirq);
+ __raw_writel(val, ixi->irqbase + IXP4XX_ICMR);
+ }
+}
+
+/*
+ * Level triggered interrupts on GPIO lines can only be cleared when the
+ * interrupt condition disappears.
+ */
+static void ixp4xx_irq_unmask(struct irq_data *d)
+{
+ struct ixp4xx_irq *ixi = irq_data_get_irq_chip_data(d);
+ u32 val;
+
+ if (ixi->is_356 && d->hwirq >= 32) {
+ val = __raw_readl(ixi->irqbase + IXP4XX_ICMR2);
+ val |= BIT(d->hwirq - 32);
+ __raw_writel(val, ixi->irqbase + IXP4XX_ICMR2);
+ } else {
+ val = __raw_readl(ixi->irqbase + IXP4XX_ICMR);
+ val |= BIT(d->hwirq);
+ __raw_writel(val, ixi->irqbase + IXP4XX_ICMR);
+ }
+}
+
+asmlinkage void __exception_irq_entry ixp4xx_handle_irq(struct pt_regs *regs)
+{
+ struct ixp4xx_irq *ixi = &ixirq;
+ unsigned long status;
+ int i;
+
+ status = __raw_readl(ixi->irqbase + IXP4XX_ICIP);
+ for_each_set_bit(i, &status, 32)
+ handle_domain_irq(ixi->domain, i, regs);
+
+ /*
+ * IXP465/IXP435 has an upper IRQ status register
+ */
+ if (ixi->is_356) {
+ status = __raw_readl(ixi->irqbase + IXP4XX_ICIP2);
+ for_each_set_bit(i, &status, 32)
+ handle_domain_irq(ixi->domain, i + 32, regs);
+ }
+}
+
+static int ixp4xx_irq_domain_translate(struct irq_domain *domain,
+ struct irq_fwspec *fwspec,
+ unsigned long *hwirq,
+ unsigned int *type)
+{
+ /* We support standard DT translation */
+ if (is_of_node(fwspec->fwnode) && fwspec->param_count == 2) {
+ *hwirq = fwspec->param[0];
+ *type = fwspec->param[1];
+ return 0;
+ }
+
+ if (is_fwnode_irqchip(fwspec->fwnode)) {
+ if (fwspec->param_count != 2)
+ return -EINVAL;
+ *hwirq = fwspec->param[0];
+ *type = fwspec->param[1];
+ WARN_ON(*type == IRQ_TYPE_NONE);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int ixp4xx_irq_domain_alloc(struct irq_domain *d,
+ unsigned int irq, unsigned int nr_irqs,
+ void *data)
+{
+ struct ixp4xx_irq *ixi = d->host_data;
+ irq_hw_number_t hwirq;
+ unsigned int type = IRQ_TYPE_NONE;
+ struct irq_fwspec *fwspec = data;
+ int ret;
+ int i;
+
+ ret = ixp4xx_irq_domain_translate(d, fwspec, &hwirq, &type);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < nr_irqs; i++) {
+ /*
+ * TODO: after converting IXP4xx to only device tree, set
+ * handle_bad_irq as default handler and assume all consumers
+ * call .set_type() as this is provided in the second cell in
+ * the device tree phandle.
+ */
+ irq_domain_set_info(d,
+ irq + i,
+ hwirq + i,
+ &ixi->irqchip,
+ ixi,
+ handle_level_irq,
+ NULL, NULL);
+ irq_set_probe(irq + i);
+ }
+
+ return 0;
+}
+
+/*
+ * This needs to be a hierarchical irqdomain to work well with the
+ * GPIO irqchip (which is lower in the hierarchy)
+ */
+static const struct irq_domain_ops ixp4xx_irqdomain_ops = {
+ .translate = ixp4xx_irq_domain_translate,
+ .alloc = ixp4xx_irq_domain_alloc,
+ .free = irq_domain_free_irqs_common,
+};
+
+/**
+ * ixp4xx_get_irq_domain() - retrieve the ixp4xx irq domain
+ *
+ * This function will go away when we transition to DT probing.
+ */
+struct irq_domain *ixp4xx_get_irq_domain(void)
+{
+ struct ixp4xx_irq *ixi = &ixirq;
+
+ return ixi->domain;
+}
+EXPORT_SYMBOL_GPL(ixp4xx_get_irq_domain);
+
+/*
+ * This is the Linux IRQ to hwirq mapping table. This goes away when
+ * we have DT support as all IRQ resources are defined in the device
+ * tree. It will register all the IRQs that are not used by the hierarchical
+ * GPIO IRQ chip. The "holes" inbetween these IRQs will be requested by
+ * the GPIO driver using . This is a step-gap solution.
+ */
+struct ixp4xx_irq_chunk {
+ int irq;
+ int hwirq;
+ int nr_irqs;
+};
+
+static const struct ixp4xx_irq_chunk ixp4xx_irq_chunks[] = {
+ {
+ .irq = 16,
+ .hwirq = 0,
+ .nr_irqs = 6,
+ },
+ {
+ .irq = 24,
+ .hwirq = 8,
+ .nr_irqs = 11,
+ },
+ {
+ .irq = 46,
+ .hwirq = 30,
+ .nr_irqs = 2,
+ },
+ /* Only on the 436 variants */
+ {
+ .irq = 48,
+ .hwirq = 32,
+ .nr_irqs = 10,
+ },
+};
+
+/**
+ * ixp4x_irq_setup() - Common setup code for the IXP4xx interrupt controller
+ * @ixi: State container
+ * @irqbase: Virtual memory base for the interrupt controller
+ * @fwnode: Corresponding fwnode abstraction for this controller
+ * @is_356: if this is an IXP43x, IXP45x or IXP46x SoC variant
+ */
+static int ixp4xx_irq_setup(struct ixp4xx_irq *ixi,
+ void __iomem *irqbase,
+ struct fwnode_handle *fwnode,
+ bool is_356)
+{
+ int nr_irqs;
+
+ ixi->irqbase = irqbase;
+ ixi->is_356 = is_356;
+
+ /* Route all sources to IRQ instead of FIQ */
+ __raw_writel(0x0, ixi->irqbase + IXP4XX_ICLR);
+
+ /* Disable all interrupts */
+ __raw_writel(0x0, ixi->irqbase + IXP4XX_ICMR);
+
+ if (is_356) {
+ /* Route upper 32 sources to IRQ instead of FIQ */
+ __raw_writel(0x0, ixi->irqbase + IXP4XX_ICLR2);
+
+ /* Disable upper 32 interrupts */
+ __raw_writel(0x0, ixi->irqbase + IXP4XX_ICMR2);
+
+ nr_irqs = 64;
+ } else {
+ nr_irqs = 32;
+ }
+
+ ixi->irqchip.name = "IXP4xx";
+ ixi->irqchip.irq_mask = ixp4xx_irq_mask;
+ ixi->irqchip.irq_unmask = ixp4xx_irq_unmask;
+ ixi->irqchip.irq_set_type = ixp4xx_set_irq_type;
+
+ ixi->domain = irq_domain_create_linear(fwnode, nr_irqs,
+ &ixp4xx_irqdomain_ops,
+ ixi);
+ if (!ixi->domain) {
+ pr_crit("IXP4XX: can not add primary irqdomain\n");
+ return -ENODEV;
+ }
+
+ set_handle_irq(ixp4xx_handle_irq);
+
+ return 0;
+}
+
+/**
+ * ixp4xx_irq_init() - Function to initialize the irqchip from boardfiles
+ * @irqbase: physical base for the irq controller
+ * @is_356: if this is an IXP43x, IXP45x or IXP46x SoC variant
+ */
+void __init ixp4xx_irq_init(resource_size_t irqbase,
+ bool is_356)
+{
+ struct ixp4xx_irq *ixi = &ixirq;
+ void __iomem *base;
+ struct fwnode_handle *fwnode;
+ struct irq_fwspec fwspec;
+ int nr_chunks;
+ int ret;
+ int i;
+
+ base = ioremap(irqbase, 0x100);
+ if (!base) {
+ pr_crit("IXP4XX: could not ioremap interrupt controller\n");
+ return;
+ }
+ fwnode = irq_domain_alloc_fwnode(base);
+ if (!fwnode) {
+ pr_crit("IXP4XX: no domain handle\n");
+ return;
+ }
+ ret = ixp4xx_irq_setup(ixi, base, fwnode, is_356);
+ if (ret) {
+ pr_crit("IXP4XX: failed to set up irqchip\n");
+ irq_domain_free_fwnode(fwnode);
+ }
+
+ nr_chunks = ARRAY_SIZE(ixp4xx_irq_chunks);
+ if (!is_356)
+ nr_chunks--;
+
+ /*
+ * After adding OF support, this is no longer needed: irqs
+ * will be allocated for the respective fwnodes.
+ */
+ for (i = 0; i < nr_chunks; i++) {
+ const struct ixp4xx_irq_chunk *chunk = &ixp4xx_irq_chunks[i];
+
+ pr_info("Allocate Linux IRQs %d..%d HW IRQs %d..%d\n",
+ chunk->irq, chunk->irq + chunk->nr_irqs - 1,
+ chunk->hwirq, chunk->hwirq + chunk->nr_irqs - 1);
+ fwspec.fwnode = fwnode;
+ fwspec.param[0] = chunk->hwirq;
+ fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
+ fwspec.param_count = 2;
+ ret = __irq_domain_alloc_irqs(ixi->domain,
+ chunk->irq,
+ chunk->nr_irqs,
+ NUMA_NO_NODE,
+ &fwspec,
+ false,
+ NULL);
+ if (ret < 0) {
+ pr_crit("IXP4XX: can not allocate irqs in hierarchy %d\n",
+ ret);
+ return;
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(ixp4xx_irq_init);
diff --git a/include/linux/irqchip/irq-ixp4xx.h b/include/linux/irqchip/irq-ixp4xx.h
new file mode 100644
index 0000000000000000000000000000000000000000..9395917d69367c9f4fe4becd6eefadf66b6d2423
--- /dev/null
+++ b/include/linux/irqchip/irq-ixp4xx.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __IRQ_IXP4XX_H
+#define __IRQ_IXP4XX_H
+
+#include <linux/ioport.h>
+struct irq_domain;
+
+void ixp4xx_irq_init(resource_size_t irqbase,
+ bool is_356);
+struct irq_domain *ixp4xx_get_irq_domain(void);
+
+#endif /* __IRQ_IXP4XX_H */