Date:   Thu, 18 Oct 2018 21:10:16 +0530
From:   Lokesh Vutla <lokeshvutla@...com>
To:     Nishanth Menon <nm@...com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Rob Herring <robh+dt@...nel.org>, <tglx@...utronix.de>,
        <jason@...edaemon.net>, <marc.zyngier@....com>
CC:     Linux ARM Mailing List <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, Tero Kristo <t-kristo@...com>,
        Sekhar Nori <nsekhar@...com>,
        Device Tree Mailing List <devicetree@...r.kernel.org>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Lokesh Vutla <lokeshvutla@...com>
Subject: [PATCH v2 09/10] irqchip: ti-sci-inta: Add support for Interrupt Aggregator driver

Texas Instruments' K3 generation SoCs has an IP Interrupt Aggregator
which is an interrupt controller that does the following:
- Converts events to interrupts that can be understood by
  an interrupt router.
- Allows for multiplexing of events to interrupts.
- Allows for grouping of multiple events to a single interrupt.

Configuration of the interrupt aggregator registers can only be done by
a system co-processor and the driver needs to send a message to this
co processor over TISCI protocol.

Add support for Interrupt Aggregator driver over TISCI protocol.

Signed-off-by: Lokesh Vutla <lokeshvutla@...com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
---
Changes since v1:
- New patch

 MAINTAINERS                             |   1 +
 drivers/irqchip/Kconfig                 |  11 +
 drivers/irqchip/Makefile                |   1 +
 drivers/irqchip/irq-ti-sci-inta.c       | 613 ++++++++++++++++++++++++
 include/linux/irqchip/irq-ti-sci-inta.h |  35 ++
 5 files changed, 661 insertions(+)
 create mode 100644 drivers/irqchip/irq-ti-sci-inta.c
 create mode 100644 include/linux/irqchip/irq-ti-sci-inta.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 8cf1a6b73e6c..35c790ab0ae7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14689,6 +14689,7 @@ F:	drivers/reset/reset-ti-sci.c
 F:	Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
 F:	Documentation/devicetree/bindings/interrupt-controller/ti,sci-inta.txt
 F:	drivers/irqchip/irq-ti-sci-intr.c
+F:	drivers/irqchip/irq-ti-sci-inta.c
 
 THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
 M:	Hans Verkuil <hverkuil@...all.nl>
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index f6620a6bb872..895f6b47dc5b 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -385,6 +385,17 @@ config TI_SCI_INTR_IRQCHIP
 	  If you wish to use interrupt router irq resources managed by the
 	  TI System Controller, say Y here. Otherwise, say N.
 
+config TI_SCI_INTA_IRQCHIP
+	bool
+	depends on TI_SCI_PROTOCOL && ARCH_K3
+	select IRQ_DOMAIN
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	  This enables the irqchip driver support for K3 Interrupt aggregator
+	  over TI System Control Interface available on some new TI's SoCs.
+	  If you wish to use interrupt aggregator irq resources managed by the
+	  TI System Controller, say Y here. Otherwise, say N.
+
 endmenu
 
 config SIFIVE_PLIC
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 44bf65606d60..aede4c1cc4a6 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -90,3 +90,4 @@ obj-$(CONFIG_NDS32)			+= irq-ativic32.o
 obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
+obj-$(CONFIG_TI_SCI_INTA_IRQCHIP)	+= irq-ti-sci-inta.o
diff --git a/drivers/irqchip/irq-ti-sci-inta.c b/drivers/irqchip/irq-ti-sci-inta.c
new file mode 100644
index 000000000000..ef0a2e8b782c
--- /dev/null
+++ b/drivers/irqchip/irq-ti-sci-inta.c
@@ -0,0 +1,613 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Texas Instruments' K3 Interrupt Aggregator irqchip driver
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@...com>
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/irqdomain.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+#define MAX_EVENTS_PER_VINT	64
+#define TI_SCI_EVENT_IRQ	BIT(31)
+
+#define VINT_ENABLE_CLR_OFFSET	0x18
+
+/**
+ * struct ti_sci_inta_irq_domain - Structure representing a TISCI based
+ *				   Interrupt Aggregator IRQ domain.
+ * @sci:	Pointer to TISCI handle
+ * @vint:	TISCI resource pointer representing IA inerrupts.
+ * @global_event:TISCI resource pointer representing global events.
+ * @base:	Base address of the memory mapped IO registers
+ * @ia_id:	TISCI device ID of this Interrupt Aggregator.
+ * @dst_id:	TISCI device ID of the destination irq controller.
+ */
+struct ti_sci_inta_irq_domain {
+	const struct ti_sci_handle *sci;
+	struct ti_sci_resource *vint;
+	struct ti_sci_resource *global_event;
+	void __iomem *base;
+	u16 ia_id;
+	u16 dst_id;
+};
+
+/**
+ * struct ti_sci_inta_event_desc - Description of an event coming to
+ *				   Interrupt Aggregator.
+ * @global_event:	Global event number corresponding to this event
+ * @src_id:		TISCI device ID of the event source
+ * @src_index:		Event source index within the device.
+ */
+struct ti_sci_inta_event_desc {
+	u16 global_event;
+	u16 src_id;
+	u16 src_index;
+};
+
+/**
+ * struct ti_sci_inta_vint_desc - Description of a virtual interrupt coming out
+ *				  of Interrupt Aggregator.
+ * @lock:		lock to guard the event map
+ * @event_map:		Bitmap to manage the allocation of events to vint.
+ * @events:		Array of event descriptors assigned to this vint.
+ * @ack_needed:		Event needs to be acked via INTA. This is used when
+ *			HW generating events cannot clear the events by itself.
+ *			Assuming that only events from the same hw block are
+ *			grouped. So all the events attached to vint needs
+ *			an ack or none needs an ack.
+ */
+struct ti_sci_inta_vint_desc {
+	raw_spinlock_t lock;
+	unsigned long *event_map;
+	struct ti_sci_inta_event_desc events[MAX_EVENTS_PER_VINT];
+	bool ack_needed;
+};
+
+static void ti_sci_inta_irq_eoi(struct irq_data *data)
+{
+	struct ti_sci_inta_irq_domain *inta = data->domain->host_data;
+	struct ti_sci_inta_vint_desc *vint_desc;
+	u64 val;
+	int bit;
+
+	vint_desc = irq_data_get_irq_chip_data(data);
+	if (!vint_desc->ack_needed)
+		goto out;
+
+	for_each_set_bit(bit, vint_desc->event_map, MAX_EVENTS_PER_VINT) {
+		val = 1 << bit;
+		__raw_writeq(val, inta->base + data->hwirq * 0x1000 +
+			     VINT_ENABLE_CLR_OFFSET);
+	}
+
+out:
+	irq_chip_eoi_parent(data);
+}
+
+static struct irq_chip ti_sci_inta_irq_chip = {
+	.name			= "INTA",
+	.irq_eoi		= ti_sci_inta_irq_eoi,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+/**
+ * ti_sci_inta_irq_domain_translate() - Retrieve hwirq and type from
+ *					IRQ firmware specific handler.
+ * @domain:	Pointer to IRQ domain
+ * @fwspec:	Pointer to IRQ specific firmware structure
+ * @hwirq:	IRQ number identified by hardware
+ * @type:	IRQ type
+ *
+ * Return 0 if all went ok else appropriate error.
+ */
+static int ti_sci_inta_irq_domain_translate(struct irq_domain *domain,
+					    struct irq_fwspec *fwspec,
+					    unsigned long *hwirq,
+					    unsigned int *type)
+{
+	if (is_of_node(fwspec->fwnode)) {
+		if (fwspec->param_count != 4)
+			return -EINVAL;
+
+		*hwirq = fwspec->param[2];
+		*type = fwspec->param[3] & IRQ_TYPE_SENSE_MASK;
+
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * ti_sci_free_event_irq() - Free an event from vint
+ * @inta:	Pointer to Interrupt Aggregator IRQ domain
+ * @vint_desc:	Virtual interrupt descriptor containing the event.
+ * @event_index:Event Index within the vint.
+ * @dst_irq:	Destination host irq
+ * @vint:	Interrupt number within interrupt aggregator.
+ */
+static void ti_sci_free_event_irq(struct ti_sci_inta_irq_domain *inta,
+				  struct ti_sci_inta_vint_desc *vint_desc,
+				  u32 event_index, u16 dst_irq, u16 vint)
+{
+	struct ti_sci_inta_event_desc *event;
+	unsigned long flags;
+
+	if (event_index >= MAX_EVENTS_PER_VINT)
+		return;
+
+	event = &vint_desc->events[event_index];
+	inta->sci->ops.rm_irq_ops.free_event_irq(inta->sci,
+						 event->src_id,
+						 event->src_index,
+						 inta->dst_id,
+						 dst_irq,
+						 inta->ia_id, vint,
+						 event->global_event,
+						 event_index);
+
+	raw_spin_lock_irqsave(&vint_desc->lock, flags);
+	clear_bit(event_index, vint_desc->event_map);
+	raw_spin_unlock_irqrestore(&vint_desc->lock, flags);
+
+	ti_sci_release_resource(inta->global_event, event->global_event);
+}
+
+/**
+ * ti_sci_inta_irq_domain_free() - Free an IRQ from the IRQ domain
+ * @domain:	Domain to which the irqs belong
+ * @virq:	base linux virtual IRQ to be freed.
+ * @nr_irqs:	Number of continuous irqs to be freed
+ */
+static void ti_sci_inta_irq_domain_free(struct irq_domain *domain,
+					unsigned int virq, unsigned int nr_irqs)
+{
+	struct ti_sci_inta_irq_domain *inta = domain->host_data;
+	struct ti_sci_inta_vint_desc *vint_desc;
+	struct irq_data *data, *gic_data;
+	int event_index;
+
+	data = irq_domain_get_irq_data(domain, virq);
+	gic_data = irq_domain_get_irq_data(domain->parent->parent, virq);
+
+	vint_desc = irq_data_get_irq_chip_data(data);
+
+	/* This is the last event in the vint */
+	event_index = find_first_bit(vint_desc->event_map, MAX_EVENTS_PER_VINT);
+	ti_sci_free_event_irq(inta, vint_desc, event_index,
+			      gic_data->hwirq, data->hwirq);
+	irq_domain_free_irqs_parent(domain, virq, 1);
+	irq_domain_reset_irq_data(data);
+	ti_sci_release_resource(inta->vint, data->hwirq);
+	kfree(vint_desc->event_map);
+	kfree(vint_desc);
+}
+
+/**
+ * ti_sci_allocate_event_irq() - Allocate an event to a IA vint.
+ * @inta:	Pointer to Interrupt Aggregator IRQ domain
+ * @vint_desc:	Virtual interrupt descriptor to which the event gets attached.
+ * @src_id:	TISCI device id of the event source
+ * @src_index:	Event index with in the device.
+ * @dst_irq:	Destination host irq
+ * @vint:	Interrupt number within interrupt aggregator.
+ *
+ * Return 0 if all went ok else appropriate error value.
+ */
+static int ti_sci_allocate_event_irq(struct ti_sci_inta_irq_domain *inta,
+				     struct ti_sci_inta_vint_desc *vint_desc,
+				     u16 src_id, u16 src_index, u16 dst_irq,
+				     u16 vint)
+{
+	struct ti_sci_inta_event_desc *event;
+	unsigned long flags;
+	u32 free_bit;
+	int err;
+
+	raw_spin_lock_irqsave(&vint_desc->lock, flags);
+	free_bit = find_first_zero_bit(vint_desc->event_map,
+				       MAX_EVENTS_PER_VINT);
+	if (free_bit != MAX_EVENTS_PER_VINT)
+		set_bit(free_bit, vint_desc->event_map);
+	raw_spin_unlock_irqrestore(&vint_desc->lock, flags);
+
+	if (free_bit >= MAX_EVENTS_PER_VINT)
+		return -ENODEV;
+
+	event = &vint_desc->events[free_bit];
+
+	event->src_id = src_id;
+	event->src_index = src_index;
+	event->global_event = ti_sci_get_free_resource(inta->global_event);
+
+	err = inta->sci->ops.rm_irq_ops.set_event_irq(inta->sci,
+						      src_id, src_index,
+						      inta->dst_id,
+						      dst_irq,
+						      inta->ia_id,
+						      vint,
+						      event->global_event,
+						      free_bit);
+	if (err) {
+		pr_err("%s: Event allocation failed from src = %d, index = %d, to dst = %d,irq = %d,via ia_id = %d, vint = %d,global event = %d, status_bit = %d\n",
+		       __func__, src_id, src_index, inta->dst_id, dst_irq,
+		       inta->ia_id, vint, event->global_event, free_bit);
+		return err;
+	}
+
+	return 0;
+}
+
+/**
+ * alloc_parent_irq() - Allocate parent irq to Interrupt aggregator
+ * @domain:	IRQ domain corresponding to Interrupt Aggregator
+ * @virq:	Linux virtual IRQ number
+ * @src_id:	TISCI device id of the event source
+ * @src_index:	Event index with in the device.
+ * @vint:	Virtual interrupt number within IA
+ * @flags:	Corresponding IRQ flags
+ *
+ * Return pointer to vint descriptor if all went well else corresponding
+ * error pointer.
+ */
+static struct ti_sci_inta_vint_desc *alloc_parent_irq(struct irq_domain *domain,
+						      unsigned int virq,
+						      u32 src_id, u32 src_index,
+						      u32 vint, u32 flags)
+{
+	struct ti_sci_inta_irq_domain *inta = domain->host_data;
+	struct ti_sci_inta_vint_desc *vint_desc;
+	struct irq_data *gic_data;
+	struct irq_fwspec fwspec;
+	int err;
+
+	if (!irq_domain_get_of_node(domain->parent))
+		return ERR_PTR(-EINVAL);
+
+	vint_desc = kzalloc(sizeof(*vint_desc), GFP_KERNEL);
+	if (!vint_desc)
+		return ERR_PTR(-ENOMEM);
+
+	vint_desc->event_map = kcalloc(BITS_TO_LONGS(MAX_EVENTS_PER_VINT),
+				       sizeof(*vint_desc->event_map),
+				       GFP_KERNEL);
+	if (!vint_desc->event_map) {
+		kfree(vint_desc);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	/* Interrupt parent is Interrupt Router */
+	fwspec.param[0] = inta->ia_id;
+	fwspec.param[1] = vint;
+	fwspec.param[2] = flags | TI_SCI_EVENT_IRQ;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (err)
+		goto err_irqs;
+
+	gic_data = irq_domain_get_irq_data(domain->parent->parent, virq);
+
+	raw_spin_lock_init(&vint_desc->lock);
+
+	err = ti_sci_allocate_event_irq(inta, vint_desc, src_id, src_index,
+					gic_data->hwirq, vint);
+	if (err)
+		goto err_events;
+
+	return vint_desc;
+
+err_events:
+	irq_domain_free_irqs_parent(domain, virq, 1);
+err_irqs:
+	ti_sci_release_resource(inta->vint, vint);
+	kfree(vint_desc);
+	return ERR_PTR(err);
+}
+
+/**
+ * ti_sci_inta_irq_domain_alloc() - Allocate Interrupt aggregator IRQs
+ * @domain:	Point to the interrupt aggregator IRQ domain
+ * @virq:	Corresponding Linux virtual IRQ number
+ * @nr_irqs:	Continuous irqs to be allocated
+ * @data:	Pointer to firmware specifier
+ *
+ * Return 0 if all went well else appropriate error value.
+ */
+static int ti_sci_inta_irq_domain_alloc(struct irq_domain *domain,
+					unsigned int virq, unsigned int nr_irqs,
+					void *data)
+{
+	struct ti_sci_inta_vint_desc *vint_desc;
+	struct irq_fwspec *fwspec = data;
+	int err;
+
+	vint_desc = alloc_parent_irq(domain, virq, fwspec->param[0],
+				     fwspec->param[1], fwspec->param[2],
+				     fwspec->param[3]);
+	if (IS_ERR(vint_desc))
+		return PTR_ERR(vint_desc);
+
+	err = irq_domain_set_hwirq_and_chip(domain, virq, fwspec->param[2],
+					    &ti_sci_inta_irq_chip, vint_desc);
+
+	return err;
+}
+
+static const struct irq_domain_ops ti_sci_inta_irq_domain_ops = {
+	.alloc		= ti_sci_inta_irq_domain_alloc,
+	.free		= ti_sci_inta_irq_domain_free,
+	.translate	= ti_sci_inta_irq_domain_translate,
+};
+
+static int ti_sci_inta_irq_domain_probe(struct platform_device *pdev)
+{
+	struct irq_domain *parent_domain, *domain;
+	struct ti_sci_inta_irq_domain *inta;
+	struct device_node *parent_node;
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	int ret;
+
+	parent_node = of_irq_find_parent(dev_of_node(dev));
+	if (!parent_node) {
+		dev_err(dev, "Failed to get IRQ parent node\n");
+		return -ENODEV;
+	}
+
+	parent_domain = irq_find_host(parent_node);
+	if (!parent_domain)
+		return -EPROBE_DEFER;
+
+	inta = devm_kzalloc(dev, sizeof(*inta), GFP_KERNEL);
+	if (!inta)
+		return -ENOMEM;
+
+	inta->sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
+	if (IS_ERR(inta->sci)) {
+		ret = PTR_ERR(inta->sci);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "ti,sci read fail %d\n", ret);
+		inta->sci = NULL;
+		return ret;
+	}
+
+	ret = of_property_read_u32(dev->of_node, "ti,sci-dev-id",
+				   (u32 *)&inta->ia_id);
+	if (ret) {
+		dev_err(dev, "missing 'ti,sci-dev-id' property\n");
+		return -EINVAL;
+	}
+
+	inta->vint = devm_ti_sci_get_of_resource(inta->sci, dev,
+						 inta->ia_id,
+						 "ti,sci-rm-range-vint");
+	if (IS_ERR(inta->vint)) {
+		dev_err(dev, "VINT resource allocation failed\n");
+		return PTR_ERR(inta->vint);
+	}
+
+	inta->global_event =
+		devm_ti_sci_get_of_resource(inta->sci, dev,
+					    inta->ia_id,
+					    "ti,sci-rm-range-global-event");
+	if (IS_ERR(inta->global_event)) {
+		dev_err(dev, "Global event resource allocation failed\n");
+		return PTR_ERR(inta->global_event);
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	inta->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(inta->base))
+		return -ENODEV;
+
+	ret = of_property_read_u32(parent_node, "ti,sci-dst-id",
+				   (u32 *)&inta->dst_id);
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0, 0, dev_of_node(dev),
+					  &ti_sci_inta_irq_domain_ops, inta);
+	if (!domain) {
+		dev_err(dev, "Failed to allocate IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/**
+ * ti_sci_inta_register_event() - Register a event to an interrupt aggregator
+ * @dev:	Device pointer to source generating the event
+ * @src_id:	TISCI device ID of the event source
+ * @src_index:	Event source index within the device.
+ * @virq:	Linux Virtual IRQ number
+ * @flags:	Corresponding IRQ flags
+ * @ack_needed:	If explicit clearing of event is required.
+ *
+ * Creates a new irq and attaches to IA domain if virq is not specified
+ * else attaches the event to vint corresponding to virq.
+ * When using TISCI within the client drivers, source indexes are always
+ * generated dynamically and cannot be represented in DT. So client
+ * drivers should call this API instead of platform_get_irq().
+ *
+ * Return virq if all went well else appropriate error value.
+ */
+int ti_sci_inta_register_event(struct device *dev, u16 src_id, u16 src_index,
+			       unsigned int virq, u32 flags, bool ack_needed)
+{
+	struct ti_sci_inta_vint_desc *vint_desc;
+	struct ti_sci_inta_irq_domain *inta;
+	struct irq_data *data, *gic_data;
+	struct device_node *parent_node;
+	struct irq_domain *domain;
+	struct irq_fwspec fwspec;
+	int err;
+
+	parent_node = of_irq_find_parent(dev->of_node);
+	if (!parent_node)
+		return -ENODEV;
+
+	domain = irq_find_host(parent_node);
+	if (!domain)
+		return -EPROBE_DEFER;
+
+	inta = domain->host_data;
+
+	if (virq > 0) {
+		/* If Group already available */
+		data = irq_domain_get_irq_data(domain, virq);
+		gic_data = irq_domain_get_irq_data(domain->parent->parent,
+						   virq);
+
+		vint_desc = irq_data_get_irq_chip_data(data);
+
+		err = ti_sci_allocate_event_irq(inta, vint_desc, src_id,
+						src_index, gic_data->hwirq,
+						data->hwirq);
+		if (err)
+			return err;
+	} else {
+		fwspec.param_count = 4;
+		fwspec.fwnode = domain->fwnode;
+		fwspec.param[0] = src_id;
+		fwspec.param[1] = src_index;
+		fwspec.param[2] = ti_sci_get_free_resource(inta->vint);
+		fwspec.param[3] = flags;
+
+		virq = irq_create_fwspec_mapping(&fwspec);
+		if (virq <= 0)
+			ti_sci_release_resource(inta->vint, fwspec.param[2]);
+
+		data = irq_domain_get_irq_data(domain, virq);
+		vint_desc = irq_data_get_irq_chip_data(data);
+		vint_desc->ack_needed = ack_needed;
+	}
+
+	return virq;
+}
+EXPORT_SYMBOL_GPL(ti_sci_inta_register_event);
+
+/**
+ * get_event_index() - Helper api to get the event index with the vint.
+ * @vint_desc:	Pointer to the IA irq descriptor
+ * @src_id:	TISCI device ID of the event source
+ * @src_index:	Event source index within the device.
+ *
+ * Return the index if all went well else MAX_EVENTS_PER_VINT.
+ */
+static u8 get_event_index(struct ti_sci_inta_vint_desc *vint_desc, u16 src_id,
+			  u16 src_index)
+{
+	int i;
+
+	for (i = 0; i < MAX_EVENTS_PER_VINT; i++) {
+		if (vint_desc->events[i].src_id == src_id &&
+		    vint_desc->events[i].src_index == src_index)
+			return i;
+	}
+
+	return MAX_EVENTS_PER_VINT;
+}
+
+/**
+ * is_event_last() -  Helper api to determine if the event is the last
+ *		      event within the vint
+ * @vint_desc:	Pointer to the IA irq descriptor
+ * @event_index:	Event index within the vint of IA.
+ *
+ * Return true if specified index is the last event else false.
+ */
+static bool is_event_last(struct ti_sci_inta_vint_desc *vint_desc,
+			  u8 event_index)
+{
+	unsigned long flags;
+	int next_event;
+	bool status;
+
+	raw_spin_lock_irqsave(&vint_desc->lock, flags);
+	next_event = find_next_bit(vint_desc->event_map, MAX_EVENTS_PER_VINT,
+				   event_index + 1);
+	status = (next_event != MAX_EVENTS_PER_VINT) ? false : true;
+	if (event_index !=
+		find_first_bit(vint_desc->event_map, MAX_EVENTS_PER_VINT))
+		status = false;
+	raw_spin_unlock_irqrestore(&vint_desc->lock, flags);
+
+	return status;
+}
+
+/**
+ * ti_sci_inta_unregister_event() - Unregister a event from an IA.
+ * @dev:	Device pointer to source generating the event
+ * @src_id:	TISCI device ID of the event source
+ * @src_index:	Event source index within the device.
+ * @virq:	Linux Virtual IRQ number
+ *
+ * Deletes the event from IA interrupt descriptor. If this event is the
+ * last event then delete the vint as well.
+ */
+void ti_sci_inta_unregister_event(struct device *dev, u16 src_id,
+				  u16 src_index, unsigned int virq)
+{
+	struct ti_sci_inta_vint_desc *vint_desc;
+	struct irq_data *data, *gic_data;
+	struct device_node *parent_node;
+	struct irq_domain *domain;
+	u8 event_index;
+
+	parent_node = of_irq_find_parent(dev->of_node);
+	if (!parent_node)
+		return;
+
+	domain = irq_find_host(parent_node);
+
+	data = irq_domain_get_irq_data(domain, virq);
+	gic_data = irq_domain_get_irq_data(domain->parent->parent, virq);
+
+	vint_desc = irq_data_get_irq_chip_data(data);
+
+	event_index = get_event_index(vint_desc, src_id, src_index);
+	if (event_index == MAX_EVENTS_PER_VINT)
+		return;
+
+	if (is_event_last(vint_desc, event_index))
+		irq_dispose_mapping(virq);
+	else
+		ti_sci_free_event_irq(domain->host_data, vint_desc,
+				      event_index, gic_data->hwirq,
+				      data->hwirq);
+}
+EXPORT_SYMBOL_GPL(ti_sci_inta_unregister_event);
+
+static const struct of_device_id ti_sci_inta_irq_domain_of_match[] = {
+	{ .compatible = "ti,sci-inta", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_inta_irq_domain_of_match);
+
+static struct platform_driver ti_sci_inta_irq_domain_driver = {
+	.probe = ti_sci_inta_irq_domain_probe,
+	.driver = {
+		.name = "ti-sci-inta",
+		.of_match_table = ti_sci_inta_irq_domain_of_match,
+	},
+};
+module_platform_driver(ti_sci_inta_irq_domain_driver);
+
+MODULE_AUTHOR("Lokesh Vutla <lokeshvutla@...om>");
+MODULE_DESCRIPTION("K3 Interrupt Aggregator driver over TI SCI protocol");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/irqchip/irq-ti-sci-inta.h b/include/linux/irqchip/irq-ti-sci-inta.h
new file mode 100644
index 000000000000..c078234fda3f
--- /dev/null
+++ b/include/linux/irqchip/irq-ti-sci-inta.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Texas Instruments' System Control Interface (TI-SCI) irqchip
+ *
+ * Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@...com>
+ */
+
+#ifndef __INCLUDE_LINUX_IRQCHIP_TI_SCI_INTA_H
+#define __INCLUDE_LINUX_IRQCHIP_TI_SCI_INTA_H
+
+#if IS_ENABLED(CONFIG_TI_SCI_INTA_IRQCHIP)
+int ti_sci_inta_register_event(struct device *dev, u16 src_id, u16 src_index,
+			       unsigned int virq, u32 flags);
+int ti_sci_inta_unregister_event(struct device *dev, u16 src_id, u16 src_index,
+				 unsigned int virq);
+
+#else /* CONFIG_TI_SCI_INTA_IRQCHIP */
+
+static inline int ti_sci_inta_register_event(struct device *dev, u16 src_id,
+					     u16 src_index, unsigned int virq,
+					     u32 flags)
+{
+	return -EINVAL;
+}
+
+static inline int ti_sci_inta_unregister_event(struct device *dev, u16 src_id,
+					       u16 src_index, unsigned int virq)
+{
+	return -EINVAL;
+}
+
+#endif /* CONFIG_TI_SCI_INTA_IRQCHIP */
+
+#endif /* __INCLUDE_LINUX_IRQCHIP_TI_SCI_INTA_H */
-- 
2.19.1

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