irqchip/ti-sci-intr: Add support for Interrupt Router driver

Texas Instruments' K3 generation SoCs has an IP Interrupt Router
that does allows for redirection of input interrupts to host
interrupt controller. Interrupt Router inputs are either from a
peripheral or from an Interrupt Aggregator which is another
interrupt controller.

Configuration of the interrupt router 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 Router driver over TISCI protocol.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

MAINTAINERS

@@ -15350,6 +15350,7 @@ F:	Documentation/devicetree/bindings/clock/ti,sci-clk.txt
 F:	drivers/clk/keystone/sci-clk.c
 F:	drivers/reset/reset-ti-sci.c
 F:	Documentation/devicetree/bindings/interrupt-controller/ti,sci-intr.txt
+F:	drivers/irqchip/irq-ti-sci-intr.c
 
 Texas Instruments ASoC drivers
 M:	Peter Ujfalusi <peter.ujfalusi@ti.com>

drivers/irqchip/Kconfig

@@ -419,6 +419,16 @@ config LS1X_IRQ
 	help
 	  Support for the Loongson-1 platform Interrupt Controller.
 
+config TI_SCI_INTR_IRQCHIP
+	bool
+	depends on TI_SCI_PROTOCOL
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	  This enables the irqchip driver support for K3 Interrupt router
+	  over TI System Control Interface available on some new TI's SoCs.
+	  If you wish to use interrupt router irq resources managed by the
+	  TI System Controller, say Y here. Otherwise, say N.
+
 endmenu
 
 config SIFIVE_PLIC

drivers/irqchip/Makefile

@@ -97,3 +97,4 @@ obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
 obj-$(CONFIG_MADERA_IRQ)		+= irq-madera.o
 obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
+obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o

drivers/irqchip/irq-ti-sci-intr.c

@@ -0,0 +1,275 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Texas Instruments' K3 Interrupt Router irqchip driver
+ *
+ * Copyright (C) 2018-2019 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@ti.com>
+ */
+
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/soc/ti/ti_sci_protocol.h>
+
+#define TI_SCI_DEV_ID_MASK	0xffff
+#define TI_SCI_DEV_ID_SHIFT	16
+#define TI_SCI_IRQ_ID_MASK	0xffff
+#define TI_SCI_IRQ_ID_SHIFT	0
+#define HWIRQ_TO_DEVID(hwirq)	(((hwirq) >> (TI_SCI_DEV_ID_SHIFT)) & \
+				 (TI_SCI_DEV_ID_MASK))
+#define HWIRQ_TO_IRQID(hwirq)	((hwirq) & (TI_SCI_IRQ_ID_MASK))
+#define TO_HWIRQ(dev, index)	((((dev) & TI_SCI_DEV_ID_MASK) << \
+				 TI_SCI_DEV_ID_SHIFT) | \
+				((index) & TI_SCI_IRQ_ID_MASK))
+
+/**
+ * struct ti_sci_intr_irq_domain - Structure representing a TISCI based
+ *				   Interrupt Router IRQ domain.
+ * @sci:	Pointer to TISCI handle
+ * @dst_irq:	TISCI resource pointer representing GIC irq controller.
+ * @dst_id:	TISCI device ID of the GIC irq controller.
+ * @type:	Specifies the trigger type supported by this Interrupt Router
+ */
+struct ti_sci_intr_irq_domain {
+	const struct ti_sci_handle *sci;
+	struct ti_sci_resource *dst_irq;
+	u32 dst_id;
+	u32 type;
+};
+
+static struct irq_chip ti_sci_intr_irq_chip = {
+	.name			= "INTR",
+	.irq_eoi		= irq_chip_eoi_parent,
+	.irq_mask		= irq_chip_mask_parent,
+	.irq_unmask		= irq_chip_unmask_parent,
+	.irq_set_type		= irq_chip_set_type_parent,
+	.irq_retrigger		= irq_chip_retrigger_hierarchy,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+/**
+ * ti_sci_intr_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_intr_irq_domain_translate(struct irq_domain *domain,
+					    struct irq_fwspec *fwspec,
+					    unsigned long *hwirq,
+					    unsigned int *type)
+{
+	struct ti_sci_intr_irq_domain *intr = domain->host_data;
+
+	if (fwspec->param_count != 2)
+		return -EINVAL;
+
+	*hwirq = TO_HWIRQ(fwspec->param[0], fwspec->param[1]);
+	*type = intr->type;
+
+	return 0;
+}
+
+/**
+ * ti_sci_intr_irq_domain_free() - Free the specified IRQs from the domain.
+ * @domain:	Domain to which the irqs belong
+ * @virq:	Linux virtual IRQ to be freed.
+ * @nr_irqs:	Number of continuous irqs to be freed
+ */
+static void ti_sci_intr_irq_domain_free(struct irq_domain *domain,
+					unsigned int virq, unsigned int nr_irqs)
+{
+	struct ti_sci_intr_irq_domain *intr = domain->host_data;
+	struct irq_data *data, *parent_data;
+	u16 dev_id, irq_index;
+
+	parent_data = irq_domain_get_irq_data(domain->parent, virq);
+	data = irq_domain_get_irq_data(domain, virq);
+	irq_index = HWIRQ_TO_IRQID(data->hwirq);
+	dev_id = HWIRQ_TO_DEVID(data->hwirq);
+
+	intr->sci->ops.rm_irq_ops.free_irq(intr->sci, dev_id, irq_index,
+					   intr->dst_id, parent_data->hwirq);
+	ti_sci_release_resource(intr->dst_irq, parent_data->hwirq);
+	irq_domain_free_irqs_parent(domain, virq, 1);
+	irq_domain_reset_irq_data(data);
+}
+
+/**
+ * ti_sci_intr_alloc_gic_irq() - Allocate GIC specific IRQ
+ * @domain:	Pointer to the interrupt router IRQ domain
+ * @virq:	Corresponding Linux virtual IRQ number
+ * @hwirq:	Corresponding hwirq for the IRQ within this IRQ domain
+ *
+ * Returns 0 if all went well else appropriate error pointer.
+ */
+static int ti_sci_intr_alloc_gic_irq(struct irq_domain *domain,
+				     unsigned int virq, u32 hwirq)
+{
+	struct ti_sci_intr_irq_domain *intr = domain->host_data;
+	struct irq_fwspec fwspec;
+	u16 dev_id, irq_index;
+	u16 dst_irq;
+	int err;
+
+	dev_id = HWIRQ_TO_DEVID(hwirq);
+	irq_index = HWIRQ_TO_IRQID(hwirq);
+
+	dst_irq = ti_sci_get_free_resource(intr->dst_irq);
+	if (dst_irq == TI_SCI_RESOURCE_NULL)
+		return -EINVAL;
+
+	fwspec.fwnode = domain->parent->fwnode;
+	fwspec.param_count = 3;
+	fwspec.param[0] = 0;	/* SPI */
+	fwspec.param[1] = dst_irq - 32; /* SPI offset */
+	fwspec.param[2] = intr->type;
+
+	err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
+	if (err)
+		goto err_irqs;
+
+	err = intr->sci->ops.rm_irq_ops.set_irq(intr->sci, dev_id, irq_index,
+						intr->dst_id, dst_irq);
+	if (err)
+		goto err_msg;
+
+	return 0;
+
+err_msg:
+	irq_domain_free_irqs_parent(domain, virq, 1);
+err_irqs:
+	ti_sci_release_resource(intr->dst_irq, dst_irq);
+	return err;
+}
+
+/**
+ * ti_sci_intr_irq_domain_alloc() - Allocate Interrupt router IRQs
+ * @domain:	Point to the interrupt router 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_intr_irq_domain_alloc(struct irq_domain *domain,
+					unsigned int virq, unsigned int nr_irqs,
+					void *data)
+{
+	struct irq_fwspec *fwspec = data;
+	unsigned long hwirq;
+	unsigned int flags;
+	int err;
+
+	err = ti_sci_intr_irq_domain_translate(domain, fwspec, &hwirq, &flags);
+	if (err)
+		return err;
+
+	err = ti_sci_intr_alloc_gic_irq(domain, virq, hwirq);
+	if (err)
+		return err;
+
+	irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
+				      &ti_sci_intr_irq_chip, NULL);
+
+	return 0;
+}
+
+static const struct irq_domain_ops ti_sci_intr_irq_domain_ops = {
+	.free		= ti_sci_intr_irq_domain_free,
+	.alloc		= ti_sci_intr_irq_domain_alloc,
+	.translate	= ti_sci_intr_irq_domain_translate,
+};
+
+static int ti_sci_intr_irq_domain_probe(struct platform_device *pdev)
+{
+	struct irq_domain *parent_domain, *domain;
+	struct ti_sci_intr_irq_domain *intr;
+	struct device_node *parent_node;
+	struct device *dev = &pdev->dev;
+	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) {
+		dev_err(dev, "Failed to find IRQ parent domain\n");
+		return -ENODEV;
+	}
+
+	intr = devm_kzalloc(dev, sizeof(*intr), GFP_KERNEL);
+	if (!intr)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(dev_of_node(dev), "ti,intr-trigger-type",
+				   &intr->type);
+	if (ret) {
+		dev_err(dev, "missing ti,intr-trigger-type property\n");
+		return -EINVAL;
+	}
+
+	intr->sci = devm_ti_sci_get_by_phandle(dev, "ti,sci");
+	if (IS_ERR(intr->sci)) {
+		ret = PTR_ERR(intr->sci);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "ti,sci read fail %d\n", ret);
+		intr->sci = NULL;
+		return ret;
+	}
+
+	ret = of_property_read_u32(dev_of_node(dev), "ti,sci-dst-id",
+				   &intr->dst_id);
+	if (ret) {
+		dev_err(dev, "missing 'ti,sci-dst-id' property\n");
+		return -EINVAL;
+	}
+
+	intr->dst_irq = devm_ti_sci_get_of_resource(intr->sci, dev,
+						    intr->dst_id,
+						    "ti,sci-rm-range-girq");
+	if (IS_ERR(intr->dst_irq)) {
+		dev_err(dev, "Destination irq resource allocation failed\n");
+		return PTR_ERR(intr->dst_irq);
+	}
+
+	domain = irq_domain_add_hierarchy(parent_domain, 0, 0, dev_of_node(dev),
+					  &ti_sci_intr_irq_domain_ops, intr);
+	if (!domain) {
+		dev_err(dev, "Failed to allocate IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id ti_sci_intr_irq_domain_of_match[] = {
+	{ .compatible = "ti,sci-intr", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ti_sci_intr_irq_domain_of_match);
+
+static struct platform_driver ti_sci_intr_irq_domain_driver = {
+	.probe = ti_sci_intr_irq_domain_probe,
+	.driver = {
+		.name = "ti-sci-intr",
+		.of_match_table = ti_sci_intr_irq_domain_of_match,
+	},
+};
+module_platform_driver(ti_sci_intr_irq_domain_driver);
+
+MODULE_AUTHOR("Lokesh Vutla <lokeshvutla@ticom>");
+MODULE_DESCRIPTION("K3 Interrupt Router driver over TI SCI protocol");
+MODULE_LICENSE("GPL v2");