irqchip: keystone: Add irq controller ip driver

On Keystone SOCs, DSP cores can send interrupts to ARM
host using the IRQ controller IP. It provides 28 IRQ
signals to ARM. The IRQ handler running on HOST OS can
identify DSP signal source by analyzing SRCCx bits in
IPCARx registers. This is one of the component used by
the IPC mechanism used on Keystone SOCs.

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Link: https://lkml.kernel.org/r/1406126430-9978-1-git-send-email-grygorii.strashko@ti.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

Documentation/devicetree/bindings/interrupt-controller/ti,keystone-irq.txt

@@ -0,0 +1,36 @@
+Keystone 2 IRQ controller IP
+
+On Keystone SOCs, DSP cores can send interrupts to ARM
+host using the IRQ controller IP. It provides 28 IRQ signals to ARM.
+The IRQ handler running on HOST OS can identify DSP signal source by
+analyzing SRCCx bits in IPCARx registers. This is one of the component
+used by the IPC mechanism used on Keystone SOCs.
+
+Required Properties:
+- compatible: should be "ti,keystone-irq"
+- ti,syscon-dev : phandle and offset pair. The phandle to syscon used to
+			access device control registers and the offset inside
+			device control registers range.
+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode interrupt
+					 source should be 1.
+- interrupts: interrupt reference to primary interrupt controller
+
+Please refer to interrupts.txt in this directory for details of the common
+Interrupt Controllers bindings used by client devices.
+
+Example:
+	kirq0: keystone_irq0@026202a0 {
+		compatible = "ti,keystone-irq";
+		ti,syscon-dev = <&devctrl 0x2a0>;
+		interrupts = <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>;
+		interrupt-controller;
+		#interrupt-cells = <1>;
+	};
+
+	dsp0: dsp0 {
+		compatible = "linux,rproc-user";
+		...
+		interrupt-parent = <&kirq0>;
+		interrupts = <10 2>;
+	};

drivers/irqchip/Kconfig

@@ -113,3 +113,10 @@ config IRQ_CROSSBAR
 	  The primary irqchip invokes the crossbar's callback which inturn allocates
 	  a free irq and configures the IP. Thus the peripheral interrupts are
 	  routed to one of the free irqchip interrupt lines.
+
+config KEYSTONE_IRQ
+	tristate "Keystone 2 IRQ controller IP"
+	depends on ARCH_KEYSTONE
+	help
+		Support for Texas Instruments Keystone 2 IRQ controller IP which
+		is part of the Keystone 2 IPC mechanism

drivers/irqchip/Makefile

@@ -34,3 +34,4 @@ obj-$(CONFIG_XTENSA)			+= irq-xtensa-pic.o
 obj-$(CONFIG_XTENSA_MX)			+= irq-xtensa-mx.o
 obj-$(CONFIG_IRQ_CROSSBAR)		+= irq-crossbar.o
 obj-$(CONFIG_BRCMSTB_L2_IRQ)		+= irq-brcmstb-l2.o
+obj-$(CONFIG_KEYSTONE_IRQ)		+= irq-keystone.o

drivers/irqchip/irq-keystone.c

@@ -0,0 +1,232 @@
+/*
+ * Texas Instruments Keystone IRQ controller IP driver
+ *
+ * Copyright (C) 2014 Texas Instruments, Inc.
+ * Author: Sajesh Kumar Saran <sajesh@ti.com>
+ *	   Grygorii Strashko <grygorii.strashko@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/irq.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include "irqchip.h"
+
+
+/* The source ID bits start from 4 to 31 (total 28 bits)*/
+#define BIT_OFS			4
+#define KEYSTONE_N_IRQ		(32 - BIT_OFS)
+
+struct keystone_irq_device {
+	struct device		*dev;
+	struct irq_chip		 chip;
+	u32			 mask;
+	u32			 irq;
+	struct irq_domain	*irqd;
+	struct regmap		*devctrl_regs;
+	u32			devctrl_offset;
+};
+
+static inline u32 keystone_irq_readl(struct keystone_irq_device *kirq)
+{
+	int ret;
+	u32 val = 0;
+
+	ret = regmap_read(kirq->devctrl_regs, kirq->devctrl_offset, &val);
+	if (ret < 0)
+		dev_dbg(kirq->dev, "irq read failed ret(%d)\n", ret);
+	return val;
+}
+
+static inline void
+keystone_irq_writel(struct keystone_irq_device *kirq, u32 value)
+{
+	int ret;
+
+	ret = regmap_write(kirq->devctrl_regs, kirq->devctrl_offset, value);
+	if (ret < 0)
+		dev_dbg(kirq->dev, "irq write failed ret(%d)\n", ret);
+}
+
+static void keystone_irq_setmask(struct irq_data *d)
+{
+	struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);
+
+	kirq->mask |= BIT(d->hwirq);
+	dev_dbg(kirq->dev, "mask %lu [%x]\n", d->hwirq, kirq->mask);
+}
+
+static void keystone_irq_unmask(struct irq_data *d)
+{
+	struct keystone_irq_device *kirq = irq_data_get_irq_chip_data(d);
+
+	kirq->mask &= ~BIT(d->hwirq);
+	dev_dbg(kirq->dev, "unmask %lu [%x]\n", d->hwirq, kirq->mask);
+}
+
+static void keystone_irq_ack(struct irq_data *d)
+{
+	/* nothing to do here */
+}
+
+static void keystone_irq_handler(unsigned irq, struct irq_desc *desc)
+{
+	struct keystone_irq_device *kirq = irq_desc_get_handler_data(desc);
+	unsigned long pending;
+	int src, virq;
+
+	dev_dbg(kirq->dev, "start irq %d\n", irq);
+
+	chained_irq_enter(irq_desc_get_chip(desc), desc);
+
+	pending = keystone_irq_readl(kirq);
+	keystone_irq_writel(kirq, pending);
+
+	dev_dbg(kirq->dev, "pending 0x%lx, mask 0x%x\n", pending, kirq->mask);
+
+	pending = (pending >> BIT_OFS) & ~kirq->mask;
+
+	dev_dbg(kirq->dev, "pending after mask 0x%lx\n", pending);
+
+	for (src = 0; src < KEYSTONE_N_IRQ; src++) {
+		if (BIT(src) & pending) {
+			virq = irq_find_mapping(kirq->irqd, src);
+			dev_dbg(kirq->dev, "dispatch bit %d, virq %d\n",
+				src, virq);
+			if (!virq)
+				dev_warn(kirq->dev, "sporious irq detected hwirq %d, virq %d\n",
+					 src, virq);
+			generic_handle_irq(virq);
+		}
+	}
+
+	chained_irq_exit(irq_desc_get_chip(desc), desc);
+
+	dev_dbg(kirq->dev, "end irq %d\n", irq);
+}
+
+static int keystone_irq_map(struct irq_domain *h, unsigned int virq,
+				irq_hw_number_t hw)
+{
+	struct keystone_irq_device *kirq = h->host_data;
+
+	irq_set_chip_data(virq, kirq);
+	irq_set_chip_and_handler(virq, &kirq->chip, handle_level_irq);
+	set_irq_flags(virq, IRQF_VALID | IRQF_PROBE);
+	return 0;
+}
+
+static struct irq_domain_ops keystone_irq_ops = {
+	.map	= keystone_irq_map,
+	.xlate	= irq_domain_xlate_onecell,
+};
+
+static int keystone_irq_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct keystone_irq_device *kirq;
+	int ret;
+
+	if (np == NULL)
+		return -EINVAL;
+
+	kirq = devm_kzalloc(dev, sizeof(*kirq), GFP_KERNEL);
+	if (!kirq)
+		return -ENOMEM;
+
+	kirq->devctrl_regs =
+		syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");
+	if (IS_ERR(kirq->devctrl_regs))
+		return PTR_ERR(kirq->devctrl_regs);
+
+	ret = of_property_read_u32_index(np, "ti,syscon-dev", 1,
+					 &kirq->devctrl_offset);
+	if (ret) {
+		dev_err(dev, "couldn't read the devctrl_offset offset!\n");
+		return ret;
+	}
+
+	kirq->irq = platform_get_irq(pdev, 0);
+	if (kirq->irq < 0) {
+		dev_err(dev, "no irq resource %d\n", kirq->irq);
+		return kirq->irq;
+	}
+
+	kirq->dev = dev;
+	kirq->mask = ~0x0;
+	kirq->chip.name		= "keystone-irq";
+	kirq->chip.irq_ack	= keystone_irq_ack;
+	kirq->chip.irq_mask	= keystone_irq_setmask;
+	kirq->chip.irq_unmask	= keystone_irq_unmask;
+
+	kirq->irqd = irq_domain_add_linear(np, KEYSTONE_N_IRQ,
+					   &keystone_irq_ops, kirq);
+	if (!kirq->irqd) {
+		dev_err(dev, "IRQ domain registration failed\n");
+		return -ENODEV;
+	}
+
+	platform_set_drvdata(pdev, kirq);
+
+	irq_set_chained_handler(kirq->irq, keystone_irq_handler);
+	irq_set_handler_data(kirq->irq, kirq);
+
+	/* clear all source bits */
+	keystone_irq_writel(kirq, ~0x0);
+
+	dev_info(dev, "irqchip registered, nr_irqs %u\n", KEYSTONE_N_IRQ);
+
+	return 0;
+}
+
+static int keystone_irq_remove(struct platform_device *pdev)
+{
+	struct keystone_irq_device *kirq = platform_get_drvdata(pdev);
+	int hwirq;
+
+	for (hwirq = 0; hwirq < KEYSTONE_N_IRQ; hwirq++)
+		irq_dispose_mapping(irq_find_mapping(kirq->irqd, hwirq));
+
+	irq_domain_remove(kirq->irqd);
+	return 0;
+}
+
+static const struct of_device_id keystone_irq_dt_ids[] = {
+	{ .compatible = "ti,keystone-irq", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, keystone_irq_dt_ids);
+
+static struct platform_driver keystone_irq_device_driver = {
+	.probe		= keystone_irq_probe,
+	.remove		= keystone_irq_remove,
+	.driver		= {
+		.name	= "keystone_irq",
+		.owner	= THIS_MODULE,
+		.of_match_table	= of_match_ptr(keystone_irq_dt_ids),
+	}
+};
+
+module_platform_driver(keystone_irq_device_driver);
+
+MODULE_AUTHOR("Texas Instruments");
+MODULE_AUTHOR("Sajesh Kumar Saran");
+MODULE_AUTHOR("Grygorii Strashko");
+MODULE_DESCRIPTION("Keystone IRQ chip");
+MODULE_LICENSE("GPL v2");