irqchip: Renesas IRQC driver

This patch adds a driver for external IRQ pins connected
to the IRQC hardware block on recent SoCs from Renesas.

The IRQC hardware block is used together with more
recent ARM based SoCs using the GIC. As usual the GIC
requires external IRQ trigger setup somewhere else
which in this particular case happens to be IRQC.

This driver implements the glue code needed to configure
IRQ trigger and also handle mask/unmask and demux of
external IRQ pins hooked up from the IRQC to the GIC.

Tested on r8a73a4 but is designed to work with a wide
range of SoCs. The driver requires one GIC SPI per
external IRQ pin to operate.  Each driver instance
will handle up to 32 external IRQ pins.

The SoCs using this driver are currently mainly used
together with regular platform devices so this driver
allows configuration via platform data to support things
like static interrupt base address. DT support will
be added incrementally in the not so distant future.

Signed-off-by: Magnus Damm <damm@opensource.se>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

3 files changed, 303 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 0f5f1c3..4a33351 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -29,6 +29,10 @@ config RENESAS_INTC_IRQPIN
 	bool
 	select IRQ_DOMAIN
 
+config RENESAS_IRQC
+	bool
+	select IRQ_DOMAIN
+
 config VERSATILE_FPGA_IRQ
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 1aaa407..e41ceb9 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -9,4 +9,5 @@ obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-shirq.o
 obj-$(CONFIG_ARM_GIC)			+= irq-gic.o
 obj-$(CONFIG_ARM_VIC)			+= irq-vic.o
 obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
+obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
 obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
diff --git a/drivers/irqchip/irq-renesas-irqc.c b/drivers/irqchip/irq-renesas-irqc.c
new file mode 100644
index 0000000..95d69bf
--- /dev/null
+++ b/drivers/irqchip/irq-renesas-irqc.c
@@ -0,0 +1,298 @@
+/*
+ * Renesas IRQC Driver
+ *
+ *  Copyright (C) 2013 Magnus Damm
+ *
+ * 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; either version 2 of the License
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/platform_data/irq-renesas-irqc.h>
+
+#define IRQC_IRQ_MAX 32 /* maximum 32 interrupts per driver instance */
+
+#define IRQC_REQ_STS 0x00
+#define IRQC_EN_STS 0x04
+#define IRQC_EN_SET 0x08
+#define IRQC_INT_CPU_BASE(n) (0x000 + ((n) * 0x10))
+#define DETECT_STATUS 0x100
+#define IRQC_CONFIG(n) (0x180 + ((n) * 0x04))
+
+struct irqc_irq {
+	int hw_irq;
+	int requested_irq;
+	int domain_irq;
+	struct irqc_priv *p;
+};
+
+struct irqc_priv {
+	void __iomem *iomem;
+	void __iomem *cpu_int_base;
+	struct irqc_irq irq[IRQC_IRQ_MAX];
+	struct renesas_irqc_config config;
+	unsigned int number_of_irqs;
+	struct platform_device *pdev;
+	struct irq_chip irq_chip;
+	struct irq_domain *irq_domain;
+};
+
+static void irqc_dbg(struct irqc_irq *i, char *str)
+{
+	dev_dbg(&i->p->pdev->dev, "%s (%d:%d:%d)\n",
+		str, i->requested_irq, i->hw_irq, i->domain_irq);
+}
+
+static void irqc_irq_enable(struct irq_data *d)
+{
+	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
+	int hw_irq = irqd_to_hwirq(d);
+
+	irqc_dbg(&p->irq[hw_irq], "enable");
+	iowrite32(BIT(hw_irq), p->cpu_int_base + IRQC_EN_SET);
+}
+
+static void irqc_irq_disable(struct irq_data *d)
+{
+	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
+	int hw_irq = irqd_to_hwirq(d);
+
+	irqc_dbg(&p->irq[hw_irq], "disable");
+	iowrite32(BIT(hw_irq), p->cpu_int_base + IRQC_EN_STS);
+}
+
+#define INTC_IRQ_SENSE_VALID 0x10
+#define INTC_IRQ_SENSE(x) (x + INTC_IRQ_SENSE_VALID)
+
+static unsigned char irqc_sense[IRQ_TYPE_SENSE_MASK + 1] = {
+	[IRQ_TYPE_LEVEL_LOW] = INTC_IRQ_SENSE(0x01),
+	[IRQ_TYPE_LEVEL_HIGH] = INTC_IRQ_SENSE(0x02),
+	[IRQ_TYPE_EDGE_FALLING] = INTC_IRQ_SENSE(0x04), /* Synchronous */
+	[IRQ_TYPE_EDGE_RISING] = INTC_IRQ_SENSE(0x08), /* Synchronous */
+	[IRQ_TYPE_EDGE_BOTH] = INTC_IRQ_SENSE(0x0c),  /* Synchronous */
+};
+
+static int irqc_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct irqc_priv *p = irq_data_get_irq_chip_data(d);
+	int hw_irq = irqd_to_hwirq(d);
+	unsigned char value = irqc_sense[type & IRQ_TYPE_SENSE_MASK];
+	unsigned long tmp;
+
+	irqc_dbg(&p->irq[hw_irq], "sense");
+
+	if (!(value & INTC_IRQ_SENSE_VALID))
+		return -EINVAL;
+
+	tmp = ioread32(p->iomem + IRQC_CONFIG(hw_irq));
+	tmp &= ~0x3f;
+	tmp |= value ^ INTC_IRQ_SENSE_VALID;
+	iowrite32(tmp, p->iomem + IRQC_CONFIG(hw_irq));
+	return 0;
+}
+
+static irqreturn_t irqc_irq_handler(int irq, void *dev_id)
+{
+	struct irqc_irq *i = dev_id;
+	struct irqc_priv *p = i->p;
+	unsigned long bit = BIT(i->hw_irq);
+
+	irqc_dbg(i, "demux1");
+
+	if (ioread32(p->iomem + DETECT_STATUS) & bit) {
+		iowrite32(bit, p->iomem + DETECT_STATUS);
+		irqc_dbg(i, "demux2");
+		generic_handle_irq(i->domain_irq);
+		return IRQ_HANDLED;
+	}
+	return IRQ_NONE;
+}
+
+static int irqc_irq_domain_map(struct irq_domain *h, unsigned int virq,
+			       irq_hw_number_t hw)
+{
+	struct irqc_priv *p = h->host_data;
+
+	p->irq[hw].domain_irq = virq;
+	p->irq[hw].hw_irq = hw;
+
+	irqc_dbg(&p->irq[hw], "map");
+	irq_set_chip_data(virq, h->host_data);
+	irq_set_chip_and_handler(virq, &p->irq_chip, handle_level_irq);
+	set_irq_flags(virq, IRQF_VALID); /* kill me now */
+	return 0;
+}
+
+static struct irq_domain_ops irqc_irq_domain_ops = {
+	.map	= irqc_irq_domain_map,
+};
+
+static int irqc_probe(struct platform_device *pdev)
+{
+	struct renesas_irqc_config *pdata = pdev->dev.platform_data;
+	struct irqc_priv *p;
+	struct resource *io;
+	struct resource *irq;
+	struct irq_chip *irq_chip;
+	const char *name = dev_name(&pdev->dev);
+	int ret;
+	int k;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	if (!p) {
+		dev_err(&pdev->dev, "failed to allocate driver data\n");
+		ret = -ENOMEM;
+		goto err0;
+	}
+
+	/* deal with driver instance configuration */
+	if (pdata)
+		memcpy(&p->config, pdata, sizeof(*pdata));
+
+	p->pdev = pdev;
+	platform_set_drvdata(pdev, p);
+
+	/* get hold of manadatory IOMEM */
+	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!io) {
+		dev_err(&pdev->dev, "not enough IOMEM resources\n");
+		ret = -EINVAL;
+		goto err1;
+	}
+
+	/* allow any number of IRQs between 1 and IRQC_IRQ_MAX */
+	for (k = 0; k < IRQC_IRQ_MAX; k++) {
+		irq = platform_get_resource(pdev, IORESOURCE_IRQ, k);
+		if (!irq)
+			break;
+
+		p->irq[k].p = p;
+		p->irq[k].requested_irq = irq->start;
+	}
+
+	p->number_of_irqs = k;
+	if (p->number_of_irqs < 1) {
+		dev_err(&pdev->dev, "not enough IRQ resources\n");
+		ret = -EINVAL;
+		goto err1;
+	}
+
+	/* ioremap IOMEM and setup read/write callbacks */
+	p->iomem = ioremap_nocache(io->start, resource_size(io));
+	if (!p->iomem) {
+		dev_err(&pdev->dev, "failed to remap IOMEM\n");
+		ret = -ENXIO;
+		goto err2;
+	}
+
+	p->cpu_int_base = p->iomem + IRQC_INT_CPU_BASE(0); /* SYS-SPI */
+
+	irq_chip = &p->irq_chip;
+	irq_chip->name = name;
+	irq_chip->irq_mask = irqc_irq_disable;
+	irq_chip->irq_unmask = irqc_irq_enable;
+	irq_chip->irq_enable = irqc_irq_enable;
+	irq_chip->irq_disable = irqc_irq_disable;
+	irq_chip->irq_set_type = irqc_irq_set_type;
+	irq_chip->flags	= IRQCHIP_SKIP_SET_WAKE;
+
+	p->irq_domain = irq_domain_add_simple(pdev->dev.of_node,
+					      p->number_of_irqs,
+					      p->config.irq_base,
+					      &irqc_irq_domain_ops, p);
+	if (!p->irq_domain) {
+		ret = -ENXIO;
+		dev_err(&pdev->dev, "cannot initialize irq domain\n");
+		goto err2;
+	}
+
+	/* request interrupts one by one */
+	for (k = 0; k < p->number_of_irqs; k++) {
+		if (request_irq(p->irq[k].requested_irq, irqc_irq_handler,
+				0, name, &p->irq[k])) {
+			dev_err(&pdev->dev, "failed to request IRQ\n");
+			ret = -ENOENT;
+			goto err3;
+		}
+	}
+
+	dev_info(&pdev->dev, "driving %d irqs\n", p->number_of_irqs);
+
+	/* warn in case of mismatch if irq base is specified */
+	if (p->config.irq_base) {
+		if (p->config.irq_base != p->irq[0].domain_irq)
+			dev_warn(&pdev->dev, "irq base mismatch (%d/%d)\n",
+				 p->config.irq_base, p->irq[0].domain_irq);
+	}
+
+	return 0;
+err3:
+	for (; k >= 0; k--)
+		free_irq(p->irq[k - 1].requested_irq, &p->irq[k - 1]);
+
+	irq_domain_remove(p->irq_domain);
+err2:
+	iounmap(p->iomem);
+err1:
+	kfree(p);
+err0:
+	return ret;
+}
+
+static int irqc_remove(struct platform_device *pdev)
+{
+	struct irqc_priv *p = platform_get_drvdata(pdev);
+	int k;
+
+	for (k = 0; k < p->number_of_irqs; k++)
+		free_irq(p->irq[k].requested_irq, &p->irq[k]);
+
+	irq_domain_remove(p->irq_domain);
+	iounmap(p->iomem);
+	kfree(p);
+	return 0;
+}
+
+static struct platform_driver irqc_device_driver = {
+	.probe		= irqc_probe,
+	.remove		= irqc_remove,
+	.driver		= {
+		.name	= "renesas_irqc",
+	}
+};
+
+static int __init irqc_init(void)
+{
+	return platform_driver_register(&irqc_device_driver);
+}
+postcore_initcall(irqc_init);
+
+static void __exit irqc_exit(void)
+{
+	platform_driver_unregister(&irqc_device_driver);
+}
+module_exit(irqc_exit);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("Renesas IRQC Driver");
+MODULE_LICENSE("GPL v2");