irqchip: Add support for Marvell Orion SoCs

This patch adds an irqchip driver for the main interrupt controller found
on Marvell Orion SoCs (Kirkwood, Dove, Orion5x, Discovery Innovation).
Corresponding device tree documentation is also added.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Gregory Clement <gregory.clement@free-electrons.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1370536034-23956-2-git-send-email-sebastian.hesselbarth@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 198 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 4a33351..68c3107 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -25,6 +25,11 @@ config ARM_VIC_NR
 	  The maximum number of VICs available in the system, for
 	  power management.
 
+config ORION_IRQCHIP
+	bool
+	select IRQ_DOMAIN
+	select MULTI_IRQ_HANDLER
+
 config RENESAS_INTC_IRQPIN
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index cda4cb5..55df3bd 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_ARCH_MXS)			+= irq-mxs.o
 obj-$(CONFIG_ARCH_S3C24XX)		+= irq-s3c24xx.o
 obj-$(CONFIG_METAG)			+= irq-metag-ext.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
+obj-$(CONFIG_ORION_IRQCHIP)		+= irq-orion.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sun4i.o
 obj-$(CONFIG_ARCH_SPEAR3XX)		+= spear-shirq.o
 obj-$(CONFIG_ARM_GIC)			+= irq-gic.o
diff --git a/drivers/irqchip/irq-orion.c b/drivers/irqchip/irq-orion.c
new file mode 100644
index 0000000..e51d400
--- /dev/null
+++ b/drivers/irqchip/irq-orion.c
@@ -0,0 +1,192 @@
+/*
+ * Marvell Orion SoCs IRQ chip driver.
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <asm/exception.h>
+#include <asm/mach/irq.h>
+
+#include "irqchip.h"
+
+/*
+ * Orion SoC main interrupt controller
+ */
+#define ORION_IRQS_PER_CHIP		32
+
+#define ORION_IRQ_CAUSE			0x00
+#define ORION_IRQ_MASK			0x04
+#define ORION_IRQ_FIQ_MASK		0x08
+#define ORION_IRQ_ENDP_MASK		0x0c
+
+static struct irq_domain *orion_irq_domain;
+
+static asmlinkage void
+__exception_irq_entry orion_handle_irq(struct pt_regs *regs)
+{
+	struct irq_domain_chip_generic *dgc = orion_irq_domain->gc;
+	int n, base = 0;
+
+	for (n = 0; n < dgc->num_chips; n++, base += ORION_IRQS_PER_CHIP) {
+		struct irq_chip_generic *gc =
+			irq_get_domain_generic_chip(orion_irq_domain, base);
+		u32 stat = readl_relaxed(gc->reg_base + ORION_IRQ_CAUSE) &
+			gc->mask_cache;
+		while (stat) {
+			u32 hwirq = ffs(stat) - 1;
+			u32 irq = irq_find_mapping(orion_irq_domain,
+						   gc->irq_base + hwirq);
+			handle_IRQ(irq, regs);
+			stat &= ~(1 << hwirq);
+		}
+	}
+}
+
+static int __init orion_irq_init(struct device_node *np,
+				 struct device_node *parent)
+{
+	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+	int n, ret, base, num_chips = 0;
+	struct resource r;
+
+	/* count number of irq chips by valid reg addresses */
+	while (of_address_to_resource(np, num_chips, &r) == 0)
+		num_chips++;
+
+	orion_irq_domain = irq_domain_add_linear(np,
+				num_chips * ORION_IRQS_PER_CHIP,
+				&irq_generic_chip_ops, NULL);
+	if (!orion_irq_domain)
+		panic("%s: unable to add irq domain\n", np->name);
+
+	ret = irq_alloc_domain_generic_chips(orion_irq_domain,
+				ORION_IRQS_PER_CHIP, 1, np->name,
+				handle_level_irq, clr, 0,
+				IRQ_GC_INIT_MASK_CACHE);
+	if (ret)
+		panic("%s: unable to alloc irq domain gc\n", np->name);
+
+	for (n = 0, base = 0; n < num_chips; n++, base += ORION_IRQS_PER_CHIP) {
+		struct irq_chip_generic *gc =
+			irq_get_domain_generic_chip(orion_irq_domain, base);
+
+		of_address_to_resource(np, n, &r);
+
+		if (!request_mem_region(r.start, resource_size(&r), np->name))
+			panic("%s: unable to request mem region %d",
+			      np->name, n);
+
+		gc->reg_base = ioremap(r.start, resource_size(&r));
+		if (!gc->reg_base)
+			panic("%s: unable to map resource %d", np->name, n);
+
+		gc->chip_types[0].regs.mask = ORION_IRQ_MASK;
+		gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
+		gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
+
+		/* mask all interrupts */
+		writel(0, gc->reg_base + ORION_IRQ_MASK);
+	}
+
+	set_handle_irq(orion_handle_irq);
+	return 0;
+}
+IRQCHIP_DECLARE(orion_intc, "marvell,orion-intc", orion_irq_init);
+
+/*
+ * Orion SoC bridge interrupt controller
+ */
+#define ORION_BRIDGE_IRQ_CAUSE	0x00
+#define ORION_BRIDGE_IRQ_MASK	0x04
+
+static void orion_bridge_irq_handler(unsigned int irq, struct irq_desc *desc)
+{
+	struct irq_domain *d = irq_get_handler_data(irq);
+	struct irq_chip_generic *gc = irq_get_domain_generic_chip(d, irq);
+	u32 stat = readl_relaxed(gc->reg_base + ORION_BRIDGE_IRQ_CAUSE) &
+		   gc->mask_cache;
+
+	while (stat) {
+		u32 hwirq = ffs(stat) - 1;
+
+		generic_handle_irq(irq_find_mapping(d, gc->irq_base + hwirq));
+		stat &= ~(1 << hwirq);
+	}
+}
+
+static int __init orion_bridge_irq_init(struct device_node *np,
+					struct device_node *parent)
+{
+	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+	struct resource r;
+	struct irq_domain *domain;
+	struct irq_chip_generic *gc;
+	int ret, irq, nrirqs = 32;
+
+	/* get optional number of interrupts provided */
+	of_property_read_u32(np, "marvell,#interrupts", &nrirqs);
+
+	domain = irq_domain_add_linear(np, nrirqs,
+				       &irq_generic_chip_ops, NULL);
+	if (!domain) {
+		pr_err("%s: unable to add irq domain\n", np->name);
+		return -ENOMEM;
+	}
+
+	ret = irq_alloc_domain_generic_chips(domain, nrirqs, 1, np->name,
+			     handle_level_irq, clr, 0, IRQ_GC_INIT_MASK_CACHE);
+	if (ret) {
+		pr_err("%s: unable to alloc irq domain gc\n", np->name);
+		return ret;
+	}
+
+	ret = of_address_to_resource(np, 0, &r);
+	if (ret) {
+		pr_err("%s: unable to get resource\n", np->name);
+		return ret;
+	}
+
+	if (!request_mem_region(r.start, resource_size(&r), np->name)) {
+		pr_err("%s: unable to request mem region\n", np->name);
+		return -ENOMEM;
+	}
+
+	/* Map the parent interrupt for the chained handler */
+	irq = irq_of_parse_and_map(np, 0);
+	if (irq <= 0) {
+		pr_err("%s: unable to parse irq\n", np->name);
+		return -EINVAL;
+	}
+
+	gc = irq_get_domain_generic_chip(domain, 0);
+	gc->reg_base = ioremap(r.start, resource_size(&r));
+	if (!gc->reg_base) {
+		pr_err("%s: unable to map resource\n", np->name);
+		return -ENOMEM;
+	}
+
+	gc->chip_types[0].regs.ack = ORION_BRIDGE_IRQ_CAUSE;
+	gc->chip_types[0].regs.mask = ORION_BRIDGE_IRQ_MASK;
+	gc->chip_types[0].chip.irq_ack = irq_gc_ack_clr_bit;
+	gc->chip_types[0].chip.irq_mask = irq_gc_mask_clr_bit;
+	gc->chip_types[0].chip.irq_unmask = irq_gc_mask_set_bit;
+
+	/* mask all interrupts */
+	writel(0, gc->reg_base + ORION_BRIDGE_IRQ_MASK);
+
+	irq_set_handler_data(irq, domain);
+	irq_set_chained_handler(irq, orion_bridge_irq_handler);
+
+	return 0;
+}
+IRQCHIP_DECLARE(orion_bridge_intc,
+		"marvell,orion-bridge-intc", orion_bridge_irq_init);