1 files changed, 113 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-jcore-aic.c b/drivers/irqchip/irq-jcore-aic.c
new file mode 100644
index 000000000..033bccb41
--- /dev/null
+++ b/drivers/irqchip/irq-jcore-aic.c
@@ -0,0 +1,113 @@
+/*
+ * J-Core SoC AIC driver
+ *
+ * Copyright (C) 2015-2016 Smart Energy Instruments, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#define JCORE_AIC_MAX_HWIRQ	127
+#define JCORE_AIC1_MIN_HWIRQ	16
+#define JCORE_AIC2_MIN_HWIRQ	64
+
+#define JCORE_AIC1_INTPRI_REG	8
+
+static struct irq_chip jcore_aic;
+
+/*
+ * The J-Core AIC1 and AIC2 are cpu-local interrupt controllers and do
+ * not distinguish or use distinct irq number ranges for per-cpu event
+ * interrupts (timer, IPI). Since information to determine whether a
+ * particular irq number should be treated as per-cpu is not available
+ * at mapping time, we use a wrapper handler function which chooses
+ * the right handler at runtime based on whether IRQF_PERCPU was used
+ * when requesting the irq.
+ */
+
+static void handle_jcore_irq(struct irq_desc *desc)
+{
+	if (irqd_is_per_cpu(irq_desc_get_irq_data(desc)))
+		handle_percpu_irq(desc);
+	else
+		handle_simple_irq(desc);
+}
+
+static int jcore_aic_irqdomain_map(struct irq_domain *d, unsigned int irq,
+				   irq_hw_number_t hwirq)
+{
+	struct irq_chip *aic = d->host_data;
+
+	irq_set_chip_and_handler(irq, aic, handle_jcore_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops jcore_aic_irqdomain_ops = {
+	.map = jcore_aic_irqdomain_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static void noop(struct irq_data *data)
+{
+}
+
+static int __init aic_irq_of_init(struct device_node *node,
+				  struct device_node *parent)
+{
+	unsigned min_irq = JCORE_AIC2_MIN_HWIRQ;
+	unsigned dom_sz = JCORE_AIC_MAX_HWIRQ+1;
+	struct irq_domain *domain;
+
+	pr_info("Initializing J-Core AIC\n");
+
+	/* AIC1 needs priority initialization to receive interrupts. */
+	if (of_device_is_compatible(node, "jcore,aic1")) {
+		unsigned cpu;
+
+		for_each_present_cpu(cpu) {
+			void __iomem *base = of_iomap(node, cpu);
+
+			if (!base) {
+				pr_err("Unable to map AIC for cpu %u\n", cpu);
+				return -ENOMEM;
+			}
+			__raw_writel(0xffffffff, base + JCORE_AIC1_INTPRI_REG);
+			iounmap(base);
+		}
+		min_irq = JCORE_AIC1_MIN_HWIRQ;
+	}
+
+	/*
+	 * The irq chip framework requires either mask/unmask or enable/disable
+	 * function pointers to be provided, but the hardware does not have any
+	 * such mechanism; the only interrupt masking is at the cpu level and
+	 * it affects all interrupts. We provide dummy mask/unmask. The hardware
+	 * handles all interrupt control and clears pending status when the cpu
+	 * accepts the interrupt.
+	 */
+	jcore_aic.irq_mask = noop;
+	jcore_aic.irq_unmask = noop;
+	jcore_aic.name = "AIC";
+
+	domain = irq_domain_add_linear(node, dom_sz, &jcore_aic_irqdomain_ops,
+				       &jcore_aic);
+	if (!domain)
+		return -ENOMEM;
+	irq_create_strict_mappings(domain, min_irq, min_irq, dom_sz - min_irq);
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(jcore_aic2, "jcore,aic2", aic_irq_of_init);
+IRQCHIP_DECLARE(jcore_aic1, "jcore,aic1", aic_irq_of_init);